[Determination of shrinkage and bending strength of GI-II infiltrated ceramic]

OBJECTIVE

To determine the shrinkage and strength of GI-II Infiltrated Ceramic for providing scientific basis of its clinical use.

METHODS

The adobes by slip-casting alumina powder of GI-II Infiltrated Ceramic were sintered at 1125 degrees C for 2 hours. The sintered alumina bodies were then divided into two groups and infiltrated by melt glass at 1125 degrees C and 1100 degrees C respectively for 6 hours. The length of the infiltrated ceramic specimens before and after fabrication was determined to calculate shrinkage. Their strength values were obtained by 3-point bending test.

RESULTS

The infiltrated ceramic infiltrated at 1125 degrees C was 0.289 +/- 0.155% in shrinkage, 367.7 +/- 76.1 MPa in strength, and 4.79 in Weibull modulus; that infiltrated at 1100 degrees C was 0.253 +/- 0.043%, 377.5 +/- 64.4 MPa, and 5.52, respectively. There was no statistically significant difference between those two groups. But their strength values were statistically high, compared with 300 MPa.

CONCLUSION

The shrinkage of GI-II Infiltrated Ceramic could be compensated by brushing spacer on dies and expansion of die stone. Its strength satisfied the requirement for clinical use of all-ceramic bridge materials. This kind of high-strength and low-shrinkage ceramic could be used for fabricating all ceramic crown and bridge core.

[The influences of crystallized compositions in the porcelain on bonding strength of titanium to porcelain]

OBJECTIVE

Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this study was to investigate the effects of self-preparation La-porcelain composition on the porcelain-titanium bonding strength and to compare with the Vita Titankeramik.

METHODS

The present study examines 5 different recipes of porcelain by weight%: SiO2, 12%-17%; LaO2, 7%-10%; Al2O3, 9%-14%; B2O3, 23%-31%; CaO, 6%-8%; K2O, 2%-3%; SrO, 2%-4%; Na2O, 1%-3%; SnO2, 8%-10%; ZrO2, 3%-5%; TiO2, 6%-8%. Specimens were tested in push type shear with a universal testing machine. Scanning electron microscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and titanium to the bond strength when fired at 800 degrees C.

RESULTS

The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P < 0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium.

CONCLUSION

Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

Coronary angiographic findings in African-American and white patients from a single institution

No data exist comparing clinical and angiographic findings in large numbers of contemporary African-American and white patients from the same hospital. Limited angiographic data on African Americans were obtained from hospitals serving predominantly minority patients, making the valid African-American:white comparisons difficult. The study included 2,624 consecutive white and 1,793 African-American patients who had angiography for diagnostic evaluation of presumed coronary artery disease at the Louisiana State University Medical Center in Shreveport between 1990 and 1997. Compared to whites of the same sex, a greater proportion of African-American patients had a history of hypertension, stroke, and heart failure. African Americans also had significantly higher systemic and left ventricular pressure, lower ejection fraction, greater echocardiographic left ventricular mass index, and more concentric hypertrophy. The overall proportion of patients with normal or minimal stenosis of coronary artery (<50% narrowing in the luminal diameter) was greater in African Americans than in whites for both men and women. This difference was predominately found in men aged > or = 55 years or older. Except among older men, African-American patients with coronary heart disease had a similar distribution of 1-, 2-, 3-vessel disease and mean stenosis score compared to whites. In conclusion, a higher frequency of normal coronaries and less frequent coronary stenosis were found in older African-American men. The African-American:white differences in angiographic findings were minimal in younger men and in women. However, African Americans had worse clinical profiles than whites.

Locating acoustic emission with an amplitude-multiplexed acoustic sensor array based on a modified mach-zehnder interferometer

We report on an amplitude-division-multiplexed interferometric sensor array for locating acoustic emission. Preliminary experiments were carried out with a modified Mach-Zehnder interferometer consisting of two sensing arms and a reference arm and demonstrated a one-dimensional location accuracy of a few centimeters. The system can be extended for two- and three-dimensional location of acoustic emissions by the addition of one or two more sensing arms, respectively, in the interferometer.

Statins as antioxidant therapy for preventing cardiac myocyte hypertrophy

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. The hypertrophic process is mediated, in part, by small G proteins of the Rho family. We hypothesized that statins, inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, inhibit cardiac hypertrophy by blocking Rho isoprenylation. We treated neonatal rat cardiac myocytes with angiotensin II (AngII) with and without simvastatin (Sim) and found that Sim decreased AngII-induced protein content, [3H] leucine uptake, and atrial natriuretic factor (ANF) promoter activity. These effects were associated with decreases in cell size, membrane Rho activity, superoxide anion (O2*-) production, and intracellular oxidation, and were reversed with L-mevalonate or geranylgeranylpyrophosphate, but not with farnesylpyrophosphate or cholesterol. Treatments with the Rho inhibitor C3 exotoxin and with cell-permeable superoxide dismutase also decreased AngII-induced O2*- production and myocyte hypertrophy. Overexpression of the dominant-negative Rho mutant N17Rac1 completely inhibited AngII-induced intracellular oxidation and ANF promoter activity, while N19RhoA partially inhibited it, and N17Cdc42 had no effect. Indeed, Sim inhibited cardiac hypertrophy and decreased myocardial Rac1 activity and O2*- production in rats treated with AngII infusion or subjected to transaortic constriction. These findings suggest that statins prevent the development of cardiac hypertrophy through an antioxidant mechanism involving inhibition of Rac1.

Identification and characterization of RA-GEF-2, a Rap guanine nucleotide exchange factor that serves as a downstream target of M-Ras

The Ras family small GTPase Rap is regulated by an array of specific guanine nucleotide exchange factors (GEFs) in response to upstream stimuli. RA-GEF-1 was identified as a novel Rap GEF, which possesses a Ras/Rap1-associating (RA) domain. Here we report a protein closely related to RA-GEF-1, named RA-GEF-2. Like RA-GEF-1, a putative cyclic nucleotide monophosphate-binding domain, a Ras exchanger motif, a PSD-95/DlgA/ZO-1 domain, and an RA domain in addition to the GEF catalytic domain are found in RA-GEF-2. However, RA-GEF-2 displays a different tissue distribution profile from that of RA-GEF-1. RA-GEF-2 stimulates guanine nucleotide exchange of both Rap1 and Rap2, but not Ha-Ras. The RA domain of RA-GEF-2 binds to M-Ras in a GTP-dependent manner, but not to other Ras family GTPases tested, including Ha-Ras, N-Ras, Rap1A, Rap2A, R-Ras, RalA, Rin, Rit, and Rheb, in contrast to the RA domain of RA-GEF-1, which specifically binds to Rap1. In accordance with this, RA-GEF-2 colocalizes with activated M-Ras in the plasma membrane in COS-7 cells, suggesting a role of RA-GEF-2 in the regulation of Rap1 and Rap2, particularly in the plasma membrane. In fact, an increase in the level of the GTP-bound form of plasma membrane-located Rap1 was observed when coexpressed with RA-GEF-2 and activated M-Ras. Thus, RA-GEF-2 acts as a GEF for Rap1 and Rap2 downstream of M-Ras in the plasma membrane, whereas RA-GEF-1 exerts Rap GEF function in perinuclear compartments including the Golgi apparatus.

