Biomedical subjects
T Kudo
Publications and source records attributed to T Kudo.
[Studies on the group-specific double combination method].
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[My views on cases presenting abnormal intracranial rete vasculosum].
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[Hypoplastic congenital anemia].
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Struma ovarii: appearance on MR images.
BACKGROUND: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images. METHODS: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison of MR images with resected specimens. RESULTS: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high, with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous materials. CONCLUSIONS: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii.
Cervical carcinoma: efficacy of thin-section oblique axial T2-weighted images for evaluating parametrial invasion.
BACKGROUND: To investigate the efficacy of thin-section oblique axial T2-weighted images in the assessment of parametrial invasion by cervical carcinoma. METHODS: One hundred parametria of 50 patients with cervical carcinoma were evaluated with pathologic correlation. We compared the sensitivity, specificity, and diagnostic accuracy in the assessment of parametrial invasion by cervical carcinoma between axial T2-weighted images and thin-section oblique axial T2-weighted images. RESULTS: Thin-section oblique axial T2-weighted images provided accurate cross sections of the cervix with excellent detail and detected parametrial invasion more accurately than did axial T2-weighted images showing cross sections of the trunk. Although the sensitivity, specificity, and accuracy for parametrial invasion were 46.4%, 91.7%, and 79.0%, respectively, on axial T2-weighted images, the corresponding values were 67.9%, 97. 2%, and 89.0%, respectively, on thin-section oblique axial T2-weighted images. There were statistically significant differences in the sensitivity (p = 0.014), specificity (p = 0.046), and accuracy (p = 0.002) in detecting parametrial invasion between these two types of images. CONCLUSIONS: Thin-section oblique axial T2-weighted images are useful for the assessment of parametrial invasion by cervical carcinoma.
Endometrial carcinoma: efficacy of thin-section oblique axial MR images for evaluating cervical invasion.
BACKGROUND: To investigate the efficacy of thin-section oblique axial magnetic resonance (MR) images in evaluating cervical invasion by endometrial carcinoma. METHODS: Sixty-seven patients with endometrial carcinoma were evaluated with pathologic correlation. We compared the accuracy in the assessment of cervical invasion by endometrial carcinoma between parasagittal MR images and thin-section oblique axial MR images by using T2-weighted and contrast-enhanced T1-weighted pulse sequences. RESULTS: Cervical invasion by endometrial carcinoma was confirmed by pathologic examination. Cervical invasion was seen in 16 patients. The accuracy rates of parasagittal T2-weighted images, thin-section oblique axial T2-weighted images, parasagittal contrast-enhanced T1-weighted images, and thin-section oblique axial contrast-enhanced T1-weighted images were 74.7%, 89.5%, 82.0%, and 95.5%, respectively. Statistically significant differences were seen between parasagittal T2-weighted images and thin-section oblique axial T2-weighted images (p = 0.002) and between parasagittal contrast-enhanced T1-weighted images and thin-section oblique axial contrast-enhanced T1-weighted images (p = 0.003). CONCLUSION: Thin-section oblique axial MR images are considered to be useful for the assessment of cervical invasion by endometrial carcinoma.
In vitro production and release of opioid peptides in the tooth pulp induced by bradykinin.
A possible relationship between met-enkephalin (ME)-like peptides and bradykinin (BK) in the rat incisor pulp was examined in in vitro experiments using whole pulp. ME-like peptide content in the pulp was increased by BK at a concentration of 1 microM, but not in higher concentrations, while the release of ME-like peptides from the pulp into the incubation medium was increased dose-dependently by BK. These effects of BK were inhibited by Des-Arg9-[Leu8]-BK, a potent BK-antagonist, suggesting that the effects of BK were mediated through a specific BK-receptor in the pulp. On the other hand, high K+ did not induce any increased release of ME-like peptides from the pulp and the BK effects were influenced neither in Ca++-free medium nor in the presence of ouabain. These results suggested that ME-like peptide releasing effect of BK was not due to depolarization of the cell membrane and was not active. In addition, kyotorphin, and enkephalin-releaser, could not only elicit a release of ME-like peptides from the pulp, but also a marked increase of the peptide content in the pulp. However, a combination of BK and kyotorphin attenuated the effect of BK or kyotorphin each other. These results suggested that there might be two kinds of mechanisms of ME-like peptide production in the pulp and those mechanisms might interfere mutually.
Influences of bradykinin and substance P on the met-enkephalin-like peptide content in the rat incisor pulp.
