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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 613 records · Page 34Linked to original sources
PubMed1996

Right ventricular ejection fraction in the preoperative risk evaluation of candidates for pulmonary resection.

The major determinants of postoperative morbidity and mortality after lung resection are the physiologic and functional statuses of the pulmonary and cardiac systems. In our previous study, serial measurements of right ventricular performance after pulmonary resection demonstrated significant right ventricular dysfunction in the postoperative period. This study evaluates the preoperative measurement of right ventricular ejection fraction as a predictor of postoperative complications. In addition to conventional cardiopulmonary functional tests, right ventricular function was assessed with a thermodilution technique at rest and during exercise in 18 patients before and 3 weeks after lobectomy or pneumonectomy. The patients were grouped according to severity of right ventricular functional defect: right ventricular ejection fraction of at least 45% (group Ia, n = 8), right ventricular ejection fraction less than 45% (group Ib, n = 10), exercise-induced increases in right ventricular ejection fraction (group IIa, n = 8), and exercise-induced decreases in right ventricular ejection fraction (group IIb, n = 10). Postoperative cardiopulmonary morbidity was recorded for two patients (25%) in group Ia, three patients (30%) in group Ib, no patients (0%) in group IIa, and five patients (50%) in group IIb. Postoperative hospital stay was 28.9 +/- 8.5 days in group Ia, 29.9 +/- 20.2 days in group Ib, 19.4 +/- 8.0 days in group IIa, and 37.5 +/- 15.9 days in group IIb (p < 0.05, group IIa vs group IIb). Although resection-induced changes in forced expiratory volume in 1 second did not differ significantly between group Ia and group Ib, these values appeared to be increased in groups IIa (not statistically significant) and IIb (significantly, p < 0.05). The measured postoperative values of forced expiratory volume in 1 second and vital capacity were significantly higher than the predicted postoperative values (p < 0.05) in group IIa, but not in groups Ia, Ib, and IIb. We conclude that evaluation of right ventricular performance is useful in determining which patients are at increased risk for medical complications after lung resection. Exercise-induced change in right ventricular ejection fraction may be a better indicator of high risk among candidates for pulmonary resection than the absolute value of this parameter.

Aged↗
PubMed1996

B-1a, B-1b and conventional B cell lymphoma from enzootic bovine leukosis.

In order to characterize the phenotypes of tumor cells and to clarify from which B cell lineage the lymphomas were derived, ten cows with enzootic bovine leukosis were examined by means of immunohistologic staining and flow cytometry. The tumor cells expressed mainly major histocompatibility complex (MHC) class II+ (10/10), BoCD11b+ (9/10), IgG1+ (8/10), B-B2+ (8/10) BoCD5+ (7/10), and lambda light chain+ (7/10). Tumor cells from only one animal expressed sIgM+ (1/10). Tumor cells from all ten animals were negative for IgG2, BoCD3, BoCD4, BoCD8, WC1-N2, and IL-2R alpha. The phenotypes of these tumor cells were all slightly different, suggesting that bovine leukemia virus (BLV)-induced lymphoma expresses phenotypic diversity. Moreover, tumor cells from seven cattle coexpressed BoCD5 and BoCD11b (B-1a cells). On the other hand, tumor cells from two of them only expressed BoCD11b (B-1b cells), and those from one were negative for both BoCD5 and BoCD11b (conventional B cells). Therefore, we concluded that BLV-induced lymphoma cells can be derived from B-1a, B-1b and conventional B cells.

Animals↗
PubMed1996

Induction of glomerulonephritis in rats with staphylococcal phosphatase: new aspects in post-infectious ICGN.

Staphylococcal neutral phosphatase (NPtase) is a highly cationic bacterial surface bound protein. It has significant affinity for human and rat immunoglobulins in vitro and an electrostatic interaction may be involved. Radioisotopic studies showed that NPtase had a high affinity for the polyanionic structures of the rat renal glomerulus. When the left kidneys of germ-free or naive (non-immune) Wistar rats were perfused with 80 micrograms of I125 NPtase, 21 micrograms of NPtase were found in the left kidneys and 11 micrograms in the isolated glomeruli 15 minutes after perfusion. Deposits of autologous immunoglobulin and C3 were seen in the glomeruli of rats immediately after perfusion with NPtase (15 min) and persisted throughout the 14-day observation period. Histologically, neutrophil influx into the glomerulus was seen at 15 minutes and increased until three hours; subepithelial electron-dense deposits were found after three days and were still visible on day 14. Proteinuria started within the first 24 hours despite the absence of an immune response at this time and was still present on day 14. Similar results were observed in immune deficient athymic nude rats in the early phase. Perfusion of heparin after NPtase inhibited the deposition of IgG and C3 and prevented proteinuria in naive but not in actively immunized rats. This result provides further evidence that specific antibodies to NPtase were not involved in the immune complex-like deposits seen in the early phase. NPtase is a novel molecule, as it reveals both high affinity for the GBM and binding of circulating immunoglobulins, by a non-antigen-antibody mechanism, to form IC-like deposits on the GBM. These deposits are capable of activating the complement system, thus triggering a series of events leading to glomerulonephritis. These results delineate an additional pathway for the pathogenesis of ICGN related to bacterial infection.

