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Biomedical subjects

H Koyama

Publications and source records attributed to H Koyama.

At least 109 records · Page 6Linked to original sources

Carotid artery reconstruction for Takayasu's arteritis the necessity of all-autogenous-vein graft policy and development of a new operation.

BACKGROUND: We have adopted an all-autogenous-vein-graft policy in carotid reconstruction for Takayasu arteritis, namely an ascendo-right carotid and right subclavian (axillary) arteries bypass using a pantaloon vein graft for patients all of whose arch branches are occluded, and an extra-anatomical bypass from the right subclavian artery for patients whose brachiocephalic artery is the only arch branch that remains patent. This report is to elaborate on these operations and to assess the long-term outcome. METHODS: Six patients were operated on according to this policy; (5 women, 1 man, age range: 14 to 59 years (mean: 30). The indications for surgery were severe cerebral ischaemia that significantly interfered with their daily lives. The pantaloon vein graft bypass was performed in four patients, and an extra-anatomical bypass in two. The specific management protocol to prevent the "postbypass hyperperfusion syndrome" and cerebral oedema included a shunt procedure to the internal carotid artery using one limb of the pantaloon vein graft, induced hypotension just before the completion of the carotid reconstruction and the administration of a glycerine-fructose solution. RESULTS: Cerebral ischaemic symptoms disappeared in all patients. All but one, who died of a ruptured thoraco-abdominal aneurysm on the 35th postoperative month, are living a normal life with a patent graft. No suture line complications have as yet been encountered (follow-up: 10 to 205 months, mean: 126 months). CONCLUSIONS: Carotid vein bypass for Takayasu arteritis, particularly, the pantaloon vein graft bypass is recommended for those of whom all aortic arch branches are occluded, resulting in severe brain ischaemia. Perioperative blood pressure control is important for prevention of the hyperperfusion syndrome.

Adolescent↗

Distinct role of cAMP and cGMP in the cell cycle control of vascular smooth muscle cells: cGMP delays cell cycle transition through suppression of cyclin D1 and cyclin-dependent kinase 4 activation.

cAMP and cGMP are known to suppress vascular smooth muscle cell (SMC) proliferation. In this study, our aim was to delineate the molecular mechanism underlying cAMP and cGMP suppression of cell cycle transition in human SMCs. cAMP inhibits both platelet-derived growth factor-stimulated cyclin-dependent kinase (cdk) 2 and cdk4 activation through upregulation of the cdk2 inhibitor p27(Kip1) and downregulation of cyclin D1 expression, which leads to a complete arrest of the cells in phase G(1). In contrast, cGMP inhibits cyclin D1 expression, inhibits cdk4 activation, and delays platelet-derived growth factor-mediated cdk2 activation, resulting in a delay in G(1)/S transition. A transient increase in p27(Kip1) in cdk2 immunoprecipitates, without changes in total cellular p27(Kip1) levels, correlates with the delay in cdk2 activation caused by cGMP. Thus, cAMP and cGMP differentially affect cell cycle through distinct regulation of cell cycle molecules in human SMCs.

8-Bromo Cyclic Adenosine Monophosphate↗

Galectin-1 regulates initial axonal growth in peripheral nerves after axotomy.

The signals that prompt the axons to send out processes in peripheral nerves after axotomy are not well understood. Here, we report that galectin-1 can play an important role in this initial stage. We developed an in vitro nerve regeneration model that allows us to monitor the initial axon and support cell outgrowth from the proximal nerve stump, which is comparable to the initial stages of nerve repair. We isolated a factor secreted from COS1 cells that enhanced axonal regeneration, and we identified the factor as galectin-1. Recombinant human galectin-1 (rhGAL-1) showed the same activity at low concentrations (50 pg/ml) that are two orders of magnitude lower than those of lectin activity. A similarly low concentration was also effective in in vivo experiments of axonal regeneration with migrating reactive Schwann cells to a grafted silicone tube after transection of adult rat peripheral nerve. Moreover, the application of functional anti-rhGAL-1 antibody strongly inhibited the regeneration in vivo as well as in vitro. The same effect of rhGAL-1 was confirmed in crush/freeze experiments of the adult mouse sciatic nerve. Because galectin-1 is expressed in the regenerating sciatic nerves as well as in both sensory neurons and motor neurons, we suggest that galectin-1 may regulate initial repair after axotomy. This high activity of the factor applied under nonreducing conditions suggests that galectin-1 may work as a cytokine, not as a lectin.

