[Therapeutic potential of recombinant adenovirus expressing p53 in hepatocellular carcinoma cell lines]

OBJECTIVE

To investigate the effects of the recombinant adenoviral vector Ad-p53 on the biological behavior of hepatocellular carcinoma (HCC) cells in vitro and in vivo.

METHODS

With recombinant adenoviral vector expressing WT-p53 (Ad-p53), p53 gene was transfected into the HCC cell line, PLC/PRF/5. The cytotoxicities of Ad-p53 to cells were measured by MTT assay. Cell growth properties and cell cycle patterns were assessed with flow cytometry. The animal model was developed by injecting HCC cells into the dorsum of nude mice. Ad-p53 was injected intratumorally. The animals were killed, and then excised tumors were weighed and analyzed for p53 and p21 protein expression using western blot assay.

RESULTS

The introduction of exogenous wild-type p53 resulted in the inhibition of cell growth, high G2/M ratio and cell apoptosis, and low S ratio in PLC/PRF/5. The expression of both p53 and p21 proteins was upregulated in the cells.

CONCLUSIONS

Replication-deficient adenoviral vector expressing WT-p53 may be useful for gene therapy of HCC.

[Effects of noninvasive positive pressure ventilation on gas exchange and patients' transformation in chronic obstructive pulmonary disease and respiratory failure]

OBJECTIVE

This paper was to observe the effects of noninvasive positive pressure ventilation (NPPV) on gas exchange and patients' transformation and to evaluate their clinical value.

METHODS

Patients were randomly treated by either NPPV, or conventional medicine. The arterial blood gas readings, heart rates (HR), and respiratory rates (HR) were obtained at admission after the treatment. It was necessary to intubate when the clinical deterioation was marked by PaCO2 > 70 mmHg, PaCO2 gradually increasing 5-10 mmHg, pH decreasing 0.05-0.1 or mental obstacle, or PaO2 < 45 mmHg.

RESULTS

NPPV significantly decreased the PaCO2 level, HR, and RR, significantly increased the PaO2 level, and also decreased the opportunity of intubation.

CONCLUSION

The results suggest that NPPV can improve the gas exchange and reduce the need of intubation in COPD patients with acute respiratory failure.

[Apoptosis in pressure overload-induced heart hypertrophy]

Pressure overload can result in heart hypertrophy, and induce apoptosis, but the phenomenon of apoptosis during the forepart of cardiomyocyte hypertrophy remains unclear. The aim of this study was to inquire into the process of cardiomyocyte apoptosis during the forepart of cardiomyocyte hypertrophy. We constructed the hypertrophy model by transverse aortic constriction of male SD rat. The apoptosis ratio was detected by TUNEL method and FCM. The result demonstrated that hypertrophy indexes increased with the time of constriction, reached the highest level at day 7, maintained that level, and then decreased at day 91. The apoptosis ratio of cardiomyocyte at day 4 was higher than that at day 0 detected by FCM method, and the ratio at day 7 was markedly lower than that at day 4. After day 28, the apoptosis ratio of cardiomyocyte went up again with the time of constriction after surgery. TUNEL method revealed that positive nuclei were observed in cardiomyocytes exclusively in the left ventricle; the apoptosis ratio increased when constriction continued. TUNEL method confirmed the result of FCM. These data indicate that cardiac hypertrophy is initiated by apoptosis of cardiomyocyte, these two factors(hypertrophy and apoptosis) maintain the balance between growth and death during the early short period of aortic constriction, and when aortic constriction goes on they are involved in the pathogenesis of heart remodeling.

Arterial thrombus dissolution in vivo using a transducer-tipped, high-frequency ultrasound catheter and local low-dose urokinase delivery

PURPOSE

To examine the hypothesis that a transducer-tipped high-frequency ultrasound drug-delivery catheter may augment the thrombolytic effects of locally delivered low-dose urokinase and result in improved recanalization rates and reduced residual thrombotic burden.

