Effect of follow-up raloxifene therapy after denosumab discontinuation in postmenopausal women

Follow-up raloxifene therapy after denosumab discontinuation resulted in a decrease in bone mass to the pre-denosumab levels and a rebound increase of bone turnover markers. The decrease in lumbar bone mineral density was particularly evident when the body mass index was low, there were previous vertebral fractures, or lumbar bone mineral density before denosumab administration was low.

INTRODUCTION

Selective estrogen receptor modulators may be an alternative to bisphosphonates for treating rebound resorption after discontinuing denosumab. This study aimed to investigate the effects of follow-up raloxifene therapy after denosumab discontinuation in postmenopausal women.

METHODS

This retrospective observational study included 61 patients who received 12-month follow-up raloxifene therapy after denosumab discontinuation. The primary endpoint was the bone mineral density change. The secondary endpoints were the changes in bone turnover markers and the incidence of new vertebral fractures.

RESULTS

Raloxifene administration for 12 months after denosumab discontinuation resulted in a significantly lower bone mineral density at all sites compared to the level at 6 months after the last denosumab treatment (lumbar spine, - 5.48%; femoral neck, - 2.95%; total hip, - 3.52%; all, p < 0.001). The decrease in lumbar bone mineral density was particularly evident when the body mass index was low, there were previous vertebral fractures, or lumbar bone mineral density before denosumab administration was low. Marked increases in the bone turnover markers from baseline were noted after switching to raloxifene. However, no new vertebral fractures occurred during raloxifene treatment.

CONCLUSIONS

Follow-up raloxifene therapy after denosumab discontinuation resulted in a decrease in bone mass to the pre-denosumab levels and a rebound increase of bone turnover markers. Therefore, raloxifene administered sequentially after denosumab discontinuation was not effective in preventing rebound phenomenon.

Comparison of fracture risk between type 1 and type 2 diabetes: a comprehensive real-world data

Population-based cohort study of 6,548,784 Korean subjects demonstrates that the risk of fracture was higher in patients with diabetes than in nondiabetic subjects. Furthermore, patients with type 1 diabetes were associated with a higher risk of fracture than patients with type 2 diabetes for all measurement sites.

INTRODUCTION

Diabetes mellitus is associated with increased fracture risk. Although the pathophysiologic effect on bone metabolism differs according to the type of diabetes, a higher risk of fracture in patients with diabetes than in nondiabetic patients has been consistently demonstrated. Considering the ever-increasing number of patients with diabetes, we aimed to provide updated information on whether this phenomenon remains valid in real-world settings by using large-scale population datasets.

METHODS

We conducted a retrospective longitudinal study using data from the Korean National Health Insurance Service dataset of preventive health check-ups between January 2009 and December 2016. The hazard ratios were calculated for any fracture, vertebral fracture, and hip fracture and were analyzed according to the presence and type of diabetes. Among 10,585,818 subjects, 6,548,784 were eligible for the analysis (2418 patients with type 1 diabetes mellitus [T1DM] and 506,208 patients with type 2 diabetes mellitus [T2DM]).

RESULTS

The mean follow-up duration (in years) was 7.0 ± 1.3 for subjects without diabetes, 6.4 ± 2.0 for those with T1DM, and 6.7 ± 1.7 for T2DM. Patients with T1DM had a higher incidence rate for all types of fractures per 1000 person-years. The fully adjusted hazard ratios (HRs) for any fracture, vertebral fracture, and hip fracture were higher in T1DM than in T2DM (1.37 [95% confidence interval (CI): 1.23-1.52] for any fracture, 1.33 [95% CI: 1.09-1.63] for vertebral fracture, and 1.99 [95% CI: 1.56-2.53] for hip fracture).

CONCLUSIONS

In this large-scale population analysis, diabetes was associated with a higher risk of all types of fractures. Patients with T1DM had a higher risk of fracture than those with T2DM for all measurement sites, and hip fractures had the highest risk. Therefore, fracture prevention training for patients with diabetes is advisable.

P–370 RPL-protease A as a potential biomarker for predicting recurrent pregnancy loss

Study question

Could the reduction of RPL-protease A be involved in the dysfunctional trophoblast for resulting in recurrent pregnancy loss (RPL).

Summary answer

Low expression of RPL-protease A may result in RPL and low serum RPL-protease A level may be a potential biomarker for predicting RPL.

What is known already

The RPL-protease A is expressed and secreted by placenta. The RPL-protease A is involved in the pathogenesis of pre-eclampsia, and the serum RPL-protease A level is higher in the patients with pre-eclampsia than that of normal groups. In our previous study, we identified that the RPL-protease A mRNA level was lower in the villi of patients with RPL than that of normal groups.

Study design, size, duration

Using the CRISPR/Cas9 system, the RPL-protease A gene knockout BeWo cell (BeWo KO) line was established, and the wild type (BeWo WT) and BeWo KO cells were applied to investigate the roles of RPL-protease A in trophoblasts. The human serum RPL-protease A levels were investigated by Western blot analysis and ELISA kit.

Participants/materials, setting, methods

The cell-cell fusion, cell counting analysis, invasion and scratch wound assays, cell cycle analysis, and immunocytochemical analysis were used to investigate cellular functions of RPL-protease A in trophoblast. The sera were obtained from 32 normal pregnant women and 60 women with RPL. The Western blot analysis and ELISA were used for detection of serum RPL-protease A levels.

Main results and the role of chance

The β-hCG was detected in fused BeWo WT cells, while the BeWo KO cells cannot fuse and did not express the β-hCG. The ability of invasion was decreased, but the capacity of migration and proliferation was higher in BeWo KO cells than BeWo WT cells. Cell fusion related factor (β-hCG), and cell invasion related factors (MMP–2 and MMP–9) were highly expressed in BeWo WT cells, and cell related factor (FAK), and cell proliferation related factors (ERK, p38, JNK, MKK3, MKK6, Raf, and Ras) were highly expressed in BeWo KO cells. The Western blot analysis and ELISA indicate that the serum RPL-protease A level was decreased in patients with RPL compared to that of normal groups.

Limitations, reasons for caution

The results of this study have the limitation of RPL-protease A functions in vitro.

Wider implications of the findings: The cellular functions of RPL-protease A in trophoblasts were investigated to explain the pathogenesis of RPL, and low serum RPL-protease A level can be used for a potential biomarker predicting RPL.

Trial registration number

Not applicable

Factors affecting willingness to get assessed and treated for osteoporosis

Individuals with poor knowledge of osteoporosis and lower socioeconomic status, including being single and having a lower level of annual income, are less likely to be assessed or treated for osteoporosis. Individuals with particular osteoporosis risk factors such as smokers and heavy drinkers are overlooked for diagnosis. Further study is needed to identify and address the existing barriers and to promote osteoporosis management for women with these risk factors.

INTRODUCTION

Despite the negative health consequences of osteoporosis and the availability of effective treatment, a pervasive and persistent prevention care gap for osteoporosis remains present throughout the world. We attempted to identify the factors affecting the willingness of patients to either undergo or avoid assessment and treatment for osteoporosis.

