Molecular regulation of gonadotropin receptor expression: relationship to sterol metabolism

We have identified a specific LHR mRNA binding protein that selectively binds to the polypyrimidine-rich bipartite sequence in the coding region of the LHR mRNA and accelerates its degradation. This process has been shown to be one of the mechanisms that is responsible for the loss of the steady-state levels of LHR mRNA following the preovulatory LH surge or the down regulation of the receptor in response to the administration of a pharmacological dose of LH or hCG. The trans factor, designated as the LHR mRNA binding protein (LRBP), was purified and its identity was established as being mevalonate kinase, an enzyme involved in cholesterol biosynthesis. When mevalonate kinase expression was abolished by treating cultured luteal cells with 25-hydroxycholesterol, the ability to undergo LH-induced down regulation of LHR mRNA was completely abrogated. Examination of the crystal structure of mevalonate kinase coupled with mutagenesis of the critical residues in the catalytic site revealed that the catalytic site is in close proximity to the LHR mRNA binding site. Further studies revealed that mevalonate kinase causes LHR mRNA degradation by acting as a translational suppressor by forming an untranslatable ribonucleoprotein (RNP) complex which is then targeted for degradation. These studies show that LHR expression in the ovary is regulated by a post-transcriptional mechanism mediated by mevalonate kinase thereby linking LHR expression with cholesterol metabolism.

Expression of vascular endothelial growth factor A during ligand-induced down-regulation of luteinizing hormone receptor in the ovary

Vascular endothelial growth factor A (VEGF-A) is one of the most important regulators of ovarian angiogenesis. In this study, we examined the temporal relationship between VEGF-A and luteinizing hormone receptor (LHR) mRNA expression during ligand-induced down-regulation of LHR. Immature female rats were treated with pregnant mare's serum gonadotropin followed by 25 IU hCG 56 h later (day 0). On day 5, treatment with hCG (50 IU) to down-regulate LHR showed a temporal decrease in VEGF-A mRNA and protein levels in parallel with decreasing LHR mRNA. This effect was specific since the expression of CYP11A1 mRNA showed no decline. Examination of VEGF-A mRNA expression, using in situ hybridization histochemistry with (35)S-labeled antisense VEGF-A mRNA probe, showed intense signal in the corpora lutea on day 5. Treatment with 50 IU hCG to down-regulate LHR mRNA showed a decline in the intensity of VEGF-A mRNA in the corpora lutea. VEGF-A mRNA expression returned to control level 53 h later when the expression of LHR mRNA also recovered. These results show that the transient down-regulation of VEGF-A mRNA and protein closely parallels the ligand-induced down-regulation of LHR mRNA. The present study establishes a close association between VEGF-A and LHR mRNA expression, suggesting the possibility that VEGF-A-induced vascularization of the ovary is dictated by the expression of LHR and this might play a regulatory role in ovarian physiology.

Molecular phylogenetic analyses reveal a close evolutionary relationship between Podosphaera (Erysiphales: Erysiphaceae) and its rosaceous hosts

Podosphaera is a genus of the powdery mildew fungi belonging to the tribe Cystotheceae of the Erysiphaceae. Among the host plants of Podosphaera, 86 % of hosts of the section Podosphaera and 57 % hosts of the subsection Sphaerotheca belong to the Rosaceae. In order to reconstruct the phylogeny of Podosphaera and to determine evolutionary relationships between Podosphaera and its host plants, we used 152 ITS sequences and 69 28S rDNA sequences of Podosphaera for phylogenetic analyses. As a result, Podosphaera was divided into two large clades: clade 1, consisting of the section Podosphaera on Prunus (P. tridactyla s.l.) and subsection Magnicellulatae; and clade 2, composed of the remaining member of section Podosphaera and subsection Sphaerotheca. Because section Podosphaera takes a basal position in both clades, section Podosphaera may be ancestral in the genus Podosphaera, and the subsections Sphaerotheca and Magnicellulatae may have evolved from section Podosphaera independently. Podosphaera isolates from the respective subfamilies of Rosaceae each formed different groups in the trees, suggesting a close evolutionary relationship between Podosphaera spp. and their rosaceous hosts. However, tree topology comparison and molecular clock calibration did not support the possibility of co-speciation between Podosphaera and Rosaceae. Molecular phylogeny did not support species delimitation of P. aphanis, P. clandestina, P. ferruginea, P. spiraeae and P. tridactyla in their current circumscriptions, which suggests the need for revision of these species.

