[Study on gene-dosage effect of high level expression of the yeast glucoamylase genes]

Diploid strains homozygous for both MAT allele and STA genes (a/a, STA1/STA1 or STA2/STA2 or STA3/STA3) and diploid strains homozygous for MAT allele but intercombinative for STA genes (a/a, STA1/STA2 or STA2/STA3 or STA1/STA3) were constructed by means of the protoplast fusion or the colchicine treatment. According to glucoamylase activity in YPS medium, we studied the gene-dosage effect and their interrelation of these three polymeric genes coding for glucoamylase. The results of the glucoamylase activity determination showed that the gene-dosage effect of glucoamylase is obvious in diploid and triploid strains homozygous for both MAT allele and STA gene, such as the glucoamylase activity of a diploid strain SFY56-6 and a triploid strain SFY56-104 homozygous for both MAT allele and STA genes were respectively 2.35 and 3.18-fold as compared with that of the their parental strain IATA-Y56 that is a haploid Saccharomyces diastaticus. Moreover, the glucoamylase activity of diploid strains homozygous for MAT allele but intercombinative for STA genes also showed the combinative gene-dosage effect to a certain extent.

Establishment of human prostate carcinoma skeletal metastasis models

BACKGROUND

Prostate carcinoma progression from an androgen dependent (AD) state to an androgen independent (AI) state occurs clinically in patients who undergo hormonal therapy. In their laboratory, the authors developed two human prostate carcinoma skeletal metastasis models, the LNCaP progression model and the ARCaP model, to investigate phenotypic and genotypic changes of prostate carcinoma cells during disease progression and to understand molecular pathways for potential therapeutic targeting.

METHODS

LNCaP or ARCaP cells were inoculated in athymic mice and were exposed to selective hormonal conditions both in vivo and in vitro. The effects of various hormonal treatment regimens on tumor volumes and distant metastasis and the effects of bone stromal cells on prostate specific antigen (PSA) expression by prostate carcinoma cells were evaluated.

RESULTS

The authors propose that prostate carcinoma progression from the AD state to the AI state assumes three AI phenotypes: AI that remains androgen responsive, AI that is unresponsive to androgen stimulation, and AI that is suppressed by or hypersensitive to androgen. AI prostate carcinoma cells interacted reciprocally with osteoblasts to produce enhanced tumor growth and osteoblastic reaction when they are deposited in bone. Bone stromal cell conditioned media stimulated prostate carcinoma cell growth and suppressed its PSA expression, as also evidenced by androgen receptor-mediated transactivation of PSA promoter reporter activity. Conditioned media obtained from prostate carcinoma cells also stimulated osteoblastic cell growth in vitro. A novel gene therapy strategy is being developed to target prostatic tumor epithelium and its supporting stroma using tissue specific and tumor-restricted, promoter-directed toxic gene expression in both cellular compartments. In addition, new strategies are being designed to target the tumor endothelial system in the stroma and tumor cell-extracellular matrix interaction mediated by isotype specific integrins.

CONCLUSIONS

Prostate carcinoma skeletal metastasis models may prove useful in developing a new targeting strategy for the prevention and treatment of patients with prostate carcinoma.

Community-based epidemiological study of glucose tolerance in Kin-Chen, Kinmen: support for a new intermediate classification

In this population-based survey, we investigated the prevalence of varying degrees of glucose tolerance among residents of Kin-Chen, Kinmen, as well as the association of glucose tolerance status with potential risk factors for type 2 diabetes and cardiovascular disease (CVD). We focused particularly on subjects with normal 2-h postload glucose level (<7.8 mmol/l) but persistent fasting hyperglycemia (PFH) (5.6-7.8 mmol/l), to examine whether PFH represents an intermediate state between normal glucose tolerance (NGT) and impaired glucose tolerance (IGT). The target population comprised 6346 residents aged 30 years and older. A total of 4354 subjects could be classified into categories of NGT, PFH, IGT, new diabetes, and known diabetes according to medical history, fasting plasma glucose levels, and the results of a 75-g oral glucose tolerance test (OGTT). The potential cardiovascular risk factors assessed included age, obesity (general and central), systolic blood pressure, and fasting levels of insulin, C-peptide, triglyceride, cholesterol, and high-density lipoprotein cholesterol (HDL-C). The age-standardized prevalences of PFH, IGT, new diabetes, and known diabetes were 2.9%, 3.5%, 4.0%, and 3.0%, respectively. Among nondiabetic subjects, the cardiovascular risk factor profiles worsened with decreasing glucose tolerance, with most values differing significantly among the NGT, PFH, and IGT groups. Subjects with PFH, who would be classified as having NGT according to conventional WHO criteria, had physical and biochemical features between those of the NGT and IGT groups. These findings support our previous observation that PFH may be a transition state between NGT and IGT in the progression toward type 2 diabetes.