METHODS

A nationwide online survey was conducted in 926 Korean women over age 50. The survey included questions addressing three domains: (1) clinical and socio-demographic characteristics, (2) questions concerning the reasons for undergoing or avoiding osteoporosis assessment or treatment, and (3) knowledge of osteoporosis as measured using the modified Korean version of Facts on Osteoporosis Quiz. The assessed and non-assessed participants were compared in terms of their clinical and socioeconomic statuses, reasons for undergoing or avoiding osteoporosis management, and levels of knowledge of osteoporosis.

RESULTS

The highest-ranked reason for undergoing osteoporosis assessment was fear of osteoporotic fracture, while the highest-ranked reason for avoiding osteoporosis assessment was not feeling a need to get tested for osteoporosis. Participants who sought assessment for osteoporosis were older and more likely to be married, and had greater knowledge of osteoporosis than those who did not seek assessment. The two groups were found to be similar in terms of tobacco use and daily alcohol use. Patients who had been diagnosed with osteoporosis but either did not initiate or discontinued osteoporosis treatment within 1 year were younger and had lower levels of annual income than those who began and continued treatment.

CONCLUSION

Individuals with poor knowledge of osteoporosis and those of lower socioeconomic status, including those who were single and had a lower level of annual income, were less likely to be assessed and treated for osteoporosis. Individuals with particular osteoporosis risk factors such as smokers and heavy drinkers are overlooked for diagnosis. Further study is needed to identify and address the existing barriers and to promote osteoporosis management for women with these risk factors.

The prevalence of osteoporosis and the rate of bone loss in Korean adults: the Chungju metabolic disease cohort (CMC) study

Because the rate of bone loss is an important risk factor for fracture, we studied longitudinal changes in bone mineral density (BMD). Although the BMD of the hip decreased over time, spine BMD remained largely stable or increased. Therefore, spine BMD may not be appropriate for assessing BMD change.

INTRODUCTION

The rate of age-dependent bone loss has been shown to be an important risk factor for fracture. However, longitudinal rates of BMD loss in Korea have not yet been reported. The objective of this study was to evaluate longitudinal changes in BMD in Korea.

METHODS

This cohort study was performed in a population of individuals 40 years of age or older living in the rural area of Chungju City, Korea. A second BMD examination was conducted approximately 4 years after a baseline examination. A total of 3755 of the 6007 subjects completed the follow-up visit, corresponding to a follow-up rate of 62.51%.

RESULTS

The age-standardized osteoporosis prevalence was 12.81% in males and 44.35% in females. In males, the average annual BMD loss at the total hip increased from -0.25% per year in their 40s to -1.12% per year in their 80s. In females, the average annual BMD loss at the total hip increased from -0.69% per year in their 40s to -1.51% per year in their 80s. However, the average annual percentage change in spine BMD in females increased from -0.91% per year in their 40s to +1.39% per year in their 80s.

CONCLUSIONS

A substantial number of subjects had osteoporosis, even though we standardized the prevalence of osteoporosis. In total hip, the mean BMD was decreased during the follow-up period; in addition, the annual percentage loss increased with age. However, spine BMD remained approximately stable or increased over time and therefore may not be appropriate for assessing BMD change.

Association of circulating dipeptidyl-peptidase 4 levels with osteoporotic fracture in postmenopausal women

Postmenopausal women with osteoporotic fracture (OF) had higher plasma dipeptidyl-peptidase 4 (DPP4) levels than those without. Furthermore, higher plasma DPP4 levels were significantly associated with higher bone turnover and a higher prevalence of OF. These results indicated that DPP4 may be associated with OF by mediating bone turnover rate.

INTRODUCTION

Evidence indicates that dipeptidyl-peptidase 4 (DPP4) plays a distinct role in bone metabolism. However, there has been no report on the association, if any, between circulating DPP4 levels and osteoporosis-related phenotypes, including osteoporotic fracture (OF). Therefore, we performed a case-control study to investigate these associations in postmenopausal women.

METHODS

This study was conducted in multiple centers in Korea. We enrolled 178 cases with OF and 178 age- and body mass index-matched controls. OF was assessed by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs. Bone turnover markers (BTMs), bone mineral density (BMD), and plasma DPP4 levels were obtained in all subjects.

RESULTS

After adjustment for potential confounders, subjects with OF had significantly higher DPP4 levels than those without (P = 0.021). Higher DPP4 levels were significantly positively associated with higher levels of all BTMs, but not with BMD at all measured sites. The differences in DPP4 levels according to OF status disappeared after an additional adjustment for each BTM, but not after adjustment for any BMD values. BTMs explained approximately half of the relationship between DPP4 and OF. The risk of OF was 3.80-fold (95% confidence interval = 1.53-9.42) higher in subjects in the highest DPP4 quartile than in those in the lowest quartile after adjustment for potential confounders, including femoral neck BMD.

CONCLUSIONS

DPP4 may be associated with OF by at least partly mediating the bone turnover rate. Circulating DPP4 levels may be a potential biomarker that could increase the predictive power of current fracture risk assessment models.

Characteristics of extracellular cyclic AMP-dependent protein kinase as a biomarker of cancer in dogs

OBJECTIVE

Early and proper diagnosis of cancer is the most critical factor for the survival and treatment of veterinary cancer patients. In this study, we evaluated extracellular cyclic AMP-dependent protein kinase A (ECPKA) level in serum as a useful cancer biomarker in dogs.

METHODS

ECPKA levels were detected in sera from dogs with cancers (n = 48), benign tumours (n = 18), and non-tumour diseases (n = 102) as well as healthy control dogs (n = 54) utilizing enzyme-linked immunosorbent assay (ELISA).

RESULTS

Sera from dogs bearing various types of cancer exhibited markedly increased levels of ECPKA by up to 7.1-, 8.8-, and 10.9-fold compared with those from dogs harbouring benign tumours, dogs with non-tumour diseases, and healthy control dogs, respectively (P < .0001). In addition, serum ECPKA level did not show statistically significant correlation with gender, breed, or age of dogs or their non-cancerous disease conditions.

CONCLUSION

Our data strongly propose that detection of serum ECPKA level is a potential and specific diagnostic tool for cancer in dogs.

Association of bone mineral density and diabetic retinopathy in diabetic subjects: the 2008-2011 Korea National Health and Nutrition Examination Survey

Because diabetic retinopathy increases fracture risk, we studied the association between bone mineral density (BMD) and diabetic retinopathy in a nationally representative sample. A significant association between the presence of diabetic retinopathy and low BMD was observed. Therefore, diabetic retinopathy might be considered as a marker of low BMD.

INTRODUCTION

Several diabetic complications, including nephropathy, retinopathy, and peripheral neuropathy, are associated with a higher fracture risk in diabetic subjects. However, in contrast to diabetic nephropathy and peripheral neuropathy, which are associated with low bone mineral density (BMD), little is known about the association between BMD and diabetic retinopathy. The aim of the present study was to determine whether the prevalence of diabetic retinopathy is associated with BMD.

METHODS

This cross-sectional study included a nationally representative sample consisting of 4357 men aged 50 years and older and 4392 postmenopausal women who participated in the Korea National Health and Nutritional Examination Survey (KNHANES) from 2008 to 2011 and underwent BMD measurement by dual-energy X-ray absorptiometry (DXA) and diabetic retinopathy assessments using seven standard gradable photographs.

