Overexpression of PIK3CG in Cancer Cells Promotes Lung Cancer Cell Migration and Metastasis Through Enhanced MMPs Expression and Neutrophil Recruitment and Activation

Metastasis is a major cause of death in lung cancer. The aim of this study is to analyze the role and mechanism of PI3K catalytic subunit gamma (PIK3CG, also known as p110γ) in lung cancer cell migration and metastasis. Knockdown (KD) and overexpression (OE) of PIK3CG expression in lung cancer cell lines A549 and H1299 in vitro cultured was achieved. Two PIK3CG-specific inhibitors, Eganelisib and CAY10505, were used to treat A549 and H1299 cells. An experimental lung metastasis mouse model was constructed using tail vein injection of LLC cells. Finally, a co-culture system was established using Transwell chambers. Compared with the NC group, the number of cells that completed migration and the expression levels of matrix metalloproteinases (MMPs) were significantly reduced in the KD group and Eganelisib and CAY10505 treatment groups, while the number of cells that migrated successfully and the expression levels of MMPs were significantly increased in the OE group. Lung tissues of mice injected with PIK3CG-stabilized overexpressed LLC cells showed more pronounced lung cancer growth, lung metastatic nodules, neutrophil infiltration and MMPs expression. Co-culture with neutrophils, soluble extracts of neutrophils and cathepsin G all promoted the migration of lung cancer cells. PIK3CG overexpression in tumor cells significantly promoted the migration and metastasis of lung cancer cell.

[Lactate promotes HMGB1 phosphorylation and release via Akt signaling pathway in gastric cancer cells HGC-27]

Objective: To investigate the molecular mechanism of how lactate induces high mobility group box 1 (HMGB1) release. Methods: Gastric cancer HGC-27 cells were divided into the control group and the lactate group (The cells were treated with lactate for 6 h). The level of HMGB1 in the cell culture medium was detected by enzyme-linked immunosorbent assay (ELISA), the localization of HMGB1 was detected using laser confocal microscopy, and the nuclear translocation of HMGB1 was detected using the nucleoplasmic separation assay. The phosphorylation and acetylation levels of HMGB1 were determined by co-immunoprecipitation, and Western blot was used to measure the phosphorylation of Akt and protein kinase C (PKC). HGC-27 cells were first treated with lactate and LY294002, the inhibitor of Akt, and then the phosphorylation of HMGB1 and Akt was analyzed by co-immunoprecipitation and Western blot, respectively. The localization of HMGB1 in cells was detected by laser confocal microscopy. EdU and Transwell assays were used to detect the proliferation and migration abilities of HGC-27 cells, respectively. HGC-27 cells were then injected into the BALB/C null mice for subcutaneous tumor implantation. Mice in the lactate group were intraperitoneally injected with lactate (0.2 g/kg/2 d), while those in the control group were intraperitoneally injected with an equal amount of PBS for 20 consecutive days. ELISA was used to detect the HMGB1 levels in the blood samples taken from the medial canthus vein of the mice, while co-immunoprecipitation and Western blot were used to detect the phosphorylation of HMGB1 and Akt in tumor tissue proteins, respectively. Results: The release levels of HMGB1 in the lactate group were (2 995.00±660.91) pg/ml and (696.33±22.03) pg/ml, after lactate treatment for 6 h and 12 h, respectively, both higher than those in the control group (485.00±105.83) pg/ml (P<0.001 and P=0.028, respectively). After lactate treatment for 6 h, the relative expression of HMGB1 protein in the cytoplasm of HGC-27 cells was 1.13±0.09, higher than that of the control group (0.83±0.07, P=0.001), while the relative expression of HMGB1 in the nucleus was 0.79±0.06, lower than that of the control group (1.07±0.06, P=0.007). The phosphorylation level of HMGB1 reached 1.41±0.09, which was higher than that of the control group (0.97±0.10, P=0.031). The phosphorylation level of Akt was 11.16±0.06, higher than that of the control group (0.91±0.022, P=0.002). The phosphorylation level and nuclear translocation of HMGB1 induced by lactate decreased obviously after Akt inhibition; the proliferation and migration abilities induced by lactate were also obviously inhibited after Akt inhibition. In vivo, the HMGB1 level in the peripheral blood was (1 280.70±389.66) pg/ml in the lactate group, which was obviously higher than that in the control group (595.11±44.75) pg/ml (P=0.008), and the phosphorylation levels of HMGB1 and Akt in tumor tissues in the lactate group were obviously enhanced compared with the control group. Conclusion: Lactate induces HMGB1 release through enhancing HMGB1 phosphorylation via the Akt signaling pathway.

[Aloin inhibits gastric cancer cell proliferation and migration by suppressing the STAT3/HMGB1 signaling pathway]

OBJECTIVE

To investigate the molecular mechanism underlying the inhibitory effect of aloin on the proliferation and migration of gastric cancer cells.

METHODS

Human gastric cancer MGC-803 cells treated with 100, 200 and 300 μg/mL aloin were examined for changes in cell viability, proliferation and migration abilities using CCK-8, EdU and Transwell assays. HMGB1 mRNA level in the cells was detected with RT-qPCR, and the protein expressions of HMGB1, cyclin B1, cyclin E1, E-cadherin, MMP-2, MMP-9 and p-STAT3 were determined using Western blotting. JASPAR database was used to predict the binding of STAT3 to HMGB1 promoter. In a BALB/c-Nu mouse model bearing subcutaneous MGC-803 cell xenograft, the effect of intraperitoneal injection of aloin (50 mg/kg) on tumor growth was observed. The protein expressions of HMGB1, cyclin B1, cyclin E1, E-cadherin, MMP-2, MMP-9 and p-STAT3 in the tumor tissue was examined using Western blotting, and tumor metastasis in the liver and lung tissues was detected using HE staining.

RESULTS

Treatment with aloin concentration-dependently inhibited the viability of MGC-803 cells (P < 0.05), significantly reduced the number of EdU-positive cells (P < 0.01), and attenuated the migration ability of the cells (P < 0.01). Aloin treatment dose-dependently down-regulated HMGB1 mRNA expression (P < 0.01), lowered the protein expressions of HMGB1, cyclin B1, cyclin E1, MMP-2, MMP-9 and p-STAT3, and up-regulated E-cadherin expression in MGC-803 cells. Prediction based on JASPAR database suggested that STAT3 could bind to the promoter region of HMGB1. In the tumor-bearing mice, aloin treatment significantly reduced the tumor size and weight (P < 0.01), lowered the protein expressions of cyclin B1, cyclin E1, MMP-2, MMP-9, HMGB1 and p-STAT3 and increased the expression of E-cadherin in the tumor tissue (P < 0.01).