HER-2/neu induces p53 ubiquitination via Akt-mediated MDM2 phosphorylation

HER-2/neu amplification or overexpression can make cancer cells resistant to apoptosis and promotes their growth. p53 is crucial in regulating cell growth and apoptosis, and is often mutated or deleted in many types of tumour. Moreover, many tumours with a wild-type gene for p53 do not have normal p53 function, suggesting that some oncogenic signals suppress the function of p53. In this study, we show that HER-2/neu-mediated resistance to DNA-damaging agents requires the activation of Akt, which enhances MDM2-mediated ubiquitination and degradation of p53. Akt physically associates with MDM2 and phosphorylates it at Ser166 and Ser186. Phosphorylation of MDM2 enhances its nuclear localization and its interaction with p300, and inhibits its interaction with p19ARF, thus increasing p53 degradation. Our study indicates that blocking the Akt pathway mediated by HER-2/neu would increase the cytotoxic effect of DNA-damaging drugs in tumour cells with wild-type p53.

[Analysis on various deduction patterns of Yunqi theory in the Seven Major Discourses in suwen (plain questions)]

It is pointed out that in the Seven Major Discourses, there are different patterns of deducing Yunqi theory. The design and method of deduction are then dealt with. In the light of the fact that there was physician in the staff of astronomical organization in the Eastern Han Dynasty as well as the cultural background as a whole, it is concluded that the KYunqi theory was proposed at the turn of middle and later period of Eastern Han Dynasty.

[Descriptions and microscopic identification of Argyreia acuta Lour]

OBJECTIVE

To provide evidences for the identification of Argyreia acuta Lour.

METHOD

By descriptions and microscopic identification.

RESULT

The characters including stomata covered by many glandular hairs in dorsal surface of leaf of Argyreia acuta were obvious.

CONCLUSION

The result provided evidences for the identification of Argyreia acuta Lour.

Differential subcellular actions of ACE inhibitors and AT(1) receptor antagonists on cardiac remodeling induced by chronic inhibition of NO synthesis in rats

Chronic inhibition of NO synthesis induces cardiac hypertrophy independent of systemic blood pressure (SBP) by increasing protein synthesis in vivo. We examined whether ACE inhibitors (ACEIs) enalapril and temocapril and angiotensin II type-I receptor antagonists (angiotensin receptor blockers [ARBs]) losartan and CS-866 can block cardiac hypertrophy and whether changes in activation of 70-kDa S6 kinase (p70S6K) or extracellular signal-regulated protein kinase (ERK) are involved. The following 13 groups were studied: untreated Wistar-Kyoto rats and rats treated with NO synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME), D-NAME (the inactive isomer of L-NAME), L-NAME plus hydralazine, L-NAME plus enalapril (3 mg. kg(-1). d(-1)) or temocapril (1 or 10 mg. kg(-1). d(-1)), L-NAME plus losartan (10 mg. kg(-1). d(-1)) or CS-866 (1 or 10 mg. kg(-1). d(-1)), L-NAME plus temocapril-CS866 in combination (1 or 10 mg. kg(-1). d(-1)), and L-NAME plus rapamycin (0.5 mg. kg(-1). d(-1)). After 8 weeks of each experiment, ratios of coronary wall to lumen (wall/lumen) and left ventricular weight to body weight (LVW/BW) were quantified. L-NAME increased SBP, wall/lumen, and LVW/BW compared with that of control. ACEIs, ARBs, and hydralazine equally canceled the increase in SBP induced by L-NAME. However, ACEIs and ARBs equally (but not hydralazine) attenuated increase in wall/lumen and LVW/BW induced by L-NAME. The L-NAME group showed both p70S6K and ERK activation in myocardium (2.2-fold and 1.8-fold versus control, respectively). ACEIs inactivated p70S6K and ARBs inactivated ERK in myocardium, but hydralazine did not change activation of either kinase. Thus, ACEIs and ARBs modulate different intracellular signaling pathways, inhibiting p70S6K or ERK, respectively, to elicit equal reduction of cardiac hypertrophy induced by chronic inhibition of NO synthesis in vivo.

[A study on the bond interface between low-fusing dental porcelain and pure titanium]

OBJECTIVE

To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area.

METHODS

The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA.

RESULTS

Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain.

CONCLUSION

Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

Endothelial cell-specific knockout of connexin 43 causes hypotension and bradycardia in mice

Connexin 43 (Cx43) is a protein expressed in a variety of mammalian tissues. However, the lack of specific blockers and the absence of known genetic mutants have hampered the investigation of the function of this protein. Cx43-null mice die shortly after birth, thus preventing functional studies in vivo. Here, we report the generation and characterization of a vascular endothelial cell-specific deletion of the Cx43 gene (VEC Cx43 KO) in mice by using the loxP/Cre system. Using homologous recombination, a mouse line was created carrying loxP sites flanking exon 2 of the Cx43 gene ("floxed" mice). To produce cell specific deletion of the Cx43 gene, these mice were crossed with animals from a line carrying the Tie 2-Cre transgene. The homozygous VEC Cx43 KO mice survived to maturity. However, they were hypotensive and bradycardic when compared with heterozygous VEC Cx43 KO mice, or to the floxed Cx43 gene mice. The hypotension was associated with marked elevation of plasma nitric oxide (NO) levels as well as elevated plasma angiotensin (Ang) I and II. We hypothesize that endothelial cell Cx43 plays a key role in the formation and/or action of NO, and that the elevation of Ang II is a secondary event. The specific cellular basis for the hypotension remains to be established, but our findings support the idea that endothelial Cx43 gap junctions are involved in maintaining normal vascular function; moreover, these animals provide the opportunity to determine more clearly the role of endothelial Cx43 in vascular development and homeostasis.

Role of the CDC25 homology domain of phospholipase Cepsilon in amplification of Rap1-dependent signaling

Phospholipase Cepsilon (PLCepsilon) is a novel class of phosphoinositide-specific PLC characterized by possession of CDC25 homology and Ras/Rap1-associating domains. We and others have shown that human PLCepsilon is translocated from the cytoplasm to the plasma membrane and activated by direct association with Ras at its Ras/Rap1-associating domain. In addition, translocation to the perinuclear region was induced upon association with Rap1.GTP. However, the function of the CDC25 homology domain remains to be clarified. Here we show that the CDC25 homology domain of PLCepsilon functions as a guanine nucleotide exchange factor for Rap1 but not for any other Ras family GTPases examined including Rap2 and Ha-Ras. Consistent with this, coexpression of full-length PLCepsilon or its N-terminal fragment carrying the CDC25 homology domain causes an increase of the intracellular level of Rap1.GTP. Concurrently, stimulation of the downstream kinases B-Raf and extracellular signal-regulated kinase is observed, whereas the intracellular level of Ras.GTP and Raf-1 kinase activity are unaffected. In wild-type Rap1-overexpressing cells, epidermal growth factor induces translocation of PLCepsilon to the perinuclear compartments such as the Golgi apparatus, which is sustained for at least 20 min. In contrast, PLCepsilon lacking the CDC25 domain translocates to the perinuclear compartments only transiently. Further, the formation of Rap1.GTP upon epidermal growth factor stimulation exhibits a prolonged time course in cells expressing full-length PLCepsilon compared with those expressing PLCepsilon lacking the CDC25 homology domain. These results suggest a pivotal role of the CDC25 homology domain in amplifying Rap1-dependent signal transduction, including the activation of PLCepsilon itself, at specific subcellular locations such as the Golgi apparatus.

