Interaction between L-type Ca2+ channels and sarcoplasmic reticulum in the regulation of vascular tone in isolated rat small arteries

A dysfunction of the sarcoplasmic reticulum (SR) causes an increase in the myogenic tone of rat skeletal muscle small arteries (A(SK)), but not that of mesenteric small arteries (A(MS)). We hypothesized that the difference depends on the activity of voltage-dependent Ca2+ channels in these vessels. To test this, we measured the membrane potential of these vessels and examined ryanodine-induced constrictions by manipulating the activity of voltage-dependent Ca2+ channels. The isolated vessels were cannulated to control the transmural pressure. To assess the vascular tone, the inner diameter was measured with a video-digitizing system. The membrane potential of A(SK) was more depolarized between 20 to 100 mm Hg of transmural pressure. A(MS) was not constricted by the Ca2+ channel agonist Bay K 8644 (1 nM(-1) microM) alone, but substantially constricted in the presence of ryanodine (1 microM). Ryanodine also augmented the KCl (20 mM)-induced constriction. In A(SK), the Ca2+ channel blocker nisoldipine fully dilated the ryanodine-induced constriction: however, the ryanodine-induced constriction was less susceptible to nisoldipine than was the myogenic and phenylephrine-induced constriction caused mainly by increased Ca2+ influx. In conclusion, the contribution of the SR function to Ca2+ metabolism depends on the activity of dihydropyridine-sensitive Ca2+ channels. The dysfunction of SR by ryanodine may impair the Ca2+ extrusion rather than increase Ca2+ influx in rat small arteries.     

Application of Ultramicrotechnique for the Diagnosis of Hereditary Metabolic Diseases

Two methods of microdetermination, enzymatic cycling and microscopic fluorometry, have been applied for the diagnosis of lysosomal diseases. A new assay method of galactocerebrosidase was developed by using the NAD cycling procedure. It was reproducible and even more sensitive than the radioassay method currently in use, and the enzyme deficiency was confirmed in the tissues from two patients and a fetus with Krabbe's disease. A microassay method of lysosomal enzymes on single fibroblasts was also established by microscopic fluorometry. With this technique a successful result of prenatal diagnosis was reported on a high risk fetus for G_M1-gangliosidosis. The basic and clinical significance of these micromethods was discussed.     

The efficacy of technetium-99m-MIBI scan and intraoperative methylene blue staining for the localization of abnormal parathyroid glands

(Received for publication on Jan. 21, 1998; accepted on July 7, 1998)     

Regulation of estrogen receptor and epidermal growth factor receptor by tamoxifen under high and low estrogen environments in MCF-7 cells grown in athymic mice

The purpose of this study was to investigate whether tamoxifen (TAM) treatment causes a downregulation of estrogen receptor (ER) and whether TAM induces epidermal growth factor receptor-1 (EGFR). We investigated the expression of ER and EGFR after the treatment of TAM in MCF-7 tumors grown in athymic mice under high and low estrogen environments. MCF-7 tumors were grown in ovariectomized athymic mice by implanting a sustained release 17beta-estradiol (E2) pellet. The E2 pellets were removed after 3 weeks of E2 treatment. Animals were then divided into the following 4 groups: i) an E2 (0. 72 mg/pellet) pellet [E2(+)]; ii) an E2 and a TAM (5 mg/pellet) pellets [E2(+)TAM]; iii) no treatment [E2(-)]; iv) a TAM pellet [E2(-)TAM]. A significant reduction in tumor size was observed in the estrogen-depleted group [E2(-) and E2(-)TAM] compared with the estrogen-completed group [E2(+) and E2(+)TAM]. TAM inhibited estrogen-stimulated growth in the estrogen-completed mice. No additional reduction of the tumor by TAM was observed in the estrogen-depleted mice. Both ER and EGFR protein levels in the tumors of the estrogen-depleted mice were higher than in the estrogen-completed mice. Expression of ER and EGFR protein was increased by TAM in the estrogen-completed mice, however it was decreased by TAM in the estrogen-depleted mice. Changes of ER and EGFR protein levels were similar in all treatments. Transforming growth factor-alpha (TGF-alpha) in tumors, which is known as a ligand of EGFR and as an estrogen-inducible protein in ER positive MCF-7 cells, was decreased by TAM in the estrogen-completed mice, by contrast, it was increased by TAM in the estrogen-depleted mice. Downregulation of ER was observed in TAM-treated mice in an estrogen-depleted environment, this action of TAM was similar to E2. These results suggest that increase of EGFR expression does not lead to a loss of ER after short-term TAM treatment in MCF-7 tumors.     

