A cost-effectiveness analysis evaluating endoscopic surveillance for gastric cancer for populations with low to intermediate risk

BACKGROUND

Gastric cancer (GC) surveillance based on oesophagogastroduodenoscopy (OGD) appears to be a promising strategy for GC prevention. By evaluating the cost-effectiveness of endoscopic surveillance in Singaporean Chinese, this study aimed to inform the implementation of such a program in a population with a low to intermediate GC risk.

METHODS

USING A REFERENCE STRATEGY OF NO OGD INTERVENTION, WE EVALUATED FOUR STRATEGIES: 2-yearly OGD surveillance, annual OGD surveillance, 2-yearly OGD screening and 2-yearly screening plus annual surveillance in Singaporean Chinese aged 50-69 years. From a perspective of the healthcare system, Markov models were built to simulate the life experience of the target population. The models projected discounted lifetime costs ($), quality adjusted life year (QALY), and incremental cost-effectiveness ratio (ICER) indicating the cost-effectiveness of each strategy against a Singapore willingness-to-pay of $46,200/QALY. Deterministic and probabilistic sensitivity analyses were used to identify the influential variables and their associated thresholds, and to quantify the influence of parameter uncertainties respectively.

RESULTS

With an ICER of $44,098/QALY, the annual OGD surveillance was the optimal strategy while the 2-yearly surveillance was the most cost-effective strategy (ICER = $25,949/QALY). The screening-based strategies were either extendedly dominated or cost-ineffective. The cost-effectiveness heterogeneity of the four strategies was observed across age-gender subgroups. Eight influential parameters were identified each with their specific thresholds to define the choice of optimal strategy. Accounting for the model uncertainties, the probability that the annual surveillance is the optimal strategy in Singapore was 44.5%.

CONCLUSION

Endoscopic surveillance is potentially cost-effective in the prevention of GC for populations at low to intermediate risk. Regarding program implementation, a detailed analysis of influential factors and their associated thresholds is necessary. Multiple strategies should be considered in order to recommend the right strategy for the right population.

Empirical evidence of the continuing improvement in cost efficiency of an endoscopic surveillance programme for gastric cancer in Singapore from 2004 to 2010

Background

Endoscopic surveillance has been proven effective in prolonging the survival of gastric cancer (GC) patients. However, there is limited evidence on the cost efficiency of delivering this intervention, especially on a national level in spite of cost efficiency being a major determinant of the actual cost-effectiveness of a cancer prevention programme. The Singapore Gastric Cancer Epidemiology Clinical and Genetic Programme (GCEP) is a demonstration project offering scheduled endoscopy to the Chinese population aged 50 years or older in Singapore. By assessing the cost efficiency of the GCEP, this study aimed to provide empirical evidence on the cost structure and mechanisms underlying cost generation in conducting GC surveillance, thus informing resource allocation and programme budgeting for the Singapore government.

Methods

From a societal perspective, we reported on the direct cost (resource consumption) of conducting endoscopic surveillance through the GCEP network. We retrospectively collected individual-level data of 216 subjects recruited at the National University Hospital, Singapore from 01/04/2004 to 31/10/2010. The Overall Cost, Clinical Cost, GCEP Cost and Personal Cost incurred in serving one subject was computed and discounted as 2004 US dollar (US$) per capita for every year. The Generalized Estimation Equation (GEE) was used to model the data.

Results

All cost indices continuously declined over the 6.5-year costing period. For the total sample, Overall Cost, Clinical Cost, GCEP Cost and Personal Cost declined by 42.3%, 54.1%, 30% and 25.7% respectively. This downward trend existed for age and gender subgroups and the high risk group only with cost reductions varying between 3.5% and 58.4%. The GEE models confirmed statistical significance of the downward trend and of its association with risk profile, where the moderate risk group had cost indices at most 77% of the high risk group.

Conclusions

Our study offered empirical evidence of improved cost efficiency of a surveillance programme for GC in the early phase of programme implementation. Mechanisms such as economies of scale and self-learning were found to be involved in the cost reduction. Our findings highlighted the importance of assessing the cost efficiency and offered valuable insights for future programme budgeting and policy making.