Cardioprotective effect afforded by transient exposure to phosphodiesterase III inhibitors: the role of protein kinase A and p38 mitogen-activated protein kinase

BACKGROUND

Phosphodiesterase III inhibitors (PDEIII-Is) improve the hemodynamic status of heart failure via inotropic/vasodilatory effects attributable to the increase in intracellular cAMP level. Direct cardioprotection by PDEIII-Is and its underlying mechanisms, however, have not been identified. We tested the infarct size-limiting effect of PDEIII-Is and the roles of cAMP, protein kinase (PK) A, PKC, and mitogen-activated protein kinase (MAPK) families in open-chest dogs. Methods and Results-- Milrinone, olprinone (PDEIII-Is), or dibutyryl-cAMP (db-cAMP) was injected intravenously 30 minutes before 90-minute ischemia, followed by 6 hours of reperfusion. Olprinone was also examined with an intracoronary cotreatment with a PKA inhibitor (H89), a PKC inhibitor (GF109203X), an extracellular signal-regulated kinase kinase (MEK) inhibitor (PD98059), or a p38 MAPK inhibitor (SB203580) throughout the preischemic period. Either PDEIII-Is or db-cAMP caused substantial hemodynamic changes, which returned to control levels in 30 minutes. Collateral flow and percent risk area were identical for all groups. Both PDEIII-Is and db-cAMP increased myocardial p38 MAPK activity during the preischemic period, which was blocked by H89, but not by GF109203X. Both PDEIII-Is and db-cAMP reduced infarct size (19.1+/-4.1%, 17.5+/-3.3%, and 20.3+/-4.8%, respectively, versus 36.1+/-6.2% control, P<0.05 each). Furthermore, the effect of olprinone was blunted by either H89 (35.5+/-6.4%) or SB203580 (32.6+/-5.9%), but not by GF109203X or PD98059. H89, GF109203X, PD98059, or SB203580 alone did not influence infarct size.

CONCLUSIONS

Pretreatment with PDEIII-Is has cardioprotective effects via cAMP-, PKA-, and p38 MAPK-dependent but PKC-independent mechanisms in canine hearts.

[Biological assessment of sintered titanium alloy for dental crown and bridge by means of slip casting]

OBJECTIVE

To evaluate the biological safety of sintered titanium alloy for dental crown and bridge, and provide a sound scientific basis for dental clinical practice.

METHODS

A series of tests, including acute toxicity test, cytotoxity test (agar overlay), sensitization test, oral mucous membrane irritation test, haemolysis test and micronucleus test were conducted to examine the dental crown/bridge-used titanium alloy which is processed with vacuum-sintered powder metallurgy.

RESULTS

The haemolysis rate of this material was 2.21% (less than 5%), an index of good blood compatibility. Cytotoxic effect was not observed in cell culture, nor was toxic effect observed in mouse toxicity test. Local mucous membrane irritation reaction was not found. No potential mutagenicity of this material was noted.

CONCLUSION

Dental crown/bridge-used titanium alloy material is of reliable was noted biological safety in dental clinical application.

[Characterization of alumina adobe and sintered body of GI-infiltrated ceramic]

OBJECTIVE

This study was conducted to elucidate the mechanism of formation of porous structure by investigating the porosity of the alumina adobe and sintered body of GI-II Infiltrate Ceramic, and its role in strengthening and toughening this kind of ceramic composite.

METHODS

The alumina powder size-mass distribution was obtained by BI-XDC powder size analysis device; the open pore parameters of alumina adobe and sintered body were analyzed using the mercury pressure method. Their fracture surfaces were observed under scanning electronic microscope.

RESULTS

Fine powder had two main size groups of 0.09-0.1 micron and 0.2-0.5 micron, respectively, and coarse powder, with size between 1.5 to 4.5 microns, occupied the majority of powder mass. Alumina adobe's pores became larger after sintering. The median pore radii of adobe and sintered body were 0.2531 micron and 0.3081 micron, respectively; the average pore radii changed from 0.0956 micron to 0.1102 micron. Under scanning electronic microscope, fine alumina powders were fused partially together and their surfaces were blunted, but coarse powders did not show such phenomena.

CONCLUSION

The alumina size distribution contributes to the formation of porous structure of alumina sintered body. This porous structure is not only the shape skeleton but also the mechanical skeleton of GI-II Infiltrated Ceramic. It plays an important role in raising the mechanical properties of this kind of ceramic composite.

Sequence diversity in genes of lipid metabolism

Elevated plasma lipoprotein levels play a crucial role in the development of coronary artery disease. Genetic factors strongly influence the levels of plasma lipoproteins, but the genes and sequence variations contributing to the most common forms of dyslipidemias are not known. We used GeneChip probe arrays to resequence the coding regions of 10 key genes of lipid metabolism. The sequences of these genes were analyzed in 80 dyslipidemic individuals. Fourteen nonsynonymous and twenty-two synonymous single nucleotide changes were identified that could be confirmed by conventional sequencing. Seven of the fourteen nonsynonymous sequence variants were polymorphisms with allele frequency >1% in the general population. The remaining seven were not found in normolipidemic controls (25 Caucasians and 25 African-Americans). The relationship between nonsynonymous sequence variations and various dyslipidemias was explored in association and family studies. No evidence was found for coding sequence variations in any of the 10 genes contributing to dyslipidemia. Only a single sequence variation, a missense mutation in the low density lipoprotein receptor gene, co-segregated with hyperlipidemia in the proband's family. This study illustrates some of the difficulties associated with identifying sequence variations contributing to complex traits.

Recent changes in the health status of the older U.S. population: findings from the 1984 and 1994 supplement on aging

OBJECTIVES

To examine the changes in the use of health care services, physical functioning, disability, and other aspects of health status in the older U.S. population between 1984 and 1994.

DESIGN AND SETTING

The 1984 and 1994 National Health Interview Survey Supplements on Aging, which were national probability samples of the civilian, noninstitutionalized population age 70 and older.

PARTICIPANTS

A total of 7,541 and 9,447 persons, representing the 17.3 million and 21.8 million U.S. population age 70 and older in 1984 and 1994, respectively.

MEASUREMENTS

Annual bed-limitation days, doctor visits, episodes and days of hospital stays, limitation in 10 measures of physical performance, disability in seven activities of daily living (ADLs) and six instrumental activities of daily living (IADLs), and participation in social activities and exercise.

RESULTS

The annual bed-limitation days and hospital stays declined significantly in both men and women between 1984 and 1994. There was a large decrease in the prevalence of limitation in physical performance and a smaller decrease in disability of IADLs. The changes were greater in women than in men. The prevalence of disability in ADLs was not changed in women in general and increased somewhat in men. Significant increases in the proportion of persons participating in certain social activities and regular exercise were found in both men and women. Jointly considering the indicators, including annual bed days and hospital stays, physical performance, ADLs, and IADLs, 4.2% more men and 3.1% more women were physically robust in 1994 than in 1984. Approximately 420,000 more older people would have lived in a severely restricted and disabled state in 1994 if the rate of limitation had not declined.

CONCLUSION

This study provides evidence of an overall improvement in the health status of older Americans but inconsistency in the trends existed for different disability measures and for population subgroups.

