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Biomedical subjects

H Kudo

Publications and source records attributed to H Kudo.

At least 55 records · Page 3Linked to original sources
PubMed2000

Transient expression of activin betaA mRNA on osteoprogenitor cells in rat bone regeneration after drill-hole injury.

We investigated the expression of activin betaA on osteoprogenitor cells in the regenerating bone and bone marrow of the rat femur after drill-hole injury, by immunocytochemistry and in situ hybridization. The periosteum and endosteum adjacent to the wound region showed marked thickening at day 3 and abundant osteoprogenitor cells, which were immunoreactive for proliferating cell nuclear antigen and showed positive reactions for alkaline phosphatase activity, and existed in the inner layer of the periosteum as well as in the endosteum. During the same period, these osteoprogenitor cells began to exhibit activin betaA immunoreactivity and mRNA expression. However, the latter expression gradually reduced the intensity as the cells started to express osteocalcin mRNA during their differentiation to osteoblasts participating in the periosteal and medullary bone formation from day 5. Immunoreactivity for activin type IB and II receptors was also found on activin betaA-immunoreactive cells between days 3 and 7. The above findings suggest that proliferating osteoprogenitor cells, before their transformation to osteoblasts, transiently produce and release activin A, which may play crucial roles in bone and bone marrow regeneration in a receptor-mediated, autocrine and paracrine fashion.

Animals↗
PubMed2000

Simple mucosal biopsy criteria differentiating among Crohn disease, ulcerative colitis, and other forms of colitis: measurement of validity.

BACKGROUND: Recently established mucosal biopsy criteria reliably differentiate idiopathic inflammatory bowel disease (IBD) from other forms of colitis (non-IBD), and Crohn disease involving the colon (CD) from ulcerative colitis (UC) but were inconvenient in practical use because of the need for relatively complicated calculations. Our objectives were to establish simple criteria in which calculation could be done in the user's head and to measure their validity. METHODS: On the basis of the above original criteria, we constructed two sets of criteria in which coefficients and constants were simplified to integral numbers. The first set of criteria consisted of the diagnostic categories 'definite IBD', 'probable IBD', 'unknown', 'probable non-IBD', and 'definite non-IBD'. Similarly, the second set had five categories from 'definite CD' to 'definite UC'. The validity of the criteria was evaluated in 117 patients with CD, 125 with UC, and 484 with non-IBD. RESULTS: In categories of probable IBD and probable non-IBD both sensitivity and specificity exceeded 96.3%. Probable CD and probable UC showed sensitivities of 95.7% and 92.0% and specificities of 93.6% and 98.3%. CONCLUSIONS: Despite simplified coefficients and constants, the validity appeared to be high enough to apply the present criteria to routine work.

Adult↗
PubMed2000

Sera from patients with sepsis induce nitric oxide production in vascular smooth muscle cells.

BACKGROUND: Nitric oxide (NO) is an important physiological mediator of vascular tone and is involved in pathophysiology of septic shock. Although plasma nitrite is a stable end product of NO oxidation derived from endogenous NO, the plasma nitrite level is also easily affected by the intake of various foods, bacterial products and renal functional status. AIMS: We propose an excellent alternative assay technique for measuring endogenous NO production. METHODS: We measured the nitrite level in cultured vascular smooth muscle cells (SMC) treated with serum obtained from patients with sepsis (4 patients), by means of a chemiluminescence detector. RESULTS: The nitrite concentrations in such cells were significantly higher as compared to those in the cells treated with normal serum. Moreover, the increased nitrite levels in the SMC treated with the sera obtained from patients with sepsis were completely inhibited by L-nitroarginine (1 mmol/L), a nitric oxide synthase inhibitor. CONCLUSION: These data suggest that this assay method enable us to know the ability of endogenous NO production in each patient.

Aged↗
PubMed2000

A solution to the long-object problem in helical cone-beam tomography.

