Beta-globin gene cluster polymorphisms are strongly associated with severity of HbE/beta(0)-thalassemia

We evaluated the contribution of 67 single nucleotide polymorphisms (SNPs) within the beta-globin gene cluster to disease severity in groups of 207 mild- and 305 severe unrelated patients from Thailand with Hemoglobin E (HbE)/beta(0)-thalassemia and normal alpha-globin genes. Our analysis showed that these SNPs comprise two distinct linkage disequilibrium blocks, one containing the beta-globin gene and the other extending from the locus control region (LCR) to the delta gene, which are separated by a recombination hotspot in the narrow region of the beta-globin gene promoter. Forty-five SNPs within the interval including the LCR region and the delta gene showed strong association with disease severity. The strongest association was observed with the XmnI polymorphism located 158-bp upstream to the G gamma gene (p = 4.6E-12). Carriers of the T allele of XmnI were more likely to have a milder disease course and higher level of fetal hemoglobin (HbF) in both the mild (p = 0.005) and severe (p = 8.7E-06) patient groups. Haplotype analysis revealed that the T allele of XmnI was nearly always in cis with the HbE allele. The high frequency of this haplotype may be favored by positive selection against malarial infection. Further studies are needed to validate this hypothesis and determine whether XmnI or another closely linked variant modulates severity and HbF levels in patients with beta(0)-thalassemia/HbE disease.

Fetal hemoglobin in sickle cell anemia: genetic determinants of response to hydroxyurea

The increase in fetal hemoglobin (HbF) in response to hydroxyurea (HU) varies among patients with sickle cell anemia. Twenty-nine candidate genes within loci previously reported to be linked to HbF level (6q22.3-q23.2, 8q11-q12 and Xp22.2-p22.3), involved in metabolism of HU and related to erythroid progenitor proliferation were studied in 137 sickle cell anemia patients treated with HU. Three-hundred and twenty tagging single nucleotide polymorphisms (SNPs) for genotyping were selected based on HapMap data. Multiple linear regression and the nonlinear regression Random Forest method were used to investigate the association between SNPs and the change in HbF level after 2 years of treatment with HU. Both methods revealed that SNPs in genes within the 6q22.3-23.2 and 8q11-q12 linkage peaks, and also the ARG2, FLT1, HAO2 and NOS1 genes were associated with the HbF response to HU. Polymorphisms in genes regulating HbF expression, HU metabolism and erythroid progenitor proliferation might modulate the patient response to HU.

The enhancement of cellular cAMP with olprinone protects autotransplanted rat kidney against cold ischemia-reperfusion injury

The administration of a cyclic nucleotide analog improves cold ischemia/reperfusion injury in several organs. The type 3 phosphodiesterase inhibitor olprinone is a potent stimulus that enhances cellular cAMP levels. The present study was performed to investigate the protective effects of enhanced intracellular cAMP levels by olprinone in rat orthotopic kidney transplantation. Autotransplantation and immediate contralateral nephrectomy were performed in Lewis rats after 18 hours of graft storage at 4 degrees C in University of Wisconsin (UW) solution with or without 25 microg/mL olprinone hydrochloride. At 2 hours after reperfusion, serum and urinary biochemical indicators of renal dysfunction and injury were measured: serum creatinine, fractional excretion of Na+ and urinary N-acetyl-D-glucosaminidase. Additionally, intracellular cAMP in kidney tissues was measured by a radioimmunology method. Compared to the only UW solution group, olprinone hydrochloride significantly reduced the increased in serum creatinine, FENa and NAG caused by renal ischemia/reperfusion injury, after 2 hours of reperfusion. The content of cAMP at the endpoint of 18 hours cold preservation was significantly greater in the UW plus olprinone hydrochloride group than that in the UW group. Two hours after reperfusion, the content of cAMP in the UW plus olprinone hydrochloride group was still significantly higher than that in the UW group without containing olprinone hydrochloride. These results support a beneficial effect of olprinone against cold ischemia and reperfusion injury via an increased intracellular cAMP levels.

HIV-1 coreceptors CCR5 and CXCR4 both mediate neuronal cell death but CCR5 paradoxically can also contribute to protection

The chemokine receptors CCR5 and CXCR4 serve, in addition to CD4, as coreceptors for human immunodeficiency virus-1 (HIV-1), and infection with HIV-1 can cause dementia. In brain-derived cells, HIV-1 envelope glycoprotein gp120 initiates a signaling cascade that involves p38 mitogen-activated protein kinase and leads to neuronal cell death. Using mixed neuronal/glial cultures from rats and mice genetically deficient in one or both HIV coreceptors, we show here that CCR5, CXCR4 or both can mediate HIV/gp120 neurotoxicity depending on the viral strain. Paradoxically, we also found evidence for a CCR5-mediated neuroprotective pathway. We identify protein kinase Akt/PKB as an essential component of this pathway, which can be triggered by the CCR5 agonists macrophage inflammatory protein-1beta and regulated-and-normal-T-cell-expressed-and-secreted. Moreover, these CCR5 ligands prevent neuronal cell death induced by stromal cell-derived factor-1, a CXCR4 agonist. Both neurons and glia coexpress CXCR4 and CCR5. Ca2+ imaging experiments demonstrate that engagement of CCR5 prevents CXCR4-triggered increases in intracellular free Ca2+. This finding suggests that CCR5 ligands can protect neurons at least, in part, by modulating CXCR4-mediated toxicity through heterologous desensitization.