METHODS

Thrombi were induced in situ bilaterally in 5- to 6-cm-long segments of the superficial femoral arteries in 9 dogs by intraluminal thermal damage and injection of thrombin. A transducer-tipped high-frequency local drug-delivery catheter was applied at 1.1 MHz and 0.6 W for 60 minutes to one superficial femoral artery segment, and an identical catheter with an inactivated ultrasound transducer was used to treat the contralateral control segment. Urokinase (5000 IU/kg) was delivered bilaterally into the thrombi during the treatment interval.

RESULTS

Angiography documented TIMI grade 2 or 3 flow in 9 (100%) segments in the ultrasound-treated group versus 6 (67%) of the controls (no ultrasound) (p = 0.058). Angiographically detected distal embolization was found in 2 ultrasound-treated segments compared with 5 controls (p = 0.02). Protruding or occlusive thrombi were seen angioscopically in 8 (89%) control segments but in only 1 (11%) of the ultrasound-treated arteries (p < 0.001). By histopathology, 7 (78%) segments in the control group had occlusive thrombi, whereas only 3 nonocclusive thrombi were found in the ultrasound-treatment group (p < 0.001).

CONCLUSIONS

Catheter-delivered high-frequency ultrasound and local low-dose urokinase infusion is efficacious for the treatment of acute thrombotic occlusions as evaluated by angiography, angioscopy, and histopathology.

Multi-residue analysis of avermectins in swine liver by immunoaffinity extraction and liquid chromatography-mass spectrometry

A multi-residue LC-MS method was developed to determine avermectin residues in swine liver. Abamectin and ivermectin (22,23-dihydroabamectin) were extracted, and cleaned up by immunoaffinty columns with immobilized anti-avermectin polyclonal antibodies. The cleaned samples were separated by high-performance liquid chromatography (HPLC) with a C8 column and determined by negative-ion atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) using selective ion monitoring (SIM) of [M-H]-. Recoveries of abamectin and ivermectin from fortified samples at 5-100 microg kg(-1) levels ranged from 74 to 94% and from 65 to 87%, respectively. The limits of detection were 5 microg of abamectin or ivermectin in 1 kg sample.

Augmentation of in-vitro clot dissolution by low frequency high-intensity ultrasound combined with antiplatelet and antithrombotic drugs

BACKGROUND

Glycoprotein IIb/IIIa antagonists and heparin are increasingly used for treatment of acute coronary syndromes. There is no data on the effect of these drugs on clot dissolution when combined with low frequency high-intensity ultrasonic energy. We examined a possible additive effect of low frequency high-intensity ultrasound with an antithrombotic, an antiplatelet and a fibrinolytic agent alone or in combinations for in vitro blood clot dissolution.

METHODS

Human blood clots were incubated for 10', 15' and 30' in normal saline containing commonly used concentrations of heparin, tirofiban, t-PA and Optison (echocardiographic contrast agent) alone and in combinations. Clots were then randomly exposed to low frequency high-intensity ultrasound (27[emsp3 ]kHz) for 5 minutes. The percent difference in clot weight and the incremental effect of ultrasound energy were calculated.

RESULTS

The most significant additive effect of ultrasound energy was detected with the combination of tirofiban and heparin (39+/-2% augmentation after 10' of incubation, p<0.0001). The greatest magnitude of percent clot weight reduction was observed with ultrasound energy combined with either t-PA alone (72+/-1% after 30' incubation, p=0.0016) or with the combination of t-PA, tirofiban, heparin and Optison (68+/-4% after 30' incubation, p=0.015).

CONCLUSIONS

Application of low frequency high-intensity ultrasound has an additive effect to antiplatelet, antithrombotic and fibrinolytic drugs, specifically with the combination of tirofiban and heparin or with t-PA; this effect is observed after a short incubation period.

