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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 451 records · Page 25Linked to original sources
PubMed1995

Recombinant human erythropoietin stimulates tubular reabsorption of sodium in anesthetized rabbits.

To determine whether recombinant human erythropoietin (rHuEPO) exerts a direct vasoconstrictive effect on renal arteries or affects renal function, we measured renal hemodynamics and renal function during a 30-min intrarenal infusion of rHuEPO in anesthetized rabbits without renal failure. Intrarenal infusion of rHuEPO at a rate of 100 U/min did not alter mean arterial pressure, renal blood flow, or renal vascular resistance, as compared with controls treated with vehicle. There were no significant rHuEPO-associated changes in glomerular filtration rate, filtration fraction, or arterial hematocrit. However, urine volume, urinary excretion of sodium and potassium, and fractional sodium excretion were significantly reduced by intrarenal infusion of rHuEPO. These observations indicate that rHuEPO has no direct effects on mean arterial pressure or renal hemodynamics, but that it stimulates net tubular sodium reabsorption, and reduces urine volume and urinary excretion of sodium and potassium in anesthetized rabbits without renal failure.

Animals↗
PubMed1995

Canine plasma erythropoietin levels in 124 cases of anemia.

Erythropoietin (EPO) levels in plasma from 124 clinically anemic dogs were determined by in vivo bioassay. In 81 anemic dogs with normal renal function, the concentration of plasma EPO showed a close correlation with the hemoglobin concentration. The plasma EPO level was obviously decreased in 43 anemic dogs with renal failure. Of these dogs with renal failure, 17 showed no detectable plasma EPO and resulted in the death of these dogs. In the remaining 26 dogs having detectable plasma EPO, the plasma concentration rate of EPO related to blood urea nitrogen and serum creatinine values.

Anemia↗
PubMed1995

Changes in skeletal muscle composition in response to swimming training for young horses.

To investigate muscular adaptation to swimming training in young horses, 18 two-year-old Thoroughbred horses were trained in a program which included both running and swimming, and the changes in skeletal muscle composition during the training period were evaluated histochemically. The horses were divided into the following three groups; Group A, trained by running only: Group B, trained by running plus a gradual increase in swimming; Group C, trained by running plus constant swimming. In Groups B and C, fast twitch-low oxidative (FT) fibers tended to decrease, while fast twitch-high oxidative (FTH) fibers to increase with the training progressed. The tendency was more remarkable in Group B. Therefore, in these two groups, it was suggested that the horses' aerobic capacity at the muscular level was improved significantly.

Aging↗
PubMed1995

Preventive effects of recombinant human erythropoietin administration on anemia associated with repeated hemodialysis in nephrectomized dogs.

The preventive effects of recombinant human erythropoietin (rhEPO) administration on progression of anemia were evaluated during hemodialysis in nephrectomized dogs. In control dogs given no rhEPO, anemia gradually progressed with repeated hemodialysis and with little erythropoietic response observed in the bone marrow. In dogs administered with rhEPO, however, an active erythropoietic response was induced in the bone marrow, indicating that anemia due to hemodialysis was being prevented.

Anemia↗
PubMed1995

Prediction of early development of chronic nonrheumatic atrial fibrillation.

The purpose of this study was to identify predictors of development of chronic nonrheumatic atrial fibrillation within one year of onset, thereby minimizing the risk of embolic complications and death. We retrospectively studied 137 patients with new-onset nonrheumatic atrial fibrillation. Chronic atrial fibrillation developed in 30 patients at the end of one year (chronic group). Atrial fibrillation remained paroxysmal in 107 patients (paroxysmal group). Clinical characteristics, electrocardiograms, and echocardiograms at the time of the onset of atrial fibrillation were compared in the two groups. Patients in the chronic group were significantly older than patients in the paroxysmal group (70.1 +/- 8.2 vs. 62.4 +/- 11.0 years, p < 0.01) and had a significantly higher incidence of congestive heart failure (13% vs. 3%, p < 0.05) and diabetes mellitus (37% vs. 19%, p < 0.05). The chronic group also exhibited higher cardiothoracic ratio (52.0 +/- 5.7% vs. 47.6 +/- 5.0%, p < 0.01), greater f-wave amplitude in lead V1 (1.48 +/- 0.91 vs. 1.06 +/- 0.45 mm, p < 0.05), larger left atrial dimension (41.0 +/- 6.4 vs. 34.2 +/- 7.6 mm, p < 0.01), and lower left ventricular ejection fraction (71.4 +/- 5.6% vs. 75.5 +/- 8.2%, p < 0.05). The presence of four or more of the following seven factors strongly predicted the development of chronic nonrheumatic atrial fibrillation within one year (88% to 100%): age > or = 65 years, congestive heart failure, diabetes mellitus, cardiothoracic ratio > or = 50%, f-wave amplitude > or = 2.0 mm, left atrial dimension > or = 38 mm, and ejection fraction < or = 76%.