RA-GEF-1, a guanine nucleotide exchange factor for Rap1, is activated by translocation induced by association with Rap1*GTP and enhances Rap1-dependent B-Raf activation

We previously identified RA-GEF-1, a novel guanine nucleotide exchange factor (GEF) for Rap1 with the ability to associate with Rap1.GTP at its Ras/Rap1-associating (RA) domain. Because it possesses a PSD-95/DlgA/ZO-1 (PDZ) domain, it was also named PDZ-GEF. In this report, we have examined the role of the RA domain of this protein in Rap1-mediated cellular responses. A mutant of RA-GEF-1 (RA-GEF-1DeltaRA) carrying a 21-residue deletion at its RA domain fully retains the in vitro GEF activity toward Rap1 but completely loses the Rap1 binding activity. In contrast, RA-GEF-1DeltaRA, expressed in COS-7 cells, exhibits a 3-fold reduction in its in vivo GEF activity toward Rap1 compared with wild-type RA-GEF-1 as examined by the Rap1 pull-down assay. Correspondingly, when coexpressed with wild-type Rap1, RA-GEF-1DeltaRA is unable to further activate B-Raf, whereas RA-GEF-1 stimulates B-Raf as efficiently as activated Rap1. Consistent with these observations, coexpression of activated Rap1 induces translocation of RA-GEF-1, which is otherwise located in the cytoplasm, to the perinuclear compartment, where Rap1 is also predominantly localized. This localization almost coincides with that of the Golgi apparatus, which was detected by anti-trans-Golgi-network 38 antibody. RA-GEF-1DeltaRA fails to show the translocation. These results indicate that RA-GEF-1 defines a novel category of GEF that is translocated to a particular subcellular compartment by association with the GTP-bound form of a small GTPase and catalyzes activation of the GDP-bound form present in the compartment, thereby causing an amplification of cellular responses induced by the small GTPase.

Possible cytotoxic effect of the expression of a connexin 43-LacZ fusion gene in cells of the vascular wall

Connexin 43 (Cx43) gap junctions are hypothesized to play a key role in many aspects of vascular function. In an effort to evaluate the importance of connexins in vascular function we took advantage of the fact that a Cx43-LacZ fusion protein has been reported to effectively reduce dye transfer in NIH 3T3 fibroblasts by acting as a dominant negative construct. We explored the use of this dominant negative construct in cultured vascular smooth muscle (VSM) cells and in transgenic mice. We examined the viability of cultured VSM cells expressing the Cx43-LacZ fusion protein under the control of a cytomegalovirus promoter. We also selectively expressed the dominant negative construct in the endothelial cells of transgenic mice under the control of a Tie 2 promoter. Transient transfection of cultured VSM cells led to good initial expression of the Cx43-LacZ fusion protein as evidenced by X-gal staining. Following 10 days of G418 selection, 300 cell clones were examined. None expressed the fusion protein, based on X-gal staining and Western blot analysis, but all contained the transgene, based on PCR analysis. The fusion protein was expressed in a few isolated cells, suggesting that cell division was inhibited by the fusion protein. In agreement with this finding was the fact that expression of the Cx43-LacZ fusion protein was not observed in any of seven Tie 2-Cx43-LacZ transgenic mouse lines. Moreover, a very low yield of mice carrying the transgene was observed (7/136; 5.1%). Analysis of 65 embryos at embryonic day 11.5 showed similar results. These data strongly suggest that the expression of the Cx43-LacZ fusion protein prevents the formation of both stable clones and transgenic animals. This may be due to a cytotoxic effect of the dominant negative construct or to the fact that successful cell propagation is not possible if gap junctional transmission is completely blocked.

Assessing the effect of fatty acids on prostate carcinogenesis in humans: does self-reported dietary intake rank prostatic exposure correctly?

BACKGROUND

Dietary fatty acids may influence prostate carcinogenesis. Although the standard for assessing dietary effects in humans is the semiquantitative food-frequency questionnaire, the extent to which self-reported intake correctly ranks prostatic exposure is unknown.

OBJECTIVE

The objective was to examine the correlation between reported intakes of different fatty acids and their concentrations in prostate tissue.

DESIGN

This was a cross-sectional study of 52 men undergoing surgical resection of the prostate gland. Usual dietary intake of saturated, total unsaturated, oleic, and linoleic fatty acids over the previous year was estimated with use of a 122-item version of the Health Habits and History Questionnaire. Concentrations in prostate tissue were measured directly by use of gas chromatography in healthy tissue collected at the time of surgery and were expressed as a percentage of total fatty acids. Correlations with 4 measures of dietary intake [g/d, g/d adjusted for total daily energy intake, % of total fat (as g/d), and % of total energy] were evaluated by Spearman's rank-order correlation coefficients.

RESULTS

Linoleic acid concentrations in prostate tissue were significantly correlated with dietary intake expressed as g/d adjusted for total energy [r = 0.29 (95% CI: 0.03, 0.49), P = 0.04], % of total fat [r = 0.36 (0.14, 0.550), P = 0.008], and % of total energy [r = 0.28 (0.04, 0.49), P = 0.042], but not as g/d. Although mean concentrations of saturated, total unsaturated, and oleic fatty acids in prostate tissue resembled mean intakes for the group, prostatic concentrations did not correlate with individual intakes.

CONCLUSION

Self-reported intake of fatty acids is a satisfactory marker of prostatic exposure at the group level, but, with the exception of linoleic acid, does not correctly rank individuals with respect to intensity of exposure.

Cytoplasmic localization of p21Cip1/WAF1 by Akt-induced phosphorylation in HER-2/neu-overexpressing cells

Amplification or overexpression of HER-2/neu in cancer cells confers resistance to apoptosis and promotes cell growth. The cellular localization of p21Cip1/WAF1 has been proposed to be critical either in promoting cell survival or in inhibiting cell growth. Here we show that HER-2/neu-mediated cell growth requires the activation of Akt, which associates with p21Cip1/WAF1 and phosphorylates it at threonine 145, resulting in cytoplasmic localization of p21Cip1/WAF1. Furthermore, blocking the Akt pathway with a dominant-negative Akt mutant restores the nuclear localization and cell-growth-inhibiting activity of p21Cip1/WAF1. Our results indicate that HER-2/neu induces cytoplasmic localization of p21Cip1/WAF1 through activation of Akt to promote cell growth, which may have implications for the oncogenic activity of HER-2/neu and Akt.

Electrooxidation potential as a tool in the early screening for new safer clozapine-like analogues

The chemical modification of clozapine (1) has permitted the finding of new analogues, e.g., olanzapine (2), quetiapine (3), 5-(4-methylpiperazin-1-yl)-8-chloropyrido[2,3-b][1,5]benzoxazepine fumarate (9), with a clinical or psychopharmacological profile similar to that of clozapine. However, when developing new derivatives, the designers are discouraged by the development of clozapine-induced agranulocytosis. Different researchers have raised the role played by the oxidizability of the molecule in such a deleterious effect. In the present paper, we examined the oxidation profile (direct scavenging abilities, efficacy in inhibiting lipid peroxidation, and electrooxidation potential) of newly developed methoxy and trifluoromethylsulfonyloxy analogues related to clozapine, some of them being described as putative antipsychotic. The oxazepine derivative 7, unlike the other diazepine derivatives (6, 10--12), was not readily oxidized. Using a statistical predictive model for hematotoxicity previously described, 7 was found in the cluster of potentially nontoxic compounds while diazepine derivatives 6 and 10-12 were classified as potentially toxic compounds. Among these original compounds, 7, which presents a preclinical clozapine-like profile and a low sensitivity to oxidation, could be a promising antipsychotic candidate with low side effects. Considering the tricyclic derivatives examined so far, some elements of structure-oxidation relationship (SOR) might be pointed out. Regarding the nature of the tricyclic ring substituent, from the most to the least sensitive to oxidation, the sequence was as follows: HO > Cl > CH(3)O > CF(3)SO(2)O. The nature of the tricyclic ring influenced also the sensitivity to oxidation; the diazepine moiety appeared to be the most reactive ring compared to oxa- and thiazepine congeners. These parameters could be advantageously integrated in the early design of new safer clozapine-like analogues.

