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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

1,202 records · Page 67Linked to original sources
PubMedDate not supplied

Impact of aging and diabetes mellitus on the expression of the proliferating cell nuclear antigen in rat testicular tissue.

This study evaluated the expression of proliferating cell nuclear antigen (PCNA), which is one of the important markers of cell proliferation, in testicular tissue with aging and progress of diabetes mellitus (DM). OLETF rats were used as animal models for non-insulin-dependent DM. They were 12, 30, 50, and 70 weeks old. The controls were age-matched nondiabetic LEIO rats. Testes were taken from all the rats and paraffin-embedded sections were cut and stained with PC 10 monoclonal AB (x50). Labeled cells were assessed in randomly selected fields. Labeling index (LI) for each stage of spermatogenesis was estimated and total LI for each specimen was calculated. In control rats, the 12-week-old animals showed the highest PCNA-LI. The indexes started to decrease in other older animals, with an increase in the number of suppressed stages as the animals aged, leading to significant differences among groups except between the 12- and 30-week-old groups. The same features were also seen in DM animals as the disease progressed. The total LI of controls were significantly higher and the number of suppressed stages was lower than those of DM animals, except among the 12-week-old group. Both aging and DM have depressing effects on the expression of PCNA in testicular tissue. The decline in PCNA expression is parallel with advancement of age and progress of DM. However, DM has a more suppressing effect than aging on that expression. This suppression could explain the decrease in male fertility potential that may be associated with both conditions.

Aging↗
PubMedDate not supplied

Na+,K+-ATPase inhibitors in rat urine: origins and physiological significance.

To identify the origins and structures of mammalian tissue-derived Na+,K+-ATPase inhibitors, we investigated the tissue distribution of inhibitors in rats. Among many tissues tested, urine was found to contain high levels of many inhibitors. The structures of the two major inhibitors were identified as neoconvalloside and periplogenin monorhamnoside, which are derivatives of strophanthidin. Urinary levels of these inhibitors, however, decreased considerably after changing the diet from the regular diet to purified synthetic diet, suggesting that the majority of the urinary inhibitors are of dietary origin. Investigation of the ingredients of the diet further revealed that alfalfa meal and ground oats are the major sources of these cardiac glycosides. As to the physiological relevance of the cardiac glycosides, a low concentration (1-50 nM) of ouabain dose-dependently enhanced aldosterone secretion from adrenal glomerulosa cells by an increase in local renin release. Ouabain was also found to be involved in AT2 receptor-specific expression in rat PC12W cells through an increment in intracellular Na+. These results suggest that Na+,K+-ATPase inhibitors, regardless of the source, are involved in the regulation of blood pressure.

Aldosterone↗
PubMedDate not supplied

Plasma VEGF concentration can predict the tumor angiogenic capacity in non-small cell lung cancer.

We assessed the clinical utility of circulating angiogenic factors as a predictor for tumor angiogenesis in primary lung cancer. Circulating vascular endothelial growth factor (VEGF) and intratumoral VEGF were assessed by enzyme-linked immuno-sorbent assay (ELISA). There was a significant increase in the mean value of both plasma and serum VEGF concentration in primary lung cancer patients (n=97) compared to those of healthy controls (n=59). There was a significant correlation between plasma VEGF levels and microvessel density (MVD), and also between plasma VEGF and intratumoral VEGF levels. Plasma VEGF in patients with lung cancer appears to be a useful indicator of tumor angiogenesis.

Adult↗
PubMedDate not supplied

A case of undifferentiated carcinoma of the gallbladder with anomalous arrangement of the pancreaticobiliary ductal system.

Anomalous junction of the pancreaticobiliary duct (AJPBD) is a congenital anomaly associated with gallbladder carcinoma. Especially patients with noncystic dilatation and without dilatation of the biliary tract are at risk of gallbladder carcinoma. A 56-year-old woman with advanced gallbladder cancer associated with AJPBD but without dilatation of the biliary tract was treated at our hospital. Although histologically cancer cells remained in the layer of the proprial mucosa, extensive metastases to lymph nodes including the paraaorta and peripancreas were detected. According to the TNM classification this case was of Stage IVB. The cancer consisted of medullary round cells, and was diagnosed as undifferentiated carcinoma. After surgery poor prognosis was expected, but three years have elapsed with no recurrence. The case is of interest because of two points of discrepancy: the primary cancer did not show deep invasion but demonstrated extensive lymph node metastases; the cancer was histologically malignant but prognosis was relatively good.

