Functional analyses of lipocalin-type and hematopoietic prostaglandin D synthases

Prostaglandin (PG) D synthase (PGDS) catalyzes the isomerization of PGH(2) to PGD(2), which acts as an endogenous somnogen and an allergic mediator. There are two distinct types of PGDS: one is lipocalin-type PGDS (L-PGDS) localized in the central nervous system, male genitals, and heart; and the other is hematopoietic PGDS (H-PGDS) in mast cells and Th2 lymphocytes. L-PGDS is the same as beta-trace, a major protein in human cerebrospinal fluid, and is also secreted into the seminal plasma and plasma. The L-PGDS concentration in various body fluids is useful as a marker for various diseases such as renal failure and coronary atherosclerosis. H-PGDS is a cytosolic enzyme and is a member of the Sigma class of glutathione S-transferase. We determined the X-ray crystallographic structures of H-PGDS and L-PGDS. We also generated the gene-knockout (KO) mice and the human enzyme-overexpressing transgenic mice for each PGDS. L-PGDS-KO mice lacked PGE(2)-induced tactile allodynia and rebound of non-rapid eye movement sleep after sleep deprivation. Human L-PGDS-overexpressing transgenic mice showed an increase in non-rapid eye movement sleep due to accumulation of PGD(2) in the brain after tail clipping. H-PGDS-KO mice showed an allergic reaction weaker than that of the wild-type mice.     

A comparison between calcium channel blocking drugs with different potencies for T- and L-type channels in preventing atrial electrical remodeling

Calcium overload plays a key role in the development of atrial electrical remodeling. The effect of an L-type Ca channel blocker in preventing this remodeling has been reported to be short lasting, partly due to down-regulation of this channel and persisting Ca entry through the T-type Ca channel. To prove if efonidipine, a dual L- and T-type Ca channel blocker exerts a greater effect than an L-type Ca channel blocker verapamil, 21 dogs underwent rapid atrial pacing at 400 bpm for 14 days, pretreatment with efonidipine in 7 (E), verapamil in 7 (V), and none in 7 (C). We measured the atrial effective refractory period (ERP) serially during 14 days of rapid pacing. In response to rapid pacing, ERP decreased progressively in C. In contrast, in E and V, ERP remained greater than ERP in C (P < 0.01) on days 2 through 7. However, on the 14th day, ERP in V decreased to the level seen in C, whereas ERP in E remained significantly longer than ERPs in C or V (P < 0.01). The blockade L-type Ca channel alone is not sufficient, but the addition of a T-type Ca channel blockade shows a more sustained effect to prevent atrial electrical remodeling.     

Simvastatin enhances the regeneration of endothelial cells via VEGF secretion in injured arteries

The search for a novel therapy for endothelial regenerating is an area of intensive investigation. Recent experimental and clinical evidence strongly suggests that 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors (statins) have several physiological effects independent of low-density lipoprotein cholesterol reduction. We here report that the carotid arterial blood flow after endothelial injury in hamsters treated with simvastatin was restored, in contrast to the situation in nontreated hamsters. Histologic observations showed a prompt recovery of endothelial cells with a much higher DNA synthesis index in repaired endothelium of hamsters treated with simvastatin. The amount of secreted vascular endothelial cell growth factor (VEGF) by cultured vascular smooth muscle cells from hamsters treated with simvastatin was significantly increased. Mevalonate reduced the amount of VEGF secretion by simvastatin in vitro. Finally, an injection of either an anti-VEGF antibody or an anti-VEGF receptor-1 (Flt-1) antibody, but not anti-VEGF receptor-2 (Flk-1), reduced the prompt endothelial healing. Simvastatin regulates endothelial regenerating by an over-release of VEGF and by this may result in prompt endothelial healing after vascular injury. Our results provide new insights into the role of statin and VEGF in the pathogenesis of vascular diseases.     