[Protein kinase B and its role in the signal transduction pathway mediated by phosphoinositide 3-kinase]

Protein kinase B (PKB) is the expression product of a proto-oncongen (c-akt), which is involved in the signaling pathways initiated by some growth factors and mediated by phosphoinositide 3-kinase (PI3K). PKB is a direct target of PI3K. Similar to many protein kinases, PKB has a specific AH/PH domain which can mediate the interaction between signaling molecules. The lipid second messengers, PI-3, 4-P2 and PI-3,4,5-P3 produced by PI3K, can bind to the AH/PH domain of PKB and of PDK (phosphoinositide dependent protein kinase). This binding translocates PKB and PDK to the plasma membrane, and activates them. PKB is also activated via phosphorylation by PDK and, in turn, will activate the anti-apoptotic machinery, glucose metabolism (glycogen synthesis, glycolysis and glucose uptake) and protein synthesis. All these lead to cell growth and proliferation.

Expression of the Wilms' tumor suppressor gene, WT1, reduces the tumorigenicity of the leukemic cell line M1 in C.B-17 scid/scid mice

The Wilms' tumor suppressor gene, WT1, encodes a transcription of the Cys2-His2 zinc finger type. Loss of WT1 gene function has been implicated in the development of malignancies including Wilms' tumor and acute leukemias. We have shown previously that ectopic expression of WT1 +KTS isoforms in murine M1 leukemic cells spontaneously induces monocytic differentiation without the requirement for external differentiation-inducing stimuli. To determine whether these observed effects in vitro corresponded to a reduction in tumorigenicity in vivo, parental M1, control M1.Neo, and M1.WT1 +KTS cells were transplanted into C.B-17 scid/scid mice, and the growth and metastatic behavior of the cell lines were monitored for a period of 20 weeks. Mice inoculated either s.c. on the flank or directly into the peritoneal cavity, with M1 cells stably expressing WT1 +KTS isoforms exhibited a marked decrease in tumor formation compared with control groups. Moreover, tumors arising in mice after the injection of M1.WT1 +KTS cells exhibited a loss in ectopic WT1 protein expression. Confirmation that the tumors arose from M1.WT1 +KTS cells was achieved by the amplification of the introduced transgene from tumor samples and indicates that the tumorigenicity of leukemic M1 cells in these animals correlates with a loss in WT1 expression. This investigation is the first to demonstrate the tumor-suppressive effects of WT1 expression in a leukemic cell line, further advancing the notion that WT1 acts as a differentiation-promoting gene during hematopoiesis and that loss of functional WT1 expression may contribute to leukemogenesis in vivo.

Effect of aging on gender differences in neural control of heart rate

To clarify the influence of gender on sympathetic and parasympathetic control of heart rate in middle-aged subjects and on the subsequent aging process, heart rate variability (HRV) was studied in normal populations of women (n = 598) and men (n = 472) ranging in age from 40 to 79 yr. These groups were divided into eight age strata at 5-yr intervals and were clinically diagnosed as having no hypertension, hypotension, diabetic neuropathy, or cardiac arrhythmia. Frequency-domain analysis of short-term, stationary R-R intervals was performed, which reveals very-low-frequency power (VLF; 0.003-0.04 Hz), low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), the ratio of LF to HF (LF/HF), and LF and HF power in normalized units (LF% and HF%, respectively). The distribution of variance, VLF, LF, HF, and LF/HF exhibited acute skewness, which was adjusted by natural logarithmic transformation. Women had higher HF in the age strata from 40 to 49 yr, whereas men had higher LF% and LF/HF between 40 and 59 yr. No disparity in HRV measurements was found between the sexes in age strata >/=60 yr. Although absolute measurements of HRV (variance, VLF, LF, and HF) decreased linearly with age, no significant change in relative measurements (LF/HF, LF%, and HF%), especially in men, was detected until age 60 yr. We conclude that middle-aged women and men have a more dominant parasympathetic and sympathetic regulation of heart rate, respectively. The gender-related difference in parasympathetic regulation diminishes after age 50 yr, whereas a significant time delay for the disappearance of sympathetic dominance occurs in men.