CONCLUSION

Aloin attenuates the proliferation and migration of gastric cancer cells by inhibiting the STAT3/HMGB1 signaling pathway.

[The common morphology and clinical significance of the axillary arch]

Axillary arch is the most common type of axillary muscle fiber variation, with about 10.8% incidence in the Chinese population. Its natural forms are varied and fluid, with different starting points and terminations, and clinicians frequently lack recognition. Under commonly applicated sentinel lymph node biopsy, the axillary arch has been endowed with more clinical significance. The fabric of axillary arch will not only block lymphatic drainage in axilla and unclear anatomical level of axillary dissection, but also compress the axillary neurovascular bundle, causing upper limb venous thrombosis, lymphedema and nerve entrapment. The intumescent axillary arch may also show abnormal axillary bulge. In addition to finding axillary arch during cadaveric study and operation, several of imaging methods availably diagnose axillary arch preoperative, which can create new way for detection of axillary arch and extension of the surgical plan of sentinel lymph node biopsy. Although embryology and comparative anatomy have been used to explain the origin of the axillary arch, most of the ideas are still hypotheses and need further study.

How Neighborhood Structural and Individual Characteristics Affect Frailty Progression: Evidence from the China Health and Retirement Longitudinal Study

OBJECTIVES

(1) To characterize the average trajectories of frailty over time in Chinese community-dwelling older adults; (2) To assess the effects of neighborhood structural and individual characteristics on frailty progression.

DESIGN

A nationally representative prospective cohort study.

SETTING

Communities in 28 provinces, China.

PARTICIPANTS

6238 respondents aged 60 and above in 447 communities from four waves of the China Health and Retirement Longitudinal Study.

MEASUREMENTS

Frailty was measured using the 61-item Frailty Index (FI).

RESULTS

The trajectory of FI was nonlinear, with an average growth rate of 0.025 that significantly slows down at the rate of 0.002 per year. Older, male, and uninsured respondents showed faster rates of growth in FI over time than younger, female, and insured counterparts. Respondents living in neighborhoods with a higher percentage of the older population and rural villages showed slower rates of growth in FI over time.

CONCLUSION

Expanding health insurance coverage and keeping a high clustering of the elderly in neighborhoods may be the potential strategies for population-level frailty prevention and interventions.

Physical activity patterns, genetic susceptibility, and risk of hip/knee osteoarthritis: a prospective cohort study based on the UK Biobank

OBJECTIVES

The effect of physical activity on hip/knee osteoarthritis (OA) and how it varies by genetic susceptibility to OA remains inconclusive.

METHODS

In a cohort study of UK Biobank, 436,166 OA-free participants were recruited in 2006-2010 and followed for knee/hip OA until the end of 2020. 28 physical activity-related items were collected at baseline. Cox regression was used to estimate associations between physical activity behaviors, as well as major activity patterns (i.e., significant principal components[PCs] identified by principal component analysis), and risk of OA, adjusting for multiple confounders. We further stratified the analyses by polygenic risk score (PRS) for OA to examine the impact of genetic susceptibility to OA on the studied association.

RESULTS

During a mean follow-up of 11.15 years, 13,227 hip and 21,119 knee OA cases were identified. 19, out of 28, studied items showed associations with increased OA risk. Compared with low adherence group(<1^st tertile of PC score for each pattern), individuals with high adherence to five identified patterns were associated with increased risk of OA. The moderate adherence to "strenuous sports"(HR = 0.93, 95%CI: 0.89-0.97) and "walking for pleasure"(HR = 0.93, 95%CI: 0.89-0.98) patterns was associated with reduced OA. Similar risk patterns were obtained in the stratified analysis by PRS levels for OA.

CONCLUSION

High intensity of most activity patterns were associated with increased OA. However, a protective effect was suggested for moderate adherence to patterns of "strenuous sports" and "walking for pleasure" that consistent across different genetic susceptibilities, underscoring the potential benefits of moderate-intensity physical activity on OA.

MiR-124 changes the sensitivity of lung cancer cells to cisplatin through targeting STAT3

OBJECTIVE

To investigate the role of micro ribonucleic acid (miR)-124 in drug resistance of non-small cell lung cancer (NSCLC), and to explore its underlying mechanism.

MATERIALS AND METHODS

The expression levels of miR-124 and signal transducer and activator of transcription 3 (STAT3) in maternal A549 cells and cisplatin-resistant A549/DDP cells were detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting. A549 and A549/DDP cells were transfected with miR-124 mimics and miR-124 negative control (NC), respectively. Changes in the expression of STAT3 were detected via qRT-PCR and Western blotting. Meanwhile, the sensitivity of cells transfected with miR-124 mimics to cisplatin was detected via methyl thiazolyl tetrazolium (MTT) assay. The effects of miR-124 on the apoptosis, invasion and metastasis of cells were detected via flow cytometry, wound healing assay and transwell assay, respectively. Moreover, wild-type and mutant-type STAT3 luciferase reporter plasmids were co-transfected with miR-124 mimics or miR-124 NC. Luciferase activity was analyzed using the dual-luciferase reporter gene assay.

RESULTS

QRT-PCR and Western blotting revealed that the expression level of miR-124 in A549/DDP cells was significantly lower than that of A549 cells. However, the expression level of STAT3 in A549/DDP cells was significantly higher than that of A549 cells. Overexpression of miR-124 remarkably reduced the expression level of STAT3 in A549/DDP cells, increased the sensitivity of A549/DDP cells to cisplatin, and inhibited the invasion and metastasis capacities of cells. In addition, luciferase reporter gene assay demonstrated that miR-124 could negatively regulate the protein expression of STAT3 by binding to its 3'-untranslated region (UTR).

CONCLUSIONS

MiR-124 regulates the sensitivity of NSCLC to cisplatin. Moreover, it inhibits the invasion and metastasis capacities through targeting STAT3, which can serve as a therapeutic target for cisplatin-based chemotherapy resistance of NSCLC.

Analysis of risk factors of stage IV gastric cancer from the SEER database

INTRODUCTION

Gastric cancer is the fourth most common cancer in the world. By the time the patients are diagnosed with stage IV gastric cancer, many patients already have distant metastases. There is no unified systemic treatment plan in existence. The use of gastrectomy is ambiguous in patients with stage IV gastric cancer. The objective of this study was to evaluate the beneficial outcome of gastrectomy in patients with stage IV gastric cancer.