Effectiveness of combined interleukin 2 and B7.1 vaccination strategy is dependent on the sequence and order: a liposome-mediated gene therapy treatment for bladder cancer.

We have developed a novel liposome-mediated immunogene therapy using interleukin 2 (IL-2) and B7.1 in a murine bladder cancer model. A carcinogen-induced murine bladder cancer cell line, MBT-2, was transfected with cationic liposome 1,2-dimyristyloxypropyl-3-dimethyl-hydroxyethyl ammonium bromide/dioleolylphosphatidylethanolamine and IL-2 plasmid. The optimized transfection condition generated IL-2 levels of 245-305 ng/10(6) cells/24 h, 100-fold higher than the levels seen with retrovirus transfection. Ninety percent of the peak level of IL-2 production was maintained for up to 11 days after transfection. Animal studies were conducted in C3H/HeJ female mice with 2 x 10(4) MBT-2 cells implanted orthotopically on day 0. Multiple vaccination schedules were performed with i.p. injection of 5 x 10(6) IL-2 and/or B7.1 gene-modified cell preparations. The greatest impact on survival was observed with the day 5, 10, and 15 regimen. Control animals receiving retrovirally gene-modified MBT-2/IL-2 cell preparations had a median survival of 29 days. Animals receiving the IL-2 liposomally gene-modified cell preparation alone had a median survival of 46 days. Seventy-five percent of animals receiving IL-2 followed by B7.1 gene-modified tumor vaccines were the only group to show complete tumor-free survival at day 60. All of these surviving animals rejected the parental MBT-2 tumor rechallenge and survived at day 120 with a high CTL response. In conclusion, liposome-mediated transfection demonstrates a clear advantage as compared with the retroviral system in the MBT-2 model. Multi-agent as opposed to single-agent cytokine gene-modified tumor vaccines were beneficial. These "targeted" sequential vaccinations using IL-2 followed by B7.1 gene-modified tumor cells significantly increased a systemic immune response that translated into increased survival.     

Sudden hemorrhage of the breast caused by breast cancer: a case report and review of the literature

A rare case of sudden hemorrhage caused by breast cancer is reported. A 71-year-old woman noted bleeding from her left breast. Physical examination of the left breast showed a localized open cavity accompanied by bleeding and coagulation. The patient had no history of breast trauma or anticoagulation therapy. Incisional biopsy followed by histological examination resulted in a diagnosis of granulation tissue with no cancer cells present. Mammography and ultrasonography indicated probable breast cancer. As a result, a second incisional biopsy was performed, which suggested invasive ductal carcinoma without histological skin invasion. A modified radical mastectomy was performed under a diagnosis of stage II breast cancer. Breast cancer with sudden hemorrhage is rare. We review the literature and discuss the cause of this unusual manifestation.     

A case report of advanced male breast cancer with an objective response to tamoxifen treatment

A 70-year-old man presented with a firm tumor in his right breast first noticed eight years ago.The tumor had enlarged gradually and had produced an ulcer with bleeding. On physical examination, a huge tumor entirely occupied the right breast and extensively had infiltrated the chest wall.Chest X-ray and CT showed massive pleural effusion and multiple small nodular lesions in the lung. Invasive ductal carcinoma of the breast was diagnosed by incisional biopsy,confirming advanced breast cancer with lung metastases and bilateral pleural effusion(T4cN2M1, Stage IV). Because ER and PgR levels were 110 fmol/mg and 190 fmol/mg, respectively, and because his general condition was poor, we selected medical treatment with tamoxifen(TAM). Thirty-two weeks later, the tumor had showed pronounced reduction with scarring. The patient underwent local excision of the scar tissue. The quality of life of the patient was favorably improved and no severe adverse events were observed. The tumor in the chest wall recurred two months after the end of TAM treatment, possibly because the patient did not accept continuous TAM therapy. The patient died from complications of brain metastasis 32 months after the start of TAM treatment. We report a rare case of advanced male breast cancer and on the effectiveness of continuous TAM treatment.     