Loss of heterozygosity and lack of mutations of the XPG/ERCC5 DNA repair gene at 13q33 in prostate cancer

BACKGROUND

Three regions of chromosome 13 were previously identified for having loss of heterozygosity (LOH) in human prostate cancer. One of them, at 13q33, was defined by LOH at markers D13S158 and D13S280. The XPG/ERCC5 gene, a DNA repair gene that when mutated in the germline leads to xeroderma pigmentosum, has been mapped to 13q33, within one megabase of D13S158 and D13S280. This paper describes LOH and mutational analysis of the XPG gene in human prostate cancers, in order to determine whether the XPG gene is involved in the development of prostate cancer.

METHODS

LOH of the XPG gene was analyzed in 40 primary prostate cancers and 14 metastases by using the microsatellite assay, and its mutations were examined in 5 cell lines, 14 metastases, and 8 tumors with LOH at 13q33 by using the single-strand conformation polymorphism (SSCP)-direct DNA sequencing analysis.

RESULTS

Four of the 29 (14%) informative primary tumors and 4 of 8 (50%) metastases showed LOH for the XPG gene. Analysis of the 8 tumors with LOH at the 13q33 region, 14 metastases, and 5 cell lines of prostate cancer revealed two polymorphisms but no mutation of the gene. The polymorphism in exon 2 did not change the amino-acid sequence of the XPG protein, but the exon 15 polymorphism altered codon 1104 from histidine to aspartic acid. The two polymorphisms also occurred in individuals without prostate cancer.

CONCLUSIONS

LOH at XPG in prostate cancer supports the conclusion that the 13q33 region contains a gene important in the development of prostate cancer, while lack of mutations of the gene suggests that XPG is not the target gene involved.

Comparison of the results between two diagnostic criteria by ADA and WHO among subjects with FPG 5.6-7.8 mmol/l in Kin-Hu and Kin-Chen, Kinmen, 1991-94

The objective of this study was to compare the results between two diagnostic criteria by ADA (1997) and WHO (1985) among those with fasting plasma glucose (FPG) level 5.6-7.8 mmol/l from a community-based survey in Kin-Hu and Kin-Chen, Kinmen conducted in 1991-94. According to official household registry, 10,797 residents aged over 30 were eligible for screening. 7580 had completed FPG screening and 1855 with FPG 5.6-7.8 mmol/l were invited to receive a 75-g oral glucose tolerance test (OGTT). 78.5% (1456/1855) had completed OGTT. The prevalence of impaired fasting glucose (IFG, by ADA) was 15.7%; the prevalence of impaired glucose tolerance (IGT, by WHO) was 22.7%; the prevalence of undiagnosed diabetes was 7.4% by ADA criteria and 10.9% by WHO criteria. It should be noticed that, among subjects with FPG 5.6-7.8 mmol/l, 50.3% of individuals with undiagnosed diabetes and 67.6% of individuals with IGT by WHO criteria would be missed by ADA criteria. Based on the above findings, the two-step screening strategy using FPG as the first line screening and OGTT for high-risk group (FPG 5.6-7.8 mmol/l) only was recommended in epidemiological study and case finding in consideration of feasibility and validity.

Effect of metformin on patients with impaired glucose tolerance

AIMS

To evaluate the effect of metformin on glucose metabolism, insulin sensitivity and rate of conversion diabetes in people with impaired glucose tolerance (IGT).

METHODS

Seventy subjects with IGT were randomized under double-blind conditions to receive either placebo (n = 37) or metformin (n = 33) at a dosage of 250 mg three times daily for a duration of 12 months. Glycaemic control, plasma insulin and other biochemical indexes were assessed before and after 3, 6 and 12 months.