Adult↗
PubMed1995

Fine structure of the parotid gland in tree shrew (Tupaia glis).

The parotid glands of Tupaia glis were examined by light and transmission electron microscopy. The acinar cells were seromucous in nature, and contained many acidophilic granules with strong affinity for periodic acid-Schiff (PAS) and weak affinity for alcian blue (AB). These granules consisted of a fine granular matrix of moderate density in which a denser corpuscles or semilunar materials were present. Intercalated duct cells had a few fine vesicles, vacuoles and very few dense granules in the apical region. In occasional epithelial cells, acidophilic, PAS-positive and AB-negative bodies with moderate density were observed in the supranuclear region. The striated ducts consisted of columnar light and dark cells containing round or small ovoid granules of moderate density and did not show the granular duct as seen in the parotid glands of kobe mole and tenrec which are placed in the order insectivora.

Alcian Blue↗
PubMed1995

Long-term follow-up of patients with a history of near fatal episodes; can inhaled corticosteroids reduce the risk of death from asthma?

We retrospectively studied the use of inhaled corticosteroids in patients who experienced near fatal episodes (NFE) to determine whether such therapy reduces the risk of death. Forty-eight patients who had near fatal episodes of asthma between January 1981 and December 1989 were divided into two groups. Group A comprised 19 patients who received beclomethasone dipropionate (BDP) daily (mean dose of BDP:687 micrograms/day: 200-2,000) following NFE, and Group B, 28 patients who did not take BDP or who took less than 6 mg BDP/month. During the follow-up period (Group A:82.9 months, Group B:66.2 months), no patients in Group A died, but eight deaths occurred in Group B (mean period between near fatal episode and death was 31.5 months: 12-66). These results suggest that the regular use of inhaled corticosteroids, even at low doses, may reduce the risk of death in patients who experience NFE.

Acute Disease↗
PubMed1995

In vitro studies of human choroidal endothelial cells.

Vascular endothelial cells play an important role in progression or healing of various retinal or choroidal diseases and they have a broad organ specificity. We have grown and studied human choroidal endothelial cells (CECs) cultured in a collagen gel, where they form tube-like structures. CECs were differentially isolated from choroidal tissues and cultured to near homogeneity. The cells were embedded in a type I collagen gel in 24-well culture dishes and incubated with M199 medium containing 10% fetal calf serum. Gels were observed using phase contrast microscopy and were evaluated histologically by light and electron microscopy. The CECs were strongly positive for factor VIII-related antigen and actively ingested diI-acetylated LDL, indicating their endothelial nature. Ultrastructural analysis of the tube-like structures revealed a central lumen surrounded by cells joined apically by junctions and showing prominent pinocytotic activity, fenestrations and basement membrane formation; these features are typical of CECs in vivo. This preparation should be a useful tool to study the development of physiology and pathology of choroidal endothelium.

Carbocyanines↗
PubMed1995

Thrombin induced cytoskeletal change in cultured bovine corneal endothelial cells mediated via protein kinase C pathway.

We studied the participation of the protein kinase C pathway in thrombin-induced cytoskeletal alterations in confluent cultured bovine corneal endothelial (BCE) cells. Cultured BCE cells were exposed to alpha-thrombin (0.1-10 U/ml for 15-60 min) and the distribution of F-actin and vinculin plaques was examined using immunofluorescent staining and electron microscopy. Phorbol 12-myristate 13-acetate (PMA, 10 nM for 15 min), the broad spectrum protein kinase inhibitors staurosporine (10 nM) and H-7 (10 nM), and highly specific PKC inhibitor calphostin C (10 nM) were used to evaluate the role of PKC/phosphorylation in this phenomenon. HA-1004 (10 nM) was used as a negative control for these inhibitors. In a parallel experiment, PKC activity of cytosol and membrane of BCE cells was also evaluated. In control samples, F-actin was distributed mainly at the periphery of cells, where it formed dense peripheral bundles; vinculin plaques were also present at the cell boundary. Exposure of BCE cells to thrombin changed the distribution of F-actin and vinculin into a diffuse pattern; a similar alteration was also induced by incubation with PMA. These phenomena were blocked by incubation with H-7, staurosporine and calphostin C. Both cytosolic and membrane PKC activity was increased after 5 to 30 min exposure of alpha-thrombin and returned to the control level after 1 h. alpha-Thrombin induces alteration in the cytoskeleton of BCE cells, and this message is transduced at least in part by PKC dependent pathways. PKC/phosphorylation may thus play an important role in physiological processes that involve alterations of the cytoskeleton.