Noninvasive transthoracic low frequency ultrasound augments thrombolysis in a canine model of acute myocardial infarction--evaluation of the extent of ST-segment resolution

BACKGROUND

Recently it has been demonstrated that transcutaneous delivery of ultrasound combined with tissue plasminogen activator (tPA) is more effective than tPA alone in recanalizing acutely thrombosed canine coronary arteries. In the present study, we investigated the incidence of partial (> or =50%) and complete (> or =70%) ST-segment elevation resolution in the precordial leads of dogs with experimental acute myocardial infarction that were treated with tissue plasminogen activator (tPA) alone or in combination with noninvasive transcutaneous delivery of high-intensity low frequency (27[emsp3 ]kHz) ultrasound.

METHODS

Thrombotic coronary occlusions were induced in the midportion of left anterior descending (LAD) coronary artery by electrical injury in 24 dogs. All dogs were given intravenous heparin and tPA. Dogs were randomized to tPA alone (n=12) or combined tPA and adjunctive transcutaneous ultrasound (US) delivery (n=12). Electrocardiograms were recorded at 1) baseline, 2) after coronary occlusion just before initiation of therapy, 3) when coronary angiography showed recanalization of the coronary artery (or at 90 minutes after initiation of therapy if reperfusion did not occur before then) and 4) 90 minutes later. ST amplitude was measured in all 6 precordial leads.

RESULTS

ST-segment amplitude at baseline was comparable between the tPA and the US group. Before initiation of therapy, sum of ST-segment elevation tended to be higher in the US group. At reperfusion and 90 minutes thereafter, sum of ST-segment amplitude tended to be smaller for the US group than in the tPA group (p<0.001 for the time effect; p=0.118 for the time x group interaction). Up to 90 minutes after initiation of therapy >/=50% resolution of the sum of precordial ST elevation was detected in 7 out of 11 dogs (63.6%) in the tPA group versus 10 out of 11 dogs (90.9%) in the US group. Ninety minutes thereafter, 3 out of 7 dogs in the tPA group (42.9%) versus 9 of 11 dogs in the US group (81.8%) had >/=50% resolution of the sum of precordial ST elevation.

CONCLUSIONS

The combination of tPA with noninvasive transcutaneous delivery of low frequency high-intensity ultrasound resulted in greater resolution of ST-segment elevation when reperfusion occurs and 90 minutes thereafter, as well as a higher rate of epicardial coronary artery reperfusion.

Inhibitory effect of voglibose and gymnemic acid on maltose absorption in vivo

AIM: To determine whether diabetic care can be improved by combination of voglibose and gymnemic acid (GA), we compared the combinative and individual effects of voglibose and GA on maltose absorption in small intestine.

METHODS: The small intestine 30 cm long from 2 cm caudal ward Treitz’s ligament of Wistar rat was used as an in situ loop, which was randomly perfused in recircular mode with maltose (10 mmol/L) with or without different dosages of voglibose and/or GA for 1 h. To compare the time course, perfusion of 10 mmol/L maltose was repeated four times. Each time continued for 1 h and separated by 30 min rinse. In the first time, lower dosages of GA (0.5 g/L) and/or voglibose (2 μmol/L) were contained except control.

RESULTS: Absorptive rate of maltose was the lowest in combinative group (P < 0.05, ANOVA), for example, the inhibition rate was about 37% during the first hour when0.5 g/L-GA and 2 μmol/L voglibose with 10 mmol/L maltose were perfused in the loop. The onset time was shortened to 30 min and the effective duration was prolonged to 4 h with the combination; therefore the total amount of maltose absorption during the effective duration was inhibited more significantly than that in the individual administration (P < 0.05, U test of Mann Whitney). The effect of GA on absorptive barriers of the intestine played an important role in the combinative effects.

CONCLUSION: There are augmented effects of voglibose and GA. The management of diabetes mellitus can be improved by employing the combination.