METHODS

Clinical information of patients with gastric cancer from 2000 to 2010 in the Surveillance, Epidemiology, and End Results database were extracted and analysed. The risk factors for stage IV gastric cancer were also analysed.

RESULTS

We observed that the median survival time for patients after surgery was greater than that for patients not treated surgically. The five-year survival rate for chemotherapy patients was higher than that of non-chemotherapeutic patients. Patients who receive both chemotherapy and surgery could achieve a more significant survival benefit. The risks following gastrectomy (partial, subtotal, hemi-) were lower than those of other surgical procedures, which provided guidance on the choice of surgical method. The numbers of regional lymph node metastasis were found to be related to prognosis.

CONCLUSIONS

In patients with stage IV gastric cancer, gastrectomy (partial, subtotal or hemi) should be selected when surgery is necessary. The number of regional lymph node metastasis could be considered as a prognostic factor for patients with stage IV gastric cancer and lymph node dissection could reduce the risk of patients undergoing surgery.

Facile Solvothermal Synthesis of Hollow BiOBr Submicrospheres with Enhanced Visible-Light-Responsive Photocatalytic Performance

In this work, hierarchical hollow BiOBr submicrospheres (HBSMs) were successfully prepared via a facile yet efficient solvothermal strategy. Remarkable effects of solvents upon the crystallinities, morphologies, and microstructures of the BiOBr products were systematically investigated, which revealed that the glycerol/isopropanol volumetric ratio played a significant role in the formation of hollow architecture. Accordingly, the underlying formation mechanism of the hollow submicrospheres was tentatively put forward here. Furthermore, the photocatalytic activities of the resulting HBSMs were evaluated in detail with photocatalytic degradation of the organic methyl orange under visible light irradiation. Encouragingly, the as-obtained HBSMs with striking recyclability demonstrated excellent visible-light-responsive photocatalytic performance, which benefits from their large surface area, effective visible light absorption, and unique hollow feature, highlighting their promising commercial application in waste water treatment.

Abstract P4-06-30: Adipose PD-L1 modulates checkpoint blockade immunotherapy efficacy in breast cancer

Programmed death-ligand 1 (PD-L1) and its receptor programmed cell death protein 1 (PD-1) play important roles in modulating antitumor immune response and are targeted by checkpoint blockade immunotherapy. While PD-L1 expression in both tumor and host cells is associated with antitumor therapeutic efficacy, the exact contribution of PD-L1 in various tissue and cell compartments to antitumor immune response remains to be elucidated. Here we show that PD-L1 expression is markedly elevated in human and mouse mature adipocytes compared to their preadipocyte counterparts. When co-cultured with mouse splenocytes in vitro, adipocytes prevent anti-PD-L1 antibody from activating CD8+T cells. Genetic ablation of adipose PD-L1 obliterates the inhibitory effect of adipocytes on anti-PD-L1 antibody. Conversely, enforced PD-L1 expression in preadipocytes confers the antibody-inhibitory activity. GW9662, a pharmacologic inhibitor of peroxisome proliferator-activated receptor γ (PPARγ) in adipogenesis, selectively reduces PD-L1 expression in mouse adipose tissue. The same PPARγ antagonist also enhances the antitumor efficacy of checkpoint blockade antibodies for treating multiple mammary tumors. Our findings provide a previously unappreciated approach to bolster anticancer immunotherapy efficacy and suggest a mechanism for the role of adipose tissue in breast cancer progression.

Citation Format: Wu B, Sun X, Gupta HB, Yuan B, Ge F, Li J, Hu Y, Curiel TJ, Li R. Adipose PD-L1 modulates checkpoint blockade immunotherapy efficacy in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-30.

Assessing Frailty in Chinese Nursing Home Older Adults: A Comparison between the Frail-NH Scale and Frailty Index

OBJECTIVE

(1) To establish appropriate FRAIL-NH cutoff points in nursing homes in Mainland China; (2) To compare the FRAIL-NH scale and Frailty Index in assessing frailty prevalence and associated factors in nursing homes.

DESIGN

A cross-sectional study.

SETTING

Six nursing homes in Changsha, China.

PARTICIPANTS

A total of 302 residents aged 60 years or older (mean aged 82.71±8.49, 71.2% female).

MEASUREMENTS

Frailty was assessed using the 34-item Frailty Index and the FRAIL-NH scale.

RESULTS

The appropriate FRAIL-NH cutoff points to classify frail status and frailest status were 1.5 (87.6% sensitivity, 63.3% specificity) and 7.5 (94.1% sensitivity, 73.4% specificity), respectively. Based on the FRAIL-NH and Frailty Index, 69.5% (48% for frail and 21.5% for frailest), and 66.5% (60.9% for frail and 5.6% for frailest) of residents were at risk of frailty, respectively. There was no statistically significant difference in the total frailty prevalence assessed by FRAIL-NH and Frailty Index (χ2=0.617, P=0.432). The FRAIL-NH Scale is significantly associated with the Frailty Index (correlation coefficient (r) = 0.74, P < 0.001), but there was a Kappa agreement of 0.39 for frailty classification between the FRAIL-NH and Frailty Index, with the Frailty Index classifying a larger number of individuals as frail. When using FRAIL-NH scale, disease and self-reported health status were associated with frail and frailest status while age was just associated with frailest status. regarding the Frailty Index, age, diseases, medications and self-reported health status were associated with frail and frailest status.

CONCLUSION

The FRAIL-NH is a simple and effective tool to assess the overall frailty rate in nursing homes, and the Frailty Index may be more suitable capturing the multidimensionality of frailty at an individual level. Careful consideration in the selection of a frailty instrument, based on the intended purpose, is necessary.

Immunoregulatory effect of neuronal-like cells in inducting differentiation of bone marrow mesenchymal stem cells

OBJECTIVE

To evaluate the immune activity of bone marrow mesenchymal stem cells (BMSCs), and explore the biological characteristics and capabilities of BMSCs and the potential to be differentiated into neuronal cells in vitro.

MATERIALS AND METHODS

The BMSCs were isolated and proliferated in vitro to generate the xenogeneic mixed lymphocyte reaction. Moreover, peripheral BMSCs (pBMSCs) were added according to different ratios, which methods were stated as follows: 1: Dulbecco's Modified Eagle Medium (DMEM) + 10% Fetal Bovine Serum (FBS) + 1 μmol/L all-trans-retinoic acid (ATRA) + 20 μg/L basic fibroblast growth factor (bFGF) + 20 μg/L epidermal growth factor (EGF); 2: DMEM + 2% dimethyl sulfoxide (DMSO) + 100 μmol/L butylated hydroxyanisole (BHA). The immunofluorescence and immunohistochemical staining were finally used to evaluate the differentiation capabilities of human BMSCs (hBMSCs) induced in neuronal cells.