Bile Ducts↗
PubMedDate not supplied

A new spectroscopic approach to cardiac energy metabolism.

The optical characteristics of the hemoglobin-free perfused rat heart have been examined in detail. For dual-wavelength spectrophotometry, absorption pairs at 605-620 nm and 587-620 nm are found to be suited for the investigation of the oxidation-reduction changes of cytochrome aa3 and oxygenation-deoxygenation of myoglobin in cardiac tissue. Techniques by which the absorption changes of myoglobin and cytochrome aa3 can be measured during one cycle of contraction-relaxation are presented. The results demonstrate that, in the aerobic state, myoglobin is more oxygenated during the systolic and diastolic periods and deoxygenated in the resting period, whereas cytochrome aa3 is more reduced in the systole and diastole and oxidized in the resting period.

Aerobiosis↗
PubMedDate not supplied

Cytotoxic and DNA damage-inducing activities of low molecular weight phenols from rhubarb.

Six new phenol (anthraquinone or stilbene) glycosides with an acyl group at 6-position of the glucopyranose moiety were isolated from rhubarb (the roots of Rheum palmatum) cultivated in Japan, together with 22 known compounds. Most of these compounds were evaluated for cytotoxic activity against tumor and normal cells and for induction of DNA damage by spore rec-assay. Among them, emodin and aloe-emodin showed higher cytotoxic activities against human oral squamous cell carcinoma (HSC-2) and salivary gland tumor (HSG) cell lines than against normal human gingival fibroblasts (HGF). Chrysophanol 8-O-beta-(6'-acetyl)glucopyranoside, 4-(4'-hydroxyphenyl)-2-butanone 4'-O-beta-D-(2"-O-galloyl-6"-O-cinnamoyl) glucopyranoside, and 6"-O-(4'''-hydroxybenzoyl) resveratroloside exhibited relatively higher cytotoxic activities against all these cells. The other glycosides of anthraquinone or stilbene showed weaker cytotoxic activity against these tumor cell lines, but may be considered as cancer chemopreventive agents. Spore rec-assay with a recombination deficient mutant of Bacillus subtilis M45 demonstrated the DNA damage-inducing activity of emodin and aloe-emodin 15-O-beta-D-glucopyranoside among, rhubarb phenols.

Bacillus subtilis↗
PubMedDate not supplied

Evidence for the presence of fatty acid methyl esters in human hepatoma tissue from a patient with hypercholesterolemia.

The lipid composition of a human hepatoma tissue (liver cell carcinoma) was examined by thin-layer chromatography (TLC), and an unusual lipid spot was found in a large quantity. It was identified as consisting of fatty acid methyl esters by TLC and gas chromatography-mass spectrometry techniques. In the fatty acid methyl ester fraction, oleate (18:1) and palmitate (16:0) were dominant. Furthermore, very unusual fatty acid methyl esters, such as methyl 2-methyl oleate, were detected. These unusual lipids could be detected neither in cirrhotic lesions of the host liver nor in normal control tissues.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Nasal continuous positive airway pressure following surfactant replacement for the treatment of neonatal respiratory distress syndrome.