RESULTS

The diabetic women with retinopathy had lower mean BMD at all measured sites than those without retinopathy, although the BMD difference between the two groups was small (3-5 %). In addition, the diabetic women with retinopathy were 2.27 times more likely to have osteoporosis following adjustments for all clinically relevant covariates. However, the prevalence of diabetes mellitus (DM) or diabetic retinopathy was not associated with the prevalence of osteoporosis in men.

CONCLUSIONS

This study has shown that the presence of diabetic retinopathy is significantly associated with a reduced BMD and increased prevalence of osteoporosis in diabetic women.

Molecular genetics of polycystic ovary syndrome: an update

Polycystic ovary syndrome (PCOS) is a complex genetic disorder caused by interplay between several 'susceptibility' genes and environment factors. In the past few years, numerous studies of genomics and transcriptomics attempted to discover genes affecting PCOS. Pre-genome wide association study (GWAS) plays a stepping stone effect on the progress of PCOS, even though most of the strongest associations are for loci rather than functional variants. A trend towards large-scale GWAS has succeeded in identifying many additional novel PCOS loci. Most of the PCOS-associated regions are shared with other diseases or symptoms, as well as with metabolism, inflammation or insulin signaling-related traits, or cancer. Moreover, susceptibility genes for early diagnosis of PCOS are expected to offer the prevention of long-term risk of obesity, cardiovascular disease, and type 2 diabetes (T2DM) as well. Furthermore, considerable advanced new technical approaches such as GWAS and next-generation sequencing will provide new opportunities in the molecular analysis of PCOS, which can, in the long term, lead to new therapeutic treatments for the disorder. The present review discusses heterogeneous clinical manifestations of PCOS, controversies surrounding the diagnosis of PCOS, and the recent findings of pre-GWAS and GWAS studies on PCOS, highlighting the relevant candidate gene families and their potential functional pathways relevant for PCOS.

Analysis of aberrantly spliced transcripts of a novel de novo GNAS mutant in a male with albright hereditary osteodystrophy and PHP1A

Pseudohypoparathyroidism (PHP) is a genetic disorder due to target-organ unresponsiveness to parathyroid hormone (PTH). PHP type 1A (PHP1A) is an autosomal dominant disease characterized by Albright hereditary osteodystrophy (AHO) and PTH resistance caused by defects at the GNAS locus. We analyzed the GNAS gene in a male with typical AHO and elevated PTH levels. We identified a novel de novo heterozygous mutation at the splice donor site in intron-7 (IVS7+1G>A, c.585+1G>A) of the GNAS gene. No GNAS mutations were detected in his parents. Our patient was diagnosed with PHP1A due to a heterozygous de novo mutation in the GNAS gene. Reverse transcriptase (RT) PCR analysis and sequencing revealed that this de novo splice mutation generated alternative splicing errors leading to the formation of 2 mutant transcripts: one with exon-7 deleted, the other with whole intron-7 included. To investigate whether these aberrantly spliced transcripts were stable, we assessed the differential expression of GNAS mRNAs in the proband's blood by real-time quantitative RT-PCR. In the proband, the relative expression levels of wild-type, exon-7-deleted, and intron-7-included GNAS mRNAs were 0.21, 6.12E-07, and 1.08E-04, respectively, relative to wild-type GNAS mRNA from a healthy control (set at 1.0). This suggests that this novel de novo splicing mutation generates rapidly decaying mutant transcripts, which might affect stimulatory G-protein activity and give rise to this sporadic case. In conclusion, this is an interesting report of aberrantly spliced mRNAs from a de novo splice mutation of the GNAS gene causing PHP1A in a male.

Annexin-1 regulated by HAUSP is essential for UV-induced damage response

DNA damage can occur through diverse stimulations such as toxins, drugs, and environmental factors. To respond to DNA damage, mammalian cells induce DNA damage response (DDR). DDR signal activates a rapid signal transduction pathway, regulating the cell fate based on the damaged cell condition. Moreover, serious damaged cells have to be eliminated by the macrophage to maintain homeostasis. Because the DDR induces genomic instability followed by tumor formation, targeting the DDR signaling can be applied for the cancer therapy. Herpes virus-associated ubiquitin-specific protease (HAUSP/USP7) is one of the well-known deubiquitinating enzymes (DUBs) owing to its relevance with Mdm2-p53 complex. The involvement of HAUSP in DDR through p53 led us to investigate novel substrates for HAUSP, which is related to DDR or apoptosis. As a result, we identified annexin-1 (ANXA1) as one of the putative substrates for HAUSP. ANXA1 has numerous roles in cellular systems including anti-inflammation, damage response, and apoptosis. Several studies have demonstrated that ANXA1 can be modified in a post-translational manner by processes such as phosphorylation, SUMOylation, and ubiquitination. In addition, DNA damage gives various functions to ANXA1 such as stress response or cleavage-mediated apoptotic cell clearance. In the current study, our proteomic analysis using two-dimensional electrophoresis, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) and nano LC-MS/MS, and immunoprecipitation revealed that ANXA1 binds to HAUSP through its HAUSP-binding motif (P/AXXS), and the cleavage and damage-responsive functions of ANXA1 upon UV-induced DNA damage may be followed by HAUSP-mediated deubiquitination of ANXA1. Intriguingly, the UV-induced damage responses via HAUSP-ANXA1 interaction in HeLa cells were different from the responses shown in the Jurkat cells, suggesting that their change of roles may depend on the cell types.

Validation of OMI HCHO data and its analysis over Asia

OMI HCHO is validated over the continental US (CONUS), and used to analyze regional sources in Northeast Asia (NA) and Southeast Asia (SA). OMI HCHO Version 2.0 data show unrealistic trends, which prompted the production of a corrected OMI HCHO data set. EOF and SVD are utilized to compare the spatial and temporal variability between OMI HCHO against GOME and SCIAMACHY, and against GEOS-Chem. CONUS HCHO chemistry is well studied; its concentrations are greatest in the southeastern US with annual cycle maximums corresponding to the summer vegetation. The corrected OMI HCHO agrees with this understanding as well as with the other sensors measurements and has no unrealistic trends. In NA the annual cycle is super-posed by extremely large concentrations in polluted mega-cities. The other sensors generally agree with NA's OMI HCHO regional distribution, but megacity signal is not seen in GEOS-Chem. Our study supports the findings proposed by others that the emission inventory used in GEOS-Chem significantly underestimates anthropogenic influence on HCHO emission over megacities. The persistent mega-city signal is also present in SA. In SA the spatial and temporal patterns of OMI HCHO show a maximum in the dry season. The patterns are in remarkably good agreement with fire counts, which illustrates that the variability of HCHO over SA is strongly influenced by biomass burning. The corrected OMI HCHO data has realistic trends, conforms to well-known sources over CONUS, and has shown a stationary large concentration over polluted Asian mega-cities, and a widespread biomass burning in SA.

Asymptotic and numerical analysis of electrohydrodynamic flows of dielectric liquid

We perform an asymptotic analysis of electrohydrodynamic (EHD) flow of nonpolar liquid subjected to an external, nonuniform electric field. The domain of interest covers the bulk as well as the thin dissociation layers (DSLs) near the electrodes. Outer (i.e., bulk) equations for the ion transport in hierarchical order of perturbation parameters can be expressed in linear form, whereas the inner (i.e., DSL) equations take a nonlinear form. We derive a simple formula in terms of various parameters which can be used to estimate the relative importance of the DSL-driven flow compared with the bulk-driven flow. EHD flow over a pair of cylindrical electrodes is then solved asymptotically and numerically. It is found that in large geometric scale and high ion concentration the EHD flow is dominated by the bulk-charge-induced flow. As the scale and concentration are decreased, the DSL-driven slip velocity increases and the resultant flow tends to dominate the domain and finally leads to flow reversal. We also conduct a flow-visualization experiment to verify the analysis and attain good agreement between the two results with parameter tuning. We finally show, based on the comparison of experimental and numerical solutions, that the rate of free-ion generation (dissociation) should be less than the one predicted from the existing formula.