Validation of the functional assessment of cancer therapy-gastric module for the Chinese population

Background

Quality of life (QoL) assessment has become an important aspect of the clinical management of gastric cancer (GC), which poses a greater health threat in Chinese populations around the world. Functional Assessment of Cancer Therapy-Gastric Module (FACT-Ga), a questionnaire developed specifically to measure QoL of patients with GC, has never been validated in Chinese subjects. The current study was designed to examine the psychometric properties of FACT-Ga as a GC specific QoL instrument for its future use in Chinese populations.

Methods

A sample of 67 Chinese patients with GC in the National University Hospital, Singapore was investigated cross-sectionally. The participants independently completed either English or Chinese versions of the FACT-Ga and the European Quality of Life-5 Dimensions (EQ-5D). Reliability was measured as the Cronbach’s α for EQ-5D, and five subscale scores and two total scores of FACT-Ga. The sensitivity to patients’ clinical status was evaluated by comparing EQ-5D and FACT-Ga scores between clinical subgroups classified by Clinical Stage and Treatment Intent. The construct validity of FACT-Ga was assessed internally by examining the item-to-scale correlations and externally by contrasting the FACT-Ga subscales with the EQ-5D domains.

Results

For both FACT-Ga and EQ-5D, patients treated with curative intent rated their QoL higher than those treated for palliation, and early stage patients scored higher than those in the late stage. The sensitivity to clinical status of FACT-Ga scores were differential as four of seven FACT-Ga scores were significant for Treatment Intent while only one subscale score was significant for Clinical Stage. Six FACT-Ga scores had Cronbach’s α of 0.8 or above indicating excellent reliability. For construct validity, 45 of 46 items converged about their respective subscales. The monotrait-multimethod correlations between QoL constructs of FACT-Ga and EQ-5D were stronger than the multitrait-multimethod correlations as theoretically hypothesized, suggesting good convergent and discriminant validities.

Conclusions

Given the excellent reliability and good construct validity, FACT-Ga scores are able to distinguish patient groups with different clinical characteristics in the expected direction. Therefore FACT-Ga can be used as a discriminative instrument for measuring QoL of Chinese patients with GC.

Caecal transcriptome analysis of colonized and non-colonized chickens within two genetic lines that differ in caecal colonization by Campylobacter jejuni

Campylobacter jejuni is one of the most common causes of human bacterial enteritis worldwide. The molecular mechanisms of the host responses of chickens to C. jejuni colonization are not well understood. We have previously found differences in C. jejuni colonization at 7-days post-inoculation (pi) between two genetic broiler lines. However, within each line, not all birds were colonized by C. jejuni (27.5% colonized in line A, and 70% in line B). Therefore, the objective of the present experiments was to further define the differences in host gene expression between colonized and non-colonized chickens within each genetic line. RNA isolated from ceca of colonized and non-colonized birds within each line was applied to a chicken 44K Agilent microarray for the pair comparison. There were differences in the mechanisms of host resistant to C. jejuni colonization between line A and line B. Ten times more differentially expressed genes were observed between colonized and non-colonized chickens within line B than those within line A. Our study supports the fact that the MAPK pathway is important in host response to C. jejuni colonization in line B, but not in line A. The data indicate that inhibition of small GTPase-mediated signal transduction could enhance the resistance of chickens to C. jejuni colonization and that the tumour necrosis factor receptor superfamily genes play important roles in determining C. jejuni non-colonization in broilers.