RESULT

At 12 months the conversion rate to diabetes was 16.2% in the placebo group compared to 3.0% for the metformin group (P = 0.011). Of subjects treated with metformin for 12 months, 84.9% became normoglycaemic compared to 51.4% of those receiving the placebo. Significant improvements in fasting glucose, glucose tolerance and insulin sensitivity were found at 12 months and at intermediate clinic assessments.

CONCLUSIONS

Metformin can improve glucose metabolism in IGT patients and may be a treatment option in their management of IGT subjects.

The impact of department sub-division on hospital performance

BACKGROUND

Chang Gung Memorial Hospital is the first hospital in Taiwan to adopt the 'sub-division management'. The hospital sub-divided extensively growing departments into two or more similar sub-divisions. This study compared the relative performance before and after the implementation of "sub-division management".

METHODS

The cardiac department of Chang Gung Memorial Hospital was subdivided into Cardiac I and Cardiac II in July 1992. This study collected the managerial information of cardiac inpatients from 1991 through 1993 in Chang Gung Memorial Hospital. By exploring the effects of the "sub-division management" and other confounding factors, we tried to find out the possible impact they brought to hospital performance.

RESULTS

Considering a time trend effect, the results of regression indicate that 'sub-division' mechanism had little effect on departmental performance. However, the performance is different between Cardiac I and Cardiac II in the aspect of total expenditure per admission, average length of stay, and average number of discharge per physician. These differences might be affected by the characteristics of physicians' sub-specialties rather than the implementation of sub-division management.

CONCLUSION

The significant decrease in mortality rate of patients in the cardiology department after the implementation might suggest that the quality of care in the cardiology department increased after the introduction of sub-divisions. The long-term effects of practice behavior induced by competition within and between sub-divisions require further organizational and behavioral studies.

Structural and functional abnormalities in the spleen of an mFtz-F1 gene-disrupted mouse

The spleen has two main functions. The first is to provide a proper microenvironment to lymphoid and myeloid cells, whereas the second involves clearance of abnormal erythrocytes. Ad4BP/SF-1, a product of the mammalian FTZ-F1 gene (mFTZ-F1), was originally identified as a steroidogenic, tissue-specific transcription factor. Immunohistochemical examination of the mammalian spleens confirmed the expression of Ad4BP/SF-1 in endothelial cells of the splenic venous sinuses and pulp vein. In mFtz-F1 gene-disrupted (KO) mice, several structural abnormalities were detected in the spleen, including underdevelopment and nonuniform distribution of erythrocytes. Examination of the spleen of KO fetuses showed failure of development of certain tubular structures during embryogenesis. These structures are normally assembled by Ad4BP/SF-1 immunoreactive cells, and most likely form the vascular system during later stages of development. Other structural abnormalities in the spleen of the KO mice included defects in the tissue distribution of type-IV collagen, laminin, c-kit, and vimentin. These morphologic defects in the vascular system were associated with a decrease in the proportion of hematopoietic cells, although differentiation of these cells was not affected significantly. A high number of abnormal red blood cells containing Howell-Jolly bodies were noted in the KO mice, indicating impaired clearance by the splenic vascular system. We also detected the presence of an mRNA-encoding cholesterol side-chain cleavage P450 in the spleen, resembling the findings in steroidogenic tissues such as the gonads and adrenal cortex. The mRNA transcript was not involved in splenic structural defects as it was detected in the spleens of both normal and KO mice, indicating that the regulatory mechanism of the P450 gene in the spleen is different from that in steroidogenic tissues. Our results indicate that a lack of the mFtz-F1 gene in mice is associated with structural and functional abnormalities of the splenic vascular system.

[In vivo degradation of PDLLA membrane made in China:a study on rats]

OBJECTIVE:The possibility of absorbable membrane materials poly PDLLA using in guided tissue regeneration(GTR)was evaluated through degradation in vivo. METHODS: membranes were implanted in the drosal subcutis of rats for periods of 1,2,4,8,12weeks.The surface morphology was observed,the mass loss was measured and molecular weight was determined with gel permeation chromatography(GPC). RESULTS: The mass loss were similar to those in virto,and molecular weight changes were the same to those in vitro,but the number average molecular weight did not fit the Pitt's model. CONCLUSION: The surface morphology of PDLLA membrane remained relatively unaltered,its integrity kept more than 12 weeks,which could meet the requirements of GTR.