RESULTS

hBMSCs inhibited the lymphocyte proliferation in the mixed lymphocyte reaction (MLR) system at a proportional inhibition rate with additional numbers of stem cells. At hour 2 after culture with method 1, the plasma of hBMSCs shrank to nuclei and perinuclear bodies and was visualized under the light microscope. At hours 3-5, most of the hBMSCs formed neuron-like cells with total cell number unchanged. Afterward, the hBMSCs turned into bipolar or multipolar shaped cells and interconnected into a large network at Day 3. With immunofluorescence and immunohistochemical staining, 60-70% of the hBMSCs showed neurospecific enolase (NSE) positive and 45-50% glial fibrillary acidic protein (GFAP) positive while the Nestin-positive cells decreased to 3.4%. However, when cultured 2 hours with method 2, the most of the hBMSCs formed bipolar or multipolar shaped cells, then died after 48 hours. 40-50% NSE and 35-40% GFAP were positively expressed. Significantly, the rate of Nestin-positive cells decreased from 63% to 1.6% from hour 2 after culture to hour 48.

CONCLUSIONS

hBMSCs may be effective for cell therapy and tissue engineering for the capability of differentiating into neuronal-like cells, as well as the capability of inhibiting lymphocyte proliferation in MLR system.

[Differential gene expression in incompatible interaction between Lilium regale Wilson and Fusarium oxysporum f. sp. lilii revealed by combined SSH and microarray analysis]

Fusarium wilt, caused by a soilborne pathogen Fusarium oxysporum f. sp. lilii, is the major disease of lily (Lilium L.). In order to isolate the genes differentially expressed in a resistant reaction to F. oxysporum in L. regale Wilson, a cDNA library was constructed with L. regale root during F. oxysporum infection using the suppression subtractive hybridization (SSH), and a total of 585 unique expressed sequence tags (ESTs) were obtained. Furthermore, the gene expression profiles in the incompatible interaction between L. regale and F. oxysporum were revealed by oligonucleotide microarray analysis of 585 unique ESTs comparison to the compatible interaction between a susceptible Lilium Oriental Hybrid 'Siberia' and F. oxysporum. The result of expression profile analysis indicated that the genes encoding pathogenesis-related proteins (PRs), antioxidative stress enzymes, secondary metabolism enzymes, transcription factors, signal transduction proteins as well as a large number of unknown genes were involved in early defense response of L. regale to F. oxysporum infection. Moreover, the following quantitative reverse transcription PCR (QRT-PCR) analysis confirmed reliability of the oligonucleotide microarray data. In the present study, isolation of differentially expressed genes in L. regale during response to F. oxysporum helped to uncover the molecular mechanism associated with the resistance of L. regale against F. oxysporum.

A review of various techniques of mouse liver transplantation

OBJECTIVES

Liver transplantation in a mouse model is a valuable tool for studying transplantation immunobiology and clinic-relevant issues. However, the successful establishment is highly technical and demanding, impeding its widespread use. Herein, the aims of this study were to review and analyze the various techniques of liver transplantation in mice to circumvent pitfalls and minimize the incidence of complications.

MATERIALS AND METHODS

A search of PubMed was made by using the key words "mouse liver transplantation" for articles published between January 1973 and July 2012. Of the 473 publications identified, 14 were shown to be closely associated with mouse liver transplantation and 4 articles discussed specific microsurgical techniques. Through reviewing these articles, a series of potential factors were collected and analyzed in combination with other murine transplantation models, which might influence successfully establishing a mouse model for liver transplantation.

RESULTS

A mouse liver transplantation model is feasible and practical for experimental studies. Mouse strain, type of anesthesia, type of perfusion and storage solution, and reconstruction of bile duct are relevant factors but not determinants for a successful transplantation. Cold and warm ischemia time should be less than 4.0 hours and 20 minutes, respectively.

CONCLUSIONS

The cuff preparation, reconstruction of the hepatic artery, and length of the anhepatic phase play critical roles in successfully establishing a liver transplantation model in mice.

[Overexpression of the glutathione S-transferase gene from Pyrus pyrifolia fruit improves tolerance to abiotic stress in transgenic tobacco plants]

Glutathione S-transferases (GSTs) are ubiquitous enzymes in animals and plants, and they are multifunctional proteins encoded by a large gene family. GSTs are involved in response to the oxidative stress including drought, salt, heavy metals, and so on. Under oxidative stress, the excessive reactive oxygen species (ROS) induce an increase in GST levels, and then the GSTs metabolize the toxic products of lipid peroxidation, damaged DNA and other molecules. Previously, a full-length cDNA of a novel zeta GST gene, PpGST, was characterized from fruit of Pyrus pyrifolia Nakai cv Huobali. In the present study, a constitutive plant expression vector of PpGSTwas constructed and transferred into tobacco (Nicotiana tabacum L. cv Xanthi) to verify the function of PpGST. As a result, the PpGSTgene was successfully integrated into the genome of the transgenic tobacco lines and expressed as expected in the transformants through Southern blotting and quantitative reverse transcription-polymerase chain reaction analysis. Growth of T1 generation plants of PpGST transgenic lines and WT under non-stressful conditions was similar, however, the transgenic tobacco lines showed relatively normal growth under drought, NaCl, and cadmium (Cd) stresses. Furthermore, the T1 transgenic tobacco lines showed significantly slower superoxide anion production rate than the WT under abiotic stress. Simultaneously, the MDA content of each T1 transgenic tobacco plant was only slightly increased and significantly lower than that of the WT under drought, salt and Cd stress. Together with the GST activity of the transgenic tobacco lines, which was significantly increased under stressful conditions, as compared with that in WT, overexpression of PpGSTin tobacco enhanced the tolerance of transgenic tobacco lines to oxidative damage caused by drought, NaCl, and Cd stresses.

Body weight difference between donor and recipient is an important affector of early graft function after renal transplantation

BACKGROUND

Poor early graft function (EGF), a frequent complication of kidney transplantation, can be caused by many risk factors, including donor kidney and body weights.

METHODS

We studied the relationship to early graft function in a rat kidney transplantation model among 3 indices: ratio of graft to body weight; ratio of native kidney to body weight, and weight difference/body weight of the recipient. We categorized 2 groups based on contralateral nephrectomy at day 1 (G1) or day 3 (G2) after transplantation. EGF was evaluated by measuring serum creatinine levels at day 1 after bilateral nephrectomy.