Urine NGAL and IL-18 are predictive biomarkers for delayed graft function following kidney transplantation

Delayed graft function (DGF) due to tubule cell injury frequently complicates deceased donor kidney transplants. We tested whether urinary neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) represent early biomarkers for DGF (defined as dialysis requirement within the first week after transplantation). Urine samples collected on day 0 from recipients of living donor kidneys (n = 23), deceased donor kidneys with prompt graft function (n = 20) and deceased donor kidneys with DGF (n = 10) were analyzed in a double blind fashion by ELISA for NGAL and IL-18. In patients with DGF, peak postoperative serum creatinine requiring dialysis typically occurred 2-4 days after transplant. Urine NGAL and IL-18 values were significantly different in the three groups on day 0, with maximally elevated levels noted in the DGF group (p < 0.0001). The receiver-operating characteristic curve for prediction of DGF based on urine NGAL or IL-18 at day 0 showed an area under the curve of 0.9 for both biomarkers. By multivariate analysis, both urine NGAL and IL-18 on day 0 predicted the trend in serum creatinine in the posttransplant period after adjusting for effects of age, gender, race, urine output and cold ischemia time (p < 0.01). Our results indicate that urine NGAL and IL-18 represent early, predictive biomarkers of DGF.

Urinary IL-18 is an early predictive biomarker of acute kidney injury after cardiac surgery

Acute kidney injury (AKI) is a frequent complication of cardiopulmonary bypass (CPB). The lack of early biomarkers for AKI has impaired our ability to intervene in a timely manner. Urinary neutrophil gelatinase-associated lipocalin (NGAL) is recently demonstrated as an early biomarker of AKI after CPB, increasing 25-fold within 2 h and declining 6 h after surgery. In the present study, we tested whether interleukin-18 (IL-18) is a predictive biomarker for AKI in the same group of patients following CPB. Exclusion criteria included pre-existing renal insufficiency and nephrotoxin use. Serial urine samples were analyzed by enzyme-linked immunosorbent assay for IL-18 in 20 patients who developed AKI (defined as a 50% or greater increase in serum creatinine after CPB) and 35 controls (age, race, and gender-matched patients who did not develop AKI after CPB). Using serum creatinine, AKI was detected only 48-72 h after CPB. In contrast, urine IL-18 increased at 4-6 h after CPB, peaked at over 25-fold at 12 h, and remained markedly elevated up to 48 h after CPB. The performance of IL-18 as demonstrated by area under the receiver operating characteristics curve for diagnosis of AKI at 4, 12, and 24 h after CPB was 61, 75, and 73% respectively. Also, on multivariate analysis, both IL-18 and NGAL were independently associated with number of days in AKI among cases. Our results indicate that IL-18 is an early, predictive biomarker of AKI after CPB, and that NGAL and IL-18 are increased in tandem after CPB. The combination of these two biomarkers may allow for the reliable early diagnosis and prognosis of AKI at all times after CPB, much before the rise in serum creatinine.

Effects of a dried Bacillus subtilis culture on egg quality

The effects of a dried Bacillus subtilis culture on the egg qualities of layers were studied. Nine hundred and sixty 25-wk-old Lohmann Brown layers were randomly divided into 5 groups with 192 layers in each group. Layers in group 1 were fed a control diet. The remaining groups received the control diet that contained either 20 mg of zinc bacitracin/kg and 4 mg of colistin sulfate/kg or 500, 1,000, or 1,500 mg of B. subtilis culture/ kg, respectively. The results showed improvements in egg production, feed consumption, and feed conversion (P < 0.05) of layers when 500 mg of B. subtilis culture/kg was added to the diets. The results also showed some special improvements in this group, including increases in eggshell thickness, yolk color, and Haugh unit, and decreases in yolk cholesterol concentration (P < 0.05). However, excessive doses of B. subtilis culture did not improve the performance of layers.

Update on the Pharmacokinetic Aspects of Antiretroviral Agents: Implications in Therapeutic Drug Monitoring

The observed inter-individual variation in antiretroviral pharmacokinetics (PK) that results in a wide range of drug exposures from fixed-dose regimens has led to increasing interest in the clinical use of therapeutic drug monitoring (TDM) to individualize dosing of antiretroviral therapy (ART). The focus of this review is to provide an overview of literature available to support therapeutic drug monitoring among the current classes of antiretrovirals, suggest patient populations that may benefit from TDM and bring forth some of the limitations that may exist for widespread use of TDM in a traditional clinical setting.