Actins↗
PubMed1995

[Comparative clinical study of azithromycin with tosufloxacin tosilate in the treatment of acute odontogenic infection].

To objectively assess azithromycin (AZM) for its clinical efficacy, safety and usefulness in the treatment of acute odontogenic infections (periodontitis, pericoronitis and osteitis of the jaw), a double-blind, randomized, multi-center trial was conducted in which tosufloxacin tosilate (TFLX) was used as the control drug. AZM was administered to 90 patients at a once-daily 500 mg dose for 3 days, while TFLX was given to 90 patients at a 150 mg t.i.d. dose for 7 days. 1. The clinical efficacy rates calculated according to evaluation at an endpoint set on the 3rd day of treatment by a committee of experts were 85.9% (73/85) in the AZM group and 78.9% (71/90) in the TFLX group. No statistically significant difference between the treatment groups was detected, and clinical equivalence was verified (p = 0.002). 2. The clinical efficacy rates according to evaluations made by investigators at the end-of-tail point was 87.1% (74/85) in the AZM group and 73.3% (66/90) in the TFLX group. The efficacy rate in the AZM group was higher than that in the TFLX group, and the difference was statistically significant (p = 0.006). 3. The bacteriological elimination rate in the AZM group was 97.5% (39/40) and that in the TFLX group was 85.7% (30/35), but the difference was deemed statistically not significant. 4. Adverse reactions were observed in 11 of 88 cases (12.5%) in the AZM group and 5 of 90 cases (5.6%) in the TFLX group. Six of 85 cases (7.1%) in the AZM group and 5 of 85 cases (5.9%) in the TFLX group showed laboratory abnormalities. However, neither adverse reactions nor laboratory abnormalities showed any differences in statistical significance between the treatment groups. 5. The safety rates, expressed as percentages of cases with no adverse events and no laboratory abnormalities, was 84.1% (74/88) in the AZM group and 90.0% (81/90) in the TFLX group. The difference between the two groups was found to be statistically insignificant. 6. The usefulness rates, the ratio of cases rated as either "Very useful" or "Useful", was 83.9% (73/87) in the AZM group, and it was statistically higher (p = 0.025) than 72.2% (65/90) obtained for TFLX group. Judging from the above results, it has been concluded that AZM is as useful as TFLX in the treatment of acute dental infections.

Adolescent↗
PubMed1995

[The solubility of calcium pyrophosphate dihydrate crystals].

The solubility of calcium pyrophosphate dihydrate crystals (CPPD crystals), which cause pseudogout, was studied in vitro and vivo. The in vitro experiment using 0.1 M tris buffer and 0.2 M glycine buffer indicated that changes in pH and pyrophosphatase activity played a major role in the solubility of CPPD crystals. An experiment using the synovial fluid from patients with pseudogout, rheumatoid arthritis, and from those with osteoarthritis suggested that changes in the synovial fluid pH due to inflammation affected the solubility of these crystals. In addition, an experiment using the air pouch in rat showed that inflammation due to the CPPD crystals was maximum at about 9 hours after CPPD injection, and that inflammatory cells appearing at this time then had a major influence on the crystals' solubility. From these results, it appeared that CPPD crystals released into the joint cavity were mostly dissolved by inflammatory cells, but that crystal dissolution was also affected by changes in the synovial fluid itself, particularly by a change in pH.

Animals↗
PubMed1995

[Arterial ageing of aorta and atherosclerosis--with special reference to elastin].

Ageing of the arterial wall is defined as the age-related structural and functional changes in arteries. These changes include distension of the lumen, kinking of the artery, and rigidity of the arterial wall. Distension of the arterial luminal diameter with hardening of the arterial wall causes chronic ischemia in peripheral tissues, leading to age-related deterioration of the organs. The ensuing pathological modification in blood circulation is mainly linked to the decrease in the elastic recoil of the arteries and to the increasing difficulty of pumping systolic blood volume towards the periphery. This results in increased systolic blood pressure in the elderly and an increasing load on the ageing heart. Age-related changes in elastic arteries are characterized as degenerative changes in the SMCs of the media associated with depositions of collagen fibers and the fragmentation of elastic fibers. Data obtained from in vivo experiments indicate that the susceptibility of aged arteries to atherogenic stimuli might be related to intrinsic cellular changes with age. Substances that can regulate the function of vascular wall cells may be continuously present in the vessel walls, perhaps as components of super-extracellular matrix complexes. One type of substance is the functional domain structure of extracellular matrix molecules exposed to specific receptors or binding proteins on the surface of the cells. The role of extracellular matrices, especially elastin, on cultured vascular cells has been discussed.

Adult↗
PubMed1995

[Establishment of metastatic sub-clone from estrogen independent Ishikawa cells and its characterization in vitro and in vivo].