[Poisoning from eating horseshoe crab and its prevention and treatment]

During the past three years on investigating and studying the poisoning of eating Horseshoe crab, it has been discovered that the major cause of the poisoning on eating Horseshoe crab in south region along the seacoast of China was taking tetrodotoxin from Carcinoscorpius rotundicauda by mistake; the symptoms of some others from eating Horseshoe crab were the result of allergic reactions from eating Tachypleus tridentatuscause, similar to the reactions from eating shrimp or crab, and which could be cured with chlorpheniramine. The effective prevention measures are not eating Horseshoe crab, especially the young ones. The size of young Carcinoscorpius rotundicauda is similar to the size of the nonpoisonous Tachypleus tridentatuscause. It is very easy to be confused and easy to eat by mistake. The treatment of the poisoning from eating Horseshoe crab is similar to the treatment of tetrodotoxin by removing the toxins from body.

[Establishment and application of a data management program for BY 960 ambulatory blood pressure monitoring system]

Report of ambulatory blood pressure monitoring may contain a large number of data which is very important for the clinical studies on subjects' blood pressure. Most of the ambulatory blood pressure monitoring systems in use at present are lacking in database managing function, which is very inconvenient to the research work. In accordance with the characteristics of BY 960 ambulatory blood pressure monitoring system (produced by Shenzhen NewEra Tech Co., Ltd.), a set of data management program was established. It can automatically transfer the ambulatory data to database sets and is confirmed to be a practical tool for the research work.

[Ultrastructural and Ca/P changes of the regenerated bone after mandibular distraction in goats]

OBJECTIVE

The aim of this study was to examine the ultra structural and the changes of Ca/P elements of the new bone resulting from mandibular distraction osteogenesis.

METHODS

Bilateral mandibular osteotomies were performed in six goats. The mandibles in all animals were lengthened 10 mm using a custom made distracter. Each 2 goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted callus were harvested and processed for SEM evaluation and Ca/P ratio analysis.

RESULTS

The newly generated bone in distraction gap was confirmed by SEM examination, and the contents of Ca, P were found to be elevated with the maturity of distracted callus.

CONCLUSION

This study suggested that newly formed bone by mandibular distraction osteogenesis in goats could be remodeled to normal bone.

[Shear strength of bond of the dentin to GI-II glass-infiltrated alumia ceramic agter varying modes of surface conditioning]

OBJECTIVE

The adequate surface conditioning method for GI-II glass infiltrated alumia ceramic was investigated.

METHODS

The test specimens were divided into 3 groups (A. HF + silicon, B. sandblasting + silicone and C. thermal silicoating + silicone). Shear bonding strengths of porcelain bonded to dentin were tested.

RESULTS

The bond strength of group A and B slightly increased after one day but decreased sharply after 30 days. However, no statistical significance was observed. The group C showed a pronounced enlargement of bond strength after one day and had a durable bond after 30 days' thermal cycling. It is statistically significant when group C was compared with group A and B.

CONCLUSION

It can be inferred that silicoating method be a better way for glass infiltrated alumia ceramic bonding.

Experimental study on AT1-receptor-peptide-induced myocardial immune damage in rat

In order to investigate the immunological damage in rat immunized with AT1-receptor peptide, 18 male Wistar rats were divided into two groups: immunized-group (n = 12), each rat was immunized with 150 micrograms AT1-receptor peptide coupled to bovine serum albumin, together with Freund's adjuvant. Control group (n = 6), sham-immunized, "immunized liquid" was same as immunized-group except AT1-receptor peptide. Systolic blood pressure (SBP) was measured by using the tail-cuff technique, antibody against AT1-receptor peptide detected by using ELISA method, and left ventricular myocardium and renal cortex sections were observed under light and electron microscopy. There was no significant difference in SBP and light microscopic observation of the tissue sections between the immunized-group and control group. The O.D. value of anti-AT1-receptor peptide antiserum was significantly higher in the immunized-group than in the rats before immunization and control group (P < 0.01). Positive rate in the immunized-group was 100%, while 0% in the control group. Ultramicroscopic morphology showed potential myocardial injury, including: increase in number of mitochondria, swelling of many mitochondria with reduction in number or absence of their cristae and cristolysis, disorder of the cardiac myofibrils, and myofibrillar disruption and myocytolysis. And lysosomes were increased in renal tubular epithelia. The AT1-receptor peptide could induce to generate the antibody against AT1-receptor peptide and lead to myocardial and renal damage in rats.

Height and risk of fatal prostate cancer: findings from the National Health Interview Survey (1986 to 1994)

PURPOSE

Height is determined by genetic and nutritional factors mediated through the endocrine system early in life and, thus, may be related to subsequent risk of fatal prostate cancer. This hypothesis was examined in a large representative U.S. national sample.

METHODS

Data from the National Health Interview Survey (NHIS) were analyzed to determine whether height was prospectively related to the risk of fatal prostate cancer in 110,042 men age > or = 50 years old interviewed between 1986 and 1994. Height was self-reported and vital status and causes of death ascertained using the National Death Index. Endpoints were deaths that listed prostate cancer as the underlying cause and deaths with any mention of prostate cancer. Relative risks (RR) and their 95% confidence intervals (CI) were calculated using Cox proportional hazards models adjusted for age, race, weight, and education.

RESULTS

Six hundred and thirty-three deaths listing of prostate cancer as the underlying cause and 910 deaths with any mention of prostate cancer were identified. Height was associated neither with risk of death with prostate cancer listed as the underlying cause nor with risk of death with any mention of prostate cancer (multivariate p for trend = 0.1318 and 0.0698, respectively). Risks were marginally greater among the tallest men compared to the shortest (< or = 171.4 vs. > or = 182.9 cm), but not significantly (RR = 1.21, 95% CI = 0.92 to 1.57, and RR = 1.24, 95% CI = 0.98 to 1.58 for 'underlying cause' and 'any mention', respectively).

CONCLUSIONS

Height alone was not related to risk of fatal prostate cancer in this population.

[Phase I clinical trial of dose escalation on three dimensional conformal radiation therapy for non-small cell lung cancer]

BACKGROUND

To establish the technique of 3-dimensional conformal radiation therapy (3DCRT) for non-small cell lung cancer (NSCLC) in stage II-IIIB,and to assess its acute side-effects and to obtain the maximum tolerance dose (MTD).

METHODS

From June,1999 to June,2000,38 cases of NSCLC in stage II-IIIB were enrolled in this study.MTD was identified by dose escalation study.After 42Gy/21Fx/4.2wks by conventional fractionated irradiation through AP/PA fields,which covered the primary tumor and lymph nodes,the technique of 3DCRT was used as boost.The boost fields encompassed the clinical lesions showed on chest CT.The planning of total dose escalation depended on the percentage,i.e.,<25%,25%-37%,and >37% of normal lung volume irradiated to over 20Gy.The scheduled dose escalation ranged from 69 to 81Gy.The criteria for stopping dose escalation was grade III or more worse radiation pneumonitis (RTOG).The boost doses were delivered with 3Gy/fraction,once a day,5 fractions a week.

RESULTS

Thirty-three cases had completed their treatments and could be evaluated by now.Acute radiation pneumonitis occurred in 26% of patients with grade I-II and 3% with grade III,and acute radiation esophagitis in 61% with grade I-II and 9% with grade III,and the hematopoietic toxicity in 58% with grade I-II and 9% with grade III.The current doses implemented were 78,78,and 75Gy respectively for patients with <25%,25%-37%,and >37% of normal lung volume irradiated.The overall immediate response rate of tumors was 88%(29/33).