The present study was aimed to examine possible influences of bradykinin (BK) and substance P (SP) on met-enkephalin (ME)-like peptide content in the rat incisor pulp. Des-Arg9-[Leu8]-BK, a potent BK-antagonist, significantly reduced the increased content of ME-like peptides induced by noxious stimulation, while the effect of BK-antagonist was reversed in combination with BK. Morphine decreased the increased content of ME-like peptides. Ethylketocyclazocine, a kappa-agonist, also decreased the increased content of the peptides. From these results, it was suggested that BK might be a trigger in the increase of ME-like peptide content induced by noxious stimulation and, in contrast, ME-like peptides in the pulp might inhibit BK release from the pulp in a negative feedback mechanism. On the other hand, [D-Pro2,D-Trp7,9]-SP, a potent SP-antagonist, did not show any significant influence to ME-like peptide content in the pulp. Furthermore, the content was not changed following cutting of inferior alveolar nerve. From these results, it was suggested that ME-like peptides in the pulp cells might be independent on SP-containing nerves in the pulp.
A new and efficient method to generate human IgG monoclonal antibodies reactive to cancer cells using SCID-hu mice.
Human monoclonal antibodies (mAbs) are very useful for treatment of cancer, but they are difficult to obtain since immunization of humans is not a practical proposition at present. As an approach to circumvent this problem, we have simultaneously inoculated cancer tissues and regional lymph node cells obtained from lung cancer patients into SCID mice to allow in vivo stimulation of human lymphocytes against autologous cancer tissues. Human immunoglobulins, especially IgG, were observed in the SCID-hu sera, and some showed high reactivity to lung cancer cell lines. Testing of human B-lymphoblastoid cell lines obtained from SCID-hu spleen and thymus for antibody activity revealed 16-45% of them to be reactive to lung cancer cells. These percentages are high as compared with previous reports. Furthermore, we could establish 4 human IgG mAbs reactive to lung cancer cell lines. These results indicate successful stimulation of specific human lymphocytes in vivo, which thereby enables efficient generation of human monoclonal antibodies using SCID-hu mice.
Presence of dopamine DA-1 receptors in human decidua.
To evaluate the role of dopamine in human parturition, we studied the presence of dopamine receptors in human decidua obtained immediately after delivery, using a radiolabelled receptor assay. [3H]SCH23390, a dopamine DA-1 receptor ligand was used to identify and characterize the DA-1 receptor. Scatchard analysis of our saturation experiments revealed one class of high-affinity binding sites. The equilibrium dissociation constant (Kd) for binding of [3H]SCH23390 to decidual DA-1 receptors was 1.87 +/- 0.16 nM (mean +/- s.d. n = 3) at 30 degrees C. The maximum binding capacity (Bmax) was 79.0 +/- 15.4 fmol/mg protein at 30 degrees C. The specificity of DA-1 receptor binding was inhibited by SCH23390 (a DA-1 antagonist), SKF38393 (a DA-1 agonist) and dopamine with the inhibitory constants (Ki) of 5.82 +/- 2.27 nM (mean +/- s.d., n = 3), 45.6 +/- 30.5 nM (mean +/- s.d. n = 3) and 2.86 +/- 1.02 microM (mean +/- s.d., n = 3) respectively. However, (+/-)-sulpiride (a DA-2 antagonist) and (-)-propranolol (a beta-adrenergic antagonist) were without effect. The specific binding of [3H]spiperone (a DA-2 receptor ligand) was not detected. We previously reported that in vitro the human decidual tissues produce significant amounts of prostaglandins in the presence of dopamine. We postulate that dopamine regulates the production of prostaglandin in human decidua via DA-1 receptors.
Are cerebrovascular factors involved in Alzheimer's disease?
Recent epidemiological studies have shown that vascular risk factors may be involved in Alzheimer's disease (AD) as well as dementia in general. To investigate the relation between a vascular disorder and AD pathology, current criteria are defective because most depend on exclusion of a cerebrovascular disorder. Epidemiological studies have indicated the possibilities that arteriosclerosis, abnormal blood pressure, diabetes mellitus and smoking may be related to the pathogenesis of AD. As for the mechanism that vascular disorders influence AD, it is presumed that amyloid deposition may be caused by a vascular disorder. Alternatively, a vascular event may cause progression of subclinical AD to a clinical stage. Insulin resistance and apolipoprotein E may also be involved in these mechanisms. Our studies show that ischemia-induced the Alzheimer-associated gene presenilin 1 (PS1) and endoplasmic reticulum-stress, generated from a vascular disorder, may unmask clinical AD symptoms caused by presenilin mutation, suggesting that a vascular factor might be involved in the onset of familial AD.
Inhibition of aldosterone production in the adrenal glomerulosa by atrial natriuretic factor.