Animals↗
PubMed1996

Quantification of tumour-induced angiogenesis by image analysis.

Quantitative techniques for in vivo and in vitro angiogenesis were developed using an image analyser. In the in vivo study, a Millipore chamber filled with mouse sarcoma 180 (S180) cells was transplanted subcutaneously to the dorsal side of a mouse, and the area of neovascularization induced by the tumour cells was quantified by image analysis. Images of vascular networks with poor contrast had their contrast improved by Laplacean transformation. The area of vascular network was 16.9 mm2 in the control group without tumour cells and 44.2 mm2 in the group with tumour cells, demonstrating a significant increase in neovascularized area by tumour cells. In the in vitro study, migration of vascular endothelial cells was induced with conditioned media of S180 cells. Image analysis was used to count automatically the nuclei of migrated endothelial cells, which were stained violet with Giemsa's solution. This automated measurement by image analyser is expected to save labour and time. Checkerboard analysis revealed that the endothelial cell migration induced by S180-conditioned medium was due to chemotaxis. The quantitation method using an automated image analyser is valuable in evaluating the induction of neovascularization by tumours and the effect of pharmacological agents on tumour angiogenesis in vivo and in vitro.

Animals↗
PubMed1996

Characterization and mapping of Ds-GUS-T-DNA lines for targeted insertional mutagenesis.

The transposition patterns of the Ds-GUS transposon T-DNA in 23 independent single-copy lines have been characterized and the map positions of 10 of them on three of the five Arabidopsis chromosomes are reported. Using overexpressed Activator (Ac) elements as a transposase source, it was found that the primary determinant of transposition frequency is the insertion site of the Ac-T-DNA. Neither the structure of the transposon T-DNA nor, in most cases, its insertion site have a significant effect on transposition frequency. Both the frequency and timing of transposition are influenced by the parent through which the transposon and transposase T-DNAs are transmitted. Overall, nearly 75% of plants in which excision has occurred bear a reinserted element and very short-range transpositions predominate, underlining the advantage of using mapped transposons for insertional mutagenesis.

Arabidopsis↗
PubMed1996

Effects of endothelin A and B receptors on aqueous humor dynamics in the rabbit eye.

This study attempted to clarify the role of endothelin A and B (ETA and ETB) receptors in modulating aqueous humor dynamics in the rabbit eye. Intraocular pressure (IOP), aqueous flow, total outflow facility, and uveoscleral outflow were measured before, and 24 hours after, intravitreal injection (20 microliters) of a selective ETB agonist, sarafotoxin S6c (SRTX S6c, 10(-5) M), into one eye and its vehicle into the contralateral eye. The measurements were also performed before and after injection of a selective ETA antagonist, 97-139 (10(-2) M) + ET-1 (10(-5) M) into one eye, and vehicle + ET-1 (10(-5) M) into the contralateral eye. In the SRTX S6c-treated eye, total outflow facility increased significantly by 106% compared with that in the vehicle-treated eye 24 hours after injection; aqueous flow and uveoscleral outflow failed to change significantly. The ETA antagonist 97-139 inhibited the decrease in aqueous flow partially, but significantly, but failed to inhibit the increase in total outflow facility caused by ET-1. Therefore, both ETA and ETB play a significant role in modulating aqueous humor dynamics in the rabbit eye. ETA can modulate aqueous humor production, at least in part. ETB can modulate total outflow facility, and the possibility for ETB in modulating aqueous humor formation cannot be ruled out.

Animals↗
PubMed1996

Effects of endothelial cells on activity of staphylokinase.