Molecular phylogeny and taxonomy of Eurasian Neoerysiphe species infecting Asteraceae and Geranium

Because Eurasian samples of Neoerysiphe collected on the Asteraceae were not identical in morphology, the molecular and morphological differences among these specimens were compared with those of the American N. cumminsiana. Neoerysiphe on Asteraceae was found to consist of at least four different species. Three of them are described as new species, viz. N. hiratae, N. joerstadii, and N. nevoi. Neoerysiphe hiratae is a Japanese species parasitizing hosts belonging to the genera Cacalia and Ligularia (tribe Senecioneae). Neoerysiphe joerstadii was found in Israel on Phagnalon rupestre (tribe Gnaphalieae). Neoerysiphe nevoi was recorded in Israel and Ukraine on a number of hosts in different genera but all belonging to tribe Cichorieae. Thus, Eurasian Neoerysiphe species infecting the Asteraceae are strongly specialised to particular tribes of this family. Phylogenetic analyses indicated that the three new species were not closely allied. Neoerysiphe hiratae is related to the American N. cumminsiana and species belonging to Oidium subg. Striatoidium. Neoerysiphe nevoi is sister to N. geranii, and N. joerstadii is allied to N. galii. In addition, Ukrainian Neoerysiphe samples on Geranium were phylogenetically and morphologically identical to Japanese samples of N. geranii, and this fungus seems to be an invasive species in Ukraine.

Vasodilator therapy with hydralazine induces angiotensin AT receptor-mediated cardiomyocyte growth in mice lacking guanylyl cyclase-A

BACKGROUND AND PURPOSE

Recent clinical guidelines advocate the use of the isosorbide dinitrate/hydralazine combination in treatment for heart failure. However, clinical and laboratory evidence suggest that some vasodilators may induce cardiac hypertrophy under uncertain conditions. This study investigated the effects and underlying mechanism of action of the vasodilator hydralazine on cardiac growth.

EXPERIMENTAL APPROACH

Wild-type mice and animals deficient in guanylyl cyclase-A (GCA) and/or angiotensin receptors (AT(1) and AT(2) subtypes) were treated with hydralazine ( approximately 24 mg.kg(-1).day(-1) in drinking water) for 5 weeks. Cardiac mass and/or cardiomyocyte cross-sectional area, fibrosis (van Giessen-staining) and cardiac gene expression (real-time RT-PCR) were measured.

KEY RESULTS

Hydralazine lowered blood pressure in mice of all genotypes. However, this treatment increased the heart and left ventricular to body weight ratios, as well as cardiomyocyte cross-sectional area, and cardiac expression of atrial natriuretic peptide mRNA in mice lacking GCA. Hydralazine did not affect cardiac hypertrophy in wild-type mice and mice lacking either AT(1) or AT(2) receptors alone. However, the pro-hypertrophic effect of hydralazine was prevented in mice lacking both GCA and AT(2), but not GCA and AT(1) receptors. However, hydralazine did decrease cardiac collagen deposition and collagen I mRNA (signs of cardiac fibrosis) in mice that were deficient in GCA, or both GCA and AT(2) receptors.

CONCLUSIONS AND IMPLICATIONS

The vasodilator hydralazine induced AT(2) receptor-mediated cardiomyocyte growth under conditions of GCA deficiency. However, attenuation of cardiac fibrosis by hydralazine could be beneficial in the management of cardiac diseases.