CONCLUSIONS

Dose escalation in a volume-dependent organ as the lungs is acceptable and applicable.The immediate response is encouraging.MTD is to be determined.The long-term follow-up is needed to observe late complications and treatment efficacy.

Adenovirus 5 early region 1A does not induce expression of the ewing sarcoma fusion product EWS-FLI1 in breast and ovarian cancer cell lines

The adenovirus 5 early region 1A (E1A) can function as a tumor suppressor gene and is being used in clinical trials as a therapeutic agent for advanced breast, ovarian, and head and neck cancer. Recently, there has been a dispute regarding whether transfection with the E1A gene can induce expression of the Ewing sarcoma oncogenic fusion transcript EWS-FLI1 (Sanchez-Prieto et al., Nat. Med., 5: 1076-1079, 1999; Melot and Delattre, Nat. Med., 5: 1331, 1999; Kovar et al., Cancer Res., 60: 1557-1560, 2000). In an effort to settle the controversy, we tested several stable E1A transfectants of cell lines MDA-MB-231, MCF-7, MDA-MB-435 (breast cancer), SKOV3-ipl (ovarian cancer), and PC-3 (prostate cancer), as well as parental and vector-transfected controls, HEK 293 cells, and RD-ES (Ewing sarcoma) cells, for the EWS-FLI1 fusion product. The EWS-FLI1 transcript could not be identified with reverse transcription-PCR in any of the 13 E1A-transfected cell lines analyzed. Furthermore, the EWS-FLI1 fusion protein could not be detected by Western blot analysis in E1A-transfected cell lines. These results suggest that E1A transfection does not necessarily lead to expression of the oncogenic EWS-FLI1 fusion transcript. Thus, the potential induction of this gene rearrangement by E1A gene therapy is unlikely to be clinically significant in the treatment of advanced malignant disease.

Obesity modifies the relationship between ambulatory blood pressure and natriuresis in children

BACKGROUND

The objective in the present study was to evaluate if obesity beginning in the first two decades of life influences the relationship between ambulatory blood pressure and urinary sodium excretion.

DESIGN AND METHODS

Eighty-five obese and 88 non-obese children aged 3-19 years were included in the study. For each subject, a 24h ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. The averages of ambulatory blood pressure and of the urinary excretion rates for sodium, potassium and creatinine were calculated separately for 24-h, awake and sleep periods as defined by a mini-diary.

RESULTS

Weight and sodium excretion are directly associated with systolic blood pressure; however, the relationship between blood pressure and sodium excretion seems to be modified in obese children as compared to controls. The interaction between sodium excretion and weight was negative indicating that the rate of change of systolic blood pressure by sodium unit is smaller for the obese than for the non-obese, even though at the same urinary sodium excretion level the obese children had higher ambulatory systolic blood pressure.

CONCLUSIONS

Obesity during the first two decades of life seems to restrict sodium excretion, leading to higher blood pressure values. The capacity to excrete sodium seems to be heterogeneous, the lowest capacity being at the highest blood pressure values. Subsets of the obese, those with the lowest ability to excrete sodium, may be further protected by low sodium intake in order to prevent a rise in blood pressure.

Blockade of connexin 43 expression by stable transfection of antisense cDNA in cultured vascular smooth muscle cells

Gap junctional communication is involved in embryogenesis, cell growth control, and coordinated contraction of cardiac myocytes. It has been hypothesized that gap junctions coordinate responses of vascular cells to constrictor or dilator stimulation. Three connexin (Cx) proteins, 37, 40, and 43, are found in the vasculature. Cx43 gap junctions are widely distributed along the vascular tree, although a precise physiologic role in vascular function is unknown because of a lack of specific functional inhibitors and of suitable animal models. To investigate the role of Cx43 in intercellular communication among vascular smooth muscle (VSM) cells, we selectively modified the expression of the Cx43 gene using antisense cDNA stable transfections in culture. Results show that in cells stably transfected with antisense Cx43 cDNA, gene expression of Cx43 could be reduced to 20% of that observed in vector-transfected cells. In spite of the mRNA and protein reduction, the antisense Cx43 cDNA-transfected cells did not show a significant reduction in dye transfer or a difference in cell growth rate as compared with control. These results suggest either that the residual amount of Cx43 protein is sufficient for dye transfer and growth control or that the dye transfer in these cells can be mediated by Cx40 or other connexin proteins. Therefore, more potent approaches, such as dominant negative and gene knockout, are required to fully block gap junctional communication in VSM cells.

The effect of phenyl substituents on the release rates of esterase-sensitive coumarin-based prodrugs

A coumarin-based prodrug system has been recently developed in our laboratory for the preparation of esterase-sensitive prodrugs of amines, peptides, and peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pKa's. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions on the release kinetics of such prodrugs and found that appropriately positioned alkyl substituents on the phenyl ring could help to facilitate the release by as much as 16-fold. Therefore, introduction of alkyl substituents on the phenyl ring should allow us to manipulate the release rates and, therefore, time profiles for different drugs.

[The effect of injuries on Fn synthesized by FBs and its implication in wound timing]

cFn synthesized by FBs around the wound was detected by immunochemistry in vitro. Using the method of ELISA, The concentration of cFn in the culture media was observed. The concentration of cFn had no change within 30 minutes after injury, but started to increase after 1 hour of the injury and kept this trend within next five hours after injury. By static analysis, it can be obtained that the concentration of cFn in culture media is time-dependent after injury.

Abdominal adiposity and clustering of multiple metabolic syndrome in White, Black and Hispanic americans

PURPOSE

The aim of this study was to evaluate the association of abdominal adiposity assessed by waist circumference (WC) with clustering of multiple metabolic syndromes (MMS) in White, Black and Hispanic Americans. MMS was defined as the occurrence of two or more of either hypertension, type 2 diabetes mellitus, dyslipidemia, hypertriglyceridemia or hyperinsulinemia.

METHODS

The number of MMS and fasting insulin (a surrogate measure of MMS) were each used as dependent variables in gender-specific multiple linear regression models, adjusting for age, smoking and alcohol intake. The contribution of WC to interethnic differences in clustering of MMS and fasting insulin concentration was assessed in gender-specific linear regression models. The risk of MMS due to large waist was estimated by comparing odds ratio for men with WC >/= 102 cm with those with WC < 102, and women with WC >/= 88 cm with women with WC < 88 cm in the logistic regression model adjusting for age, smoking and alcohol intake.

RESULTS

WC was positively and independently associated with clustering of MMS and increased fasting insulin concentration adjusting for age, smoking and alcohol intake in the three ethnic groups (p < 0.01). Black ethnicity was associated with clustering of MMS and fasting insulin concentration (p < 0.01). Hispanic ethnicity was also associated with clustering of MMS in men and associated with fasting insulin concentration in both men and women (p < 0.01). In both men and women, the risk of MMS clustering was strongly associated with increased WC in all ethnic groups independent of BMI.

CONCLUSION

WC appears to be a marker for multiple metabolic syndromes in these ethnic groups. The results of this investigation lend support to the view that waist measurement should be considered as a clinical variable for assessing the risk of cardiovascular diseases.