This paper presents a new algorithm for the long-object problem in helical cone-beam (CB) computerized tomography (CT). This problem consists in reconstructing a region-of-interest (ROI) bounded by two given transaxial slices, using axially truncated CB projections corresponding to a helix segment long enough to cover the ROI, but not long enough to cover the whole axial extent of the object. The new algorithm is based on a previously published method, referred to as CB-FBP (Kudo et al 1998 Phys. Med. Biol. 43 2885-909), which is suitable for quasi-exact reconstruction when the helix extends well beyond the support of the object. We first show that the CB-FBP algorithm simplifies dramatically, and furthermore constitutes a solution to the long-object problem, when the object under study has line integrals which vanish along all PI-lines. (A PI line is a line which connects two points of the helix separated by less than one pitch.) Exploiting a geometric property of the helix, we then show how the image can be expressed as the sum of two images, where the first image can be reconstructed from the measured CB projections by a simple backprojection procedure, and the second image has zero PI-line integrals and hence can be reconstructed using the simplified CB-FBP algorithm. The resulting method is a quasi-exact solution to the long-object problem, called the ZB method. We present its implementation and illustrate its performance using simulated CB data of the 3D Shepp phantom and of a more challenging head-like phantom.

Algorithms↗
PubMed2000

Dietary zinc deficiency decreases glutathione S-transferase expression in the rat olfactory epithelium.

Zinc deficiency leads to olfactory and gustatory dysfunction, but little is known about the underlying molecular mechanism of this phenomenon. We examined the effect of dietary zinc deficiency on the rat olfactory epithelium. Immunoreactivities of glutathione S-transferase (GST) mu, neuron-specific enolase (NSE) and proliferating cell nuclear antigen (PCNA), and in situ hybridization of GST mu mRNA in the olfactory epithelia were examined under different dietary zinc intake conditions. Adult male rats were fed a zinc-deficient (ZD) diet (0.5 mg zinc/kg diet), whereas control rats, including pair-fed (PF) and zinc-adequate (ad libitum consumption, AL) groups, were fed a zinc-adequate diet (58 mg zinc/kg diet) for 7 wk. We also examined the effect of zinc replacement (ZR) by subsequently feeding half of the ZD group a zinc-adequate diet for 5 wk after the initial 7-wk deprivation. No significant differences in immunoreactivity for NSE in olfactory epithelial receptor cells or for PCNA in basal cells were noted among groups. Intense GST mu immunoreactivity and hybridization signals were observed in olfactory supporting cells of AL, PF and ZR groups, but very minimal or no such signal was noted in ZD rats. Our findings indicated that zinc deficiency reduces GST mu expression in the supporting cells of rat olfactory epithelia but does not affect receptor cell proliferation or maintenance.

Actins↗
PubMed2000

Quasi-exact filtered backprojection algorithm for long-object problem in helical cone-beam tomography.

Exact reconstruction from axially truncated cone-beam projections acquired with a helical vertex path is a challenging problem for which solutions are currently under investigation by some researchers. This paper deals with a difficult class of this problem called the long-object problem. Its purpose is to reconstruct a central region of interest (ROI) of a long object when the helical path extends only a little bit above and below the ROI. By extending the authors' recent approach based on the triangular decomposition of the Grangeat formula, we derive quasi-exact reconstruction algorithms whose overall structure is of filtered backprojection (FBP) style. Unlike the previous similar approaches to the long-object problem, the proposed FBP algorithms do not require additional two circular scans at the ends of the helical path. Furthermore, the algorithms require a significantly smaller detector area and achieve improved image quality even for a large pitch compared with the approximate Feldkamp algorithms. One drawback of the proposed algorithms is the computational time, which is much longer than for the Feldkamp algorithms. We show some simulation results to demonstrate the performances of the proposed algorithms.

Algorithms↗
PubMed2000

Immunocytochemical analyses and targeted gene disruption of GTPBP1.

We previously identified a gene encoding a putative GTPase, GTPBP1, which is structurally related to elongation factor 1alpha, a key component of protein biosynthesis machinery. The primary structure of GTPBP1 is highly conserved between human and mouse (97% identical at the amino acid level). Expression of this gene is enhanced by gamma interferon in a monocytic cell line, THP-1. Although counterparts of this molecule in Caenorhabditis elegans and Ascaris suum have also been identified, the function of this molecule remains to be clarified. In the present study, our immunohistochemical analyses on mouse tissues revealed that GTPBP1 is expressed in some neurons and smooth muscle cells of various organs as well as macrophages. Immunofluorescence analyses revealed that GTPBP1 is localized exclusively in cytoplasm and shows a diffuse granular network forming a gradient from the nucleus to the periphery of the cells in smooth muscle cell lines and macrophages. To investigate the physiological role of GTPBP1, we used targeted gene disruption in embryonic stem cells to generate GTPBP1-deficient mice. The mutant mice were born at the expected Mendelian frequency, developed normally, and were fertile. No manifest anatomical or behavioral abnormality was observed in the mutant mice. Functions of macrophages, including chemotaxis, phagocytosis, and nitric oxide production, in mutant mice were equivalent to those seen in wild-type mice. No significant difference was observed in the immune response to protein antigen between mutant mice and wild-type mice, suggesting normal function of antigen-presenting cells of the mutant mice. The absence of an eminent phenotype in GTPBP1-deficient mice may be due to functional compensation by GTPBP2, a molecule we recently identified which is similar to GTPBP1 in structure and tissue distribution.