RESULTS

The 3 indices, ie, weight difference/body weight of recipient (G1 and G2: P < .0001), ratio of native kidney to body weight (G1: P < .0001; G2: P = .0013), and ratio of graft to body weight (G1: P = .0064; G2: P = .014) strongly correlated with EGF regardless of the time of contralateral nephrectomy.

CONCLUSIONS

The index of weight difference/body weight of recipient sensitively and predominantly influenced EGF, which probably reflects the systemic metabolic profile.

Lower incidence and severity of tomato virus in elevated CO(2) is accompanied by modulated plant induced defence in tomato

Elevation in atmospheric CO(2) concentration broadly affects plant phenology and physiology, and these effects may alter the performance of plant viruses. The effects of elevated CO(2) on the susceptibility of tomato plants to Tomato yellow leaf curl virus (TYLCV) were examined for two successive years in open top chambers (OTC) in the field. We experimentally tested the hypothesis that elevated CO(2) would reduce the incidence and severity of TYLCV on tomato by altering plant defence strategies. Our results showed that elevated CO(2) decreased TYLCV disease incidence (by 14.6% in 2009 and 11.8% in 2010) and decreased disease severity (by 20.0% in 2009 and 10.4% in 2010). Elevated CO(2) also decreased the level of TYLCV coat protein in tomato leaves. Regardless of virus infection, elevated CO(2) increased plant height and aboveground biomass. Additionally, elevated CO(2) increased the leaf C:N ratio of tomato, but decreased soluble protein content in leaves. Notably, elevated CO(2) increased the salicylic acid (SA) level in uninfected and infected plants. In contrast, elevated CO(2) reduced jasmonic acid (JA) in uninfected plants while it increased JA and abscisic acid (ABA) in virus-infected plants. Furthermore, combined exogenous SA and JA application enhanced resistance to TYLCV more than application of either SA or JA alone. Our results suggest that the modulated antagonistic relationship between SA and JA under elevated CO(2) makes a great contribution to increased tomato resistance to TYLCV, and the predicted increases in tomato productivity may be enhanced by reduced plant virus susceptibility under projected rising CO(2) conditions.

Heterologous expression of the single-mutation glucose isomerase (GIG138P) gene in Streptomyces lividans and its genetic instability

A 1.3-kb PstI-BamHI fragment containing the single-mutation glucose isomerase (GIG138P, GI1) gene and its natural promoter was inserted into PstI-BglII linearized Streptomyces vector pIJ702. The ligation mixture was then introduced into Streptomyces lividans TK54 protoplasts; transformants were identified based on their thiostrepton resistance (ThR) and insertional inactivation of the melanin phenotype; and three white colonies, XY-2, 6, and 9, harboring recombinant expression plasmid pYH703, were obtained. Enzyme assay and SDS-PAGE analysis indicated that the GI1 gene was expressed, the intracellular GI1 specific activity was 6 U/mg, and GI1 accounted for 20% of the soluble proteins in S. lividans. Restriction analysis and Southern blot of pYH703 showed the existence of plasmid deletion, presumably owing to the interaction between the mel and GI1 sequences. Continuous liquid cultures of the recombinant strain demonstrated that the GI1 specific activity and GI1 expression in S. lividans decreased, and more obviously under non-selective conditions.

[Determination of phospholipid in Cibotium barometz by supercritical fluid extraction and RP-HPLC]

A supercritical fluid extraction (SFE) method was used to extract phospholipids in Cibotium barometz. After a homogeneous design experiment, SFE conditions were obtained which were pressure at 31.5 MPa, temperature at 46.2 degrees C and a 0.37 L/kg modifier in supercritical fluid. The sample was extracted for 2 hours. A RP-HPLC method was developed for the determination of phosphatidylcholine. RP-HPLC conditions included a RP-HPLC column packed with Waters Symmetry C18(5 microns), a mobile phase composed of methanol-1% phoshporic acid(90:10) and the detection wavelength at 206 nm. The content of phosphatidylcholine was 0.198%(RSD 4.2%), and the method can be a measure of quality control for Cibotium barometz and its preparations.

[Studies on the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang]

This paper first reported the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang. With the active constituents and yield of extracts as index, the each other effect of each drug and effect on total complex prescription in extraction were studied. And the effects of pressure and temperature were also studied. The results showed the effects were different in complex prescription extraction and single prescription. Active constituents can be extracted, but a obvious effect exist each other and effects together the yield of extract, extraction rate and content of active constituents of complex prescription extraction, which are concerned in extraction conditions. These study results have important reference on the modernization of traditional Chinese medicines.

Fabricating and imaging carbon-fiber immobilized enzyme ultramicroelectrodes with scanning electrochemical microscopy

The scanning electrochemical microscope (SECM) is used to image the activity of enzymes immobilized on the surfaces of disk-shaped carbon-fiber electrodes. SECM was used to map the concentration of enzymatically produced hydroquinone or hydrogen peroxide at the surface of a 33-microm diameter disk-shaped carbon-fiber electrode modified by an immobilized glucose-oxidase layer. Sub-monolayer coverage of the enzyme at the electrode surface could be detected with micrometer resolution. The SECM was also employed as a surface modification tool to produce microscopic regions of enzyme activity by using a variety of methods. One method is a gold-masking process in which microscopic gold patterns act as mask for producing patterns of chemical modification. The gold masks allow operation in both a positive or negative process for patterning enzyme activity. A second method uses the direct mode of the SECM to produce covalently attached amine groups on the carbon surface. The amine groups are anchors for attachment of glucose oxidase by use of a biotin/avidin process. The effect of non-uniform enzyme activity was investigated by using the SECM tip to temporarily damage an immobilized enzyme surface. SECM imaging can observe the spatial extent and time-course of the enzyme recovery process.

[Studies on the supercritical CO2 fluid extraction and separation of psoralen, isopsoralen and fatty oils from Psoralea corylifolia]

Opimum extraction conditions were studied by supercritical carbon dioxide fluid extraction technology and orthogonal tests. Crystal of psoralen can be achieved directly from the extractives. Magnified experiments were carried out. The chemical constituents of fatty oils were analyzed by GC-MS. The result shows that the optimum conditions are: extraction pressure 27 MPa, extraction temperature 70 degrees C; seperation pressure 9 MPa, seperation temperature 60 degrees C. Six components such as oleic acid, linoleic acid etc. were identified in the fatty oils.