Molecular cloning of mouse ERK5/BMK1 splice variants and characterization of ERK5 functional domains

The mitogen-activated protein kinases (MAPKs) play important roles in regulation of cell growth and survival. Human MAPK 5 (ERK5) or Big MAP kinase 1 (BMK1) is a recently cloned member of the MAPK family. To identify ERK5-related kinases, we searched the GenBanktrade mark expressed sequence tag (EST) data base for mouse cDNAs with homology to human ERK5. A full-length mouse cDNA that was highly homologous to the human ERK5 was identified. Further analysis of ERK5 polymerase chain reaction products generated from mouse embryo cDNA yielded three mouse ERK5 cDNAs (mERK5a, mERK5b, and mERK5c). Sequence analysis showed that these cDNAs are alternative splice products of the mouse ERK5 gene. Interestingly, expressed mERK5b and mERK5c act as dominant negative inhibitors based on inhibition of mERK5a kinase activity and mERK5a-mediated MEF2C transactivation. However, the physiological significance of mERK5b and mERK5c is not fully understood. Further investigation using these mouse ERK5 splice variants and other constructed mutants identified functional roles of several regions of mERK5, which appear to be important for protein-protein interaction and intracellular localization. Specifically, we found that the long C-terminal tail, which contains a putative nuclear localization signal, is not required for activation and kinase activity but is responsible for the activation of nuclear transcription factor MEF2C due to nuclear targeting. In addition, the N-terminal domain spanning amino acids (aa) 1-77 is important for cytoplasmic targeting; the domain from aa 78 to 139 is required for association with the upstream kinase MEK5; and the domain from aa 140-406 is necessary for oligomerization. Taken together, these observations indicate that ERK5 is regulated by distinct mechanisms determined by its unique structure and presumably the presence of multiple splice variants.

[Alveolar macrophage and airway inflammation in patients with chronic obstructive pulmonary disease]

OBJECTIVE

To investigate the effects of alveolar macrophage(AM) on airway inflammation of chronic obstructive pulmonary disease(COPD).

METHODS

Broncho alveolar fluid(BALF) and bronchial mucosa biopsies were performed as usual. The levels of macrophage inflammatory-1 alpha (MIP-1 alpha), gelatinase B (MMP-9), interleukin(IL)-8 in BALF and the culture supernatants of AMs were measured with ELISA. The levels of endothelin (ET) were measured with radioimmunoassay method. The AMs expressing lymphocytic functional associated antigen-1 (LFA-1) in BALF, the AMs in mucosa and the thickness of mucosa were measured with immunocytochemistry and immunohistochemistry technique.

RESULTS

The levels of MIP-1 alpha, MMP-9, IL-8 and ET in the culture supernatants of AMs in patients with COPD were (1 446.9 +/- 126.7) microg/L, (16.98 +/- 5.15) microg /L, (43.98 +/- 5.54) ng/L, (168.10 +/- 21.22) microg/L respectively; while those were (1 123.5 +/- 90.6) microg/L, (5.24 +/- 0.93) microg/L, (25.99 +/- 6.05) ng/L, (124.68 +/- 9.96) microg/L in a control group. The number of macrophages in mucosa in patients with COPD was (1.71 +/- 0.48) cells/Hp, while that was (0.59 +/- 0.18) cells/Hp in the control group (0.63 +/- 0.25) x 10(4). Statistical significance was found between the two groups. The number of AMs and polymorphonuclear leucocyte in BALF were inversely correlated with forced expiratory volume in one second as percentage of predicted value(FEV(1)% Pre) (r = -0.511, P < 0.01; r = -0.562, P < 0.01). The levels of MMP-9 and ET in the culture supernatants of AMs were inversely correlated with FEV(1)% Pre(r = -0.678, P < 0.01; r = -0.871, P < 0.01). Both the level of MIP-1 alpha and the positive number of AM expressing LFA-1 in BALF were positively correlated with the number of AMs in BALF(r = 0.572, P < 0.01; r = 0.625, P < 0.01).

CONCLUSION

AM may be involved in the process of airway inflammation and subsequent airway obstruction.