Animals↗
PubMed2000

Effect of steroid on hyperoxia-induced ICAM-1 expression in pulmonary endothelial cells.

Intercellular adhesion molecule-1 (ICAM-1) of the vascular endothelium plays a key role in the development of pulmonary oxygen toxicity. We studied the effect of steroid on hyperoxia-induced ICAM-1 expression using cultured endothelial cells in vitro. Human pulmonary artery endothelial cells (HPAECs) were cultured to confluence, and then the monolayers were exposed to either control (21% O(2)-5% CO(2)) or hyperoxic (90% O(2)-5% CO(2)) conditions with and without a synthetic glucocorticoid, methylprednisolone (MP). MP reduced hyperoxia-induced ICAM-1 and ICAM-1 mRNA expression in a dose-dependent manner. Neutrophil adhesion to hyperoxia-exposed endothelial cells was also inhibited by MP treatment. In addition, MP attenuated hyperoxia-induced H(2)O(2) production in HPAECs as assessed by flow cytometry. An electrophoretic mobility shift assay demonstrated that hyperoxia activated nuclear factor-kappaB (NF-kappaB) but not activator protein-1 (AP-1) and that MP attenuated hyperoxia-induced NF-kappaB activation dose dependently. With Western immunoblot analysis, IkappaB-alpha expression was decreased by hyperoxia and increased by MP treatment. These results suggest that MP downregulates hyperoxia-induced ICAM-1 expression by inhibiting NF-kappaB activation via increased IkappaB-alpha expression.

Cell Adhesion↗
PubMed2000

Roles of ICAM-1 for abnormal leukocyte recruitment in the microcirculation of bleomycin-induced fibrotic lung injury.

To assess the importance of endothelial intercellular adhesion molecule-1 (ICAM-1) in microvascular leukocyte kinetics in diseased lungs, we investigated the transitional changes in ICAM-1 expression, vascular diameter, and leukocyte behavior in rat pulmonary microcirculation during the development of acute lung injury (ALI) and chronic fibrosis (FIB) evoked by bleomycin (BLM). Observations were made in the isolated perfused lung with a real-time confocal laser luminescence microscope. Microvascular cell kinetics were evaluated by measuring the behavior of fluorescence- labeled leukocytes and erythrocytes in the presence or absence of anti-ICAM-1 monoclonal antibody (1A29). Arteriolar ICAM-1 showed little change at any time after BLM treatment. Venular ICAM-1 was first enhanced at the initial phase of ALI followed by the second upregulation at the early phase of FIB. Capillary ICAM-1 showed a sustained increase at both ALI and FIB. Arteriolar and venular diameters were not altered but capillary diameter decreased during ALI and early FIB stages. Although firm adherence of leukocytes to arteriolar and venular walls was not observed, rolling leukocytes were increased in venules both at the initial phase of ALI and at the early phase of FIB. The leukocyte rolling in venules correlated well with transitional changes in ICAM-1 and was inhibited by 1A29. Sustained entrapment of leukocytes in capillaries was attributed to changes in vascular diameter as well as augmented ICAM-1. In conclusion, ICAM-1 plays an important role in microvascular leukocyte recruitment in both ALI and FIB in the BLM-injured lung.

Animals↗
PubMed2000

Preventive effects of a herbal medicine on bone loss in rats treated with a GnRH agonist.