Randomised clinical trial investigating the effects of combined administration of octreotide and methylglucamine diatrizoate in the older persons with adhesive small bowel obstruction

OBJECTIVE

To investigate the effects of combined administration of octreotide and methylglucamine diatrizoate in the older persons with adhesive small bowel obstruction.

PATIENTS AND METHODS

One hundred and sixty-two consecutive patients who had suffered from adhesive intestinal obstruction without clinical evidence of strangulation or gangrene were randomised into two groups, a control group (treated conservatively, n=82) and a contrast group (treated with combined administration of octreotide and methylglucamine diatrizoate, n=80). A laparotomy was performed in both the two groups if symptoms of strangulation developed or the obstruction did not resolve spontaneously after 72 h.

RESULTS

Statistically significant rapid reduction in pain score, lower amount of nasogastric drainage, shorter hospital stay, lower operative rate and lower postoperative morbidity were observed in the contrast group. Among the non-operative patients, earlier passage of stool and gas, earlier first oral intake and shorter duration of nasogastric tube placement were significantly more frequently observed in the contrast group. No difference in the rate of readmission was found between the two groups.

CONCLUSIONS

Combined administration of octreotide and methylglucamine diatrizoate accelerates resolution of small bowel obstruction by a specific therapeutic effect and is safe for the older persons.

Irreducible correlation functions of the S matrix in the coordinate representation: application in calculating Lorentzian half-widths and shifts

By introducing the coordinate representation, the derivation of the perturbation expansion of the Liouville S matrix is formulated in terms of classically behaved autocorrelation functions. Because these functions are characterized by a pair of irreducible tensors, their number is limited to a few. They represent how the overlaps of the potential components change with a time displacement, and under normal conditions, their magnitudes decrease by several orders of magnitude when the displacement reaches several picoseconds. The correlation functions contain all dynamical information of the collision processes necessary in calculating half-widths and shifts and can be easily derived with high accuracy. Their well-behaved profiles, especially the rapid decrease of the magnitude, enables one to transform easily the dynamical information contained in them from the time domain to the frequency domain. More specifically, because these correlation functions are well time limited, their continuous Fourier transforms should be band limited. Then, the latter can be accurately replaced by discrete Fourier transforms and calculated with a standard fast Fourier transform method. Besides, one can easily calculate their Cauchy principal integrations and derive all functions necessary in calculating half-widths and shifts. A great advantage resulting from introducing the coordinate representation and choosing the correlation functions as the starting point is that one is able to calculate the half-widths and shifts with high accuracy, no matter how complicated the potential models are and no matter what kind of trajectories are chosen. In any case, the convergence of the calculated results is always guaranteed. As a result, with this new method, one can remove some uncertainties incorporated in the current width and shift studies. As a test, we present calculated Raman Q linewidths for the N2-N2 pair based on several trajectories, including the more accurate "exact" ones. Finally, by using this new method as a benchmark, we have carried out convergence checks for calculated values based on usual methods and have found that some results in the literature are not converged.

Osmotic adjustment segregates with and is positively related to seed yield in F3 lines of crosses between Brassica napus and B. juncea subjected to water deficit

For osmotic adjustment to be used as a selection criterion for adaptation to drought there is a need to demonstrate its segregation and association with seed yield in a population. This study examined osmotic adjustment and seed yield in F3 lines derived from crosses between Brassica napus (cvv. Karoo, Monty) and B. juncea (line JN25). A clear separation of the level of osmotic adjustment was observed among 20 F3 lines of Karoo × JN25 (7 high and 13 low) and 20 F3 lines of Monty × JN25 (8 high and 12 low) under glasshouse conditions. When the 3 parents and 8 selected F3 lines were grown in a low-rainfall environment in the field, the segregation of osmotic adjustment was largely similar to that observed in the glasshouse. Yield reduction, with irrigated plots as controls, was up to 30% for genotypes with low osmotic adjustment but only 10% for those with high osmotic adjustment. Osmotic adjustment was closely correlated with the accumulation of K+ (r = 0.91), soluble sugars (r = 0.90) and proline (r = 0.96), whereas other solutes (Na+, NH4+, Cl–, NO3–, Mg2+ and Ca2+) made little or no contribution to osmotic adjustment. Proline concentrations were very low in well-watered plants but sharply increased by 5- to 15-fold in plants subjected to water deficit, and net proline accumulation showed a higher association with total seed number (r = 0.86) and yield (r = 0.89) than did the concentrations of K+ (r = 0.75 to 0.82) or soluble sugars (r = 0.68 to 0.72). The study suggests that leaf proline concentration could be a good indicator of osmotic adjustment in Brassica oilseeds.