The use of transducer-tipped ultrasound catheter for recanalization of thrombotic arterial occlusions

Ultrasound energy is currently being used and intensively investigated for recanalization of thrombotically occluded arteries. The ultrasonic energy is mainly applied either by a transcutaneous approach or by a percutaneous approach through a catheter with an external ultrasound transducer. Catheter-delivered transducer-tipped ultrasound thrombolysis is a new and innovative method. In this article we summarize the current available data on the use of this new type of catheter and discuss future directions and clinical applications.

Noninvasive transcutaneous low frequency ultrasound enhances thrombolysis in peripheral and coronary arteries

Previous studies have shown that external ultrasound with low frequencies and high intensities can enhance thrombolytic drug-induced clot dissolution during in vitro experiments. In this series of studies, we evaluated the efficacy of peripheral and coronary thrombolysis in vivo in animals by using noninvasive transcutaneous ultrasound combined with thrombolytic drugs (streptokinase and tPA) and/or microbubbles agents (dodecafluoropentane [DDFP] and perfluorocarbon-exposed sonicated dextrose albumin [PESDA]). Thrombotic occlusions were induced in 74 rabbit iliofemoral arteries and 24 canine left anterior descending (LAD) coronary arteries in this in vivo study. By using the combination of transcutaneous ultrasound and streptokinase, the angiographic patency rate in rabbit iliofemoral arteries was higher (56%-100%) than with ultrasound (6%; P < or = 0.0036) and streptokinase alone (6%; P < or = 0.0012). Also, with transcutaneous ultrasound and microbubbles, the angiographic patency rates were 76%-100% as compared with ultrasound alone (0%, P < or = 0.0003) or microbubbles alone (9%, P < or = 0.0001). In the canine study of acute myocardial infarction, thrombolysis in myocardial infarction (TIMI) grade flow at 90 minutes in the tPA alone group was 0.92 +/- 1.4 as compared with 2.42 +/- 1.9 in the tPA plus transthoracic ultrasound group (P = 0.006). There was much improved reperfusion with tPA plus ultrasound as compared with tPA alone. In vivo animal studies demonstrate that noninvasive transcutaneous ultrasound can greatly enhance the effect of clot dissolution with thrombolytic drugs and/or microbubbles, and has the potential for clinical application as an adjunctive method to improve arterial thrombolysis.

Proteasome activity is required for T lymphocyte aggregation after mitogen activation

The proteasome is a multicatalytic complex of proteases involved in T lymphocyte proliferation and activation through multiple mechanisms. In this study, we investigated its role in lymphocyte aggregation. We found that blocking proteasome activity by a proteasome-specific inhibitor lactacystin (LAC) prevented clustering of T lymphocytes after stimulation with various mitogens. Expression of adhesion molecules ICAM-1 and LFA-1 at cell surfaces of activated T cells was decreased after treatment with LAC. Mechanisms by which the proteasome intervenes in the expression of these adhesion molecules were different. LAC inhibited ICAM-1 expression at the mRNA level, whereas LFA-1 inhibition was probably at a post-translational level. Downregulation of these molecules after proteasome inhibition likely contributes to the observed repression of T cell aggregation. Our results show that the proteasome plays an important role in cell-cell interaction during T cell activation.

Proteasomes modulate balance among proapoptotic and antiapoptotic Bcl-2 family members and compromise functioning of the electron transport chain in leukemic cells

The mechanism underlying apoptosis induced by proteasome inhibition in leukemic Jurkat and Namalwa cells was investigated in this study. The proteasome inhibitor lactacystin differentially regulated the protein levels of proapoptotic Bcl-2 family members and Bik was accumulated at the mitochondria. Bik overexpression sufficed to induce apoptosis in these cells. Detailed examination along the respiration chain showed that lactacystin compromised a step after complex III, and exogenous cytochrome c could overcome this compromise. Probably as a result, the succinate-stimulated generation of mitochondrial membrane potential was significantly diminished. Bcl-x(L) interacted with Bik in the cells, and Bcl-x(L) overexpression prevented cytochrome c leakage out of the mitochondria, corrected the mitochondrial membrane potential defect, and protected the cells from apoptosis. These results show that proteasomes can modulate apoptosis of lymphocytes by affecting the half-life of Bcl-2 family members, Bik being one of them.