The study was designed to evaluate the effects of a traditional Chinese herbal medicine Hochu-ekki-to (Bu-zong-yi-qi-tang), which was composed of 10 herbal medicines and had been used for the treatment of oligospermia and as a postoperative medication in Japan, on bone loss in rats treated with a gonadotropin-releasing hormone (GnRH) agonist. Female rats at 40 weeks of age were divided into 4 groups of 8 rats each. In the three experimental groups, each animal received subcutaneous injections of the long-acting GnRH agonist, buserelin acetate, once every four weeks throughout the experiment. Beginning at 48 weeks of age, the experimental groups were given diets containing conjugated estrogens or Hochu-ekki-to for 8 weeks. The administration of the GnRH agonist reduced the bone mineral density in the whole femur to 91.0% of that in the control group. However, administration of conjugated estrogens and Hochu-ekki-to increased the serum concentrations of estradiol 16.8- and 5.3-fold respectively compared with concentrations in the GnRH agonist-treated group, resulting in the augmentation of the bone mineral density to 110.3% and 106.2% respectively. These findings indicate that Hochu-ekki-to enhances the reduced bone mineral density and causes a slight elevation of the serum estradiol levels in the chemically castrated rats.

Animals↗
PubMed2000

Delayed cerebrospinal fluid rhinorrhea seven months after transsphenoidal surgery for pituitary adenoma--case report.

A 51-year-old female had undergone transsphenoidal surgery for pituitary adenoma producing growth hormone. Cerebrospinal fluid (CSF) leakage occurred during surgery. The sella turcica and sphenoid sinus were packed with abdominal fat and fibrin glue, buttressing the closure with a fragment of sphenoid bone. No CSF rhinorrhea occurred postoperatively. Severe meningitis developed 7 months later. CSF rhinorrhea occurred 10 days after readmission. Exploration through the transsphenoidal approach identified a small hole at the floor of the sella and CSF leaking into the sphenoid sinus through the hole. The CSF leakage stopped after the second surgery. Delayed CSF rhinorrhea without bromocriptine administration is very rare. The cause of delayed CSF rhinorrhea remains unclear. CSF rhinorrhea should be suspected if meningitis develops even months after transsphenoidal surgery.

Adenoma↗
PubMed2000

Polypropylene mesh substitute for the fascial defect after using for the dural repair--technical note.

Use of the anterior sheath of the rectus abdominis muscle (anterior sheath) as a dural substitute and patching of the large defect of the anterior sheath with polypropylene mesh are described. Five patients were treated using the anterior sheath and the mesh. No postoperative complications such as cerebrospinal fluid leakage, infection, or abdominal wall hernia occurred. The mesh is useful as a patch for the sheath defect.

Abdominal Muscles↗
PubMed2000

[Tracheal mucosal bulla found on tracheal extubation in a patient with pemphigus vulgaris--a case report].

A 49-year-old female with pemphigus vulgaris underwent the removal of a meningioma under general anesthesia. Neither bulla nor erosion was observed on her skin and oral cavity mucosa. She had been on prednisolone 15 mg for six years daily to avoid the recurrence of skin lesion. Anesthesia was induced and maintained with total intravenous anesthesia with propofol and fentanyl. No adverse episodes were encountered during the operative procedure. We checked the tracheal mucosa using bronchofiberscope before extubation. A small bulla was found on the tracheal mucosa, where the cuff of the tracheal tube was located. The trachea was extubated slowly under bronchofiberscopic observation, and no other bullae were found. It would have been formed by mechanical stimulation of the tracheal tube. This case suggests that we have to pay careful attention to the formation of bullae at any part of the body by mechanical stimuli during anesthetic management of patients with pemphigus vulgaris.

Anesthesia, General↗
PubMed1999

Injection of antisense oligos to nNOS into nucleus tractus solitarii increases blood pressure.

We investigated the cardiovascular effects of bilateral microinjection of antisense oligodeoxynucleotides (oligos) into the nucleus tractus solitarii (NTS) to neuronal nitric oxide synthase (nNOS) to suppress the expression of nNOS molecular biologically. In urethane-anesthetized, paralyzed Wistar-Kyoto rats, bilateral microinjection of nNOS antisense oligos (20 pmol in a 50nl volume) into the NTS produced a significant increase in mean arterial blood pressure at 30-60min after injection, compared with rats injected with nNOS sense or scrambled oligos. Immunohistochemical study demonstrated that nNOS immunoreactivity in the rat NTS was suppressed by nNOS antisense oligos. These results indicate that suppression of the nNOS gene using antisense in the NTS increases blood pressure.

Animals↗
PubMed1999

In vivo evaluation of a novel alginate dressing.