An estrogen (E) independent sub-clone (EIIL) was separated from a human endometrial carcinoma cell line, Ishikawa, by culturing the wild type under an E free condition for 350 days. The cells were then implanted into nude mice subcutaneously and tumors allowed to develop for 35 days. The primary lesions were then excised to stimulate recurrence. One animal developed recurrence with multiple distant metastases. The primary tumor and metastatic tumors from the animal were studied for ErbB-2 expression by immunohystochemical techniques or by a reverse transcription followed by polymerase chain reaction (RT-PCR). Expressions of epidermal growth factor (EGF) receptors, aromatase, nidogen, E receptors, hepatocyte growth factors (HGF) and beta-actin were also examined. The results showed that metastatic lesions expressed high levels of ErbB-2, nidogen and aromatase but unchanged levels of EGF receptors and HGF. The metastatic lesions expressed one third of the E receptors which were detected in the EIIL in vitro. These observations suggest that a decrease in ER along with increased expression of nidogen and aromatase is associated with the process of metastasis and the model appears to be of value in studying the process of the acquisition of a metastatic phenotype.

Animals↗
PubMed1995

[A case of tongue cancer effectively treated with tegafur].

We administered a slow-release formulation of tegafur (SF-SP) to a patient with cancer of the tongue. We would like to report the findings of this case which showed clear improvement. SF-SP was administered at 800 mg/day to a 58 year-old male for cancer of the tongue (T4N1). By the 17th day after the start of SF-SP administration, the tumor had shrunk, and by the 37th day the submandibular lymph nodes could not be located by touch. At the completion of the test on the 60th day, no cancer cells were detected. Following the completion of the test, there have been no symptoms of recurrence and a complete response was observed. At present, we are continuing administration of SF-SP and making observations.

Adenocarcinoma↗
PubMed1995

[Estramustine phosphate, estrogen conjugated with nitrogen mustard inhibits the growth of endometrial cancer cells in vitro].

Estra-1,3,5 (10)-triene-3,17-diol (17 beta)-, 3-[bis(2-chloroethyl) carbamate] (Estramustine EM) was tested for its anticancer effect on human endometrial cancer cell lines: Ishikawa and its estrogen (E) independent sub-clone EIIL (Estrogen Independent Ishikawa Line). The results showed: (1) EM inhibited growth of both cell lines in a dose dependent manner giving ID50 for Ishikawa as 12 microM and for EIIL as 65 microM. (2) The addition of EM to the culture medium caused cell detachment and death associated with a breakdown of DNA to approximately 90 base pair fragments. (3) Reverse transcription-polymerase chain reaction to examine expressions of c-erbB-2, nidogen and fas showed that EM completely abolished fas expression and resulted in a 40% decrease in nidogen expression in Ishikawa but not in EIIL. No change was seen in c-erbB-2 expression. The present data indicate that the E component of EM does not stimulate the growth of Ishikawa or EIIL. Since the growth of both cell lines was inhibited but apparently in an E receptor (ER) dependent manner, EM may be of value in an adjuvant therapy for endometrial cancer, especially an ER positive one.

Adenocarcinoma↗
PubMed1995

[Concurrent chemoradiotherapy followed by surgery for advanced stage III non-small cell lung cancer (NSCLC)].

Forty-two patients with stage IIIA (bronchoscopically T3 and/or bulky N2) and stage IIIB NSCLC were treated with concurrent chemoradiotherapy (CRT). Treatment consisted of CDDP, 20 mg/m2 and etoposide, 40 mg/m2 by continuous infusion (day 1-5) of weeks 1 and 5 simultaneously with chest radiotherapy (RT), 50 Gy, 2 Gy/Fx, 5 Fx/week. Surgery was attempted 3-5 weeks after RT in pts clinically downstaged. Between 10/90 and 12/92, 43 previously untreated pts were enrolled and 42 were eligible. Pts characteristics were: male/female = 37/5; mean age, 61 yrs (range, 31-74 yrs); stage IIIA/IIIB = 10/32; 15 adenocarcinoma, 24 squamous cell, 2 large cell, 1 unclassified; PS 0/1/2 = 11/24/7. Excluding 1 ineligible pts, 42 pts were evaluated for CRT response. The response rate was 81% (1 CR, 33 PR, 5 NC, 1 PD, 2 NE). Clinical downstaging was achieved in 20 pts (48%). Twenty-one pts (50%) received surgery and 19 of them were completely resected. In 7 resection specimens, no tumor was observed. Toxicity of CRT was well tolerable (Grade 4 leukopenia, 15%; Grade 2-3 esophagitis, 15%). We conclude that this intensive combined modality therapy is acceptable and appears to increase the response rate as well as resectability. Prospective randomized studies should be conducted for further evaluation of this treatment modality.

Adult↗