Higher levels of small dense low-density lipoprotein (LDL) are associated with cardiac autonomic neuropathy in patients with type 2 diabetes

AIM

To investigate the relationship between small dense LDL cholesterol and cardiac autonomic neuropathy among patients with Type 2 diabetes.

METHODS

A total of 175 patients who had not taken lipid-lowering agents previously were enrolled consecutively in this study. Small dense LDL cholesterol level was measured using polyacrylamide tube gel electrophoresis, which fractionates LDL cholesterol into seven components according to particle size and charge. We analysed the mean LDL cholesterol particle size and the proportion of small dense LDL cholesterol.

RESULTS

The mean (± sd) patient age was 56 (± 14) years, the mean (± sd) duration of diabetes was 10.3 (± 8.3) years, the mean (± sd) proportion of small dense LDL cholesterol was 21.3 (± 17.6)% and the mean (± sd) LDL cholesterol size was 26.33 (± 0.8) nm. Men with cardiac autonomic neuropathy had a longer duration of diabetes compared with those without cardiac autonomic neuropathy. Women with cardiac autonomic neuropathy had a larger waist circumference, higher plasma triglyceride levels, smaller mean (± sd) LDL cholesterol size [26.8 (± 4.3) nm vs 26.4 (± 6.9) nm; P < 0.01] and larger mean (± sd) proportion of small dense LDL cholesterol [10.1 (± 9.9)% vs 19.1 (± 16.8)%; P < 0.01] compared with those without cardiac autonomic neuropathy. After adjusting for other confounding risk factors, the triglyceride/ HDL cholesterol ratio (odds ratio = 1.698, 95% CI: 1.07-2.69; P = 0.025) and mean LDL cholesterol size (odds ratio = 0.873, 95% CI: 0.77-0.99; P = 0.038) remained as independent risk factors for cardiac autonomic neuropathy in women.

CONCLUSIONS

A more atherogenic lipid profile such as the triglyceride: HDL cholesterol ratio and a smaller mean LDL cholesterol particle size were related to the prevalence of cardiac autonomic neuropathy in women with Type 2 diabetes.

Competition between the bulk and the dissociation layer in electrohydrodynamic flow of dielectric liquid around coplanar electrodes

An experimental and numerical study has been conducted on the electrohydrodynamic flow around coplanar electrodes with a dielectric liquid: dodecane mixed with the surfactant Span 80. It is shown that the flow is asymmetric, although the electrode is symmetrically arranged, and numerically, we have shown that a difference in the ionic size can reproduce such asymmetric patterns. It is also found that the dissociation layer effect becomes more important in determining the flow pattern than is predicted from the conventional theory where the Langevin formula is used for the recombination constant. In numerical simulations, reducing the recombination constant to 0.035-0.055 times the Langevin value turned out to produce good comparisons between the experimental and the numerical results for the electrode pairs with 1 and 0.2 mm gaps.

Analysis of etching mechanism and etched slope control of silicon for nanoimprinting lithography

In the nanoimprint lithography (NIL) process, profile control of imprint masters is a very important task. Therefore, we attempted to control the etched slope of imprint masters as a function of adding O2 to CF4 plasma. Etched profile mechanisms and relationships between the etch kinetics and plasma chemistry were explored using zero-dimensional-based modeling. O2 flow rate increased to 24 sccm, the Si etch rate increased in the range of 186-393 nm/min, while the etch rate rapidly decreased as the O2 flow rate increases beyond 24 sccm. Meanwhile, change in the etch rate of SiO2 followed a similar tendency as the etch rate of Si as a function of O2 flow rate in the CF4/O2 mixing gases. The Si and SiO2 etch rate were expected to be closely dependent on the F radical intensity in CF4/O2 mixing gases. Moreover, the results of simulated normalized lateral etch critical dimension (NLECD) are in agreement with the measured NLECD as a function of O2 flow rate in the CF4/O2 mixing gases.

Subclinical Cushing's syndrome associated with an adrenocortical oncocytoma

Oncocytoma is a neoplasm that can arise in several organs, and it has been more commonly described in the kidney, salivary gland and thyroid. Oncocytoma arising in the adrenal gland is a rare finding. Moreover, functioning adrenocortical oncocytoma is exceptionally rare. A 47-yr-old man was incidentally discovered to have a right adrenal mass. The patient had no clinical features suggestive of increased adrenal function. However, hormonal evaluation showed a disturbed cortisol circadian rhythm, supranormal urinary cortisol excretion, a low level of ACTH, and a lack of suppressibility of cortisol secretion after dexamethasone. Right adrenalectomy was performed, and this revealed a well-circumscribed dark-brown tumor that measured 2.4x2.2 cm. The tumor consisted almost exclusively of large eosinophilic and epitheloid cells whose cytoplasm was packed with eosinophilic granulations, which corresponded to the numerous mitochondria confirmed on electron microscopy. This is a rare case of subclinical Cushing's syndrome that was caused by adrenocortical oncocytoma.

Semi-automated disk-type solid-phase extraction method for polychlorinated dibenzo-p-dioxins and dibenzofurans in aqueous samples and its application to natural water

A disk-type solid-phase extraction (SPE) method was used for the extraction of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in natural water and tap water. Since this SPE system comprised airtight glass covers with a decompression pump, it enabled continuous extraction with semi-automation. The disk-type SPE method was validated by comparing its recovery rates of spiked internal standards with those of the liquid-liquid extraction (LLE). The recovery ranges of both methods were similar in terms of (13)C-labeled internal standards: 64.3-99.2% for the LLE and 52.4-93.6% for the SPE. For the native spike of 1,3,6,8-tetrachlorinated dibenzo-p-dioxin (TCDD) and octachlorinated dibenzo-p-dioxin (OCDD), the recoveries in the SPE were in the normal range of 77.9-101.1%. However, in the LLE, the recoveries of 1,3,6,8-TCDD decreased significantly. One of the reasons for the low recovery is that the solubility of this congener is high. The semi-automated SPE method was applied to the analysis of different types of water: river water, snow, sea water, raw water for drinking purposes, and tap water. PCDD/F congeners were found in some sea water and snow samples, while their concentrations in the other samples were below the limits of detection (LODs). This SPE system is appropriate for the routine analysis of water samples below 50L.

Relationship between polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene with glucose metabolism and cardiovascular risk factors in Korean women

BACKGROUND

Recently, klotho has been proposed as a link between cardiovascular diseases and premature aging, but the relationship between KLOTHO genes and cardiovascular risk factors, especially glucose metabolism, in humans is unclear.

OBJECTIVES

We investigate the relationship between polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene with glucose metabolism and cardiovascular risk factors in Korean women.