PTEN/MMAC1 is infrequently mutated in pT2 and pT3 carcinomas of the prostate

Deletion of the q23-24 region of human chromosome 10 is one of the most frequent genetic alterations in prostate cancer, suggesting that inactivation of a tumor suppressor gene in this region is involved in the development or progression of this carcinoma. A candidate gene, PTEN/MMAC1, has been identified from this chromosomal region; mutations of this gene have been found in various advanced tumors and cell lines including those of prostate cancer. To further define the role of PTEN/MMAC1 in the development of prostate cancer and its spectrum of genetic alterations, we analysed 40 pT2 or pT3 prostate tumors for allelic loss, mutations, and homozygous deletions using PCR-based methods. Six tumors showed loss of heterozygosity for one of the ten markers analysed, while one tumor showed loss of two markers. None of the markers within PTEN/MMAC1 was lost. Direct sequencing of PCR amplified exons and intron/exon junctions of all 40 tumors revealed three sequence variants, one of which was a point mutation in exon 9, while the other two were polymorphisms. Using multiplex PCR, no homozygous deletions were detected in any of the neoplasms. Our results showing a low frequency of alterations of PTEN/MMAC1 in pT2 and pT3 prostate cancers suggest that this gene plays an insignificant role in the development of most low stage carcinomas of the prostate.

Progression to type 2 diabetes among high-risk groups in Kin-Chen, Kinmen. Exploring the natural history of type 2 diabetes

OBJECTIVE

To examine the natural history of 654 high-risk subjects (340 men and 314 women) with fasting hyperglycemia (first fasting plasma glucose [FPG] level 5.6-7.8 mmol/l) who also exhibited 2-h postload glucose concentrations < 11.1 mmol/l and an FPG level < 7.8 mmol/l in a 75-g oral glucose tolerance test (OGTT). We were particularly interested in comparing the likelihood of developing type 2 diabetes for those with persistent fasting hyperglycemia (PFH), impaired glucose tolerance (IGT), and normal glucose tolerance (NGT). PFH is a relatively new definition, and those with PFH used to be defined as NGT according to WHO criteria.

RESEARCH DESIGN AND METHODS

Subjects were located in a 1992-1994 community-based population survey and followed up and reexamined during 1995-1996. An OGTT was used to determine who had progressed to type 2 diabetes. Risk factors predictive of subsequent progression to type 2 diabetes were determined by comparing baseline variables from the 1992-1994 survey with data of those who had or had not progressed to type 2 diabetes in 1995-1996.

RESULTS

Of 654 high-risk subjects screened in the baseline survey, 481 (73.5%, 255 men and 226 women) were followed up. Of these, 8.1% had progressed to diabetes (4.1% progression/year, 95% CI 2.3-5.9). Of 131 baseline IGT subjects, 17.6% progressed to diabetes (8.8% progression/year, 6.3-11.3), but only 7.4% of 95 PFH subjects (3.7% progression/year, 2.0-5.4) and 3.5% of 255 NGT subjects (1.8% progression/year, 0.1-3.0) progressed to diabetes.

CONCLUSIONS

The rates of progression to type 2 diabetes were lowest from the NGT subgroup, highest from the IGT group, with the PFH group in the middle, suggesting that PFH might be a transitional condition that precedes IGT and diabetes. Other significant predictors of subsequent diabetes were baseline BMI, baseline hyperuricemia, baseline FPG, and 2-h plasma glucose concentration.

[ACTH receptor, ACTH receptor anomaly, and familial glucocorticoid deficiency]

Familial glucocorticoid deficiency (FGD) is an autosomal recessive syndrome with hereditary adrenocortical unresponsiveness to ACTH. After the cloning of ACTH receptor or melanocortin-2 receptor (MC-2R) cDNA, several kinds of mutations in the receptor genes have been reported. However, the apparently normal ACTH receptor gene in some affected children suggests that the etiology of FGD is heterogeneous. In this short review, we describe the recent advances in the molecular biology of ACTH receptor genes, its post-receptor signal transduction in the adrenocortical cells, and the molecular genetics of the FGD and a related syndrome, Allgrove syndrome. We also discuss that this kind of work will help us to understand better about the molecular mechanism of the glucocorticoidogenesis in the human being.