Comparative tissue factor pathway inhibitor release potential of heparins

Tissue factor pathway inhibitor (TFPI) is released following the administration of unfractionated heparin, low-molecular-weight heparins, defibrotide and PI-88. In this study, the comparative effects of heparin, a low-molecular-weight heparin-gammaparin and a heparin-derived oligosaccharide mixture-subeparin (C3) were studied on functional and immunologic tissue factor pathway inhibitor activity levels in a non-human primate (Macaca mulatta) model. The dose-dependent effect was studied following intravenous and subcutaneous administration. Following the administration of 1 mg/kg of heparin, gammaparin, and C3, the functional levels of TFPI at 5 minutes were 2.40, 2.56, and 1.08 U/mL and the corresponding TFPI immunologic levels were 4.3-, 4.0-, and 2.1-fold, increased, respectively, over the baseline value. From these results, it can be concluded that heparin and gammaparin produced similar levels of TFPI release. Hence, gammaparin and heparin have similar TFPI release potential despite their differences in molecular weight. The influence of molecular weight, charge density, and interactions with heparin cofactor II on TFPI release are also discussed.

Cbfa1/osf2 transduced bone marrow stromal cells facilitate bone formation in vitro and in vivo

It has been well established that core binding factor a-1/osteoblast-specific factor-2 (cbfa1/osf2) is a key regulator of osteoblast differentiation and function, however, it is not known whether it can induce bone formation in vitro and in vivo. To investigate the effect of cbfa1/osf2 on bone formation, we used a recombinant adenoviral vector carrying the mouse cbfa1/osf2 gene to transduce primary cultured bone marrow stromal cells (MSCs) of BALB/c mice. We found that Ad-cbfa1/osf2-transduced MSCs produced cbfa1/osf2 protein and differentiated into osteoblast-like cells. The transduced MSCs had increased alkaline phosphatase activity, increased expression of osteocalcin, osteopontin and bone sialoprotein, and increased matrix mineralization in vitro. To observe the induction of bone formation in vivo, MSCs transduced with Ad-cbfa1/osf2 were transplanted into a 5 mm diameter critical-sized skull defect in BALB/c mice, with type I collagen as scaffolding material. Healing of the defect in treatment and control groups was examined grossly and histologically at four weeks. Skull defects transplanted with Ad-cbfa1/osf2-transduced MSCs had an average of 85% osseous closure at four weeks. Control groups in which the defects were not treated (group 1), treated with collagen only (group 2), or treated with collagen and nontransduced MSCs (group 3) showed little or no osseous healing. These studies indicate that cbfa1/osf2 can induce osteoblast differentiation and bone formation both in vitro and in vivo, suggesting that MSCs transduced with the cbfa1/osf2 gene may be useful in treating bone defects.

[Changes in T-lymphocyte subsets of peripheral blood in patients with filarial chyluria]

OBJECTIVE

To study the changes in T-lymphocyte subsets CD4+:CD8+ of peripheral blood in 29 patients with present chyluria(PPC), 29 patients with chyluria history but without chyluria (PNPC) and 38 healthy controls.

METHODS

The determination of CD3+, CD4+ and CD8+ was conducted using test reagents kits.

RESULTS

The percentage of CD3+, CD4+ cell were signfcantly decreased in PPS group than in PNPC and healthy control group, the ratio of CD4+/CD8+ being under 1.0. The T-lymphocyte subsets (CD3+, CD4+, CD8+) and CD4+/CD8+ ratio of both PNPC and healthy control group were all within normal range.

CONCLUSION

The immune function of the patients with filarial chyluria was impaired in terms of the changes in T-lymphocyte subsets.

Osmotic adjustment and seed yield of Brassica napus and B. juncea genotypes in a water-limited environment in south-western Australia

The relationship between osmotic adjustment and seed yield of Brassica oilseeds was examined at a low rainfall site, Merredin, Western Australia, in 1998 and 1999. Genotypes of B. napus and B. juncea were subjected to rain-fed and irrigated treatments at the seed-fill stage. The B. juncea lines showed small or even no yield reduction under rain-fed conditions, and generally had no yield advantage over the B. napus cultivars where irrigated. In both species, an inverse correlation was found between the magnitude of osmotic adjustment and the percentage of yield reduction. Genotypes with low osmotic adjustment, under rain-fed conditions, had a yield reduction of up to 40%, whereas those with high osmotic adjustment had only 0–10% yield reduction. In contrast, seed oil concentrations decreased from 41% under irrigation to 38% under water deficits and the differences among genotypes were not related to osmotic adjustment. In 1999, osmotic adjustment was again observed for most of the genotypes, but its association with seed yield was not as obvious as in the previous year and usually only the osmotically adjusting B. juncea genotypes maintained a good yield under water deficits. Not all the B. juncea genotypes expressed osmotic adjustment despite the fact that they were generally more drought resistant than the B. napus genotypes. In both years, however, osmotic adjustment was associated with increased harvest indices of B. napus and B. juncea, indicating that this physiological trait can be beneficial to Brassica yield in a water-limited Mediterranean-type environment.