Staphylokinase (SAK), produced by Staphylococcus aureus, induces fibrinolytic activity in circulation without systemic fibrinolytic activation. Since the effect of blood vessels on the activity of SAK has not yet been clarified, plasminogen activator (PA) activity of SAK in the presence or absence of endothelial cells was analyzed. The endothelial cells used in this experiment were of a cloned established cell line (TKM-33). In the expression of PA activity by SAK or streptokinase (SK), the kinetic constants revealed as Vmax/km were increased about 1.5-fold in the presence of endothelial cells. Furthermore, an initial lag phase which was observed during the plasminogen activation by SAK was markedly shortened in the presence of endothelial cells. In the case of SK, an initial lag phase was not observed in the absence or presence of endothelial cells. Although PA activity of SAK was inhibited by alpha 2-antiplasmin (alpha 2-AP), the inhibitory effect of alpha 2-AP in the presence of endothelial cells was weaker than in the absence of endothelial cells. The cyanogen bromide digested fibrinogen fragment-2 (FCB-2) distinctly enhanced the PA activity of SAK in the absence and the presence of endothelial cells. However, alpha 2-AP and FCB-2 did not cause a significant alteration of PA activity of SK even in the absence or presence of endothelial cells. These findings suggest that PA activity of SAK is enhanced by endothelial cells, but inhibited by alpha 2-AP. Moreover, PA activity of SAK is further enhanced by fibrin clot in the presence of endothelial cells.

Cell Line↗
PubMed1996

Phylogenetic analysis of Borrelia species based on flagellin gene sequences and its application for molecular typing of Lyme disease borreliae.

We determined almost complete flagellin gene sequences of various Borrelia species and aligned them with previously published sequences. A neighbor-joining phylogenetic analysis showed that the genus Borrelia was divided into the following three major clusters: New World relapsing fever borreliae (Borrelia turicatae, Borrelia parkeri, and Borrelia hermsii), Old World relapsing fever borreliae (Borrelia crocidurae, Borrelia duttonii, and Borrelia hispanica), and Lyme disease borreliae (Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii). Agents of animal spirochetosis (Borrelia coriaceae and Borrelia anserina) and species of unknown pathogenicity (Borrelia miyamotoi and Borrelia lonestari) were related to relapsing fever borreliae. Although the Lyme disease borreliae, two related species (Borrelia japonica and Borrelia andersonii), and some newly described genomic groups (groups PotiB2, VS116, DN127, Hk501, and Ya501) were closely related to each other, each taxon formed an independent branch on the phylogenetic tree. The data obtained in this study indicate that the flagellin genes are useful in Borrelia taxonomy. To distinguish the Lyme disease borreliae from related organisms easily, we designed an oligonucleotide primer set for the flagellin gene and performed a PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. The primer set amplified an approximately 580-bp DNA fragment that included species-specific restriction sites, and HapII, HhaI, CelII, HincII, or DdeI digestion of the product resulted in distinctively different PCR-RFLP patterns. The PCR-RFLP typing method which we developed should facilitate rapid identification of Lyme disease borreliae and related organisms obtained from biological and clinical specimens.

Animals↗
PubMed1996

Borrelia tanukii sp. nov. and Borrelia turdae sp. nov. found from ixodid ticks in Japan: rapid species identification by 16S rRNA gene-targeted PCR analysis.

Based on the results of RFLP-ribotyping, whole DNA/DNA hybridization and phylogenetic analysis of the 16S rRNA gene, we previously defined two genomic groups of spirochetes closely related to Borrelia burgdorferi sensu lato: group Hk501 for strains isolated from Ixodes tanuki ticks and group Ya501 for strains isolated from Ixodes turdus ticks. In this report, we propose that group Hk501 should be classified as Borrelia tanukii sp. nov. and group Ya501 as Borrelia turdae sp. nov. The alignment of previously published Borrelia 16S rRNA gene sequences led us to design species-specific PCR primer sets. The primers allowed the rapid identification of B. tanukii and B. turdae.

Animals↗
PubMed1996

Promoting effect of unilateral nephrectomy on urinary bladder carcinogenesis in rats.

The effect of unilateral nephrectomy on the growth of bladder tumors was investigated in male F344 rats treated with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine(BBN) for 6 weeks by means of macroscopical and microscopical examinations. Unilateral nephrectomy 4 weeks after the initiation of BBN administration significantly increased both the number and the volume of visible tumors per rat as compared with the sham-operated group. Histological examination also revealed that the numbers of papillonodular hyperplasia and cancer per basement membrane were significantly increased by unilateral nephrectomy. The results imply a growth-enhancing effect of unilateral nephrectomy on carcinogenesis of the rat bladder.

Animals↗
PubMed1996

A case of ureteral reflux identified by ultrasound.