Protective effect of a poly-phytocompound on early stage nephropathy secondary to experimentally-induced diabetes

Diabetic nephropathy (DN) is a severe and life-threatening complication of long-standing diabetes. As one of the main causes of end-stage renal disease, the prevention and treatment of DN in early stage, and the slowing down of DN progression are of utmost importance and are topics of several ongoing research studies. Nutraceuticals endowed with antioxidant-anti-inflammatory properties may offer an opportunity of integrative treatment for this condition. Male Wistar rats were randomly assigned to two groups. One group of rats (diabetic group) received a single tail-vein injection of STZ compound (50 mg/kg) under light anaesthesia. A protective dose of 0.5 ml of 5 percent dextrose was given intraperitoneally 30 min before the administration of STZ. One diabetic group was fed a normal pellet diet (group A) while group B was fed the diet added with DTS (panax pseudoginseng, eucommia ulmoides), (Kyotsu Jigyo, Tokyo, Japan) in the proportion of 50/25 (percent weight/weight), at the dose of 50 mg/kg/day throughout the experimental period. At the end of 8 weeks, 24-hour urine was collected for the measurement of the albumin concentration: blood samples were collected for serum biochemistry and the rats were sacrificed for kidney measurement of oxidative stress and histomorphological features. Nephrin and Macrophage Chemoattractant Protein-1 (MCP-1) gene expression were also assessed by fluorescence real-time quantitative PCR after RNA extraction and cDNA synthesis. STZ-treated animals showed significantly increased in lipid peroxidation in the kidney and in proteinuria. DTS supplementation did not affect plasma glucose but significantly decreased malonyldialdehyde (MDA) plasma level and the overall redox parameters together with a partial mitigation of proteinuria. Histological analysis showed also that DTS significantly reduced the glomerular volume together with glomerulosclerosis and interstitial fibrosis score (p less than 0.05), the latter two being correlated to proteinuria (p less than 0.05). DTS supplementation also enabled a reduction of diabetes-induced decrease of nephrin mRNA expression and a 67 percent reduction of MCP-1 mRNA up-regulation (p less than 0.01). Taken altogether, these data show that, besides the mandatory control of glycemia, intervention with a nutraceutical with antioxidant and anti-inflammatory properties may have beneficial effects when integrated in the mainstream of the therapeutic regimen.

Effect of long- and short-term treatments with pravastatin on diabetes mellitus and pancreatic fibrosis in the Otsuka-Long-Evans-Tokushima fatty rat

BACKGROUND AND PURPOSE

The effects of statins on diabetes mellitus (DM) are controversial, and their effects on pancreatic fibrosis are poorly defined. We investigated the effect of long- and short-term treatments with pravastatin on the development of DM and pancreatic fibrosis in DM-prone Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats.

EXPERIMENTAL APPROACH

Male OLETF rats were divided into four groups at 12 weeks of age. The first group received a standard rat diet until the end of the experimental period at age 80 weeks. The second group was given a diet containing 0.05% pravastatin from 12 weeks of age, before the onset of DM and pancreatic fibrosis, and the third group was given the same pravastatin diet from 28 weeks of age, after the onset of DM and pancreatic fibrosis, until age 80 weeks. The fourth group received the same pravastatin diet only for 16 weeks, from 12 to 28 weeks of age, and switched to a standard diet. Progressions of DM and pancreatic fibrosis were evaluated.

KEY RESULTS

Long-term treatments with pravastatin, either from 12 or 28 weeks of age, decreased serum glucose concentration and fibrotic area, elevated superoxide dismutase activity and down-regulated transforming growth factor-beta1 mRNA in the pancreas. In contrast, after a short-term treatment with pravastatin, these parameters markedly deteriorated after its cessation.

CONCLUSIONS AND IMPLICATIONS

The results suggest that long-term treatment with pravastatin improves DM and pancreatic fibrosis via anti-oxidative and anti-fibrotic properties, whereas cessation of pravastatin abolishes these beneficial effects, and accelerates DM and pancreatic fibrosis.

A randomized controlled trial of plasma real-time PCR and antigenemia assay for monitoring CMV infection after unrelated BMT

Preemptive therapy is the standard strategy for preventing CMV disease after allogeneic hematopoietic SCT. In this study, unrelated BMT recipients were randomly assigned to a plasma real-time PCR group or an antigenemia group to compare the value of these monitoring tools for CMV reactivation. Ganciclovir (GCV) was started at 5 mg/kg/day when PCR reached 300 copies per ml or when antigenemia reached three positive cells per two slides. A total of 88 patients were randomized into the antigenemia group (n=45) or the PCR group (n=43). A significantly higher number of patients reached the threshold in the antigenemia group than in the PCR group (73.3 vs 44.2%, P=0.0089). However, only three patients (one in the antigenemia group and two in the PCR group) developed early CMV disease. These patients exclusively had colitis and were successfully treated with GCV or foscarnet. The median number of antigenemia-positive cells at the start of GCV was 47 in the PCR group. These findings suggest that antigenemia assay with the current cutoff was too sensitive and led to unnecessary use of GCV. However, the appropriateness of the threshold may be different by the methodology used, and therefore, it is difficult to generalize.