Animals↗

Sentinel Node Biopsy in Breast Cancer.

Axillary lymphnode dissection (ALND) for breast cancer patients provides local control and information for the determination of the type of adjuvant therapy.The benefit of axillary surgery itself for survival is considered to be limitedto patients with positive nodes. Sentinel node biopsy is a recently developed, minimally invasive technique for precisely predicting axillary nodal status. As this technique has less morbidity and greater accuracy than ALND, it replaces ALND for patients with node negative breast cancer. In this report, we outline thecurrent status of sentinel node biopsy for breast cancer patients and introduceour preliminary results.

Journal Article↗

Sentinel Node Biopsy in Breast Cancer Patients with Clinically Negative Lymph-Nodes.

BACKGROUND: The purpose of the present study is to evaluate the usefulness ofdye-guided sentinel node biopsy in breast cancer patients with clinically negative nodes and to clarify the anatomic distribution of sentinel nodes in the axilla. METHODS: Sentinel node biopsy was performed in patients with T1 or T2 breast cancer who had clinically negative nodes, using an indocyanin green dye-guided method. Thereafter, complete axillary dissection was performed. Sentinel node andcomplete axillary lymph-node dissection specimens were examined separately, andthe incidence of metastases was compared. RESULTS: We identified sentinel nodes in 115 (76.7%) of 150 patients with clinically negative nodes. The mean number of sentinel nodes was 1.7 (range, one toeight nodes). The mean size of sentinel nodes was 9.0 mm (range, 2.0 to 28.0 mm). Of the 31 patients who had a tumor-positive sentinel node, 14 (45.2%) patients had only the sentinel node involved. There was concordance on histological examination between sentinel node and axillary node status in 111 (96.5%) of 115 cases. Of the sentinel nodes 89.1% were located cranially to the intercostobrachial nerve and within 2 cm of the lateral edge of the pectoralis minor muscle. CONCLUSIONS: Sentinel node biopsy guided by indocyanin green dye is an easy technique with an acceptable detection rate of sentinel nodes for breast cancer patients with clinically negative nodes. Most of the sentinel nodes were locatednear the lateral edge of the pectoralis minor muscle and cranial to the intercostobrachial nerve.

Journal Article↗

Desert toads discriminate salt taste with chemosensory function of the ventral skin.

Toads obtain water by absorption across their skin. When dehydrated, desert toads exhibit stereotyped hydration behavior in which they press their ventral skin onto a moist surface. However, dehydrated toads avoid surfaces moistened with hyperosmotic NaCl and KCl solutions (Hoff KvS, Hillyard SD. 1993. J. Exp. Biol. 183:347-351). We have studied neural mechanisms for this avoidance with physiologic, behavioral, and morphologic approaches. Spinal nerves innervating the ventral skin could be stimulated by exposure to a hyperosmotic NaCl solution applied to the outer surface of the skin. This neural response occurred with much longer latency than to mechanical stimulation and could be reduced by amiloride, a blocker for Na+ channels known to be responsible for epithelial ion transport and salt taste transduction. In behavioral experiments, avoidance of a NaCl solution was also reduced by adding amiloride to the solution, suggesting involvement of amiloride-sensitive Na+ channels for detecting the hyperosmotic salt solution. Neural tracing with fluorescent dye revealed spinal nerve endings and connections to putative receptor cells, both located in the deeper layer of the epidermis. Either of these or both may be associated with the transduction of Na+ flowing into the skin. The ability of toads to detect hyperosmotic salt solutions in their environment reveals a previously unknown chemosensory function for spinal nerves in anuran amphibians.

Action Potentials↗

Adjuvant Therapy with High-Dose Medroxyprogesterone Acetate for Operable Breast Cancer.