Ligand binding and structural properties of segments of GABAA receptor alpha 1 subunit overexpressed in Escherichia coli

The gamma-aminobutyric acid, type A (GABA(A)), receptor is the target for numerous therapeutic compounds. In the present study, the Gln(28)-Leu(296), Gln(28)-Arg(276), Gln(28)-Arg(248), and Gln(28)-Glu(165) (numbering of bovine precursor protein) segments of its alpha(1) subunit were overexpressed in Escherichia coli, along with Cys(166)-Leu(296) produced previously, for structural analysis by circular dichroism and ligand binding studies by fluorescence spectroscopy. Results showed that the protein segments were rich in beta-sheet structures. Binding of the fluorescent benzodiazepine Bodipy-FL Ro-1986 was evident from fluorescence resonance energy transfer and fluorescence anisotropy measurements. The binding affinity was in the micromolar range. The binding was attributable more to Cys(166)-Leu(296) than to Gln(28)-Glu(165) and was inhibited by known central benzodiazepine site ligands. Three point mutations, Y187A, T234A, and Y237A, were found to perturb protein secondary structures. Studies with the single Trp mutants W198Y and W273Y indicated that Trp(273) was closer to the binding site than Trp(198).

[Properties and infiltration arts of machinable infiltration ceramic(MIC)]

OBJECTIVE

The purpose of this study is to explore the infiltration arts of MIC and study the effects of different packing density of Al2O3 matrix on the properties of MIC.

METHODS

alpha-Al2O3 specimens were fabricated by pouring alpha-Al2O3 slip with different powder/liquid ratios(P/L = 3.5, 7.5, 10.5) into a mold, and subsequently pre-fired at 1160 degrees C for 6 hours to form Al2O3 matrix. The packing density of the matrices were measured. Infiltration concepts were introduced into this study by infiltrating molten mica micro-crystalline glass into the porous Al2O3 matrix at 1160 degrees C for 6 hours to form a continuous interpenetrating composite. The composite then underwent micro-crystallization by nucleating at 550 degrees C for 1 hour and crystallizing at 900 degrees C for 1 hour, which resulted in the MIC. Mechanical properties including three point flexural strength, elastic modulus, Vicker's hardness, indentation fracture toughness and Weibull's modulus of flexural strength were determined. Parameters of machinability(H/KIC)2 of MIC were calculated. XRD and SEM were employed to study its microstructure.

RESULTS

The resulted matrices reached packing densities of 63%, 76%, 78% with P/L of 3.5, 7.5 and 10.5. The MIC attained high strength and good machinability after infiltration. Three-point flexural strength and indentation fracture toughness were 342, 431, 374 MPa and 4.05, 4.14, 5.02 MPa m1/2 for MIC with packing density of 63%, 76%, 78% separately. And parameters of machinability were 5.41, 6.84 and 7.39 respectively. Packing density of Al2O3 matrix significantly influenced the mechanical properties. Maximum properties were obtained with a matrix packing density of 75%(P/L = 7.5), with a Weibull's modulus of flexural strength of 6.8. Machinability decreased with the increase of P/L ratio. Micro-crystallizing treatment resulted in the formation of evenly distributed mica crystalline in the composite, which contributed to the high strength of this composite material.

CONCLUSION

MIC is a new infiltrated ceramic with favorable strength and machinability which can satisfy the prosthodontic requirements as all ceramic crown and bridge materials, it also shows promising outlook for future developments and clinical usage.

[Study on the toxicity of horseshoe crabs in mice]

In order to study the toxicity of horseshoe crabs(tachypleus tridentatus and carcinoscorpius rotundicauda) in the sea of China, the extracts of tissues from tachypleus tridentatus and carcinoscorpius rotundicauda were injected into the abdominal cavity of mice for testing their poisoning effects. The results showed that the toxicity of carcinoscorpius rotundicauda was much higher than that of tachypleus tridentatus. The length of time from the injection to the death was much shorter for Carcinoscorpius rotundicauda than that for tachypleus tridentatus. The signs before death for Carcinoscorpius rotundicauda poisoning were restless, jumping and spasm but that for Tachypleus tridentatus was lethargy. The toxicity of adult horseshoe crabs was much higher than that of young horseshoe crabs.

Augmentation with a 5-HT(1A), but not a 5-HT(1B) receptor antagonist critically depends on the dose of citalopram

Pharmacokinetic and pharmacodynamic parameters of the selective serotonin reuptake inhibitor 1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-5-phtalancarbonitril (citalopram) were determined in order to find optimal conditions for augmentation of its effect on extracellular serotonin [5-hydroxytryptamine (5-HT)] through blockade of 5-HT(1A) and 5-HT(1B) autoreceptors. Citalopram dose-dependently (0.3-10 micromol/kg s.c.) increased serotonin levels in ventral hippocampus of conscious rats. At plasma levels above approximately 0.15 microM, the effect of citalopram on extracellular 5-HT was augmented by both a 5-HT(1A) [N-[2-[4-(2-mehoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridil) cyclohexa necarboxamide trihydrochloride (Way 100635), 1 micromol/kg s.c.] and a 5-HT(1B) receptor antagonist (2'-methyl-4'-(5-methyl-[1,2, 4]oxadiazol-3-yl)biphenyl-4-carboxylic acid [4-methoxy]-3-(4-methylpiperazin-1-yl)phenyl]amide (GR 127935), 1 micromol/kg s.c.). However, at plasma levels of the selective serotonin reuptake inhibitor below 0.15 microM, the effects of the antagonists diverged viz. the 5-HT(1B) receptor antagonist was still able to potentiate citalopram's effect on extracellular 5-HT, while the 5-HT(1A) receptor antagonist was no longer effective. These results suggest that in contrast to 5-HT(1B) autoreceptors, indirect activation of 5-HT(1A) autoreceptors by citalopram is critically related to the dose of selective serotonin reuptake inhibitor administered. The latter may have consequences for selective serotonin reuptake inhibitor augmentation strategies with 5-HT(1A) receptor antagonists in the therapy of depression and anxiety disorders.

Bubble Motion in Aqueous Surfactant Solutions

This paper presents the results of numerical simulations of the unsteady motion of a single bubble that is released or injected into water. The governing equations are solved with a finite difference method using an adaptive boundary-fitted coordinate system. Results are shown for bubbles in the size range 0.72 to 1.5 mm. The effects of surfactants on the motion and shape of the bubble are investigated. When the surfactant concentration is sufficiently small, the bubble attains a maximum velocity before slowing down to its steady-state velocity. Although the steady-state velocity is nearly independent of surfactant concentration, the maximum velocity can be comparable to steady-state velocity in pure water. This behavior is observed even when the bubble is allowed to equilibrate prior to releasing it. The formation of an immobilized surfactant cap is observed soon after the bubble is released. The effect of the injection velocity on the bubble velocity profile is investigated. The effects of the sorption rate constants and the bulk surfactant concentration on the behavior of the bubble are investigated. The feasibility of using experimental measurements and simulations of unsteady bubble velocities to estimate sorption rate constants is discussed. Copyright 2000 Academic Press.

Alcohol intake and mortality: findings from the National Health Interview Surveys (1988 and 1990)

The authors used prospective data from two supplemental studies of the National Health Interview Survey, the 1988 Alcohol Supplement and the 1990 Health Promotion and Disease Prevention Supplement, to examine the relation between alcohol intake and mortality. Their study included 17,821 men and 25,874 women aged 40 years or older at baseline; during an average of 6 years of follow-up, 5,540 deaths occurred. The alcohol-mortality relation was U-shaped for men and J-shaped for women. On the basis of categorical analyses adjusted for age, race, smoking, and baseline diseases, men who drank 2 drinks per day had a significantly lower risk of death compared with abstainers (relative risk = 0.60, 95% confidence interval (CI): 0.45, 0.82). The relative risk was 0.75 (95% CI: 0.55, 1.03) after further adjustment for marital status, education, and self-perceived health status. For women, the corresponding relative risks were 0.69 (95% CI: 0.61, 0.78) and 0.79 (95% CI: 0.70, 0.90) for those who drank less than 1 drink per day. When drinking category was considered as an ordinal variable and fitted with a quadratic function in the Cox model, the estimated optimal alcohol intake was approximately less than 1 to 1 drink per day for men and lifetime infrequent to less than 1 drink per day for women. Data from these representative US cohorts demonstrated that less than 2 drinks per day for men and less than 1 drink per day for women are associated with the lowest all-cause mortality.