Several forms of the polypeptide atrial natriuretic factor (ANF) have been isolated recently from rat and human atria and identified; they are probably associated with the secretory granules of atrial tissue. The potent ability of ANFs to increase urine sodium content is mediated by their direct action on the kidney. We report here the high intrinsic activity of a synthetic replicate of one form of this molecule, ANF(8-33)(ref. 7), to inhibit directly basal aldosterone secretion and its ability to antagonize the stimulatory effects of adrenocorticotropin (ACTH) and angiotensin II (AN-II) on the secretion of aldosterone by rat adrenoglomerulosa cells in vitro. Our results suggest that ANF is of clinical importance in the management of aldosterone-dependent hypertension by modifying the adrenocortical response to endogenous ACTH and AN-II.
Effects of stool dilution on the faecal Helicobacter pylori antigen test.
OBJECTIVE: To examine the effects of stool dilution on the results of the faecal Helicobacter pylori antigen test. METHODS: Stool samples from nine children with H. pylori infection were diluted with normal saline at dilutions of 1, 5, 10, 50, 100 and 500 times, and optical density (OD) was measured. RESULTS: The faecal H. pylori antigen test yielded positive results for all samples at dilutions of 1:10 and less, although the sample from the case whose original stool showed the lowest OD value changed from positive to negative at a dilution of 1:50. CONCLUSION: Our results suggest that stools at dilutions of less than 1:10 usually do not yield false-negative results in the faecal H. pylori antigen test, even in patients with low faecal antigen levels.
Telomerase activity and apoptosis as indicators of ageing in placenta with and without intrauterine growth retardation.
Telomerase activity (TA) and apoptosis were analysed in placenta with and without intrauterine growth retardation (IUGR). Thirty-one specimens were taken from chorionic villi in the first trimester (Group A), 32 placenta specimens were obtained from cases without IUGR in second and third trimester (Group B) and 12 specimens of placenta tissue were obtained from cases of asymmetric IUGR between 26 and 39 weeks of gestation (Group C). TA was analysed by the Telomeric Repeat Amplification Protocol (TRAP) and in situ TRAP assay. Apoptotic changes were assessed by immunohistochemical staining using Bcl-2 monoclonal antibody and by terminal transferase-mediated in situ end-labelling (TUNEL). TA was detected in 29 of the 31 (93.5 per cent) chorionic villi (Group A) and in 20 of the 32 (62.5 per cent) placenta without IUGR (Group B), whereas weak TA was observed in the placenta of all 12 asymmetric IUGR cases (Group C). Significantly higher Bcl-2 immunoreactivity was observed in trophoblastic cells of Group A (85.9+/-4.2 per cent) and Group B (72.8+/-7.2 per cent) than Group C (54.84+/-4.83 per cent), while TUNEL positive cells were identified at a significantly higher frequency in the trophoblastic cells of Group C (9.7+/-7.4 per cent) than Group A (1.1+/-1.9 per cent) or Group B (2.9+/-3.7 per cent).
Long-term outcomes and predictors of iliac angioplasty with selective stenting: is primary stenting necessary?
Percutaneous transluminal angioplasty (PTA) has become one of the initial treatment options in patients with iliac artery occlusive disease. Stents have been recommended to correct procedural complications and improve long-term patency. Many series advocate routine stent placement after an otherwise uncomplicated PTA (primary stenting) in an attempt to prevent recurrent disease. Currently, many physicians in the United States seem to use stents in the iliac artery more liberally, even on a routine basis. There is little evidence to support this practice, however. It is still unclear whether a stent should be inserted primarily or selectively. This article provides the data from an 11-year experience of angioplasty with selective stenting for iliac artery occlusive lesions and reviews the current literatures on the iliac artery stent placement.
Uterine cirsoid aneurysm: MRI and MRA.
Uterine cirsoid aneurysm is uncommon. It is important to make a diagnosis of this disease preoperatively, because repeated curettages may induce life-threatening massive genital bleeding. We present a case of a 51-year-old woman with uterine cirsoid aneurysm in whom MRI and MRA were very useful for the preoperative diagnosis. The radiologic appearances on ultrasonography, CT, conventional SE MRI, MRA, dynamic MRI, and pelvic angiography are presented. Conventional SE T1-weighted and T2-weighted images demonstrated multiple flow voids in the uterus and bilateral adnexal regions. MRA demonstrated a cluster of distinct, tortuous, and coiled vascular channels in the pelvis. MRA could obtain images almost equal to angiography and was considered to be an excellent noninvasive imaging technique for the diagnosis of uterine cirsoid aneurysm.