Detection and genotyping of GBV-C/HGV variants in China

We detected GBV-C/HGV sequences in the sera from 64 out of a total of 324 subjects in the south of China. In agreement with findings of others, we noted an especially high rate of infection among intravenous drug addicts and patients with chronic hepatitis C virus infection. The detection was achieved by nested PCR to amplify the 5' noncoding region (5'NCR) of the viral genome. Sequence analysis of the resulting 234 bp product revealed a total of 26 different sequences of which 25 were found to belong to the genotype G3, which is the most prevalent genotypes among Asian isolates, and one belonged to genotype G1, common among African isolates. The sequence divergence between the genotypes was largely clustered in a short variable region (V2) within the 5'NCR, and we showed that genotyping may be achieved equally well by analysis of this variable region as by the more detail analysis of the entire 5'NCR or of the entire viral genome.

Investigation of the electrochemical and electrocatalytic behavior of single-wall carbon nanotube film on a glassy carbon electrode

The electrochemical behavior of a film of single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups was studied extensively on a glassy carbon (GC) electrode. One stable couple corresponding to the redox of the carboxylic acid group, which was supported by XPS and IR experiments, was observed. The electrode process involved four electrons, while the rate-determining step was a one-electron reduction. The SWNT film-modified electrode showed favorable electrocatalytic behavior toward the oxidation of biomolecules such as dopamine, epinephrine, and ascorbic acid.

Inhibitory effect and mechanism of acarbose combined with gymnemic acid on maltose absorption in rat intestine

AIM: To compare the combinative and individual effect of acarbose and gymnemic acid (GA) on maltose absorption and hydrolysis in small intestine to determine whether nutrient control in diabetic care can be improved by combination of them.

METHODS: The absorption and hydrolysis of maltose were studied by cyclic perfusion of intestinal loops in situ and motility of the intestine was recorded with the intestinal ring in vitro using Wistar rats.

RESULTS: The total inhibitory rate of maltose absorption was improved by the combination of GA (0.1 g/L-1.0 g/L) and acarbose (0.1 mmol/L-2.0 mmol/L) throughout their effective duration (P < 0.05, U test of Mann-Whitney), although the improvement only could be seen at a low dosage during the first hour. With the combination, inhibitory duration of acarbose on maltose absorption was prolonged to 3 h and the inhibitory effect onset of GA was fastened to 15 min. GA suppressed the intestinal mobility with a good correlation (r = 0.98) to the inhibitory effect of GA on maltose absorption and the inhibitory effect of 2 mmol/L (high dose) acarbose on maltose hydrolysis was dual modulated by 1 g/L GA in vivo indicating that the combined effects involved the functional alteration of intestinal barriers.

CONCLUSION: There are augmented effects of acarbose and GA, which involve pre-cellular and paracellular barriers. Diabetic care can be improved by employing the combination.

Coronary remodeling of proximal and distal stenotic atherosclerotic plaques within the same artery by intravascular ultrasound study

The aim of this intravascular ultrasound study was to compare the type and the degree of vessel remodeling in proximal and distal de novo lesions within the same coronary artery in patients with stable angina pectoris. Seventy-six de novo coronary artery lesions in 38 coronary arteries of 38 patients were imaged by intravascular ultrasound. The vessel area (VA) within the external elastic lamina and the lumen area (LA) were measured, and the wall area (VA-LA) was calculated at the lesion site, and the proximal and distal reference sites. The VA ratio was defined as (lesion VA/average of the proximal and distal reference VAs) to represent the degree of vessel remodeling. The proximal coronary segments showed compensatory enlargement more often (68% vs 29%, p < 0.01) than the distal segments, and the VA ratio at the lesion site was significantly larger (1.1 +/- 0.3 vs 1.0 +/- 0.2, p <0 .01) in proximal segments than in distal segments. The type of coronary remodeling was discordant in 61% and concordant in only 39% of coronary arteries between the proximal and distal segments. The type of coronary remodeling of proximal and distal coronary lesions was inhomogeneous, even within the same vessel. Proximal coronary segments showed more prominent compensatory enlargement than distal segments, which have a similar degree of luminal narrowings.