IV-DSA is a new diagnostic tool for axillary lymph node metastasis in breast cancer patients

BACKGROUND AND OBJECTIVE: The aim of this study is to know whether intravenous digital subtraction angiography (IV-DSA) is useful to detect axillary lymph node metastasis of breast cancer and to evaluate the anigiogenesis of lymph nodes in the axilla. PATIENTS AND METHODS: Forty three primary breast cancer patients (N0: 26 cases, N1: 5 cases, N2: 2 cases) who underwent IV-DSA between January and November 2000 were included in the study. Infinix CB apparatus (Toshiba, Japan) was used to collect IV-DSA images and when a mass became stained in the axilla, it was considered to be metastatic. The angiogenesis was studied by examining microvessel density (MVD) after lymph node immunostaining for factor VIII. Primary tumor was detected by IV-DSA in all 43 cases. RESULTS: Axillary lymph node metastases were detected by IV-DSA in 34.9% of cases (15/43), and by pathology in 37.2% (16/43). The sensitivity, specificity, and accuracy of the diagnostic method were 75.0% (12/16), 88.9% (24/27), and 83.7% (36/43), respectively. MVD, calculated after immunostaining for factor VIII, was significantly lower in the in metastatic region of lymph nodes identified by DSA (88.5 +/- 35.0) than in metastasis-free lymph nodes (141.1 +/- 34.0, P < 0.0001). CONCLUSIONS: IV-DSA is useful in the diagnosis of axillary lymph node metastasis of breast cancer. Our results suggest that the primary factors involved in the mechanism of DSA display may be different from high/low MVC values.     

Cell growth inhibition and gene expression induced by the histone deacetylase inhibitor, trichostatin A, on human hepatoma cells

OBJECTIVE: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation in tumor cells. The effect of the HDAC inhibitor, trichostatin A (TSA), on hepatoma cells, however, has not been well studied. In this study, we examined cell viability and gene expression profile in hepatoma cell lines treated with TSA. METHODS: To study cell growth inhibition and induction of apoptosis by TSA on human hepatoma cell lines including HuH7, Hep3B, HepG2, and PLC/PRF/5, cells were treated with TSA at various concentrations and analyzed by the 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively. Changes in gene expression profile after exposure to TSA were assessed using a cDNA microarray consisting of 557 distinct cDNA of cancer-related genes. The levels of acetylated histones were examined by the chromatin immunoprecipitation (ChIP) assay using anti-acetylated histone H3 or H4 antibody. RESULTS: The MTT assay demonstrated that TSA showed cell growth inhibition not only in a concentration-dependent but also a time-dependent manner on all cell lines studied. The TUNEL assay also revealed the potential of TSA to induce apoptosis. The microarray analysis revealed that 8 genes including collagen type 1, alpha2 (COL1A2), insulin-like growth factor binding protein 2 (IGFBP2), integrin, alpha7 (ITGA7), basigin (BSG), quiescin Q6 (QSCN6), superoxide dismutase 3, extracellular (SOD3), nerve growth factor receptor (NGFR), and p53-induced protein (PIG11) exhibited substantial induction (ratio >2.0) after TSA treatment in multiple cell lines. ChIP assay, in general, showed a good correlation between the expression level of mRNA and levels of acetylated histones in these upregulated genes. CONCLUSIONS: This study showed cell growth inhibition and the gene expression profile in hepatoma cell lines exposed to TSA. The alteration in levels of acetylated histones was closely associated with expression of specific cancer-related genes in hepatoma cells.     

Clinical significance of heparanase activity in primary resected non-small cell lung cancer

Clinicopathological significances of heparanase activity in non-small cell lung cancer (NSCLC) were investigated by analyzing 76 resected specimens of NSCLC. Heparanase activities in NSCLC were significantly higher than non-cancerous lung tissues (P < 0.0001). The heparanase activities of NSCLC were significantly higher in larger diameter tumors (P = 0.0141) or with metastasis to ipsilateral mediastinal lymph nodes (P = 0.0004). The activities of heparanase in primary tumors were increased significantly according to the pathological stage of the progression of the disease (P =0.0009). Among the clinicopathological parameters, histological cell type and evidence of ipsilateral lymph node metastasis showed a significant association with elevated heparanase activities, whereas age, degree of differentiation and tumor diameter did not. Kaplan-Meier curves for overall and disease-free survival demonstrated a significant difference between patients with elevated and non-elevated heparanase activity by log-rank test (P = 0.0145 and 0.0002, respectively). Multivariate analysis showed heparanase activity was an independent factor to influence disease-free survival in our study. These results suggest that heparanase activity could be used as a prognostic indicator for postoperative patients with NSCLC and heparanase might be a promising molecular target for treatment of NSCLC.     

A case of liver metastasis of colon cancer responding remarkably to 5'-DFUR

A 65-year-old man was referred to our hospital because of diarrhea due to sigmoid colon cancer. Abdominal CT scan revealed a hepatic tumor (S8) about 2 cm in diameter. We performed a sigmoidectomy and planned to resect the liver metastasis 1 or 2 months later. Pathological findings showed moderately differentiated adenocarcinoma, s, n1. Two weeks after the surgery, 5'-DFUR was administered at 600 mg/day. An abdominal CT scan 2 months later demonstrated regression of the liver metastasis and another scan 4 months later showed the tumor had disappeared. 5'-DFUR was administered for about 2 years. Five years after the surgery, the patient is alive without recurrence and CEA level is in normal range.     