Survivin associates with cell proliferation in renal cancer cells: regulation of survivin expression by insulin-like growth factor-1, interferon-gamma and a novel NF-kappaB inhibitor

Although survivin has been widely recognized as an attractive target for cancer therapy, the exact mechanism regarding the regulation of survivin and its effect on cell proliferation have yet to be clearly defined in renal cell carcinoma (RCC). We investigated herein the association between survivin expression and cell proliferation in a RCC cell line, KU19-20. In KU19-20 cells, cell proliferation and survivin expression were significantly induced by IGF-1, whereas they were inhibited by a novel NF-kappaB inhibitor dehydroxymethyl-epoxyquinomicin (DHMEQ) and IFN-gamma. The combination of DHMEQ and IFN-gamma inhibited cell proliferation synergistically with a pronounced attenuation of survivin expression. Furthermore, treatment with survivin-specific siRNA reduced expression of survivin and significantly inhibited cell proliferation. Survivin expression was thus associated with cell proliferation in KU19-20 cells. The regulation of survivin by IFN-gamma and/or an NF-kappaB inhibitor may therefore be a potential treatment modality for RCC.     

G3139 induces cell death by caspase-dependent and -independent apoptosis on human melanoma cell lines

G3139 is an 18-mer phosphorothioate oligodeoxynucleotide (ODN) which has been targeted on the initiation codon region of the bcl-2 gene. Currently, clinical trials on G3139 for diverse tumors are underway in phase II and phase III. However, basic investigations of bcl-2 antisense ODN (G3139) and reverse ODN (G3622) have not been fully examined. In this report, we investigate cell death caused by G3139 and G3622 and the impact of antisense ODN in melanoma cell lines. We confirmed that G3139 reduced the level of bcl-2 protein and both G3139 and G3622 inhibited cell proliferation and induced apoptosis. G3139 was noted to produce a more intense effect than G3622. Although the general caspase inhibitor, Z-VAD-fmk, prevented apoptosis incompletely, the inhibition ratio of both ODNs was approximately equivalent. Our results suggested that inhibition of cell proliferation by ODNs is produced by apoptosis, but that the apoptotic pathway is not fully induced by the caspase-dependent pathway. Upon examination of the intracellular apoptotic protein dynamics, AIF localized within the mitochondria was translocated to the cytosol within 24 h, and subsequently to the nuclei after 48 h of treatment with G3139. Our results imply the following: the transfection of ODNs can induce apoptosis, the anti-tumor effect of G3139 is better than G3622, and the difference in the anti-tumor effect is specifically based upon the reduction of expression of the target DNA in malignant tumors. We consider that antisense ODNs may be an important tool for anti-tumor chemotherapy and the targeting of specific DNA is important in enhancing the anti-proliferative effect against tumors.     

Early breast cancer

Breast cancer remains a common disease throughout the world. Here we review new knowledge about early breast cancer obtained during the past 5 years. The prognosis of early breast cancer is generally favorable. Especially, ductal carcinoma in situ has been regarded as a non-life-threatening disease. Therefore, early diagnosis and early onset of the treatment has been important. Early age at menarche, late age at first birth, and late age at menopause are related to breast cancer risk. Examination by mammography and ultrasonography is still the most effective means of detection for premenopausal and postmenopausal women, respectively. Additionally, there have been important advances in MRI, sentinel lymph node biopsy, breast-conserving surgery, partial breast irradiation, neoadjuvant systemic therapy, and adjuvant systemic therapy. Another approach to keeping the disease under control is the elucidation of breast cancer's molecular biological features. Assessment of potential molecular targets can lead to early diagnosis and molecular targeted treatment.