Alginate dressings are currently used in the management of epidermal and dermal wounds, and provide a moist environment that leads to rapid granulation and reepithelialization. However, a cytotoxic effect on proliferation of fibroblasts and residual material with inflammation in healing wounds have been reported recently. We have developed a new alginate dressing (AGA-100), which does not have an inhibitory effect on proliferation of fibroblasts. The purpose of this study was to evaluate the new alginate dressing with respect to wound healing in full- and partial-thickness pig wounds and with respect to biodegradation following implantation into rabbit muscle. Kaltostat and Sorbsan, both well-established commercial dressings, were used as control. The closure rate of full-thickness wounds treated with AGA-100 was significantly higher on day 15 compared with that with Kaltostat and Sorbsan. Reepithelialization rate of partial-thickness wounds treated with Sorbsan was statistically significantly lower on day 3 than those with the other two dressings. As to dressing debris remained in the healing wound, a large amount of foreign debris was noted in all the full-thickness wounds treated with Kaltostat or Sorbsan, while only about one-third of wounds treated with AGA-100 showed a little dressing debris. AGA-100 implanted into the muscle of rabbits was bioresorbed completely within 3 months. Therefore, dressing residue in AGA-100-treated full-thickness wounds might be fully absorbed in a few months. In conclusion, it is shown that our newly developed AGA-100 possesses superior properties compared with typical alginate dressings.

Alginates↗
PubMed1999

Prevention of osteopenia induced with a gonadotropin-releasing hormone agonist in rats.

We investigated the effects of conjugated estrogens as an add-back replacement drug, incadronate sodium as a bisphosphonate, and alfacalcidol as a vitamin D(3) analog on femoral bone mineral density (BMD) and bone mineral content (BMC) in female rats chronically treated with the gonadotropin-releasing hormone (GnRH) agonist leuprorelin acetate. The chemical castration of the rats by the administration of GnRH agonist for 16 weeks reduced the BMD values to 92.3%, 91.3%, and 93.3% of those of the normal control animals in the whole femur, metaphysis, and diaphysis of the femur, respectively. The BMC value was decreased to 91.0% of that of the normal control animals by the chronic GnRH agonist treatment. However, a simultaneous 8-week administration of conjugated estrogens, bisphosphonate, and vitamin D(3) analog markedly augmented the BMC values to 110.3%, 110.1%, and 114.4%, respectively, of those in the rats treated with the GnRH agonist alone. These findings indicate that antiosteoporotic agents could be useful for preventing induced osteopenia under the careful monitoring of biochemical markers of osteoblastic activity or bone resorption and BMD or BMC in patients undergoing GnRH treatment.

Animals↗
PubMed1999

Decreased expression of the peroxisomal bifunctional enzyme and carbonyl reductase in human hepatocellular carcinomas.

Human hepatocellular carcinomas (HCC) are known to frequently exhibit clear-cell or fatty change. The expression of three enzymes related to fatty acid metabolism, the peroxisomal bifunctional enzyme (enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase, BE), cytosolic carbonyl reductase (CR) and the alpha-class glutathione S-transferase (GST) was investigated immunohistochemically in 45 HCC samples, to examine their relevance to this phenomenon and to antioxidant cellular defence. The tumour sizes ranged from 3 mm to 37 mm in diameter (mean 19 mm). Of 8 highly differentiated carcinomas (Edmondson's grade 1), 5 and 6 showed positive staining for BE and CR respectively, like the surrounding non-hepatoma tissues. Of 37 Edmondson's grade II-IV lesions, 31 exhibited negative or only weakly positive staining for both enzymes, as compared with the surrounding tissues. The combined rates for weakly positive and negative staining for BE or CR were proportional to the degree of dedifferentiation. However, 3 of 26 grade III tumours showed enhanced staining. Intensities of staining for CR were in accordance with those for BE in 40 of the total of 45 HCC. Immunoblot analysis also demonstrated concerted alteration of the two enzymes in carcinoma tissues. The staining of the alpha-class GST was hardly changed in Edmondson's grade I and II cases but was decreased in 24 of 31 grade III and IV lesions. The great majority of the BE-negative carcinomas did not demonstrate fatty or clear-cell change. These results suggested that BE and CR might be possible markers for the analysis of multistage hepatocarcinogenesis but that decrease or loss was not reflected in increased fat storage.

3-Hydroxyacyl CoA Dehydrogenases↗