[Mediastinal germ cell tumor with somatic-type malignancy successfully treated with chemotherapy followed by surgical resection combined with lobectomy: report of a case]

A 28-year-old male visited our hospital with complaint of chest pain. Clinical examination revealed a huge mediastinal mass which was diagnosed as non-seminomatous germ cell tumor. The patient underwent 5 cycles of chemotherapy (bleomycin, etoposide, and cisplatin) followed by resection of the tumor combined with left upper lobectomy. Final pathological diagnosis was germ cell tumor with somatic-type malignancy. While the prognosis of mediastinal germ cell tumor with somatic-type malignancy is known to be extremely poor, multimodality at an early stage is the key to successful treatment.

[Right pneumonectomy for typical bronchial carcinoid in a 19-year-old man]

A 19-year-old man visited our hospital with a diagnosis of carcinoid arising from the right intermediate bronchus. Clinical examination revealed T3N1M0 lung cancer, so right pneumonectomy with mediastinal lymph node dissection was performed after obtaining informed consent from the patient and his parents. Final pathological diagnosis was T2N2M0 typical carcinoid. Typical bronchial carcinoid with lymph node metastasis is very rare in patients under 20 years old.

Phase II study of irinotecan plus S-1 combination for previously untreated advanced non-small cell lung cancer: Hokkaido Lung Cancer Clinical Study Group 0601

e19012

Background: Platinum-containing therapy is a standard first-line treatment for advanced non-small cell lung cancer (NSCLC). Platinum-free regimens can be alternative if they can provide similar efficacy with better tolerability. This study evaluated the efficacy and safety for combination of irinotecan and S-1, a newly developed oral 5-fluorouracil derivative, for chemotherapy-naïve advanced NSCLC. Methods: In this multicenter phase II trial, we initially planned to enroll 40 patients. Chemotherapy consisted of 4-week cycles of irinotecan (100 mg/m2 IV, day 1 and 15) and S-1 (80 mg/m2 orally, day 1–14). Primary end point was response rate; secondary endpoints were overall survival (OS), progression-free survival (PFS), and safety. Association of UGT1A1 genotypes (*6 and *28) with frequency of severe toxicity was also examined. Results: A total of 112 cycles was administered into 40 patients (median, 3 cycles: range, 1–6). Median age was 64 years (range, 42–75); 29 patients (73%) had adenocarcinoma, and 8 patients (20%) had squamous cell carcinoma. Majority of the patients (32 cases, 80%) had stage IV disease. Twelve patients exhibited partial response (PR), and 17 patients exhibited stable disease (SD), resulting in response rate of 30% [95% confidence interval (95% CI), 16.6–46.5] and disease control rate of 72.5% (95% CI, 56.1–85.4). Median OS and PFS were 13.8 months (95% CI, 10.7–16.9) and 4.7 months (95% CI, 3.4–6.0), respectively. Hematological toxicities of grade 3 or 4 were neutropenia (32.5%) and anemia (5.0%). The most common non-hematologic toxicities of grade 3 or 4 included diarrhea (15.0%) and anorexia (17.5%). There were no treatment-related deaths. Among the 40 patients, there were 1 homozygous and 8 heterozygous for UGT1A1*6, whereas 7 heterozygous for UGT1A1*28; none of the patients had both genotypes. Patients with homozygous or heterozygous for UGT1A1*6 showed a trend for high incidence of grade 3 diarrhea (p = 0.055). No association of UGT1A1*28 with severe toxicity was observed in this study. Conclusions: Irinotecan and S-1 combination is an alternative treatment with tolerable toxicity for previously untreated advanced NSCLC.

No significant financial relationships to disclose.