TCDD-inducible poly(ADP-ribose) polymerase: a novel response to 2,3,7,8-tetrachlorodibenzo-p-dioxin

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes pleotropic effects in mammalian species through modulating gene expression. Here we analyzed TCDD-induced mRNA expression by using mRNA differential display and report the cloning of a novel TCDD-inducible poly(ADP-ribose) polymerase (TiPARP). TiPARP cDNA contains an open reading frame of 657 amino acid residues; the carboxyl half shares sequence similarity to the catalytic domain of PARP, a family of enzymes that catalyze poly ADP-ribosylation of proteins. Expression of the cDNA by in vitro transcription/translation reveals a protein of approximately 75 kDa. The expressed TiPARP exhibits PARP activity toward histone. TiPARP is highly homologous to RM1 which is induced during long-term potentiation, a memory formation process, and to TIL which is induced in T cells infiltrating progressing tumors. TiPARP mRNA is expressed in a broad range of mouse tissues. Together, these data demonstrate that TiPARP is a novel target of TCDD that may contribute to multiple responses to TCDD by modulating protein function through poly ADP-ribosylation.

Dependence of papanicolaou gradings of exfoliated urothelial cells upon GSTM1 and GSTT1 polymorphism in benzidine-exposed workers of the Shanghai dye industry

The distribution of the polymorphic alleles of the genes coding for glutathione S-transferases (GSTs) M1 and T1 was compared with the results of cytological grading of exfoliated urothelial cells (Pap test) in a non-diseased high-risk group of workers formerly exposed to benzidine in the Shanghai dyestuff industry (n = 317). All subjects were genotyped for GSTT1 and M1 gene polymorphism by allele-specific PCR. Individuals were stratified according to their job and duration of exposure. A subgroup of 78 individuals with cytological gradings of grade III or higher in the Pap test showed a significant under-representation of the combination of GSTT1 0/0 and M1 0/0 genotypes compared with 238 subjects with a cytological classification lower than grade III (OR 0.55, 95% CI 0.31-0.98. P=0.04). These results suggest that neither the GSTM1 0/0 or GSTT1 0/ 0 genotype alone nor their combination had a clear association with cytopathological changes in exfoliated urothelial cells from individuals previously exposed to benzidine in Shanghai. This contradicts the results of studies indicating that the GSTM1 0/0 genotype is associated with an increased risk for bladder cancer in the general population, mostly outside China.

[Association between DLST gene polymorphism and Alzheimer's disease]

OBJECTIVE

To investigate the association between the polymorphic alleles of dihydrolipoamide succinyltransferase (DLST) gene cDNA at position A19117G in intron 13 and C19183T in exon 14 and the risk for sporandic Alzheimer's disease (SAD).

METHODS

The polymorphism of DLST gene was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques in 105 patients with sporadic Alzheimer disease and 109 normal controls.

RESULTS

The frequency of AT/AC genotype was found to be significantly higher in SAD patients (21%) than in controls (10%) with an odds ratio of 2.36 (P < 0.05). The frequencies of AC/AC, AT/AT genotypes and AC allele were slightly decreased in cases with SAD as compared with controls. While the frequencies of the GC/GC genotype and GC allele were slightly higher in SAD patients than in controls. However, these differences were not statistically significant (P > 0.05).

CONCLUSION

The AT/AC genotype of DLST gene is associated with an increased risk for SAD.

Formation of brainstem (nor)adrenergic centers and first-order relay visceral sensory neurons is dependent on homeodomain protein Rnx/Tlx3

Brainstem visceral sensory and (nor)adrenergic neurons play crucial roles in modulating cardiovascular and respiratory functions. The origins and formation of these neurons are poorly understood. Here we show that these two classes of neurons are derived from Mash1-positive precursor cells, and can be prospectively identified by combinatorial expression of two homeobox genes, Rnx and Phox2 (Phox2a or Phox2b). It was previously shown that Rnx-deficient mice die from respiratory failure. Here we show that Rnx function is required for formation of first-order relay visceral sensory neurons in the brainstem. In addition, as in Phox2b-deficient mice, the development of most (nor)adrenergic centers is compromised in Rnx mutants. We also provide genetic evidence to show that Rnx and Phox2 proteins may function independently to specify the (nor)adrenergic phenotype. Our studies reveal a surprising ontogenetic relationship between relay visceral sensory and (nor)adrenergic neurons, and suggest that it may be a common theme in the developing nervous system that the same set of transcriptional regulators is associated with formation of multiple components within a neuronal network.