Predictive values of waist circumference for dyslipidemia, type 2 diabetes and hypertension in overweight White, Black, and Hispanic American adults

Waist circumferences (WC) >/=102 cm for men and >/=88 cm for women have been proposed by an expert panel as cut-points for identifying increased risk for the development of obesity comorbidities for most adults. The aim of this investigation was to examine the predictive values of these WC cut-points for hypercholesterolemia, low concentration of high (HDL-C), and high concentration of low (LDL-C) density lipoprotein cholesterol, hypertriglyceridemia, type 2 diabetes, and hypertension in overweight American adults. Data from NHANES III were utilized for the analysis. Predictive abilities were determined by calculating sensitivity, specificity, positive (PV+) and negative (PV-) predictive values in overweight subjects with BMI 25-29.9 kg/m(2). Sensitivity of WC cut-point was stronger for high LDL-C compared to other risk factors with the highest values recorded in the 40-59 and 60-69 year age groups in men and women, respectively. PV+ of WC cut-points for dyslipidemia, type 2 diabetes, and hypertension were low in men compared to women. PV+ tended to increase with age, from 19-39, 40-59 to 60-90 year age groups in Whites, Blacks, and Hispanic men. In men, the highest PV+ were recorded for hypertriglyceridemia in the 60-90 years old groups, with values of 71.6%, 52.5%, and 43.3% in Whites, Blacks, and Hispanics, respectively. The CVD risk factor associated with the highest PV+ in women was diabetes with values of 97.2% in Whites and 88.9% in Blacks, and hypertriglyceridemia with a value of 93.8% in the 17-39 year age group in Hispanics. Among Black men 40-59 years of age, only 32% of a population of overweight hypertensives were detected by the WC cut-points, and among Black women, 40-59 years of age, only 54% were detected. Given the low sensitivity of these cut-points for detecting hypertension, one of the major co-morbidities of obesity, these cut-points failed to provide adequate evidence for the use of WC in determining or evaluating patients as to co-morbid states. We recommend further studies to determine a set of specific cut-points associated with increased risk of CVD in different population groups.

Impact of birth weight on ethnic variations in subcutaneous and central adiposity in American children aged 5-11 years. A study from the Third National Health and Nutrition Examination Survey

OBJECTIVE

To determine the types of subcutaneous adiposity represented by different measurements of skinfold thickness that are associated with birth weight in white (n=759), Black (n=916) and Hispanic (n=813) American children aged 5-11 y. We also determined the contribution of birth weight to ethnic differences in subcutaneous and central adiposity.

DESIGN AND METHODS

Data for this analysis were from the Third US National Health and Nutrition Examination Survey. The outcome measures were triceps, subscapular, suprailiac and thigh skinfold thicknesses at 5-11 y of age. Central adiposity was defined as ratios of subscapular to triceps (STR) and central-peripheral (CPR) (subscapular+suprailiac)/(triceps+thigh) skinfolds. Partial correlation analyses were used to determine the association between birth weight and measures of subcutaneous fatness, while multiple linear regression analyses were used to determine the independent contribution of birth weight to ethnicity variations in subcutaneous and central adiposity adjusting for sex, age and BMI.

RESULTS

Overall, birth weight was negatively associated with subscapular skinfold and central adiposity in White, Black and Hispanic American children (P < 0.05). Birth weight was also negatively associated with suprailliac skinfold in both Blacks and Hispanics (P < 0.01) and with sum of the four skinfolds in Blacks (P < 0.05). Compared with White, Black ethnicity was negatively associated with triceps, suprailliac thigh and sum of skinfold thicknesses controlling for birth weight, sex, age and BMI (P < 0.01). Compared with White, Hispanic ethnicity was negatively associated with triceps, thigh and sum of skinfold thicknesses (P < 0.01). Both Black and Hispanic ethnicity was positively associated with STR and CPR (P < 0.01).

CONCLUSIONS

In this population of American children, the association of birth weights with subcutaneous and central fat accumulation may be due to fetal programming. Since the impact of fetal conditions is likely to be modified by life course, defining the interaction between factors that are present at birth and subsequent exposures is one of the essential challenges for future research.

[Pharmacognostical studies on the stem and leaf of Mussaenda pubescens]

Morphological and microscopic chracteristics of Mussaenda pubescens Ait. f, a traditional Chinese medicine were described and illustrated with line drawings. TLC and UV analysis of the medicinal material were also undertaken. These studies provide referential information for identification and development of this medicinal material.

Modulation of apoptosis, tumorigenesity and metastatic potential with antisense H-ras oligodeoxynucleotides in a high metastatic tumor model of hepatoma: LCI-D20

BACKGROUND/AIMS

To investigate the effect of antisense H-ras DNA on tumorigenesity, apoptosis and metastasis of a high metastatic tumor model of human hepatocellular carcinoma in nude mice LCI-D20.

METHODOLOGY

LCI-D20 cells in primary culture were treated with 10 microns/L antisense oligodeoxynucleotide (ODN) drugs in vitro. 1.5 x 10(6) LCI-D20 cells with or without pretreatment were inoculated into each elevated subcutaneous (s.c.) flap in 14 nude mice, 6 animals for antisense H-ras oligodeoxynucleotide treated cells, 4 for H-ras non-specific antisense oligodeoxynucleotide treated cells, and the rest 4 for cells without pretreatment.

RESULTS

In in vitro cell culture study, 5-day continuous suppression of H-ras expression by antisense H-ras oligodeoxynucleotide resulted in significant inhibition of the proliferation of LCI-D20 cells (t = 31.529, P < 0.01). In situ end-labeling detection showed that apoptotic cell death was significantly increased in cells with 5-day treatment of antisense H-ras oligodeoxynucleotide (34.0 +/- 4.5%) in comparing with cells without treatment (2.5 +/- 1.2%, t = 13.434, P < 0.01) or treated with non-specific antisense oligodeoxynucleotide (4.8 +/- 1.4%, t = 12.453, P < 0.01) at the corresponding time. In the in vivo experiment, at week 6, no palpable tumor could be found in 50% (3/6) of animals receiving cells with pretreatment of antisense H-ras oligodeoxynucleotide, while 100% (4/4, 4/4) of animals in the 2 control groups developed palpable tumors. Tumor growth in antisense H-ras treated animals was significantly retarded in comparison with that of the untreated (t = 3.509, P < 0.01) or non-specific antisense oligodeoxynucleotide treated animals (t = 3.452, P < 0.01). 75% to 100% of animals in the 2 control groups developed lung metastases, while in antisense H-ras treated animals lung metastasis foci could not be found by random serial section and microscopy (u = 2.536, P < 0.01; u = 3.162, P < 0.01, respectively).

CONCLUSIONS

Specific inhibition of H-ras expression by antisense H-ras oligodeoxynucleotides could not only induce apoptotic cell death, inhibit the growth rate of LCI-D20 cells in vitro and in vivo, but also alter in vivo tumorigenesity and metastatic potential of LCI-D20 cells.