To evaluate whether nasal continuous positive airway pressure (N-CPAP) could be an alternative to ventilator treatment in infants with severe respiratory distress syndrome (RDS) after surfactant treatment, we performed the trial on 15 newborn babies with birth weight > or = 1500 g. All babies were put on N-CPAP as soon as the diagnosis of RDS was established. The N-CPAP system that we used in this study consisted of no ventilator. When FiO2 > or = 0.7 was required for maintaining PaO2 > 50 mmHg, surfactant treatment was decided. After the tracheal instillation of surfactant (120 mg/kg body weight), the babies were randomly assigned into 2 groups. In the ventilator group (n = 7), the babies were connected to mechanical ventilation following surfactant instillation. In the N-CPAP group (n = 8), the babies were extubated immediately after instillation of surfactant and were connected to N-CPAP. There was a marked improvement in the ratio of arterial PO2 to alveolar PO2 (a/A PO2) immediately following surfactant treatment and the effect was sustained during the study period of 72 hours in both groups. No significant differences in a/A PO2 were noted in 2 groups. There was a significantly higher PaCO2 in the N-CPAP group than in the ventilator group. PaCO2 declined significantly in the ventilator group 8 hours after surfactant treatment. A delayed decline in PaCO2 until 48 hours after surfactant instillation in the N-CPAP group was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Dioxide↗
PubMedDate not supplied

Liveborn twin with intrauterine death of one twin: report of two cases.

Twin pregnancies carry a greater mortality and morbidity rate than singleton pregnancies. In case of an intrauterine fetal death (IUFD), the risk of mortality and morbidity of the surviving twin is increased. The pathogenesis is usually due to twin to twin transfusion. The donor twin is hypovolemic, anemic and often shows a growth retardation or even severe enough to cause an IUFD. The recipient twin is hypervolemic, polycythemic and weighs more than its co-twin. In this paper we reported two cases of liveborn twin complicated by an IUFD of its co-twin. Both cases were monochorionic twins. The first case was born at 29 weeks and 6 days of gestation, a male infant weighed 1054 g. His co-twin was stillborn and weighed 722 g. At birth the surviving infant showed respiratory distress syndrome (RDS), anemia and bilateral periventricular echogenicity (PVE). The second case was a female infant with a gestational age of 26 weeks and 2 days and weighed 850 g. Her stillborn co-twin weighed 804 g. Both twins showed signs of hydrops, and the liveborn infant had RDS, marked anemia (Hb 6 g/dl) and hypoalbuminemia. We will discuss the possible pathogenesis in our cases and also review some literature.

Echoencephalography↗
PubMedDate not supplied

Comparative study of the effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on generation and mobilization of neutrophils in cyclophosphamide-treated neutropenic mice.

To examine the differential in vivo effects of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the recovery from neutropenia caused by chemotherapy, we directly compared the actions of these CSFs on neutrophil count in the bone marrow, spleen, and peripheral blood of mice treated with an anticancer drug, cyclophosphamide (CPA). Both G-CSF and GM-CSF stimulated the generation of neutrophils in bone marrow, but GM-CSF is only about 1/20 as effective as G-CSF. Both CSFs also stimulated the release of the generated neutrophils therefrom. G-CSF mobilized the neutrophils into both the circulation pool and the marginal pool, and these neutrophils were able to migrate into the inflammatory site when stimulated by casein. On the other hand, GM-CSF mobilize the neutrophils into the marginal pool but not the circulation pool, and they were not able to migrate into the inflammatory site. These findings indicate that G-CSF physiologically plays an important role as a factor which stimulates neutrophil mobilization from bone marrow into circulation as well as neutrophil generation in the bone marrow.

Animals↗
PubMedDate not supplied

Granulocyte colony-stimulating factor shortens the optimal interval of repetition of chemotherapy with cyclophosphamide in mice.

To examine the effect of human granulocyte colony-stimulating factor (G-CSF) on the hemopoietic response to repeated treatment with the anticancer drug cyclophosphamide (CPA) in mice, we determined the optimal time interval between CPA doses which was required to equalize the recovery of neutrophils in the first and second cycle. G-CSF-treatment significantly shortened the optimal time interval of CPA doses when compared with treatment with the control vehicle. The studies on resistance to a second CPA cycle and hemopoietic parameters indicated that the resistance correlated positively with the granulocyte colony-forming cel (G-CFC) population in marrow, in both control and G-CSF-treated mice. In G-CSF-treated mice, moreover, the resistance correlated positively with the ratio of G-CFC in proliferative state and negatively correlated with the neutrophil levels in peripheral blood. These results suggest that G-CSF shortens the optimal time interval between CPA doses not only by accelerating the recovery of G-CFC but also by affecting the hemopoietic environment.

Animals↗