[Expression of murine interleukin 12(mIL-12) in insect cells]

Since human IL-12 is species-specific in its functions and elicits little biological responses from mouse lymphocytes, it is necessary to express recombinant murine IL-12 for the usage in studying the effects of this cytokine in various rodent models. Thereby, we can investigate the role of IL-12 in immune response in vivo and evaluate its potential clinical utility. Thus, we firstly constructed two expression vectors, pVL1393-mp40 and pVL1393-mp35. They were used to co-transfect the insect cells(Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-mp40 and AcNPV-mp35 were visually screened out, and mp40 and mp35 were co-expressed in the insect cells co-infected by AcNPV-mp40 and AcNPV-mp35. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the recombinant mIL-12 was expressed successfully in the insect cells. The molecular weights of recombinant mp40 and mp35 were 40 KDa and 22 KDa on SDS-PAGE under reducing conditions, respectively. The apparent molecular weight of recombinant mIL-12 is 80 KDa under non-reducing conditions of Western blot. Biological activity of the recombinant product was detected in conditional medium using antibody-capture bioassay. The expression level of recombinant mIL-12 was about 10-15 micrograms/10(6) cells, as compared with the calibration curve of mIL-12.

Intrasynaptosomal free calcium and nitric oxide metabolism in central nervous system oxygen toxicity

BACKGROUND

Central nervous system (CNS) oxygen (O2) toxicity is complex, and the etiology of its most severe manifestation, O2 convulsions, is yet to be determined. A role for nitric oxide (NO) has been proposed, although recent data have indicated that NO is synthesized from L-arginine by an enzyme, NO synthase (NOS). The enzyme is dependent on free calcium (Ca2+) concentration, therefore increases in intracellular Ca2+ may constitute the physiological and pathophysiological mechanisms for stimulating the synthesis of NO.

METHODS

In this study, the intrasynaptosomal free calcium concentration ([Ca2+]i) was measured by the fluorescence of fura-2/AM, and cGMP (as an indirect marker of NO levels) was by radioimmunoassay (RIA) in the rat hippocampus after hyperbaric oxygen (HBO) exposure. We also investigated the effects of daurisoline (DSL, calcium channel blocker) and N-nitro-L-arginine (LNNA, NOS inhibitor) on the above biochemical parameters and the development of oxygen toxicity.

RESULTS

The results show that when the rats were exposed to HBO at 0.5 MPa the intrasynaptosomal Ca2+ and cGMP levels increased by two and three times, respectively, whereas with the use of DSL prior to HBO, the accumulation of [Ca2+]i and cGMP dropped to 56% and 60%, correspondingly. In the rats medicated with LNNA prior to HBO. [Ca2+]i and cGMP levels dropped to 70% and 36% of the HBO group. At the same time, the appearance of CNS oxygen toxicity was delayed and the survival rate increased. The protective effects of LNNA were reversed by L-arginine pretreatment. These findings suggest that the neuronal Ca2+ overload during HBO exposure is a major factor in the pathogenesis of CNS O2 toxicity, and cGMP-NO pathways may be directly involved in HBO-induced seizures.

Human mu-opioid receptor overexpressed in baculovirus system and its pharmacological characterizations

AIM

To overexpress human mu-opioid receptor (muOR) with characteristics similar to those of mammalian origin.

METHODS

Human muOR with a tag of 6 consecutive histidines at its carboxyl terminus was expressed in recombinant baculovirus infected Sf9 insect cells. Then the pharmacological characterizations of the product were studied by receptor binding assay and cAMP assay.