Relationship between serum hepatitis B virus DNA and surface antigen with covalently closed circular DNA in HBeAg-negative patients

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is responsible for viral persistence. This study aimed to investigate the serum surrogate markers for cccDNA and to evaluate the intrahepatic viral events associated with disease activity in HBeAg-negative chronic hepatitis B patients. Thirty-three treatment-naïve patients with a negative HBeAg who had a liver biopsy were studied. Active disease was defined as a serum alanine aminotransferase >40 IU/L and a serum HBV DNA >10,000 copies/ml. This study showed significant correlation between serum HBV DNA and both log cccDNA (r = 0.41, P = 0.018) and log total intrahepatic HBV DNA (r = 0.71, P < 0.0001). No significant correlation was observed between serum HBsAg and log cccDNA (P = 0.15) or log total intrahepatic HBV DNA (P = 0.97). Fourteen and 19 patients had inactive and active disease, respectively. The median log cccDNA and log total intrahepatic HBV DNA (copies/10(6) cells) were significantly higher in patients with active disease compared with those with inactive disease (4.11 vs. 3.53, P = 0.03 and 5.46 vs. 4.64, P < 0.001, respectively). The HBV replicative efficiency, defined as the ratio of serum HBV DNA to cccDNA, was approximately 20% higher in patients with active disease. No significant difference was observed in the HBsAg levels and the ratio of serum HBsAg to cccDNA between the two groups. In conclusion, serum HBV DNA, but not HBsAg, reflects the amount of cccDNA and the replication efficiency of HBV in patients with HBeAg-negative chronic hepatitis B.

Chirped-quasi-periodic structure for quasi-phase-matching

We propose in this paper a chirped-quasi-periodic structure using the projection method. This type of new structure combines the advantages of chirped and quasi-periodic structures, and can be used for both multiple quasi-phase-matching and multiple bandwidths control. Numerical simulation of second-harmonic generation performance is in good agreement with the Fourier spectrum of the structure.

Significant histopathology in Chinese chronic hepatitis B patients with persistently high-normal alanine aminotransferase

Current guidelines recommend antiviral therapy for chronic hepatitis B (CHB) patients with elevated alanine aminotransferase (ALT) and high viral load. Scant histological data exist for CHB patients with persistently normal ALT (PNALT) because disease progression is thought to be rare. To identify potential predictors of significant histology in the presence of PNALT, we compared the clinical characteristics and histology of Chinese CHB PNALT patients to those in patients with elevated ALT. Percutaneous liver biopsy was performed in 522 CHB patients with Chinese ethnicity who had not had antiviral treatment. Differences in age, ALT, viral load, hepatitis B e antigen (HBeAg) status and liver histology were compared between eligible PNALT (252) and elevated ALT (270) patients. Of the PNALT patients, 38.5% had normal liver histology, 25.4% had significant necroinflammation and/or fibrosis and 8.4% had established cirrhosis. Furthermore, histopathological differences between patients with high-normal ALT (0.5-1.0 x the upper limit of normal (ULN)) and low-normal ALT (≤ 0.5 x ULN) were evaluated. There was a significantly greater prevalence of histopathology in the high-normal group (40.0%) than in the low-normal group (16.6%) (P < 0.001). Multiple logistic regression identified that significant histopathology findings in PNALT patients correlated with age (P < 0.001) and ALT level (P < 0.001), with age >40 years and ALT >0.5 x ULN predicting significant histopathology. Our data indicate that liver biopsy is recommended in CHB patients >40 years of age, particularly when their ALT is 0.5-1.0 x ULN. The findings above provide evidence for indication of antiviral therapy in patients with PNALT and significant histopathological change.

Supratentorial Brain AVM Embolization with Onyx-18 and Post-Embolization Management. A Single-Center Experience