[Supercritical-CO2 fluid extraction of fatty oils from Perilla frutescens seeds and pharmacological study]

Fatty oils from the seeds of Perilla frutescens were extracted by supercritical-CO2 fluid or petroleum ether and its quality was analyzed by GC-MS method. Pharmacological action of lowering blood-lipid for the oils was studied. The results showed that the technology of supercritical-CO2 extraction of the oils of P. frutescens seeds is superior than that of petroleum ether and the oil from SFE-CO2 have the action of lowering blood-lipid with low toxicity.

[Studies on the supercritical-CO2 fluid extraction and quality evaluation of ginger oils]

Essential oils from the dried rhizomes of Zingiber officinale were extracted by supercritical-CO2 fluid(SFE-CO2) and traditional water still distillation (WSD) methods, and the SFE extraction technology and quality (GC-MS, etc.) of the oils were studied. The results showed that the SFE-CO2 contains 49 constituents, such as 6-paradol, etc, the ginger peppery component of them gets to 22.90%.

[Study on the supercritical-CO2 fluid extraction of Prunus mandshurica oils]

The paper reported technological study on extracting Prunus mandshurica oils by supercritical-CO2 fluid, mainly researched the influence of pressure, temperature, time and flow rate of CO2 on the oil yield, determined optimum technology of extracting the oils, compared the oils from SFE-CO2 and traditional technology.

Diagnosis and treatment of pulmonary hamartoma

From 1970 to 1997, 67 patients with pulmonary hamartoma were operated on in our hospital. There were 38 men and 29 women with a M/F ratio of 1.3:1. The mean age was 47 years (range 21 to 82 years). The peak incidence was 40 to 60 years. 39% patients had pulmonary symptoms: hemoptysis, cough, phlegm and chest pain. All were solitary. 68.7% tumors were located in right lung and 64.2% in upper or middle lobe. 80.6% hamartomas were less than 3 cm in transverse diameter. On chest films, the opacity was homogeneous in 79.1% cases, heterogeneous in 20.9% and calcifications in 9.0%. The vast majority of shadows were heterogeneous on CT films. Operation is the best treatment for hamartomas. Postoperative mortality was 1.5%. There was none recurrences and canceration during the follow-up (mean 14 years).

Simultaneous determination of maltose and glucose using a screen-printed electrode system

A screen-printed sensor system consisting of a glucose oxidase (GOD) electrode and an amyloglucosidase/glucose oxidase (A/G) electrode was constructed to determine maltose and glucose simultaneously in a mixture. Sensor construction was optimised so that it contained 20 units of GOD/40 units of amyloglucosidase and 0.2 mM 1,1'-ferrocenedimethanol. These components were deposited onto a screen-printed carbon electrode and an outer membrane was printed from 3.5% hydroxyethyl cellulose (HEC) solution. The optimum pH was 4.8. The linear range of the system was up to 40 mM glucose or 20 mmol/L maltose with coefficients of variation (CVs) ranging from 3.5% to 5.29%. The results obtained by using the enzyme electrode system agreed well with those obtained by the Fehling titration method. When stored dry, especially at 4 degrees C, the enzyme electrodes showed good stability over four months.

Diagnosis and treatment of stage-III peripheral squamous cell carcinoma of right upper lung

During a 12-year period, 44 patients were surgically treated for stage-III peripheral squamous cell carcinoma of the right upper lobe. The mean time from the discovery of the shadow in the right upper lobe to the confirmation of the diagnosis was 2 months. All patients underwent the resection of the right upper lobe with the dissection of the right mediastinal lymph nodes, among them, 4 patients had sleeve lobectomy of the right upper lobe. P-TNM staging: 23 cases were in stage-IIIa, 21 cases in stage-IIIb. The frequency of the postoperative complications was 20.4% (9/44 cases). The 1-year survival rate of all patients was 61% (27/44 cases). None of stage-IIIb patients lived longer than 3 years. The postoperative 3- and 5-year survival rates of stage-IIIa cases were 65.2% (15/23 cases) and 21.7% (5/23 cases) respectively. In this article, the patients' clinical features, the causes of delayed-diagnosis, the operative and postoperative management were discussed. We suggest that the stage-IIIa patients should be given surgical treatment, whereas, for the patients of stage-IIIb, palliative operation was given just for the purpose of reliving the symptoms.

[Supercritical-CO2 fluid extraction of the fatty oil in Terminalia chebula and GC-MS analysis]

The fatty oils in Terminulia chebula were extracted by supercritical-CO2 fluid extraetion, and their fatty acids and its relative contents were determined by GC-MS. 12 fatty acids were identified. Palmitic acid, linoleic acid and oleic acid of them are main constituents. Compared with petroleum ether extraction method, the extraction rate from SFE-CO2 is higher and extraction time shorter.

[Technological study on the supercritical-CO2 fluid extraction of Curcuma longa oils]

This paper first reports technological study on the extraction of Curcuma longa oils by supercritical-CO2 fluid, mainly studies the influence of pressure, temperature, flow rate of CO2 and time on the yield of the oils, determines optimum technology of extracting the oils, analyzes chemical constituents extracted, compares the oils from SFE-CO2 and SD technology, studies industrial test on the SF-CO2 extraction. The results shows pressure and temperature are more important factors of influence; the optimum technological condition is the extracted pressure 25 MPa and temperature 45 degrees C, isolated pressure I 12.5 MPa and temperature I 60 degrees C, isolated pressure II 6MPa and temperature II 38 degrees C, CO2 flow rate 9 Kg/Kg.h, and extracted time 2 h; the constituents from SFE-CO2 and SD methods are identical, but their content has some difference; SFE-CO2 technology is better than that of SD, which is high yield shorter time, etc.; the industrial production of the oils with SFE-CO2 method is available.

[Study of supercritical-CO2 fluid extraction in extracting essential oils of Amomun tsao-ko]

Essential oils from Amomum tsao-ko are extracted by supercritical-CO2 fluid and the oils are analyzed by GC-MS. 1, 8-cineole, trans-geraniol eicosatrienoic acid methylester and d-nerolidol of them are the major constitutents, 12 constitutents of them are first obtained from the plant.

[Supercritical-CO2 fluid extraction of natural VE and fatty oil from the oil foot of Brassica campestris and GC-MS analysis]

Natural VE and fatty oil from the oil foot of Brassica campestris are extracted by supercritical-CO2. After saponification and esterification these acidesters and natural VE in the extraction are analyzed by GC-MS. The results show that the fatty acids from SFE-CO2 contain 10 components which of oleic acid, linodeic acid and linolenic acid are main components, linodenic acid and linoleic acid of them are increased signifantly, at the same time, natural VE can be extracted from the materials and the rate of extraction gets to 95%.