RESULTS

The maximal binding capacity for the [3H]diprenorphine and [3H]ohmefentanyl (Ohm) were 9.1 +/- 0.7 and 6.52 +/- 0.23 nmol/g protein, respectively. The [3H]diprenorphine or [3H] Ohm binding to the receptor expressed in Sf9 cells was strongly inhibited by alpha-selective agonists [D-Ala2, N-methyl-Phe4, glyol5] enkephalin (DAGO), Ohm, and morphine, but neither by the delta-selective agonist [D-Pen2, D-Pen5] enkephalin (DPDPE) nor by the kappa-selective agonist ¿trans-(+/-)-3, 4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]¿ benzacetamide (U50488). NaCl 100 mmol.L-1 and guanosine triphosphate (GTP) 50 mumol.L-1 could reduce mu agonists Ohm and etorphine affinity binding to the expressed muOR. DAGO and Ohm effectively inhibited forskolin-stimulated cAMP accumulation. This agonist-dependent effect was blocked by opioid antagonist naloxone.

CONCLUSION

The overexpression of human muOR with a tag of six consecutive histidines at its carboxyl terminus in Sf9 insect cells retained the characteristics of wild-type human muOR.

[Biosynthesis of a single peptide chain containing human chorionic gonadotropin beta and ovine common alpha subunits tandem]

hCG beta-oLH alpha chimeric cDNA was constructed by using overlapping PCR to contact the codons of C-terminal end of hCG beta with the codons of N-terminal end of oLH alpha, then it was subcloned into nuclear polyhedrosis virus (AcNPV) expression vector pVL1393 to construct expression vector pVL1393-hCG beta-oLH alpha. The insect cells (Sf9) were cotransfected by the expression vector pVL1393-hCG beta-oLH alpha and BaculoGold AcNPV linearized genomic DNA, and recombinant viruses AcNPV-hCG beta-oLH alpha were screened out by plaque assay. Further the insect cells were infected by the recombinant viruses, the recombinant hCG beta-oLH alpha was purified by immunoaffinity chromatography column coupling anti-hCG beta monoclonal antibody from the conditioned media of infected cells. The results of SDS-PAGE silver staining and western blotting showed that hCG beta-oLH alpha single peptide chain had apparent molecular weights of 40.5 kD and 38.0 kD under non-reducing and reducing conditions respectively, indicating the occurrence of disulfide bonds and significant tertiary structure in the single peptide chain. From the results of competitive inhibition of 125I-hCG beta binding we can conclude that the anti-hCG beta antibody-binding activity of hCG beta-oLH alpha chimera is lower than that of native hCG, but higher than that of native hCG beta. Therefore, we assume that the hCG beta-oLH alpha chimera should have potential application as a target antigen of anti-hCG fertility regulatory vaccine.

Expression of the Wilms' tumor suppressor gene, WT1, is upregulated by leukemia inhibitory factor and induces monocytic differentiation in M1 leukemic cells

The Wilms' tumor gene, WT1, encodes a transcription factor of the Cys2-His2 zinc finger type. The functional significance of WT1 expression in leukemias, in addition to tissues and cell lines of hematopoietic origin, has not been determined. Using the murine myeloblastic leukemia cell line M1 as a model for macrophage differentiation, expression of WT1 is shown to be activated in M1 cells 24 hours after differentiation induction by leukemia inhibitory factor (LIF). Upregulation of WT1 in these cells is associated with cellular differentiation, coinciding with expression of the monocyte/macrophage marker c-fms, and the appearance of mature cells. WT1 isoforms lacking the KTS insert are unable to be ectopically expressed in M1 cells. Stable expression of the WT1 isoforms containing the KTS insert leads to spontaneous differentiation of the M1 myeloblasts through the monocytic differentiation pathway. These cells express c-fms, in addition to the myeloid-specific cell surface marker Mac-1. Exposure of these cells to LIF results in the rapid onset of terminal macrophage differentiation, accompanied by apoptotic cell death. These results show that the WT1 gene is an important regulator of M1 cell monocytic differentiation in vitro, and suggests a potential role for this gene in the molecular control of hematopoiesis.