SUMMARY

Onyx is increasingly used in endovascular therapy of intracranial arteriovenous malformations (AVMs). However, the embolic effect and post-embolization management are still under discussion. We report our experience in the treatment of supratentorial brain arteriovenous malformations (SBAVMs) with Onyx and discuss post-embolic management. From June 2006 to July 2008, 20 patients with SBAVM were embolized with Onyx. There were 14 men and six women ranging from 14 to 64 years of age (mean 38.3 years). Initial symptoms included spontaneous hemorrhage (n=12), headaches (n=4), seizure (n=3) and incidentally disclosed after head trauma (n=1). After the endovascular procedure, all had subsequent treatment (follow-up angiogram, stereotactic radiosurgery or microsurgery) according to the obliteration degree. At angiography, seven patients (35%, 7/20) were completely obliterated (over 95% closure) after embolization while one suffered a small subarachnoid hemorrhage without permanent clinical sequelae. Four patients (20%, 4/20) were subtotally obliterated (over 80% closure), one patient who suffered severe cerebral edema after embolization underwent decompressive craniectomy, two patients had additional radiosurgery and one patient had follow-up angiogram. Nine patients (45%, 9/20) were partially obliterated (20-80% closure), five patients had additional surgery, two patients had additional radiosurgery and two patients had follow-up angiogram (one patient had intraventricular hemorrhage three months after embolization). Of all 20 AVMs, an average of 2.2 ml Onyx was used per patient and average volume reduction was 80% (range, 30%-99%). Onyx is suitable for embolization of SBAVMs because of its diffuse controllable properties. We suggest clinical follow-up after complete obliteration, additional radiosurgery or angiographic follow-up after subtotal obliteration and additional surgery after partially obliteration. More cases with long-term follow-up are needed to evaluate the long-term prognosis of our post-embolization management.

Magnetic properties in Co and Mn-doped ZnO powders and thin films

Zn0.86Co0.14O powder and thin films were prepared by standard solid-state reaction processes and radio-frequency (RF) magnetron sputtering. Magnetic measurements indicate that the powder is paramagnetic for temperatures above 3 K, while the thin films annealed in vacuum are ferromagnetic at room temperature. The saturated magnetization was found to be about 0.6 microB/Co, while the coercive force was found to be 200 Oe at room temperature. The very similar results were also obtained in Zn0.96Mn0.04O powder and thin films. Such different results for the powder and thin films indicate that growth conditions and defects play an important role in producing ferromagnetism.

Primary small-bowel non-Hodgkin's lymphoma: a study of clinical features, pathology, management and prognosis

The records of 34 patients diagnosed with primary small bowel non-Hodgkin's lymphoma during a 10-year period between January 1996 and December 2005, including 27 cases for which complete follow-up records were available, were studied. Abdominal pain (70.6% of patients) was the main presenting symptom, followed by intestinal obstruction (38.2%). The most common primary site was the ileum (58.8%), followed by the jejunum (26.5%) and duodenum (17.6%); one case had tumours at two sites in the small bowel. Twenty-seven patients had small bowel B-cell lymphoma (24 diffuse large B-cell lymphoma; three mucosa-associated lymphoid tissue B-cell lymphoma) and seven patients had small bowel T-cell lymphoma. Cumulative survival in patients with small bowel B-cell lymphoma was higher than that in patients with small bowel T-cell lymphoma. Data on 16 male and eight female patients with diffuse large B-cell lymphoma showed that 62.5% of these patients presented with disease stages I or II and 37.5% with stages III or IV. Cumulative survival in patients at stages IE or IIE was significantly higher than that of patients at stages IIIE or IVE. Four of five patients who died from diffuse large B-cell lymphoma had abnormal levels of lactate dehydrogenase and serum albumin.

Loss of expression of Kruppel-like factor 6 in primary hepatocellular carcinoma and hepatoma cell lines