Evaluation of propargyl bromide for control of barnyardgrass and Fusarium oxysporum in three soils

With the scheduled phasing out of methyl bromide, there is an urgent need for alternatives. We evaluated the efficacy of propargyl bromide as a potential replacement for methyl bromide for the control of barnyardgrass (Echinochloa crus-galli) and Fusarium oxysporum in an Arlington sandy loam, a Carsitas loamy sand and a Florida muck soil. Soil was mixed with barnyardgrass seeds or F oxysporum colonized on millet seeds, and treated with propargyl bromide at a range of concentrations. The mortality of the fungi and weed seeds was determined after 24 h of exposure at 30 degrees C. The concentrations required to inhibit 50% barnyard seed germination (LC50) were 2.8, 2.4 and 48.5 micrograms g-1 in the sandy loam, loamy sand and muck soil, respectively. In contrast, the LC50 values for F oxysporum were 11.2, 10.8 and 182.1 micrograms g-1 in the sandy loam, loamy sand and muck soil, respectively. The low efficacy of propargyl bromide in the muck soil was a result of the rapid degradation and high adsorption of the compound in the soil. The degradation half-life (t1/2) was only 7 h in the muck soil at an initial concentration of 6.8 micrograms g-1, compared to 60 and 67 h in the sandy loam and loamy sand, respectively. The adsorption coefficients (Kd) were 0.96, 0.87 and 5.6 cm3 g-1 in the sandy loam, loamy sand and muck soil, respectively. These results suggest that registration agencies should consider site-specific properties in recommending application rates for propargyl bromide.

Alterations in the adhesion behavior of osteoblasts by titanium particle loading: inhibition of cell function and gene expression

Total joint replacement prostheses are required to withstand corrosive environments and sustain millions of loading and articulation cycles during their term of implantation. Wear debris generation has been implicated as one of the primary causes of periprosthetic osteolysis and subsequent implant loosening in total joint replacements. Particulate debris consisting of metals, polyethylene, ceramics, and bone cement have each been shown to provoke a biological response in joint tissues. The major cell types within the interfacial granulomatous fibrous tissues consist of fibroblasts, macrophages, lymphocytes, and foreign-body giant cells. Osteoblasts are one of the principal cell types in the bone tissue adjacent to prostheses, maintaining physiologic bone remodeling through the balanced coordination of bone formation and resorption in concert with osteoclasts. To date the phenomenon of osteoblast phagocytosis of titanium particles has been suggested, but has not been sufficiently studied or confirmed. This study seeks to clarify the influence of titanium particles on osteoblast adhesion, deformability, proliferation, and gene expression profile. These studies were accomplished by performing biorheological testing, Northern blot analysis and RNase protection assay. The uptake of metallic particles by the osteoblast resulted in a particle-filament complex formation, which induced a series of variations in cell function. Understanding these variations is critical to expanding our knowledge of implant loosening and elucidating the nature of prosthetic joint failure. This study suggests that the impact of titanium particles on osteoblast function and subsequent implant loosening may have been previously underestimated.

[Suppression of glutamate neurotoxicity by 5-HT in hippocampal neurons]

The effects of excess glutamate on the survival rate of cultured hippocampal neurons, the population spike (PS) of CA1 area of hippocampal slices and the Ca(2+) current of hippocampal neurons were observed in rats. Decreased survival rate of hippocampal neurons in the presence of excess glutamate was partially reversed by 5-HT, which was in association with a less decrease of PS magnitudes. The Ca(2+) inward current induced by glutamate was significantly diminished in the presence of 5-HT. It is suggested that 5-HT can inhibit excess glutamate-induced neurotoxicity by suppressing the glutamate triggered calcium influx.

Induction of CYP1A1. The AhR/DRE paradigm: transcription, receptor regulation, and expanding biological roles

The CYP1A1 gene encodes microsomal cytochrome P4501A1 that catalyzes the metabolism of many xenobiotics, including the oxygenation of polycyclic aromatic hydrocarbons (PAH). Induction of CYP1A1 enhances the metabolism of PAHs, and therefore, represents an adaptive response to chemical exposure in mammalian cells. Mechanistic studies reveal an AhR/DRE paradigm for the induction, which involves activation of the aryl hydrocarbon receptor (AhR) by an agonist, dimerization of AhR with the Ah recceptor nuclear translocator (Arnt), followed by binding of the AhR/Arnt heterodimer to the dioxin-responsive enhancer (DRE) and transcription of the gene. The AhR mediated transcription is tightly regulated through, at least, two mechanisms: (a) the cytoplasmic AhR interacts with hsp90 and an immunophilin chaperone AIP for proper folding and receptivity, and (b) the agonist-activated, nuclear AhR is degraded through the ubiquitin-26S proteasome mediated protein turnover, such that the transcription by AhR is controlled at a physiologically adequate level. In addition to CYP1A1 induction, AhR mediates a broad range of biological responses to CYP1A1 inducers, typified by the environmental contaminant dioxin, via modulating gene expression. Thus, mechanistic studies of CYP1A1 induction have provided insights into P450 induction, PAH carcinogenesis, dioxin action, AhR function, and receptor-mediated mammalian gene expression.