BACKGROUND: Medroxyprogesterone acetate (MPA) produces a comparable or higherresponse rate in metastatic breast cancer compared with tamoxifen which is alsocommonly used for adjuvant endocrine therapy. Several studies in the West have indicated the efficacy of MPA when used as an adjuvant to surgery in certain subsets of patients. The present study was undertaken as a multicenter open study in Japan to investigate the safety and efficacy of MPA in adjuvant endocrine therapy. Method and Patients: A combination of 800 mg/day MPA and a fluorouracil compound for 6 months was given postoperatively to 119 patients with stage II or IIIabreast cancer in 32 participating hospitals between June 1987 and June 1989. RESULTS: Among the 119 patients, 59 patients (49.6%) experienced some kind ofadverse reaction. The major adverse reaction was abnormal menstruation, seen in 13 (25.0%) of the 52 premenopausal patients. Vaginal bleeding was a major adverse reaction in the 67 postmenopausal patients (8/67 or 11.9%). An increase in body weight and moon face were observed in 23 (19.3%) and 9 (7.6%) of the 119 patients, respectively. Administration of drugs was discontinued because of adversereaction in 17 patients (14.3%), and dose reduction or temporary suspension wasnecessary in 7 patients (5.9%). Increase in body weight was the main reason fordiscontinuation of the treatment. No severe adverse reactions were observed. After a median follow-up of 74.5 months (range, 2.2-90.0 months), 84 of the 119 patients are alive with no evidence of disease. The 3-year and 5-year disease-freesurvival rates were 88.2% and 82.6% in stage II patients, and 64.7% and 52.9% in stage IIIa patients, respectively. The 3-year and 5-year disease-free survivalrates according to age were 87.8% and 79.3% in patients aged 50 years or more, and 78.6% and 71.4% in patients aged under 50 years. CONCLUSION: These results show that 800 mg/day MPA plus a fluorouracil compound can be administered with acceptable morbidity as an adjuvant treatment to selected breast cancer patients.

Journal Article↗

Separation of selenium-containing proteins in human and mouse plasma using tandem high-performance liquid chromatography columns coupled with inductively coupled plasma-mass spectrometry.

An analytical method that uses two different high-performance liquid chromatography (HPLC) columns in tandem has been developed that separates three major selenium-containing proteins (albumin, glutathione peroxidase, and selenoprotein P) found in human blood plasma. The first column was a heparin affinity column and the second was a gel filtration column whose outlet was directly connected to an inductively coupled plasma-mass spectrometer. The method successfully separated plasma selenium into the three selenium-containing proteins and revealed the preferential retention of selenium in the form of selenoprotein P in a selenium-deficient human and in selenium-deficient mice. Our results also confirm the results of previous studies that showed a preference for supplemented selenium to be taken up as selenoprotein P in rats. Advantages of the tandem column method are that it allows rapid and convenient analyses of the distribution of plasma selenium, and that it is suitable for stable isotope tracer studies and metal interaction studies.

Adult↗

Prospective Randomized Study of Cyclophosphamide, Epirubicin, and 5-Fluorouracil versus Cyclophosphamide, Adriamycin, and 5-Fluorouracil in Advanced or Recurrent Breast Cancer.

BACKGROUND: Treatment with cyclophosphamide, adriamycin, and 5-fluorouracil (CAF), a widely used, potent regimen is sometimes restricted by the myelotoxicityand myocardiotoxicity of adriamycin (ADR). In a prospective randomized controlled study of patients with advanced or recurrent breast cancer, the efficacy and toxicity of a CEF regimen, in which epirubicin (EPI) was substituted for ADR, was compared with CAF. METHODS: 138 female patients under 75 years of age who had unresectable or recurrent breast cancer during the period from October, 1989 to September, 1991, were randomized to one of two treatment regimens. The first regimen consisted of cyclophosphamide 100 mg p.o. d1-14, adriamycin 30 mg/m(2) i.v. d1, 8 and 5-fluorouracil 500 mg/m(2) i.v. d1, 8 (CAF). In the second regimen, EPI 30 mg/m(2) i.v. d1, 8was substituted for ADR (CEF). Both regimens were delivered q4 weeks. RESULTS: Of 138 patients, 105 (CEF 56, CAF 49) were evaluable for response and survival, and all were evaluable for toxicity (CEF 68, CAF 70). The median course of lots CEF and CAF was 3 cycles. Response rates (complete response plus partial response) with CEF and CAF were 35.7% (20/56) and 36.7% (18/49), respectively. Adverse effects were similar in the two groups, but severe leukopenia (CEF 36.8%, CAF 64.3%) and hepatic toxicity (CEF 1.5%, CAF 12.9%) were encountered more frequently with CAF than with CEF. The duration of 50% survival was 135.9 weeks for CEF and 172.1 weeks for CAF (not significant). CONCLUSION: At an equal dose of EPI and ADR response rates and survival of the CEF group were similar to those of the CAF group, but adverse effects were fewer in the CEF group.