KLF6 (Zf9, COPEB), an ubiquitous transcription factor, maps to chromosome 10p. Recently, KLF6 was found to have a more generalized role in tumorigenesis as a candidate tumor suppressor gene for some tumors. However, results from other published studies seem not to be in agreement with data from previous studies. Gene-expression analysis is increasingly important in biological research. Loss of expression is one of the mechanisms to functionally inactivate a tumor suppressor gene. To investigate the expression change of KLF6 gene associated with HCC as a step toward a better understanding of the molecular pathophysiology, and to provide the basis for analysis of KLF6 gene in HCC carcinogenesis. We analyzed the expression of KLF6 mRNA in 26 samples of HCC tissues and hepatoma cell lines(Hep3B and HepG2) detected by Real-Time quantitative RT-PCR (qRT-PCR) and conventional RT-PCR assay. To confirm and extend the data obtained at RNA level, we performed detailed immunoblotting analysis on HCC tissues and hepatoma cell lines using a rabbit polyclonal antibody specific for KLF6. NKLF6 detected by qRT-PCR from HCC and corresponding noncancerous tissues was 0.04+/-0.038 and 0.116+/-0.101, respectively. These data demonstrated that KLF6 mRNA level was significantly decreased in HCC, compared with corresponding noncancerous tissues (t =3.683 , P<0.001). The frequency of Hepatoma Cell Lines with KLF6 down-regulation detected by conventional PT-PCR, seems to be consistent with a previous study using real-time PCR assays in tumor samples. KLF6 expression levels were determined by Western blot. Compared to the matched surrounding tissues, a clear decrease of KLF6 protein levels in tumor tissues was observable (t=13.59, P<0.001). Hepatoma cell lines also showed low-level of KLF6 protein (P<0.01) expression. Immunohistochemistry and immunocytochemistry showed a faint diffused staining in the HCC tissues and hepatoma cell lines, and endogenous KLF6 protein was detected mostly in the cytoplasm. KLF6 gene appeared markedly reduced in HCC tissues and hepatoma cell lines. Frequent down-regulation of KLF6 strongly suggested that it is a candidate of tumor suppressor gene for HCC.

Observation of locomotor functional recovery in adult complete spinal rats with BWSTT using semiquantitative and qualitative methods

STUDY DESIGN

Experimental rat model of spinal cord transection .

SETTING

China rehabilitation research center.

OBJECTIVE

To investigate locomotor functional recovery in spinal rats with BWSTT using semiquantitative and qualitative methods.

METHODS

Five-day postoperative (dpo), adult female complete spinal rats (at T(8) level) received 40 days of body weight-supported treadmill training (BWSTT). Signs of functional recovery were examined with average combined scores (ACOS) and Basso Beattie and Bresnahan (BBB) scales at different time points.

RESULTS

At 1-dpo, none of the spinal rats exhibited hindlimb movements. The spinal rats displayed functional progress with time, but the rare could recover to full weight-bearing hindlimb at 45-dpo. BBB and ACOS scores in the BWSTT group obtained better scores than those in the spinal cord injury (SCI) group at 30- and 45-dpo. Furthermore, all BBB and ACOS scores of spinal rats reached statistical significance between 7- and 30-dpo, and between 15- and 30-dpo. However, only ACOS but not BBB scores in the SCI and BWSTT groups showed statistics differences between 15- and 45-dpo, and between 30- and 45-dpo. The Spearman correlation coefficients of BBB and ACOS scores were 0.913 and 0.972 for the SCI and BWSTT groups, respectively.

CONCLUSIONS

The results confirmed the existence of partial spontaneous hindlimb functional recovery in adult chronically spinal cord-transected rats, and that BWSTT can improve motor performance. In addition, our study suggests that qualitative and semiquantiative methods are strongly correlated with locomotor recovery in spinal rats, and the latter may be more sensitive in reflecting minor variance at different time points.

Refined Techniques for Intestinal Transplantation in Rat

Intestinal transplantation (IT), unlike other solid-organ transplantations, such as liver, kidney, and heart, has relatively disappointing results in humans. Significant advances have been made during the past 40 years, but rejection, graft-versus-host disease (GVHD), and infection remain the major obstacles to successful IT. These aspects may be studied using a rat model of IT. Without a microscope and traditional suture for vascular reconstruction, we simplified the procedure using a "three cuffs" technique for orthotopic intestinal transplantation (OIT). Technical modifications of our OIT model that induced good results included (1) adopting a "double cuffs" technique on the graft aorta, (2) using a portal cuff anastomosis to reconstitute the natural and physiologic portal graft drainage with the cuff fixed to the recipient first, and (3) administering a large volume of crystalloid or whole blood to maintain blood pressure and reduce ischemic injury to the graft during operation. In our group, the survival rate of recipients was 87.5% (21 of 24 rats), the average volume of bleeding in the recipient operation was less than 1 mL, and the cold ischemic time, 50 +/- 11 minutes.