Reflux nephropathy is known to be a major cause of renal failure in children. Vesico-ureteral reflux is usually diagnosed by voiding cysto-urethrography (VCG). However, it has been observed that conventional VCG is not always reliable for the diagnosis of ureteral reflux. In the case of a 5 year old girl with recurrent febrile urinary tract infection, VCG showed no ureteral reflux. Urodynamic study revealed a large bladder capacity and significant residual urine. Renal scintigram delineated a right renal scar. Simple ultrasound examination with videotape recording during voiding definitely demonstrated the presence of significant ureteral reflux when she voided, that is, there was marked dilatation of the right distal ureter and ballooning of the right renal pelvis on voiding, and quick refilling of the bladder concomitantly with the disappearance of the pelvic ballooning. Therefore, an ultrasound during voiding may be useful for diagnosing ureteral reflux in patients where a VCG does not reveal reflux.

Child, Preschool↗
PubMed1996

Possible role for a polysaccharide antigen shared between Streptococcus pyogenes and S. mutans in the pathogenesis of poststreptococcal glomerulonephritis.

Streptococcus mutans has been shown to share a polysaccharide (PS) antigen with S. pyogenes strains isolated from patients with acute poststreptococcal glomerulonephritis (PSGN), using a monoclonal antibody f-77 reactive with the PS. To investigate the pathogenetic role of the shared PS in PSNG, experimental nephritis was induced in animals. Rats were immunized thrice with heat-killed cells of S. mutans or S. pyogenes, followed by an intravenous injection of live cells of S. pyogenes. Histologic examination showed that both animal groups had comparable degrees of diffuse proliferative nephritis characterized by immune deposits. The shared PS antigen was detected in glomeruli of all nephritic rats by immunofluorescence using monoclonal antibody f-77. Furthermore, all nephritic rats had an elevated antibody titer to the shared PS antigen. These results suggest that prior sensitization (infections such as dental caries) to S. mutans modulates immune responses to subsequent S. pyogenes infections and induces immune-complex disease (PSGN) through the shared PS antigen.

Acute Disease↗
PubMed1996

Analysis of histological heterogeneity in renal cell carcinoma: tumor size-related histological change and its prognostic significance.

BACKGROUND: It is well recognized that the histology of renal cell carcinoma (RCC) is often heterogeneous. It is also believed that the prognosis of patients with large tumors is generally poorer than those with small tumors. However, there has been no detailed study on changes in histological features of RCCs associated with tumor growth. This study was conducted to investigate whether there are any specific histological changes related to tumor size and to study the prognostic value of histological parameters in RCCs. METHODS: The presence or absence of each histological component (3 cell types and 5 histological architectures) was investigated in 110 RCCs. The tumor size-associated changes in the histological composition of the RCCs were evaluated, and the prognostic significance of the histological parameters was analyzed using univariate and multivariate analysis. RESULTS: The percentage of RCCs with multiple cell types increased with tumor size, whereas increases in multiplicity were not as prominent in the histological architectures. Several characteristic changes, however, were observed in both cell types and architectures. RCCs with a pure clear cell, pure alveolar pattern or cystic architectural pattern decreased, while those with granular or spindle/pleomorphic cell types, or papillary or solid architectural patterns increased with tumor size. A univariate analysis revealed that a clear cell type and an alveolar or cystic architectural pattern were associated with a better prognosis, while spindle/pleomorphic cells and a solid architecture pattern correlated with a poorer prognosis. Multivariate analysis of cell types and architectures showed, however, that only the presence of spindle/pleomorphic cell types and a solid architecture were independent prognostic variables. CONCLUSION: The histological composition of RCCs varied according to the size of the tumor. Sarcomatous components increased with tumor size and were independently associated with a poor prognosis. Further study is warranted to correlate specific genetic alterations with tumor growth-related histological changes in RCCs.

Adult↗
PubMed1996

Estimate criteria for diagnosis and severity in benign prostatic hyperplasia.