Journal Article↗

Mediastinal lymph node involvement as the initial manifestation of occult thyroid cancer in the surgical treatment of lung cancer: report of a case.

A 63-year-old man was referred to our institute for the treatment of squamous cell carcinoma of the upper lobe of his right lung. A right upper lobectomy of the lung was performed with a mediastinal lymph node dissection. The postoperative pathological examination of the dissected specimens revealed one of the superior mediastinal lymph nodes to be morbid with micrometastasis of occult thyroid cancer, while no node involvement was seen due to lung cancer. A right lobectomy of the thyroid gland with a modified radical neck dissection was done 4 years later after the confirmation of the absence of any recurrent sign of lung cancer. In the resected specimen, papillary thyroid microcarcinoma was observed with several intraglandular metastases and right regional lymph node involvement. Eight months later, a new primary lung cancer developed in the left lung, and a left upper lobectomy of the lung with a mediastinal lymph node dissection was performed. At that time, the absence of mediastinal lymph node metastasis from lung cancer or thyroid cancer was confirmed. Mediastinal lymph node involvement as the initial manifestation of occult thyroid cancer in surgical treatment for lung cancer is rare, but it is important to be aware of the possibility of incidentally detecting occult thyroid cancer in surgical dissections in this area for lung cancer. The appropriate surgical treatment should be determined while carefully considering the prognosis of the lung cancer as well as that of any coexisting malignancy.

Carcinoma, Papillary↗

Advanced primary Hodgkin's disease of the spleen cured by surgical resection: report of a case.

We describe herein the case of a 61-year-old man who underwent successful resection of advanced primary Hodgkin's disease of the spleen. On admission, computed tomography and ultrasonography showed a fist-sized, slightly enhanced mass, and angiography demonstrated a typical neoplastic tumor stain in the spleen. Exploratory laparotomy revealed a hard mass invading the splenic hilar lymph nodes, gastric upper body, transverse colon, pancreatic tail, and left lateral segment of the liver. The patient underwent splenectomy with combined resection of the surrounding organs invaded by the tumor, followed by postoperative chemotherapy. Histological examination showed many Reed-Sternberg cells, and the tumor was subsequently diagnosed as Hodgkin's disease of the spleen. The patient is currently well without any signs of recurrence 4 years after surgery.

Hodgkin Disease↗

Matrix interferences in the analysis of digested biological tissues with inductively coupled plasma-mass spectrometry.

To investigate the physiological roles or toxicity of trace or toxic elements, multielement analysis of limited quantities of samples in the biological tissues is required. Inductively coupled plasma mass spectrometry (ICP-MS) suits this requirement, but spectral and nonspectral interferences are inevitable. We examined correction methods for the nonspectral interferences by analyzing signals of 21 elements in various concentrations of HNO3 as well as five major elements (Na, K, P, Ca, and Cl). Using internal standards, the interferences caused by the major elements were corrected, but the interferences caused by HNO3 were impossible to correct for elements with high ionization potentials. The analytical results using the standard addition method on 14 elements in standard reference materials and fresh brain tissues confirmed the accuracy of this method. Thus, we concluded that the standard addition method is useful to correct for the nonspectral interferences.

Artifacts↗

Using the spleen for time-delay correction of the input function in measuring hepatic blood flow with oxygen-15 water by dynamic PET.

By the spleen, we calculated a time-delay correction of the input function for quantitation of hepatic blood flow with oxygen-15 water and dynamic positron emission tomography. The time delay (deltat) between the sample site and the spleen was calculated based on nonlinear multiple regression analysis when splenic blood flow was determined. Then hepatic blood flow was quantified by a method using the input function and incorporating deltat, which was assumed to be equal to the time delay between the sample site and the liver. Then hepatic arterial and portal blood flows were estimated separately as well as the delay time for passage within the organs of the portal circulation. The mean coefficient of variation and the mean sum of squares of errors decreased to about 70% when total hepatic blood flow was calculated from the results for regions of interest in three slices of the same liver segment. We concluded that using the spleen for time-delay correction of the input function for measuring hepatic blood flow by this method gave satisfactory results.