Inhibition of tissue factor-activated platelets by low-molecular-weight heparins and glycoprotein IIb/IIIa receptor antagonist

Thrombotic disorders can lead to vascular distress and platelet activation eventually resulting in the rupture of the lesions where a sizable amount of tissue factor (TF) is generated during the pathogenesis of arterial diseases. Since low-molecular-weight heparins (LMWHs) and platelet glycoprotein (GP) IIb/IIIa inhibitors are clinically used for the management of acute coronary syndrome (ACS), studies were taken to determine the effects of these agents on TF-mediated activation of platelets. Freshly drawn native whole blood (WB) from normal healthy volunteers (n = 6) supplemented with a predetermined amount of TF was incubated with equivalent anti-Xa adjusted amounts of various LMWHs at 0.01-1.0 U/ml and tirofiban from 10 to 100 ng/ml. Platelet activation was assessed by measuring the expression of P-selectin (CD62) and the generation of platelet aggregates. At 0.01 U/ml, enoxaparin exhibited a stronger inhibition of TF-induced platelet activation compared to ardeparin and dalteparin. At 0.1 U/ml, these LMWHs produced a comparable inhibition of total P-selectin expression, and at 1.0 U/ml, a marked inhibition was noted. Since enoxaparin produced the best concentration-dependent inhibition of P-selectin expression (saline: 76 +/- 10% vs. 1.0 U/ml enoxaparin: 18 +/- 7%; P < .02) and platelet aggregate formation (saline: 63 +/- 7% vs. 1.0 U/ml enoxaparin: 35 +/- 6%, P < .035), this agent was used for additional studies. Unlike enoxaparin, tirofiban produced a weak concentration-dependent inhibition of platelet activation. At 100 ng/ml, tirofiban produced a 40% inhibition of P-selectin expression and about 60% inhibition of platelet aggregate formation. To elucidate the potential interaction between tirofiban and enoxaparin, the effect of 10 and 100 ng/ml tirofiban was studied with enoxaparin-supplemented WB in a 0.01-1.0 U/ml range. Additive effects between these two agents were noted only at lower concentrations. Thus, at therapeutic concentrations (0.8-1.2 U/ml), enoxaparin itself was capable of inhibiting TF-mediated activation of platelets to > 70%; whereas tirofiban failed to produce such concentration-dependent inhibition. This suggests that the simultaneous administration of GPIIb/IIIa receptor antagonist with LMWH may not have any added benefit in the clinical management of patients with ACS.

[Correlation between enhanced anoxic tolerance induced by hypoxic preconditioning and the stability of mitochondrial membrane potential in cultured hypothalamic cells]

The relationship between enhanced anoxic tolerance induced by hypoxic preconditioning and mitochondrial membrane potential (MMP) was studied in cultured hypothalamic cells. Dynamic changes in MMP were monitored by confocal laser scanning microscopy and expression of B-cell lymphoma/leukemia-2 (bcl-2) was examined by flowcytometry. Hypoxic preconditioning increased the cell survival rate and decreased the lactate dehydrogenase leakage under acute anoxia, in addition to maintaining MMP at a relatively higher level and inducing bcl-2 overexpression during anoxia. The results suggest that hypoxic preconditioning can enhance the tolerance of hypothalamic cells to anoxia, and the underlying mechanism may be related to increased stability of MMP. Overexpression of bcl-2 induced by hypoxic preconditioning may play a role in sustaining the stability of MMP.

Global anticoagulant effects of a novel sulfated pentomanan oligosaccharide mixture

PI-88 is a potent antiproliferative agent, which is developed for various indications in cancer. This agent is obtained from yeast fermentation and is primarily composed of pentamannose and tetramannose oligosaccharide units. PI-88 is capable of producing anticoagulant effects, which are mediated by heparin cofactor II. The purpose of this study was to determine the anticoagulant properties of PI-88 in native whole blood, freshly drawn from human volunteers, supplemented with PI-88 at various concentrations (0-100 microg/mL). Whole blood activated clotting time (ACT) was measured using Hemochron instruments. PI-88 produced a strong anticoagulant effect at 100 microg/mL (479.0+/-59.5 sec). This anticoagulant effect was comparable to that observed in interventional cardiology and open-heart surgery. At the lower level, PI-88 produced concentration-dependent effects on ACT. Using thromboelastographic techniques (TEG), the effect of PI-88 was measured in terms of various parameters. PI-88 produced potent anticoagulant effects in the TEG studies. At the concentration of 25 microg/mL, it produced a complete anticoagulant effect in whole blood. Whole blood samples supplemented with PI-88 showed a concentration-dependent decrease in the generation of various markers of clotting activation. These results clearly suggest that PI-88 exerts an anticoagulant effect in whole blood. Because of the low-molecular-weight nature and a novel mechanism of action, this new drug may be considered for further development, particularly in cancer patients.