Surgical treatment and prognosis of bronchial carcinoid tumor

In order to understand the effect of surgery in the treatment of the bronchial carcinoid tumor and the factors affecting prognosis, 18 cases of bronchial carcinoid tumor are presented, including 5 cases with Cushing's syndrome. There were lobectomy in 10, lung wedge resection in 3, excision of intraluminal tumor of bronchus in 3, exploratory thoracotomy in 2 cases. No operation death. Pathological examination revealed 14 cases were typical carcinoid tumor and 4 cases were atypical carcinoid tumor. By 2-13 years follow-up, 3, 5 and 10 years survival rate were 82%, 78% and 70% respectively. Bronchial carcinoid tumor is often confused with small cell carcinoma of lung, the correct diagnosis can be obtained by light microscopic, electron microscopic and immunohistochemistry studies. Those patients accompanied with ectopic-ACTH secretion always have Cushing's syndrome, resection of tumor can produce good result. Proper operation method depends on the location of the tumor and patient's extent of cardiac and pulmonary reserve. Atypical carcinoid tumor had high malignancy and poor prognosis. The size of tumor, lymph node involvement and adjuvant therapy seem no definite effect on the patients' survival rate.

Factors affecting removal and prognosis of thymic tumors

One hundred and ten cases of thymic tumors were intervened surgically, including 92 thymoma, 8 thymic carcinoid, and 10 thymic carcinoma. In this series, 50.9% of the cases were complicated with various syndromes, 44.5% with myasthenia gravis (MG). Resection rate was correlated with the size and invasion of the tumor. There was significant difference in resection rate among thymoma, thymic carcinoid and thymic carcinoma. The degree of invasion undoubtedly influenced on resection. The 3-, 5- and 10- year survival rate of the thymoma were 82.7%, 68.1% and 40.0%, respectively. The prognosis depended on the pathological classification and the severity of the neighbouring invasion, but MG had no significant effect on prognosis. Recurrence and metastasis of the tumor were the main cause of late death.

Diagnosis and surgical treatment of bronchogenic cysts

Between 1974 and 1993, 22 patients with bronchogenic cysts were operated on in our hospital; there were 14 men and 8 women, ranging in age from 11 to 62 years. The cyst locations were mediastinal in 13 (59.1%) and intrapulmonary in 9 (40.9%). There were symptoms (chest pain and recurrent bronchiolitis) in 20 patients (91%). The preoperative complications included infection in the lung and in the cyst and dysphagia due to esophageal compression. Chest pain was the main symptom in mediastinal cyst and recurrent infection of lung in intrapulmonary cyst. Plain chest radiograms showed that a round shadow, occasional air-fluid levels, and peripheral calcification may be found in cysts. An operation is the best treatment for cysts. All cysts were completely excised. No postoperative complications, late complications, or recurrence developed in our patients.

[Surgical treatment and diagnosis of adult bronchogenic cysts]

Between 1974 and 1993, 22 adults with bronchogenic cysts were operated in our hospital: 14 men and 8 women, ranging from 11 to 62 years old. The location was mediastinal in 13 (59.1%) and intrapulmonary in 9 (40.9%). Cysts were symptomatic (chest pain and recurrent bronchiolitis) in 20 patients (91%). The perioperative complications include infection in lungs and in the cysts and dysphagia due to esophageal compression. Chest pain was the main symptom in mediastinal cyst and recurrent infection of lungs in intrapulmonary cysts. Plain chest radiographs showed round shadows. Occasional air-fluid levels, peripheral calcification may be found. Operation is the best method for treating cysts. All cysts were completely excised. No perioperative, late complication or recurrence developed in our patients. Operation was recommended in most instances to confirm the diagnosis, to relieve symptoms, and to prevent complications.

Abnormal cardiovascular reflexes in patients with achalasia

Using 3 non-invasive tests, abnormalities of cardiovascular reflex function were found in 7 of 15 patients with achalasia. Abnormalities of heart rate responses to the Valsalva maneuver, deep breathing, and standing were noted in patients with autonomic neuropathy defect. The findings are consistent with the hypothesis that an abnormality of vagal function may contribute to the pathogenesis of achalasia.

NADPH-binding protein of the neutrophil superoxide-generating oxidase of guinea pigs

Polymorphonuclear neutrophil membranes, activated in a cell-free system, contain all of the essential components required for superoxide formation including the NADPH-binding component. Arylazido-beta-alanyl- [32P]NADPH--3'-O-(3-[N-(4-azido-2-nitrophenyl)amino] propionyl)-[32P]NADPH--an NADPH analogue and photoaffinity probe, has been used to identify the specific NADPH binding component of the oxidase in activated membranes. A protein of about 52 kDa was photodependently labeled in the activated membranes by arylazido-beta-alanyl-[32P]NADPH. Specificity of labeling was indicated by the absence of such labeling in nonactivated membranes. The 52-kDa-labeled protein was the only isotopically labeled protein extracted from the labeled membranes with the chaotrope sodium perchlorate. Sodium perchlorate extraction of the 52-kDa protein from activated membranes correlates with the loss of the membranes' superoxide-generating capability. Reconstitution of the lost activity for sodium perchlorate-extracted membranes was accomplished by reincubating the extracted membranes with cytosol. It is proposed that the arylazido- beta-alanyl-[32P]NADPH-labeled protein of 52- to 57-kDa present on the activated membranes is the NADPH-binding protein of the neutrophil superoxide-generating oxidase.

Identification of the NADPH-binding protein of the neutrophil superoxide-generating oxidase of guinea pigs