MATERIAL AND METHODS

In 251 women (mean age 51.3+/-6.9 yr), body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose, insulin and lipid profiles were measured. The genotyping of polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene was performed by allelic discrimination using a 5' nuclease polymerase chain reaction assay.

RESULTS

Allele frequencies of G395A polymorphism was 0.829 for the G allele and 0.171 for the A allele and allele frequencies of C1818T polymorphism were 0.804 for the C allele and 0.196 for the T allele, both of which were in compliance with Hardy-Weinberg equilibrium and the two polymorphisms were in linkage disequilibrium (D'=0.43, p<0.01). Mean systolic blood pressure was significantly higher in A allele carriers of G395A polymorphism compared with non-carriers, and the significance was persistent even after adjustment for age and BMI. Mean fasting plasma glucose was significantly higher in T allele carriers of C1818T polymorphism compared with non-carriers, and the significance was persistent even after adjustment for age and BMI. Subjects without any minor allele from either single nucleotide polymorphisms (SNP) had significantly lower mean values for systolic, diastolic blood pressure and fasting plasma glucose levels compared with subjects with both minor allele from either SNP.

CONCLUSIONS

We observed that KLOTHO G395A polymorphism was associated with blood pressure and KLOTHO C1818T polymorphism was associated with glucose metabolism in Korean women. Further studies are needed to clarify this relationship.

Impact of circulating bone-resorbing cytokines on the subsequent bone loss following bone marrow transplantation

Cytokines including IL-6 and TNF-alpha play an important role in the pathogenesis of postmenopausal osteoporosis. However, the relationship between changes in the cytokine levels and subsequent bone loss in patients undergoing a bone marrow transplantation (BMT) is unclear. A total of 46 patients undergoing an allogeneic BMT were prospectively investigated. The bone turnover markers and the serum cytokines were measured before BMT and serially after BMT. Bone mineral density (BMD) was measured before and 1 year after BMT. At 1 year after BMT, the lumbar spine BMD had decreased by 4.8%, and the total proximal femoral BMD had decreased by 12.3%. The serum IL-6 and TNF-alpha levels increased until 2 and 3 weeks after BMT, respectively. The lumbar BMD was significantly decreased as the serum IL-6 and TNF-alpha levels increased by post-BMT 3 weeks. The lumbar BMD decreased significantly as the cumulative prednisolone and cyclosporine dose increased. Patients with GVHD > or =grade II had higher lumbar bone loss than patients with GVHD <grade I. In conclusion, immunosuppressants, GVHD occurrence and increase in bone-resorbing cytokines in the early post-BMT period were associated with later bone loss after BMT. Further studies are needed to elucidate the precise mechanism.

Relationship between circulating cytokine levels and thyroid function following bone marrow transplantation

The relation between thyroid hormone changes and cytokines in bone marrow transplantation (BMT) patients has not been studied. This prospective study was designed to determine the relation between thyroid hormones and cytokine levels after BMT and their effects on the mortality. We studied 80 patients undergoing allogeneic BMT. Serum thyroid hormone parameters and cytokine levels were measured before and serially during 6 months after BMT. Serum T(3) decreased to a nadir 3 weeks post-BMT and serum T(4) was lowest at 3 months post-BMT. Serum thyroid stimulating hormone (TSH) sharply decreased to a nadir at 1 week and recovered. Serum interleukin-6 increased for 2 weeks after BMT and declined thereafter. Serum tumor necrosis factor-alpha increased for 3 weeks after BMT and declined thereafter. After 3 weeks post-BMT, both cytokine levels were negatively correlated with serum T(3) and T(4) levels. A total of 29 patients died before 1 year post-BMT and 51 patients survived longer than 1 year. Those patients who died before 1 year post-BMT had significantly lower levels of T(4) at 3 weeks, 3 and 6 months than surviving patients. In conclusion, increased levels of serum IL-6 and TNF-alpha were negatively correlated with thyroid hormone concentrations in BMT recipients suggesting the role of these cytokines in euthyroid sick syndrome.

Treatment of taste and odor material by oxidation and adsorption

Massive blooms of blue-green algae in reservoirs produce the musty-earthy taste and odor, which are caused by compounds such as 2-MIB and geosmin. 2-MIB and geosmin are rarely removed by conventional water treatment. Their presence in the drinking water, even at low levels (ng/L), can be detected and it creates consumer complaints. So those concentrations have to be controlled as low as possible in the drinking water. The removals by oxidation (O3, Cl2, ClO2) and adsorption (PAC, filter/adsorber) were studied at laboratory and pilot plant (50 m3/d) to select suitable 2-MIB and geosmin treatment processes. The following conclusions were derived from the study. Both of the threshold odor levels for 2-MIB and geosmin appeared to be 30 ng/L as a consequence of a lab test. For any given PAC dosage in a jar-test, removal efficiencies of 2-MIB and geosmin were increased in proportion to PAC dosage and were independent of their initial concentration in raw water for the tested PAC dosages. In comparison of geosmin with 2-MIB, the adsorption efficiency of geosmin by PAC was superior to that of 2-MIB. The required PAC dosages to control below the threshold odor level were 30 mg/L for geosmin and 50 mg/L for 2-MIB at 100 ng/L of initial concentration. Removal efficiencies of odor materials by Cl2, ClO2, and O3 were very weak under the limited dosage (1.5 mg/L), however increased ozone dosage (3.8 mg O3/L) showed high removal efficiency (84.8% for 2-MIB) at contact time 6.4 minutes. According to the initial concentrations of 2-MIB and geosmin, their removal efficiencies by filter/adsorber differed from 25.7% to 88.4%. For all those, however, remaining concentrations of target materials in finished waters were maintained below 30 ng/L. The longer run-time given for the filter/adsorber, the higher the effluent concentration generated. So it is necessary that the run-time of the filter/adsorber be decreased, when 2-MIB or geosmin occurs in raw water.

A novel function of phosphorothioate oligodeoxynucleotides as chemoattractants for primary macrophages

Phosphorothioate cytosine-guanine oligodeoxynucleotides (CpG PS-ODNs) has been reported to induce Th1 immune responses against coadministered Ags more efficiently than phosphodiester CpG ODNs (CpG PO-ODNs). Here, we demonstrated that PS-ODNs, but not PO-ODNs, have a chemotactic effect on primary macrophages, which is independent of the CpG motif. In addition, the conjugation of a hexameric dG run (dG(6) run) at the 3' terminus reduced the concentration required for the optimal chemotactic activity of PS-ODNs by approximately 10-fold. Endosomal maturation blockers, such as monensin and chloroquine, inhibited the chemotactic effect of PS-ODNs. The inhibition of the activities of p38 mitogen-activated protein (MAP) kinase, and extracellular signal-related kinases (ERKs) as well as phosphoinositide 3-kinase with their specific inhibitors also resulted in suppressing the chemotaxis of primary macrophages induced by PS-ODNs. These results indicate that the PS-ODN-mediated chemotaxis requires the activation of ERKs, p38 MAP kinase, and phosphoinositide 3-kinase as well as endosomal maturation. In addition, the phosphorylations of the p38 MAP kinase, ERKs, and protein kinase B, Akt, were induced by PS-ODN, which were further enhanced by the presence of both a dG(6) run and CpG motifs. Our findings suggest that the chemotactic activity of PS-ODNs may be one of the mechanisms by which PS-ODNs exhibit stronger immunomodulatory activities than PO-ODNs in vivo.