A case of hepatic metastasis from colon cancer successfully treated with 5-FU, levofolinate (l-LV) and low-dose CPT-11

The patient was a 67-year-old man in whom hepatic metastasis from transverse colon cancer was detected 15 months after transverse colectomy (D2). We treated the patient by systemically administering 2 courses of 5-FU 750 mg/day with l-LV 350 mg/day (once weekly for 6 weeks per course). Assessment of therapeutic effects by CT showed PD in the patient. As a second-line therapy, we treated the patient by systemically administering 3 courses of 5-FU 750 mg/day, l-LV 350 mg/day and CPT-11 40 mg/day x 3 days (once a week for 4 weeks per course). After 3 courses of this chemotherapy, CT examination revealed a reduction in the tumor size of the liver, and CEA levels decreased at the end of this chemotherapy. This chemotherapy also showed no high-grade toxicities. l-LV/5-FU/low-dose CPT-11 seems to be effective for metastatic colon cancer, and safe from the toxicity standpoint.     

Successful combination therapy with 5'-DFUR and MPA for breast cancer with spinal and vertebral metastases

We report a case of breast cancer with spinal and vertebral lesions. A 49-year-old premenopausal woman with a left breast tumor was admitted to our hospital for acute weakness of the lower limbs and dysuria. She could neither stand nor walk. The tumor in the left breast was 5.0 cm in diameter with skin ulcer, and it was diagnosed as breast cancer. Magnetic resonance (MR) image showed multiple vertebral and spinal metastases from breast cancer. Chemotherapy, consisting of cyclophosphamide, doxorubicin and 5-fluorouracil (CAF) was initiated. Her symptoms dramatically changed for the better. She became able to walk and urinate. We performed palliative mastectomy after 3 cycles of CAF therapy. Histopathological findings of breast tumor showed scirrhous carcinoma. Although the estrogen and progesterone receptor status of primary tumor was negative, chemo-endocrine therapy, consisting of medroxyprogesterone acetate (MPA) and doxifluridine (5'-DFUR) was given as daily therapy, and vertebral and spinal lesions were reduced. Her condition has remained stable for 4 years. For patients with metastatic breast cancer, complete remission is uncommon, and disease stabilization is a reasonable goal of successful therapy. In this respect, therapy with CAF, followed by MPA and 5'-DFUR, was successful in the patient.     

Clinical clerkship of home care for medical students

A clinical clerkship of home care has been introduced in our program for third-year medical students since 1998 at this university. In our clinical clerkship of home care, medical students are not only dispatched to visiting nursing stations, but they also participate in home care service activities with visiting nursing people at patients' homes. Through these experiences the students have an opportunity to study the policy of community medicine and home care, and to gain the knowledge of teamwork. OBJECTIVE AND METHOD: The clerkship of home care (1 week program) was introduced to all of the third-year medical students. The students were dispatched to visiting nursing stations and they had to take part in home care service activities at patients' homes with community care visiting nurses. After this program was finished, questionnaires were given to all the students and visiting nurses to examine the necessity and scheduling of this program and to evaluate the students by the visiting nurses, etc. RESULT: A total of 621 students participated in our program for the past 6 years since 1998, and 90 visiting nurses from 30 visiting nursing stations gave actual trainings to our students every year at patients' homes. 98% of the students as well as 97% of the home care nurses returned questionnaires. After the program, 95.1% of the students and 97.8% of the visiting nurses agreed that this program was meaningful for both sides and it should be continued. Furthermore, regarding a question of the suitability of the third-year medical students to be in the program, 70% of the students and 48% of the visiting nurses agreed. As to a question of the training duration, 80% of the students and 87% of the visiting nurses also agreed. Both students and visiting nurses were in agreement that this home care clerkship was important. Meanwhile, both students and visiting nurses also expressed a degree of some difficulty for this clinical clerkship training. These results suggested that there were some factors to be resolved in order to carry out the clinical clerkship as a success. The clinical trainings for community-based home care are not carried out sufficiently under present medical education because clinical clerkships are always performed at a bedside of a university hospital. It is hard for the students to learn community-based home care and the time related progression of a patient's disease. Therefore, clinical clerkship of home care is a good and effective method to educate the students in those areas.