Association of renal function and delta-aminolevulinic acid dehydratase polymorphism among Vietnamese and Singapore workers exposed to inorganic lead

OBJECTIVES

To investigate the effect of delta-aminolevulinic acid dehydratase (ALAD) polymorphisms on the association between blood lead and renal function among Vietnamese and Singaporean workers who were exposed to low to medium levels of inorganic lead, and to study the distribution of ALAD polymorphism among Vietnamese, Chinese, Malays and Indians.

METHODS

A total of 459 male and female workers were studied. Blood and urine were collected for each worker in order to determine ALAD genotype, blood lead, and urinary delta-aminolevulinic acid (ALAU). Renal function tests included urine albumin (Ualb), urine beta2 microglobulin (Ubeta2m), urinary alpha1 microglobulin (Ualpha1m), N-acetyl-glucosaminidas (NAG), and urine retinol blinding protein (RBP). A multiple regression model with interaction term was applied to fit the entire data and to explore the modifying effect of ALAD polymorphism on the relation of blood lead to each renal function parameter.

RESULTS

ALAD1-1 was the predominant genotype for all the ethnic groups while ALAD2-2 was the rarest. The frequency of ALAD2 allele was higher among Malays (8.8%) and Indians (10.6%) compared to the Chinese (5.0%) and Vietnamese (4.3%). The geometric mean of blood lead for all workers was 19.0 microg/dl. The models for Ubeta2m, Ualpha1m, and NAG showed that the ALAD1-2/2-2 group had higher beta coefficients than the ALAD1-1 group. Corresponding to 10 microg/dl blood lead, ALAD1-1 homozygotes had an increment of 1.288 microg/g Cr, 1.175 mg/g Cr, and 1.995 U/g Cr for Ubeta2m, Ualpha1m, and NAG, respectively. ALAD1-2/2-2 subjects had higher increments of 3.802 microg/g Cr, 2.138 mg/g Cr, and 3.89 U/g Cr for Ubeta2m, Ualpha1m, and NAG, respectively.

CONCLUSION

The frequency of the ALAD2 allele is as low in Vietnamese workers as in Chinese. Workers with the ALAD2 allele appeared more susceptible to the effects of lead (especially at higher levels) on renal function.

Rabi oscillation damped by exciton leakage and Auger capture in quantum dots

The decoherence of Rabi oscillation (RO) caused by biexciton, population leakage to the wetting layer (WL), and Auger capture in semiconductor quantum dots is theoretically analyzed with multilevel optical Bloch equations. The corresponding effects on the quality factor of RO are also discussed. We have found that the biexciton effect is relatively trifling, as the pulse duration is longer than 5 ps. The population leakage to the WL leads to a decrease of the RO average even though the damping rate is similar to that observed in the experiment. Auger capture in quantum dots results in RO damping that is consistent with the experimental data, which implies that Auger capture is an important decoherence process in quantum dots.

Coherent control of a V-type three-level system in a single quantum dot

In a semiconductor quantum dot, the IIx and IIy transitions to the polarization eigenstates, |x> and |y>, naturally form a three-level V-type system. Using low-temperature polarized photoluminescence spectroscopy, we have investigated the exciton dynamics arising under strong laser excitation. We also explicitly solved the density matrix equations for comparison with the experimental data. The polarization of the exciting field controls the coupling between the otherwise orthogonal states. In particular, when the system is initialized into \Y>, a polarization-tailored pulse can swap the population into |x>, and vice versa, effectively operating on the exciton spin.

The changes of gene expression profiles in hydatidiform mole and choriocarcinoma with hyperplasia of trophoblasts