Critical regions for deubiquitinating activity of DUB-2 expressed in T-lymphocytes

Ubiquitin- and proteasome-mediated protein degradation is involved in many intracellular processes, including cell cycle regulation, transcriptional activation, and signal transduction in all eukaryotes. Novel subfamily members of the ubp superfamily, DUB-1 and DUB-2, are known to be immediate-early genes and are specifically expressed in B-lymphocytes and T-lymphocytes, respectively. With the site-directed mutagenesis in four conserved amino acids (Cys60, Asp133, His298, and His307) and a series of deletion in the carboxy-terminal region, we demonstrate that these conserved amino acids are critical, but not the C-terminus, for the deubiquitinating activity of DUB-2.

DUB-2A, a new member of the DUB subfamily of hematopoietic deubiquitinating enzymes

Protein ubiquitination is an important regulator of cytokine-activated signal transduction pathways and hematopoietic cell growth. Protein ubiquitination is controlled by the coordinate action of ubiquitin-conjugating enzymes and deubiquitinating enzymes. Recently a novel family of genes encoding growth-regulatory deubiquitinating enzymes (DUB-1 and DUB-2) has been identified. DUBs are immediate-early genes and are induced rapidly and transiently in response to cytokine stimuli. By means of polymerase chain reaction amplification with degenerate primers for the DUB-2 complementary DNA, 3 murine bacterial artificial chromosome (BAC) clones that contain DUB gene sequences were isolated. One BAC contained a novel DUB gene (DUB-2A) with extensive homology to DUB-2. Like DUB-1 and DUB-2, the DUB-2A gene consists of 2 exons. The predicted DUB-2A protein is highly related to other DUBs throughout the primary amino acid sequence, with a hypervariable region at its C-terminus. In vitro, DUB-2A had functional deubiquitinating activity; mutation of its conserved amino acid residues abolished this activity. The 5' flanking sequence of the DUB-2A gene has a hematopoietic-specific functional enhancer sequence. It is proposed that there are at least 3 members of the DUB subfamily (DUB-1, DUB-2, and DUB-2A) and that different hematopoietic cytokines induce specific DUB genes, thereby initiating a cytokine-specific growth response. (Blood. 2001;98:636-642)

Effects of a hexameric deoxyriboguanosine run conjugation into CpG oligodeoxynucleotides on their immunostimulatory potentials

CpG oligodeoxynucleotides (ODNs) are promising immunomodulatory agents for treating human diseases and vaccine development. Phosphodiester CpG ODNs were demonstrated to have poor immunostimulatory potentials for cytokine production. However, the conjugation of consecutive deoxyriboguanosine residues, called a dG run, at the 3' terminus of phosphodiester CpG ODNs significantly enhanced TNF-alpha and IL-12 production from mouse splenic dendritic cells (DCs). The optimal induction of cytokine production was achieved by the addition of a hexameric dG (dG6) run. In contrast, the existence of a dG6 run either at the 5' terminus of phosphodiester CpG ODNs or at the 3' terminus of phosphorothioate CpG ODNs diminished CpG-mediated cytokine induction, suggesting that the effects of a dG run depend on its location and the chemical property of the ODN backbone, respectively. In addition, we provided the evidence that the conjugation of a dG6 run caused the structural transformation of CpG ODNs, which facilitates their targeting into mouse APCs such as splenic DCs, B cells, and peritoneal macrophages with a scavenger receptor type A ligand specificity. Among primary APCs, DCs were the most potent for CpG ODN-mediated IL-12 production. Furthermore, we demonstrated that the conjugation of a dG6 run into the 3' terminus of phosphodiester CpG ODNs was crucial for their ability to generate Th1 immunity in vivo. Thus, the conjugation of a dG6 run into phosphodiester CpG ODNs would be an alternative way to optimize their immunostimulatory potentials in vitro and in vivo.

Dual functions of the heartless fibroblast growth factor receptor in development of the Drosophila embryonic mesoderm

The Drosophila embryonic mesoderm forms by invagination of the ventral-most blastoderm cells. Subsequent development of this germ layer involves the dorsolateral migration of the internalized cells and expansion by cell division, followed by the specification of particular cell fates through the coordinate actions of both intrinsic and extrinsic regulatory mechanisms. The latter include several intercellular signals that function across germ layers. These processes combine to generate a diversity of mesodermal sub-types, including the cardial and pericardial cells of the heart or dorsal vessel, a complete set of somatic muscle founders each with its unique identity, a population of cells that form the visceral musculature, and other cells that develop into hemocytes and the fat body. Here, we review recent evidence for the involvement of a fibroblast growth factor receptor (FGFR) encoded by the heartless (htl) gene in early directional migration of the Drosophila mesoderm. In addition, we provide new data that 1) demonstrate a second role for Htl in promoting the specification of the precursors to certain cardiac and somatic muscle cells in the Drosophila embryo, independent of its cell migration function, 2) suggest that Ras and at least one other signal transduction pathway act downstream of Htl, and 3) establish a functional relationship between the Ras pathway and Tinman (Tin), a homeodomain factor that is essential for specifying some of the same dorsal mesodermal cells that are dependent on Htl. Finally, parallels between requirements for FGFR signaling in Drosophila and vertebrate mesoderm development are considered.

Analysis of cis-acting sequences and trans-acting factors regulating the interleukin-3 response element of the DUB-1 gene

The murine DUB-1 gene is a hematopoietic-specific, immediate-early gene that encodes a growth-regulatory deubiquitinating enzyme. DUB-1 contains an IL-3-inducible enhancer element that is activated in a JAK2-dependent, STAT5-independent manner. In this study, we have further characterized this novel IL-3 response element. Transcriptional reporter assays in Ba/F3 cells revealed that two AP-1 sites, a GATA motif, and an Ets site are required for induction of DUB-1 enhancer activity. Gel shift assays indicated that IL-3 activates the binding of an AP-1 complex containing JunD to the AP-1 sites and the binding of another protein complex to the Ets motif. The latter complex was not detectable in Ba/F3 cells stably transfected with a dominant-negative mutant of JAK2. As previously shown, these cells do not express DUB-1 mRNA or protein. Furthermore, we demonstrated that GATA-1 constitutively binds to the DUB-1 enhancer element. The involvement of GATA-1 may be important for the hematopoietic-restricted expression pattern of DUB-1. This combination of inducible and constitutive elements of the DUB-1 enhancer appears to account for the unique STAT-independent expression characteristics of DUB-1.

Signal transduction pathway for anterior-posterior development in Drosophila

In Drosophila, the establishment of embryonic polarity along the anterior-posterior axis of the egg is determined by the activity of maternal gene products that accumulate during oogenesis. Amongst these are the Bicoid, the Nanos, and the terminal class gene products, some of which are oncoproteins involved in signal transduction for the formation of terminal structures in the embryo. Several signal transduction pathways have been described in Drosophila, and this review explores the potential of oncogene studies using one of those pathways - the terminal class signal transduction pathway - to better understand the cellular mechanisms of proto-oncogenes that mediate cellular responses in vertebrates including humans.