Adult↗

Aquaporin-5 (AQP5), a water channel protein, in the rat salivary and lacrimal glands: immunolocalization and effect of secretory stimulation.

Aquaporin-5 (AQP5) is a water channel protein and is considered to play an important role in water movement across the plasma membrane. We raised anti-AQP5 antibody and examined the localization of AQP5 protein in rat salivary and lacrimal glands by immunofluorescence microscopy. AQP5 was found in secretory acinar cells of submandibular, parotid, and sublingual glands, where it was restricted to apical membranes including intercellular secretory canaliculi. In the submandibular gland, abundant AQP5 was also found additionally at the apical membrane of intercalated duct cells. Upon stimulation by isoproterenol, apical staining for AQP5 in parotid acinar cells tended to appear as clusters of dots. These results suggest that AQP5 is one of the candidate molecules responsible for the water movement in the salivary glands.

Adrenergic beta-Agonists↗

Two cases of inflammatory bowel disease with multiple myeloma.

A significant increase has been reported in reticuloendothelial neoplasms in patients with inflammatory bowel diseases. We present two rare cases of multiple myeloma in patients with inflammatory bowel diseases. One was in a 58-year-old woman with ulcerative colitis, and the other was in a 59-year old woman with Crohn's disease. In both patients, multiple myeloma occurred during long-term observation of inflammatory bowel disease and during the inactive stage of intestinal inflammation. The multiple myeloma appeared to have resulted from monoclonal gammopathy of undertermined significance in both patients, and was diagnosed by characteristic serum and bone marrow findings. Our findings suggested that multiple myeloma should be particularly considered in women of middle or advanced age with ulcerative colitis or Crohn's colitis and serum monoclonal gammopathy.

Female↗

Stimulation by low concentrations of fluoride of the proliferation and alkaline phosphatase activity of human dental pulp cells in vitro.

Fluoride has been used for decades, either systemically or topically, to prevent dental caries. The purpose of this study was to clarify the effects of low concentrations of fluoride on proliferation, differentiation and extracellular-matrix synthesis in normal human dental pulp cells (DP-1 and DP-2) in vitro. The effects were compared with those on a human osteoblastic osteosarcoma cell line, TE-85. Fluoride at micromolar concentrations significantly and dose-dependently stimulated [3H]thymidine incorporation into DNA in DP-1, DP-2 and TE-85 cells, with optimal effects around 50 microM, by 127 +/- 7%, 124 +/- 0.6% and 152 +/- 13.4%, respectively. To assess the potential influence of fluoride on cell differentiation, the effects of mitogenic concentrations on alkaline phosphatase activity were measured. Fluoride significantly increased the enzyme's activity in DP-1 and TE-85 by 177 +/- 12% and 144 +/- 12.3%. To evaluate the effect on extracellular-matrix synthesis, the synthesis of type I collagen was indirectly determined by an assay of procollagen type I c-peptide production. Fluoride significantly increased that production by 150 +/- 8.7% in TE-85, but not in either DP-1 or DP-2. These observations suggest that fluoride, if used at low concentrations, could be a useful therapeutic agent where increased regeneration of dentine is desired, such as after pulp amputation, by stimulating the proliferation and differentiation of the dental pulp cells.

Alkaline Phosphatase↗

Preliminary studies on hepatic carnitine palmitoyltransferase in dairy cattle with or without fatty liver.

The hepatic mitochondrial carnitine palmitoyltransferase (CPT) activity was measured by fluorimetric assay in dairy cows with or without fatty liver. CPT activities in 13 lactating cattle and in 6 non-lactating cows were 304.4+/-86.6 micromol CoA/min per g protein and 169.3+/-84.8 micromol CoA/min per g protein, respectively. This difference was significant (p < 0.05). CPT activities in early lactation (0-110 days after calving), mid-lactation (111-220 days after calving) and late lactation (over 220 days after calving) were 278.9+/-68.0, 312.4+/-124.1 and 320+/-59.3 micromol CoA/min per g protein, respectively. There was no significant difference between the values at different stages of lactation. The CPT activity in 10 lactating cows with fatty liver unrelated to calving was 201.3+/-80.0 micromol CoA/min per g protein. CPT activity in 10 cattle with fatty liver was significantly lower than that in normal lactating cattle. Based on these findings, clinical fatty liver unrelated to calving appears to be associated with a decrease in hepatic CPT activity.

Animals↗