Predominant expression of murine Bmx tyrosine kinase in the granulo-monocytic lineage

In the course of systematic cloning of protein tyrosine kinases (PTKs) expressed in hematopoietic stem and progenitor cells, we have identified the murine homologue of human Bmx. It encodes a protein containing the five domains characteristic of the Tec family of cytoplasmic src-related PTKs: pleckstrin homology (PH), Tec homology (TH), src homology 3 and 2 (SH3 and SH2), and tyrosine kinase (TK). In adults, Bmx expression was found primarily in bone marrow and at a lower level in lung and heart. During fetal development it was also found in the spleen at late stage of gestation and in neonates. Analysis of bone marrow subpopulations showed that Bmx was expressed in the progenitor cell population and maturing hematopoietic cells of the granulo/monocytic lineage where expression increased with maturation and differentiation. At the periphery, a high level of Bmx expression was also found in neutrophils and monocytes/macrophages. Bmx expression was not detected in the primitive hematopoietic stem cell population, and cells of the B-, T-, and erythroid-lineages. It was also not detected in most of the cell lines examined. Our results indicate that Bmx is another member of the Btk/Itk/Tec PTK family, which is predominantly expressed in the granulo-monocytic lineage within the hematopoietic system.

The bioavailability of ginkgolides in Ginkgo biloba extracts

A new Ginkgo biloba leaf extract, BioGinkgo 27/7, was prepared using a method that enriches ginkgolide B. The bioavailability of ginkgolides in these extracts was assessed in rabbits in comparison with a commercially available standardized 24/6 extract. It was found that, after a single dose, a higher concentration of ginkgolides was maintained for a longer period of time with these extracts than was found with commercial extract prepared by existing methods.

[Inhibition of gastric motility by microinjection of CCK-8 into rat amygdala]

Intranulear microinjection and electrical stimulation technique were employed to evaluate the effect of ventromedial hypothalamus (VMH) on the gastric inhibition elicited by basomedial amygdala nucleus (BMA) excitation. The results were as follows: (1) Microinjections of CCk-8 (50 ng/microliter) into bilateral BAM resulted in significant decrease in intragastric pressure (IGP) and gastric motility frequency (GMF) (P < 0.01). (2) Neither CCK-A receptor antagonist [L364, 718] nor CCK-8 receptor antagonist [L365, 260] induced effects on IGP or GMF when given alone. (3) If bilateral BMA were pretreated with [L364, 718], CCK-8 could no longer induce any inhibitory effects, whlie [L365, 260] had no similar suppressive effect. (4) The inhibitory effects were not found in other nuclei in the amygdaloid body, such as bed nucleus of the stria terminalis intramygdaloid (BSTIA) and amygdaloid nucleus medial (Me). (5) Electrical stimulation of unilateral VMH or BMA would result in the inhibition of IGP and GMF. (6) After electric coagulation of VMH unilateraly injection of CCK-8 to or stimulation of homolateral VMH could no longer inhibite IGP or GMF. The above results suggest that in BMA CCK-8 exerts inhibitory effect on both motility and intragastric pressure through CCK-A receptors.

Comparison of the prevalence in two diabetes surveys in Pu-Li, Taiwan, 1987-1988 and 1991-1992

The objective of this study was to investigate the prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in Pu-Li, Taiwan from 1991-1992, and to compare the results with a similar study conducted in 1987-1988. We also wished to compare different approaches in asking about patient history and to determine how this effects data authenticity. Both were community-based cross-sectional studies with stratified cluster sampling of residents age > or = 30. Blood samples were taken for screening and 75 g oral glucose tolerance tests were performed for diagnosis. The total number of eligible subjects in the second study was 2719 (1424 men, 1295 women). Complete data and samples were collected for 1118 (536 men, 582 women). The response rate was 41.1% (37.6% for men, 44.9% for women). The crude prevalence was 10.3% (5.6% known, 4.7% new). Using standard world population (Segi), the age-adjusted prevalence rate was 8.3% (4.0% known, 4.3% new). The 1991-1992 study had a response rate (crude 41.1%, adjusted 51.3%) which was slightly lower than the 1987-1988 study (crude 44.8%, adjusted 55.9%). The age-adjusted prevalence rates for new NIDDM were similar (4.4 vs. 4.3%) while the age-adjusted prevalence of known NIDDM in the second survey (4.0%) was lower than the first survey (6.9%), which apparently was overestimated due to the simplicity of questions regarding history. In conclusion, prevalence of new DM in this area appears to be stable, and when doing a survey regarding previous DM, it is better to include treatment history rather than depending on self-reporting of NIDDM alone.