The purpose of this study is to investigate changes of gene expression profiles in hydatidiform moles (HM) and choriocarcinoma and to explore causes of trophoblastic hyperplasia. Using cDNA microarray, 4,096 genes were analyzed in two pairs of the tissues of HM versus normal villi and in two pairs of normal primary culture trophoblasts versus JAR cell line of choriocarcinoma. The expressions of two genes in normal villi and HM, as well as in JAR and JEG-3, were examined with the help of immunohistochemistry, immunoblot, and reverse transcriptase-polymerase chain reaction in order to confirm the findings of cDNA microarray. Twenty-four genes were upregulated and 65 genes were downregulated in all HM. Four hundred thirty-three genes were upregulated and 380 genes were downregulated in JAR. Forty-six genes were upregulated in both HM and choriocarcinoma, whereas 13 genes were downregulated. Genes associated with the inhibition of cell proliferation were significantly downregulated, whereas genes associated with cell proliferation, malignant transformation, metastasis, and drug resistance were upregulated. Thymidine kinase-1 (TK-1) and small subunit ribonucleotide reductase (RRM-2) were overexpressed in HM, JAR, and JEG-3. The expressions of TK-1 and RRM-2 in moles were positively correlated with proliferative index of trophoblasts. Our results suggest that altered expression of genes exist in HM and choriocarcinoma. Trophoblastic hyperplasia may be involved in the overexpression of DNA synthetic enzymes.

Inhibition of LZIP-mediated transcription through direct interaction with a novel host cell factor-like protein

Host cell factor 1 (HCF-1) is a cellular transcriptional coactivator which coordinates the assembly of enhancer complex through direct interactions with viral and cellular trans-activators such as VP16, Oct-1, LZIP, and GA-binding protein. These interactions are mediated by the beta-propeller domain comprising the first 380 residues of HCF-1 with six kelch repeats. Here we describe the identification and characterization of a novel HCF-like kelch repeat protein, designated HCLP-1. HCLP-1 is a ubiquitously expressed nuclear protein which is composed almost entirely of a six-bladed beta-propeller. HCLP-1 selectively interacts with LZIP but not with VP16. The physical interaction between HCLP-1 and LZIP leads to the repression of the LZIP-dependent transcription. The HCLP-1-binding domain of LZIP maps to residues 109-315, which contain the bZIP DNA-binding motif. Electrophoretic mobility shift assay demonstrates that HCLP-1 indeed interferes with the binding of LZIP to its DNA target. Thus, HCLP-1 serves a transcriptional co-repressor function mediated through its inhibitory interaction with the LZIP transcription factor. Our findings suggest a new mechanism for transcriptional regulation by HCF-like proteins.

[Effects of artesunate on progestrone estrogen content and decidua in rats]

AIM

To observe the effect of artesunate on content of progesterone, estrogen and decidua of pregnant rats and study the efficacy and mechanism of artesunate for termination of early pregnancy.

METHODS

Serum content of progesterone, estrogen and TNF-alpha were measured with RIA. The effects of artesunate on the ovary, decidua and fetus of pregnant rats were studied using histochemistry techniques. Decidual cells were estimated using cell culture.

RESULTS

Artesunate 40 mg.kg-1 s.c. on day 6-10 of gestation significantly decreased the concentration of serum progesterone in early pregnant rats; decidual cells and fetus of treated groups were found to be degenerated at d 11. Artesunate was shown to directly damage the decidual cells. Cultured human decidual cells were exposed to artesunate for 48 h, the LC50 was found to be 25 +/- 3 mL.L-1.

CONCLUSION

The damage of artesunate on decidua and placenta may be the mechanisms of its contragestational action.

Termination of early pregnancy in the mouse, rat and hamster with DL111-IT and RU486

The effectiveness of DL111-IT and RU486 given alone and in combination for terminating early pregnancy was tested in the rat, mouse, and hamster. In the mouse and rat, the combination of RU486 and DL111-IT is much more effective in terminating pregnancy than either of the two compounds used alone (single or multiple treatment). A low-effective dose of DL111-IT in combination with a non-effective or a sub-effective dose of RU486, exerted additive or synergistic effects resulting in resorption of embryos and termination of pregnancy. The serum progesterone concentrations were significantly suppressed by these combinations when pregnancy was terminated. In the hamster, single treatment with DL111-IT plus RU486 exhibited a strong effect on interrupting early pregnancy. The ED50 of RU486 in combination of a non-effective dose of DL111-IT was decreased to 163-fold lower dose than RU486 given alone. It is concluded that in mouse, rat, and hamster, the synergistic action between DL111-IT and RU486 not only greatly enhances efficacy in terminating pregnancy but also reduces substantially the dose required to produce this effect.