A cell-free system prepared from polymorphonuclear neutrophils is capable of NADPH-dependent generation of superoxide anion, but requires the simultaneous presence of plasma membranes, cytosol, arachidonate and guanosine 5'-[gamma-thio]triphosphate (GTP[S]). The isolated membranes from such a preparation are able to catalyse NADPH-dependent superoxide formation independently of added cytosol and activators. Such activated membranes, activated in the cell-free system, must consequently contain all of the essential components required by the oxidase for superoxide formation, including the NADPH-binding component. Arylazido-beta-alanyl-[32P]NADPH (3'-O-(3-[N-(4-azido-2-nitrophenyl)-amino] propionyl)-[32P]NADPH), an NADPH analogue and photoaffinity probe, is shown to act in the dark as a substrate for the oxidase activity in the activated membranes and an irreversible photodependent inhibitor following photoirradiation. The photoaffinity probe has been used to identify the specific NADPH-binding component of the oxidase in the activated membranes. In contrast with the sensitivity of the activated membranes, photoirradiation of arylazido-beta-alanyl-[32P]-NADPH under identical conditions, but with non-activated membranes, did not prevent subsequent activation of the treated membranes by cytosol, arachidonate and GTP[S]. However, photoirradiation of the cytosolic fraction in the presence of arylazido-beta-alanyl-[32P]NADPH resulted in an inhibition of the cytosol's ability to activate superoxide generation upon subsequent incubation with plasma membranes in the presence of arachidonate and GTP[S]. These observations are taken as a strong indication that the NADPH-binding protein of the oxidase is a cytosolic factor which associates with the plasma membrane upon activation. The superoxide-generating activity of the activated membranes was inhibited irreversibly in a concentration- and photo-dependent manner by arylazido-beta-alanyl-NADPH. The arylazido-beta-alanyl-NADPH-photodependent inhibition of superoxide generation in the activated membranes correlated with the photodependent labelling of a protein of 55.6 kDa by the arylazido-beta-alanyl-NADPH. Specificity of labelling was indicated by a lack of labelling of the 55.6 kDa region in the non-activated membranes and protection of the photodependent inhibition and labelling of the 55.6 kDa protein by NADPH. It is proposed that the arylazido-beta-alanyl-NADPH-labelled 55.6 kDa protein present on the activated membranes is the NADPH-binding protein of the neutrophil superoxide-generating oxidase.

Ontogeny of Leu-enkephalin and beta-endorphin innervation of the preoptic area in male and female rats

The distribution of endogenous opioid peptide-containing fibers in the medial preoptic area of developing male and female rats was examined using immunohistochemical methods. In particular, the ontogeny of leucine-enkephalin (leu-enk) and beta-endorphin (beta-endo) innervation was studied using antisera directed against these compounds. The distribution of Leu-enk and beta-endo differed at each age examined from birth to postnatal day 12 (P12). Furthermore, the patterns of fiber innervation differed across development. Leu-enk-like immunoreactivity was initially densest in the lateral preoptic region of both sexes, ultimately expanding into the medial preoptic region to become densest in the lateral portion of the medial preoptic nucleus by P12. This latter pattern was observed only in males, however, as females continued to exhibit diffuse medial preoptic Leu-enk-like immunoreactivity at P12. In contrast, the distribution and developmental pattern of beta-endo-like immunoreactivity was similar in both sexes; diffuse staining was observed in the medial preoptic region at birth, later becoming dense only in the periventricular and parastrial nuclei. The time course of development of Leu-enk and beta-endo innervation of the medial preoptic area suggests that the sexually dimorphic expression of opioid immunoreactivity occurs after preoptic neurons appear in their sexually dimorphic configuration. Therefore, although the development of opioid-containing pathways could be influenced by the perinatal gonadal steroid hormone environment, medial preoptic Leu-enk and beta-endo innervation might not contribute directly to the sexually dimorphic neuronal organization of the preoptic area.

[Manometry indexes for evaluating esophageal function in patients with achalasia]

In 43 patients with achalasia (postoperative 18, post-dilatation 15, preoperative 10, and 10 normal people) esophageal manometry, esophageal emptying barium test and endoscopy were employed. The results showed that the esophageal emptying index EEI was 13.3 +/- 9.0 in the postoperative group, 4.7 +/- 7.6 in the post dilatation group, 50.0 +/- 17.4 in the normal group, 2.9 +/- 4.3 in the preoperative group. A linear relationship was seen between EEI and the lower esophageal barium retention area (So) (t = -5.00, P < 0.001). In patient with higher EEI and smaller So stronger esophageal emptying function was noted at swallowing. 80% of patients with less than 12 esophageal anti-reflux index (ARI) suffered from gastroesophageal reflux EEI and ARI can evaluate not only the esophageal motor functions but also the therapeutic effects of different treatment methods. The therapeutic effects are determined by esophageal peristalsis pressure and LES relaxation rate after LES is relaxed.

Similar high molecular weight forms of growth hormone-releasing hormone are found in rat brain and testis

We have utilized a new radioimmunoassay for rat growth hormone-releasing hormone (GHRH) to investigate the presence of GHRH in different organ systems of adult rat, and specifically the rat central nervous system (CNS). The highest concentration of GHRH was found, as expected, in the hypothalamus, but significant amounts were also located in the brain cortex, predominantly the frontal cortex, as well as in the testis. Smaller amounts were identified in the cerebellum and brain stem. Sephadex and reversed phase high performance liquid chromatography demonstrated that while hypothalamic GHRH exclusively eluted at the position of rat GHRH (1-43), in testis and brain the major form was predominantly (testis) or wholly (brain) of a higher molecular weight. While this molecular species has yet to be further characterized, the data suggest the similar GHRH-like species exist in the CNS as well as the testis.

Mathematics achievement of children in China and the United States

First and fifth graders in Beijing and Chicago were given a battery of mathematics test. Whether tested with problems requiring solely computation or with ones requiring application of knowledge about mathematics, American children's performance was consistently inferior to that of Chinese children. Interviews with American children suggested that they like mathematics, believe they are doing well in mathematics, and do not perceive mathematics as a difficult subject. American children's poor performance appears to be attributable, in part, to low motivation for devoting more attention to mathematics. Low standards held by American parents for academic achievement and lower interest in teaching mathematics by American teachers appear to contribute to American children's poor performance.

Relationship between growth hormone-releasing hormone and somatostatin in the rat: effects of age and sex on content and in-vitro release from hypothalamic explants

Secretion of GH in the rat has been shown to be dependent upon age and sex. Using rat hypothalamic explants in vitro, we have studied the release and hypothalamic content of GH-releasing hormone (GHRH) and somatostatin in male and female Wistar rats at four different ages (10, 30 and 75 days, and 14 months). Basal release of GHRH was not significantly different between male and female rats, but at all ages males released more GHRH in response to stimulation by both 28 and 56 mmol potassium/l than female rats (P less than 0.05). Neither basal nor potassium-stimulated release of GHRH altered with age. In contrast, both basal and potassium-stimulated secretion of somatostatin increased significantly (P less than 0.01) with age, but was the same in the two sexes. Hypothalamic GHRH content, as assessed by the extractable tissue content following incubation, was significantly (P less than 0.01) lower in 10-day-old rats compared with older rats, but remained constant after 30 days of age. Somatostatin content, in contrast, increased progressively with age (P less than 0.01). The hypothalamic content of the two peptides was the same in both sexes. In conclusion, our findings demonstrate that male rats release more GHRH in vitro than female rats, possibly reflecting the increased pulse amplitude of GH seen in males in vivo; the progressive fall in secretion of GH previously reported during ageing appears to parallel the progressive increase in somatostatin release and content seen in our in-vitro system.