The study of spectrosgraphic properties and molecular recognition of cali

The absorption spectrum and fluorescence spectrum of calix[n]arenes are studied systematically. The self-association of calix[n]arenes is proposed and the self-association constant is also obtained. The recognition properties of calix[n]arenes are studied and the inclusion constant is calculated.

[A report of the treatment of isolated systemic hypertension in the elderly patients (5 years follow up)]

One hundred and sixteen patients with isolated systemic hypertension were treated with Nitrendipine for five years. The result showed that it was effective, persistent and stable. There was no influence on lipid and glucose metabolism. The incidence of stroke was decreased and it could protect the renal function.

[Construction of plasmid gene bank of V. cholerae O139 and detection of O-antigen genes]

Because O-antigen biosynthesis genes are a tandem gene cluster. Gnomic fragments of 4-20 kilobases (kb) were obtained by digesting genomic DNA of V. cholerae O139 with restriction endonuclease EcoRI, then plasmid gene bank was constructed. Recombinant colony, E. coli DH5 alpha (pMG320), expressing O-antigen of V. cholerae O139 was detected from the bank by immunological agglutinative reaction. The futher analysis showed O-antigen expressed by recombinant colony had both immunogenicity and reactogenicity, and the size of O-antigen biosynthesis genes was about 4.6 kb.

[Effects of intermittent hypoxia on long-term potentiation in hippocampal dentate gyrus of rat]

AIM

To investigate the effects of intermittent hypoxia on the hippocampal synaptic plasticity in rat.

METHODS

The evoked potentials were recorded extracellularly, then the LTP were induced by tetanic stimulation in rat hippocampal dentate gyrus.

RESULTS

Compared with control group, the amplitude of LTP was significantly reduced in hippocampus of rat treated with intermittent hypoxia.

CONCLUSIONS

The present results suggest that the hippocampal synaptic plasticity could be decreased by the treated of intermittent hypoxia.

[Death manners of primary cultured hippocampal neurons of rats in response to excess corticosterone exposure]

AIM AND METHODS

The death types of rat hippocampal neuronal cells in primary culture under various doses of corticosterone were questioned by in situ staining methods.

RESULTS

CORT triggered two cellular death pathways: necrosis and apoptosis. Moreover, high concentrations of CORT increased the necrotic and apoptotic percentages in dose-dependent and time-dependent manners.

CONCLUSION

The factors that lead to hippocampal neuronal cells necrosis or apoptosis induced by CORT may be contributed by the impaired of energy metabolism and the vulnerability of neurons to the excess glutamate neurotoxicity.

Gas exchange by pods and subtending leaves and internal recycling of CO(2) by pods of chickpea (Cicer arietinum L.) subjected to water deficits

Terminal drought markedly reduces leaf photosynthesis of chickpea (Cicer arietinum L.) during seed filling. A study was initiated to determine whether photosynthesis and internal recycling of CO(2) by the pods can compensate for the low rate of photosynthesis in leaves under water deficits. The influence of water deficits on the rates of photosynthesis and transpiration of pods and subtending leaves in chickpea (cv. Sona) was investigated in two naturally-lit, temperature-controlled glasshouses. At values of photosynthetically active radiation (PAR) of 900 micromol m(-2) s(-1) and higher, the rate of net photosynthesis of subtending leaves of 10-d-old pods was 24 and 6 micromol m(-2) s(-1) in the well-watered (WW) and water-stressed (WS) plants when the covered-leaf water potential (Psi) was -0.6 and -1.4 MPa, respectively. Leaf photosynthesis further decreased to 4.5 and 0.5 micromol m(-2) s(-1) as Psi decreased to -2.3 and -3.3 MPa, respectively. At 900--1500 micromol m(-2) s(-1) PAR, the net photosynthetic rate of 10-d-old pods was 0.9-1.0 micromol m(-2) s(-1) in the WW plants and was -0.1 to -0.8 micromol m(-2) s(-1) in the WS plants. The photosynthetic rates of both pods and subtending leaves decreased with age, but the rate of transpiration of the pods increased with age. The rates of respiration and net photosynthesis inside the pods were estimated by measuring the changes in the internal concentration of CO(2) of covered and uncovered pods during the day. Both the WW and WS pods had similar values of internal net photosynthesis, but the WS pods showed significantly higher rates of respiration suggesting that the WS pods had higher gross photosynthetic rates than the WW pods, particularly in the late afternoon. When (13)CO(2) was injected into the gas space inside the pod, nearly 80% of the labelled carbon 24 h after injection was observed in the pod wall in both the WW and WS plants. After 144 h the proportion of (13)C in the seed had increased from 19% to 32% in both treatments. The results suggest that internal recycling of CO(2) inside the pod may assist in maintaining seed filling in water-stressed chickpea.