Intrathecal injection of corticotropin inhibited nitric-oxide synthase-positive neuron increase in rat spinal cord after formalin-induced hyperalgesia

AIM

To study the effects of corticotropin (Cor) on formalin-induced hyperalgesia and the change of nitric-oxide synthase (NOS)-positive neurons in spinal dorsal horn in rats.

METHODS

Measurement of pain intensity rating (PIR), NADPH-d histochemistry, and Fos immunohistochemistry were adopted.

RESULTS

The increases of NOS-positive neurons, Fos, NOS/Fos double labelling neurons of the spinal dorsal horn and the PIR after formalin injection were markedly inhibited by intrathecal injecting (ith) Cor (0.5-1.5 U), which were obviously attenuated by L-arginine (Arg, 5-15 nmol, ith), the substrate of NOS.

CONCLUSION

Cor inhibits formalin-induced hyperalgesia by the decrease of NOS-positive neurons in the spinal dorsal horn of rats.

Analysis of a vertical-cavity surface-emitting laser-based bidirectional free-space optical interconnect

The design of a bidirectional free-space optical interconnect system is presented. Vertical-cavity surface-emitting laser (VCSEL) arrays as a coherent light source and VCSEL beam collimation are described. Hologram array design and a way to improve the diffraction efficiency by use of a copying technique utilizing Dupont photopolymers are presented. Scattering from the hologram as a noise source is measured. An optical model for the design of system parameters such as the VCSEL beam diameter, size and apodization of the hologram, and size of the detector is given on the basis of cross-talk analysis of the system. The effect of VCSEL wavelength variation on system design is considered. Aberrations caused by the Fourier lens in the system are calculated, and ways for correction of the aberrations are discussed.

Characterization of Dupont photopolymers in infrared light for free-space optical interconnects

Dupont photopolymer as a potential holographic material for an optical interconnect system was studied. The optimized conditions of recording plane-wave holograms with ∼99% effective diffraction efficiency for infrared reconstruction were obtained by testing different Dupont photopolymers and different copying parameters. The scattering ratios of the holograms recorded with Dupont photopolymers HRF600-10, HRF600-20, and HRF600-38 were measured and compared.

Embryotoxicity and teratogenicity of DL111-IT, an early pregnancy-terminating agent, in the subsequent gestation following administration in rats

DL 111-IT is a new non-hormonal early pregnancy-terminating agent. The subsequent embryotoxic and teratogenic effects of DL111-IT were studied in the rats whose first pregnancy had been terminated by the agent. The secondary pregnancy of the treated rats were allowed to initiate at 30-, 45-, and 90-day intervals, respectively, after the termination of the first pregnancy. The toxicities primed with DL111-IT, such as resorbed embryos and nephrohydrosis fetuses, were found to be 8.0% and 8.5%, respectively, in the rats with pregnancy at 30-day interval. This is significantly different from 4.0% resorbed embryos and 2.4% nephrohydrosis fetuses in vehicle control (P less than 0.05). However, the rate of resorbed embryos decreased to 7.0% or 6.0% in the rats with pregnancy at 45- or 90-day intervals, respectively. No other significant embryotoxicity and teratogenicity were observed in those rats initiating their pregnancy 45 days later after first-pregnancy termination by DL111-IT. Thus, DL111-IT appears to have very low subsequent toxicity in the course of rat pregnancy cycles.

[Latin square vs twin crossover design for mouse blood glucose assay to estimate insulin potency]

According to parallel line analysis, a Latin square design was used for estimating insulin potency in mouse blood glucose assay. Four to six groups of 4 x 4 Latin squares were used to estimate 80%, 100% and 120% standard preparations and the recovery rates were 95-106%. Meanwhile, in comparison with twin crossover design, 13 batches of variant preparations including some beyond expiry dates were checked by Latin square design. The results showed that the potencies were about the same in two designs. The average fiducial limit rates were still less than 25% but 40% or so of animal numbers were saved. Therefore, Latin square design in a precise and accurate assay for the estimation of insulin.