Application of temperature-sensitive mutations to oncogene studies in Drosophila

Recessive oncogenes are genetic functions important in the regulation of tissue growth and differentiation. These genetic functions are defined on the basis of the phenotype expressed by homozygotes. Defining the role of these genes in normal developmental and physiological processes is important to the development of accurate models of the normal regulation of growth and differentiation. Drosophila can be a good system to investigate the neoplastic mechanism of oncogenes and provide a greater understanding in the developmental progression of both invertebrates and vertebrates. The lethal (2) giant larvae gene is a recessive oncogene of Drosophila and temperature sensitive mutations of this gene have been isolated. Here, the application of temperature-sensitive mutations in Drosophila oncogene studies is discussed.

Increased intracellular cAMP renders HL-60 cells resistant to cytotoxicity of taxol

The treatment of advanced cancers with paclitaxel (taxol) is hindered by the development of drug resistance. Resistance to taxol is known to be associated with multidrug resistance (MDR) and a mutation affecting either the alpha- or beta-subunit of tubulin. In this study, we demonstrated that an intracellular cAMP level may also play an important role in resistance to taxol in HL-60, acute promyelocytic leukemia cells. Exposure of HL-60 cells to various doses of taxol for 18 hr resulted in cell death. However, pretreatment of the cells with cAMP analogs such as N6:O2-dibutyl cAMP (Db-cAMP), 8-(4-chlorophenylthio) cAMP (CPT-cAMP) and 8-bromo-cAMP (8-Br-cAMP) or an intracellular cAMP elevating agent such as forskolin apparently rendered HL-60 cells more resistant to taxol, but not with dimethyl sulfoxide (DMSO) or retinoic acid (RA), well known differentiating agents. To investigate whether protein kinase A (PKA) activated by an increase in intracellular cAMP level could be involved in increased taxol resistance of the cells, we examined the effects of PKA inhibitors, including H-89 and KT5720, on taxol resistance induced by Db-cAMP. The PKA inhibitors significantly abolished Db-cAMP-induced taxol resistance. These results suggest that cAMP analogs may render tumor cells more resistant to taxol via PKA activation.

The first oncogene in Drosophila melanogaster

Discovered by Bridges in the 1930s, lethal (2) giant larvae was the first of more than 27 recessive oncogenes identified in Drosophila, which provides an excellent model to study neoplastic mechanisms due to the fact that homologs of human oncogenes and tumor suppressors have been isolated and most of the complexes and associated pathways are conserved. This review explores the potential of neoplastic studies in Drosophila to help understand the genomic mechanisms of neoplastic development in vertebrates and invertebrates. Starting from neoplasms and genetic mutations, the article introduces the reader to one of the possibilities that the studies on neoplastic mechanisms of oncogenes in Drosophila can provide a great understanding of the developmental progression in both vertebrates and invertebrates.

The lethal (2) giant larva (l(2)gl), a recessive oncogene, is required during embryonic and post-embryonic development in Drosophila

Recessive oncogenes have genetic functions important for the regulation of tissue growth and differentiation. Defining the role of these genes in normal developmental and physiological processes is important to the development of the accurate models of the normal regulation of growth and differentiation. We report here a genetic analysis of the requirement for the lethal (2) giant larva function during development. The results demonstrate that the lethal (2) giant larva function is required during embryonic and post-embryonic development to maintain the normal developmental capacity.

Characterization of maternal and zygotic D-raf proteins: dominant negative effects on Torso signal transduction

The maternal D-raf serine/threonine kinase acts downstream of Torso (Tor) for specification of cell fates at the embryonic termini. D-raf activity is also required in other signal transduction pathways and consistent with its pleiotropic role, we find accumulation of a 90-kD D-raf protein throughout embryonic development. We also characterize the accumulation of maternal D-raf proteins in 0-2-hr embryos derived from females with germ cells lacking D-raf activity. Accumulation of a 90-kD or truncated mutant D-raf protein is observed for some of these embryos, while others lack the maternal D-raf protein. Then to determine whether rescue of the Tor pathway is influenced by pools of nonfunctional maternal D raf. wild-type D-raf mRNA was injected into embryos that inherit maternal stores of inactive 90-kD of truncated D-raf protein. For embryos lacking the maternal D-raf protein, a high level of terminal rescue is obtained. In contrast, rescue is reduced or not observed for embryos that accumulate mutant maternal D-raf proteins. These findings suggest that mutant forms of D-raf may deplete the embryo of a positive activator and/or form inactive protein complexes that affect rescue of the Tor pathway.

Remodeling of nuclear architecture during the cell cycle in Drosophila embryos

Little is known about what determines the nuclear matrix or how its reorganization is regulated during mitosis. In this study we report on a monoclonal antibody, mAb2A, which identifies a novel nuclear structure in Drosophila embryos which forms a diffuse meshwork at interphase but which undergoes a striking reorganization into a spindle-like structure during pro- and metaphase. Double labelings with alpha-tubulin and mAb2A antibodies demonstrate that the microtubules of the mitotic apparatus co-localize with this mAb2A labeled structure during metaphase, suggesting it may serve a role in microtubule spindle assembly and/or function during nuclear division. That the mAb2A-labeled nuclear structure is essential for cell division and/or maintenance of nuclear integrity was directly demonstrated by microinjection of mAb2A into early syncytial embryos which resulted in a disintegration of nuclear morphology and perturbation of mitosis.

The activity of D-raf in torso signal transduction is altered by serine substitution, N-terminal deletion, and membrane targeting

The Raf family of serine/threonine kinases are essential components in many receptor tyrosine kinase-mediated signal transduction pathways. Here, we analyze the function of D-raf in the Torso (Tor) pathway required to specify cellular fates at the embryonic poles. Using mutant embryos lacking endogenous D-raf protein, we show that D-raf's serine/threonine kinase activity is essential for its role in Tor signal transduction and that human Raf-1 will substitute for D-raf in this pathway. After Tor activation, D-raf becomes hyperphosphorylated. We identified two putative serine phosphorylation sites (S388 and S743) in SF9 cells and demonstrate that S743 or its phosphorylation is essential for D-raf function in embryos. Alanine substitution at S388, N-terminal truncation, or targeted membrane association permits transmission of the Torso signal by D-raf, but these D-raf molecules differ in their rescuing potential and relative biological activity. Membrane-targeted D-raftor4021 showed the highest level of activity, followed by alanine-substituted D-rafS388A and N-terminal-truncated D-raf delta 445. Since the activity profiles for these altered forms of D-raf are distinct, these findings indicate that each structural modification differentially affects the regulation and/or propagation of the Tor signal by these mutant D-raf proteins.

Thiophosphorylated substrate analogs are potent active site-directed inhibitors of protein-tyrosine phosphatases

Thiophosphotyrosyl protein and peptide substrate analogs were found to be potent and specific protein-tyrosine phosphatase inhibitors with IC50s in the range of 0.2-30 microM. The analogs were based on highly reactive substrates and included thiophosphotyrosyl forms of reduced carboxamidomethylated and maleylated lysozyme and peptides based on tyrosine phosphorylation sites of lysozyme, alpha s2-casein, and platelet-derived growth factor receptor. These analogs inhibited protein-tyrosine phosphatases from both the intracellular and transmembrane classes and from a variety of species ranging from a prokaryote (Yersinia enterolitica) to man. The extent of inhibition of phosphatase activity by a given analog varied with the phosphatase species. In contrast, protein kinases and protein-serine/threonine phosphatases were not significantly affected by these analogs. The mechanism of inhibition was investigated using rat brain protein-tyrosine phosphatase-1 as a prototype. These studies indicated that the inhibition was rapid and reversible and was competitive in nature. The Ki for inhibition by various thiophosphotyrosyl analogs was generally proportional to the apparent Km for the corresponding phosphorylated substrates. Unphosphorylated substrate molecules were generally much weaker inhibitors than the corresponding thiophosphotyrosyl substrate analogs. Taken together these results point to an active site-directed mechanism for inhibition. These specific inhibitory probes could be used to study substrate binding mechanisms as well as physiological roles of various protein-tyrosine phosphatases.