BACKGROUND: Standard severity criteria for benign prostatic hyperplasia (BPH) are needed to facilitate clinical and epidemiologic investigations in the common terminology. PATIENTS AND METHODS: A total of 692 BPH patients from 8 institutions were judged by specialized physicians for their overall disease severity and severity in 4 domains: symptom, function, anatomy, and quality of life (QOL). The items measuring severity in these 4 domains were the International Prostate Symptom Score (I-PSS) questionnaire, uroflowmetry, transrectal ultrasonography (TRUS), and questionnaires on bother and I-PSS QOL index, respectively. By Spearman's rank correlation and multiple regression analysis using physicians' judgement as the criterion variable (gold standard) the items and their cut-off levels were selected so that high predictivity, practicality and clinical significance were maintained, while the number of items in use was minimized. RESULTS: The item(s) and their ranges of values for each severity grade were summarized as follows; the evaluation domain (the selected item(s): range of mild, moderate, severe): symptom (I-PSS: 0-7, 8-19, 20-35), function (maximum flow rate and residual urine volume: > or = 15 mL/s and < 50 mL, > or = 5 mL/s and < 100 mL, < 5 mL/s or > or = 100 mL), anatomy (prostate volume on TRUS: < 20 mL, < 50 mL, > or = 50 mL), QOL (QOL index: 0 and 1, 2 to 4, 5 and 6). The overall severity was efficiently predicted when defined according to the combinations of severity grades of the 4 domains. These criteria predicted physicians' judgement with accuracy of about 80% for overall severity and severity of individual domains. CONCLUSION: The proposed criteria are valid, practical, and would be useful for the common scale of the BPH severity in clinical and epidemiologic studies.

Humans↗
PubMed1996

Estimate criteria for efficacy of treatment in benign prostatic hyperplasia.

BACKGROUND: Various treatment modalities for benign prostatic hyperplasia (BPH) have emerged and are now in use or await evaluation of clinical usefulness. It is difficult, however, to compare their efficacies on a single scale, because standardized criteria for therapeutic efficacy of BPH treatments have not been established. PATIENTS AND METHODS: A total of 692 BPH patients from 8 institutions in Japan received various treatments, and were judged by specialized physicians for overall efficacy, and for efficacy in 4 domains: symptom, function, anatomy, and quality of life (QOL). Efficacy of treatment was graded as excellent, good, fair or poor, and assessed using items based on conventional clinical measurements. These items included 1) the difference (post-pretreatment value), 2) relative ratio (post/pre) and, 3) the individual values of pre- or posttreatment measurements. The cut off levels for each grade were heuristically selected by Spearman's rank correlation and multiple regression analysis so that the results accurately predicted physicians' judgement, while the feasibility was maintained. RESULTS: The results for each efficacy grade (range of excellent, range of good, range of fair, range of poor) were summarized as follows: Symptom: (post/pre treatment ratio of I-PSS) < or = 0.25, < or = 0.5, < or = 0.75, > 0.75. Function: (post-pre of Qmax) > or = 10 mL/s, > or = 5 mL/s, > or = 0.25 mL/s, < 0.25 mL/s. Anatomy: (post/pre ratio of prostate volume) < or = 0.5, < or = 0.75, < or = 0.9, > 0.9. QOL: (pre-post of QOL index) > or = 4, 3, 2 and 1, < or = 0. The overall efficacy grade was defined as the median of efficacy grades of 3 domains: symptom, function and QOL. The agreement rates between the criteria and physicians' judgement on the dichotomous efficacy (either excellent plus good, or fair plus poor) were approximately 80% in individual domains and overall estimate, and consistent among various treatments. CONCLUSION: The proposed criteria are fairly accurate, simple, and practical, and thus may be useful as a standard method for assessing the clinical efficacy of BPH treatments.

Evaluation Studies as Topic↗
PubMed1996

Bladder dysfunction in patients with benign prostatic hyperplasia: relevance of cystometry as prognostic indicator of the outcome after prostatectomy.

BACKGROUND: We correlated cystometric findings to the clinical features of benign prostatic hyperplasia (BPH) and compared them in terms of outcome after prostatectomy. METHODS: Cystometric findings obtained from 78 patients who underwent prostatectomy were correlated with clinical features in BPH patients. In 41 consecutive patients of this group, prospective periodical cystometry was also performed. RESULTS: Low bladder compliance correlated significantly with an increase in age and prostate volume, detrusor instability and impaired contractility. Low compliance also correlated with irritative symptoms, decreased maximum flow rate, increased post-void residual urine and an increase in the American Urological Association symptom score. Postoperative persistent incontinence was associated with low bladder compliance and detrusor instability. In a prospective study, bladder dysfunction was not completely restored in 53% of patients examined at a mean interval of 7.7 months after prostatectomy. CONCLUSIONS: Among the cystometric parameters investigated, low compliance was the most relevant to the clinical features of BPH and had some predictive value for the outcome after prostatectomy. In about half of the BPH patients with bladder dysfunction preoperatively, this condition was irreversible for a significant period of time after prostatectomy, in spite of surgical relief of the infravesical obstruction.

Age Factors↗