Hepatocellular carcinoma and aflatoxin exposure in Zhuqing Village, Fusui County, People's Republic of China

Hepatocellular carcinoma (HCC) is a common cause of cancer morbidity and mortality in Asia and Africa. Epidemiological studies have found that dietary exposure to aflatoxin B1 (AFB1) and chronic infection with hepatitis B virus are two major risk factors for HCC. We have collated the incidence and mortality data of malignant tumors from 1973 to 1999 in Zhuqing Village, Fusui County, an area with very high HCC rates, and found that this cancer accounted for 64% of the total cancer incidence. Dietary intake of AFB1 was monitored for 1 week in a study group consisting of 15 males and 14 females from different households in this village. Four of 29 participants (13.8%) and 3 of 15 (20%) male participants were hepatitis B virus surface antigen positive. AFB1 was detectable in 76.7% (23 of 30) of ground corn samples (range, 0.4-128.1 ppb), 66.7% (20 of 30) of cooking peanut oil samples (range, 0.1-52.5 ppb), and 23.3% (7 of 30) of rice samples (range, 0.3-2.0 ppb) collected from each household. Mean levels of serum AFB1-albumin adducts in this group were 1.24 +/- 0.31 pmol/mg of albumin at the beginning of the study and 1.21 +/- 0.19 pmol/mg of albumin at the end of the period. Urinary AFB1 metabolites were detectable in 88.9% (24 of 27) samples (range, 0.9-3569.7 ng/24-h urine). These data provide the exposure and disease risk information for establishing intervention studies to diminish the impact of aflatoxin exposure in this high-risk population.

Syntheses and characterizations of metal complexes derived from cis,cis-1,3,5-triaminocyclohexane-N,N',N"-triacetic acid

A convenient six-step procedure is developed to routinely prepare the hexadentate ligand cis,cis-1,3,5-triaminocyclohexane-N,N',N"-triacetic acid (H3tachta) as an HCl salt. Complexes of gallium(III) and indium(III), [Ga(tachta)] and [In(tachta)], are synthesized from the reactions of the ligand and the corresponding metal precursors. Copper(II), palladium(II), and cobalt(II) complexes, [Cu(Htachta)], [Pd(Htachta)], and [Co(Htachta)], are obtained from the reactions of H3tachta with the corresponding metal chlorides. The structures of H3tachta.3HCl.2H2O (C12H28Cl3N3O8) and [Ga(tachta)] (C12H18GaN3O6) are characterized. The crystal of H3tachta.3HCl.2H2O is monoclinic, of the space group P2(1)/c, with a = 15.1688(4) A, b = 8.4708(2) A, c = 15.9408(2) A, beta = 108.058(1) degrees, and Z = 4; that of [Ga(tachta)] is cubic, of space group Pa3, with a = 14.0762(1) A and Z = 8. The gallium atom of [Ga(tachta)] is six-coordinated in the solid state, and the complex assumes a pseudooctahedronal geometry with the completely deprotonated hexadentate ligand encapsulating the metal ion.

Influence of ejection fraction and valvular regurgitation on the accuracy of aortic valve area determination

OBJECTIVE

To examine the influence of left ventricular dysfunction, aortic regurgitation, and mitral regurgitation on commonly used methods for aortic valve area (AVA) determination.

BACKGROUND

Each method for AVA determination has its inherent limitations.

METHODS

AVA determinations by transesophageal echocardiography (TEE) using planimetry, transthoracic echocardiography (TTE) with application of the continuity equation, and cardiac catheterization applying the Gorlin formula were performed in 74 patients with aortic stenosis. The severity of the aortic stenosis was defined by consensus of at least two methods. Over- or underestimation of AVA associated with ejection fraction, aortic regurgitation, mitral regurgitation, or severity of the aortic stenosis for each method in relation to the other two methods was assessed.