Tumors in hepatobiliary tract and pancreatic islet tissues of transgenic mice harboring gastrin simian virus 40 large tumor antigen fusion gene

Gastrin is expressed in the gastric antrum and in fetal pancreatic islets but not in adult islets. We have now identified the hepatobiliary tract as another, previously unknown, potential site of gastrin gene expression. Two human gastrin simian virus 40 large tumor antigen (SV40 T antigen) fusion genes containing 1.5 kb of 5' flanking sequence and 10.5 kb that included 5.5 kb upstream, 1.5 kb downstream, and the entire transcribed region were used to generate transgenic mice. Analysis of several transgenic lines, derived from both fusion genes, revealed development of transmissible hepatobiliary tract tumors and pancreatic islet cell tumors. Analysis of each of the tumor cells demonstrates expression of SV40 T antigen but no expression of gastrin. Of the two fusion genes, only the 10.5-kb sequence induces hyperplasia of gastrin-producing cells in the antrum. Analysis of these cells demonstrates expression of SV40 T antigen and gastrin, suggesting that the 10.5-kb sequence is sufficient for gastrin cell hyperplasia in the antrum. These data raise the possibility that gastrin is transiently expressed in the hepatobiliary tract.

Genetic conservation of hlyA determinants and serological conservation of HlyA: basis for developing a broadly cross-reactive subunit Escherichia coli alpha-hemolysin vaccine

The HlyA determinant among Escherichia coli isolates from patients with symptomatic urinary tract infection was compared in this report with a prototype HlyA encoded by pSF4000 by DNA-DNA hybridization tests with 20-base synthetic oligonucleotides and monoclonal antibody binding and neutralization assays. Hybridization results demonstrated that 349 (98%) of 357 definitive reactions among 54 hemolytic strains shared homology with seven DNA probes spanning many HlyA regions corresponding to residues (R) 41 to 47, 55 to 61, 248 to 254, 306 to 312, 336 to 343, 402 to 408, and 929 to 935. Genetic divergence was identified by lack of hybridization signals among 17 to 76% of the hemolytic strains within the distal portion of a predicted hydrophobic region corresponding to R491 to 319 and within a predicted hydrophilic region corresponding to R491 to 497 and R532 to 538. Serological studies demonstrated that 26 (81%) culture supernatants of 32 hemolytic strains were bound by all 12 monoclonal anti-HlyA antibodies. Among five of six remaining strains, the culture supernatants were bound by 3 to 11 monoclonal antibody preparations. There was only one hemolytic culture supernatant that failed to be bound by any monoclonal antibody, although the strain hybridized with nine hemolysin DNA probes. In addition, hemolytic activity of all 24 different culture supernatants tested was reduced by at least twofold by one monoclonal antibody specific for R2-161. These data extend and support previous views that the HlyA determinant is conserved among E. coli strains and suggest that a broadly cross-reactive HlyA subunit vaccine can be developed.

Stimulation of transcript elongation requires both the zinc finger and RNA polymerase II binding domains of human TFIIS

The eukaryotic transcriptional factor TFIIS enhances transcript elongation by RNA polymerase II. Here we describe two functional domains in the 280 amino acid human TFIIS protein: residues within positions 100-230 are required for binding to polymerase, and residues 230-280, which form a zinc finger, are required in conjunction with the polymerase binding region for transcriptional stimulation. Interestingly, a mutant TFIIS with only the polymerase binding domain actually inhibits transcription, whereas a mutant in which the polymerase binding and zinc finger domains are separated by an octapeptide is only weakly active. The zinc finger itself has no effect on transcription, but in contrast to the wild-type protein, it binds to oligonucleotides. These findings suggest that TFIIS may interact with RNA polymerase II such that the normally masked zinc finger can specifically contact nucleotides in the transcription elongation zone at a position juxtaposed to the polymerization site.

Cloning, expression and characterization of the human transcription elongation factor, TFIIS

The cDNA for the human elongation factor, TFIIS, has been cloned and expressed in E. coli with the T7 expression system. This 280-amino acid TFIIS protein is shorter by 21 residues than that of the mouse. The missing 21 residues are located in the amino-terminal region, which is not thought to be required for transcriptional stimulation. Apart from this gap, human and mouse proteins reveal 96% overall identity and 98.5% sequence similarity if conservative substitutions are taken into account. The bacterially expressed human protein and the purified calf thymus proteins are indistinguishable in their ability to stimulate transcript elongation by purified RNA polymerase II. Estimation of the native molecular size of the human protein in solution indicates that it exists as a dimer.

RNA polymerase II transcription terminates at a specific DNA sequence in a HeLa cell-free reaction

Recently, we identified a specific DNA sequence from the gastrin gene that regulates RNA polymerase II transcription termination in vivo. In the studies presented here, we examined the processing and termination activity of this sequence in vitro. When present in an in vitro synthesized RNA, this sequence (U9A2U5AU4AU4AU5) does not serve as an RNA processing signal on incubation with HeLa whole-cell extract. However, transcription of template DNA in HeLa whole-cell extract does terminate near the 5' end of this sequence. Nuclease S1 and exonuclease VII mapping of the 3' region of the in vitro synthesized RNAs confirm these results. The termination activity of the sequence A9T2A5TA4TA4TA5 is independent of the distance from the promoter and of the nature of the DNA template (linear vs. circular). The termination activity of the sequence shows a strong orientation dependence. These results strongly suggest that the termination activity of this cis-acting element is modulated by a trans-acting cellular factor. The unique structural feature of this sequence, a 10.5-base-pair inverted repeat, may determine the specificity of interaction of the trans-acting factor with the cis-acting element, resulting in accurate termination of transcription.

A specific DNA sequence controls termination of transcription in the gastrin gene

We located and characterized a downstream transcriptional regulatory element in the human gastrin gene by transferring the gastrin gene 3' fragment, from which the polyadenylation signal sequence was deleted, into the shuttle vector pSCAT10 at a site located immediately downstream from the chloramphenicol acetyltransferase (CAT) gene and upstream from the simian virus 40 polyadenylation region. Study of CAT RNA derived from the hybrid plasmids, indicated regulation of transcription on the gastrin gene fragment. Analysis of deletion mutants generated from the 5' region of the fragment by CAT assay and by S1 nuclease mapping of mRNAs indicated the possible involvement of an oligothymidylate-rich sequence in transcription regulation. Mapping of gastrin gene RNA 3' ends to the 5' side proximal to the oligothymidylate-rich sequence clearly demonstrated that this sequence is a transcriptional terminator element. This unique sequence, interspersed with one or two adenines, which also functions in an orientation-dependent manner, is located 192 nucleotides downstream from the gastrin gene polyadenylation site, and serves as a transcriptional termination signal.