RESULTS

Mean AVAs were 1.05 +/- 0.51 by TEE, 1.06 +/- 0.51 by TTE, and 1.08 +/- 0.53 by cardiac catheterization. An overestimation of the severity of the aortic stenosis by the Gorlin formula in patients with moderate-to-severe aortic regurgitation as compared to TEE-derived data was found (P = 0.014). A similar trend of overestimation by catheterization in comparison with the TTE data was found. In the context of moderate-to-severe mitral regurgitation, AVA determination by TTE overestimated the degree of aortic stenosis as compared to TEE (P = 0.011) and cardiac catheterization (P = 0.023).

CONCLUSIONS

Overall mean AVA did not differ between methods, suggesting that these three methods are equally accurate in a nonselected clinical patient group. However, in the presence of significant aortic regurgitation, the two echocardiographic methods appear more accurate. Our observation of an overestimation of the severity of aortic stenosis by TTE in the presence of moderate-to-severe mitral regurgitation indicates that this possibility should be accounted for in clinical decisions based on TTE determinations of AVA.

The experimental study on the effect calcitonin gene-related peptide on bone resorption mediated by interleukin-1

To investigate the effect of calcitonin gene-related peptide (CGRP) on bone resorption mediated by interleukin-1 beta(IL-1 beta) in vitro, the osteoclasts isolated from the long bones of newborn SD rats were co-cultured with osteoblasts on ivory slices placed in 24-well plates. 24 h later, conditioned media containing CGRP and/or IL-1 beta were added to the wells respectively, and continued culturing for 48 h. After the cells were stripped off by ultrasonication, the ivory slices were stained in toludine blue. The number and the total area of resorption lacunae on each slice were measured by computer imaging analysis system. Our results showed that IL-1 beta significantly stimulated bone resorption, but CGRP inhibited the effect mediated by IL-1 beta in a dose-dependent manner. It is suggested that CGRP may inhibit osteoclastic bone resorption through two ways: One is that CGRP functions directly on osteoclasts to block their activation; the other is that CGRP regulates the release of cytokines by osteoblasts and indirectly affects the function of osteoclasts.

Resonance Rayleigh scattering method for the determination of trace amounts of cadmium with iodide-basic triphenylmethane dye systems

In dilute phosphoric acid solution, cadmium (II) reacts with a large excess of I- to form [CdI4]2- which reacts further with basic triphenylmethane dyes such as crystal violet (CV), ethyl violet (EV), methyl violet (MV), brilliant green (BG) or malachite green (MG) to form an ion-association complex. This results in a significant enhancement of resonance Rayleigh scattering (RRS) intensity and the appearance of new RRS spectra. The characteristics of RRS spectra of the ion-association complexes, the influencing factors and the optimum conditions of these reactions have been investigated. The intensity of RRS is directly proportional to the concentration of cadmium from 0 to 60 ng mL(-1) for EV and MV systems, 0 to 80 ng mL(-1) for CV system, and 0 to 100 ng mL(-1) for BG and MG systems. The methods exhibit high sensitivities and the detection limits for cadmium are between 0.35 and 2.00 ng mL(-1) depending on the different reaction systems. The new RRS method was applied to the direct determination of traces of cadmium in pure zinc and synthetic water samples.

Instrumentation and calibration protocol for imaging dynamic features in dense-scattering media by optical tomography

Instrumentation is described that is suitable for acquiring multisource, multidetector, time-series optical data at high sampling rates (up to 150 Hz) from tissues having arbitrary geometries. The design rationale, calibration protocol, and measured performance features are given for both a currently used, CCD-camera-based instrument and a new silicon-photodiode-based system under construction. Also shown are representative images that we reconstructed from data acquired in laboratory studies using the described CCD-based instrument.