Effect of Avian Influenza Virus subtype H9N2 on the expression of complement-associated genes in chicken erythrocytes

The H9N2 subtype avian influenza virus can infect both chickens and humans. Previous studies have reported a role for erythrocytes in immunity. However, the role of H9N2 against chicken erythrocytes and the presence of complement-related genes in erythrocytes has not been studied. This research investigated the effect of H9N2 on complement-associated gene expression in chicken erythrocytes. The expression of complement-associated genes (C1s, C1q, C2, C3, C3ar1, C4, C4a, C5, C5ar1, C7, CD93 and CFD) was detected by reverse transcription-polymerase chain reaction (RT-PCR). Quantitative Real-Time PCR (qRT-PCR) was used to analyse the differential expression of complement-associated genes in chicken erythrocytes at 0 h, 2 h, 6 h and 10 h after the interaction between H9N2 virus and chicken erythrocytes in vitro and 3, 7 and 14 d after H9N2 virus nasal infection of chicks. Expression levels of C1q, C4, C1s, C2, C3, C5, C7 and CD93 were significantly up-regulated at 2 h and significantly down-regulated at 10 h. Gene expression levels of C1q, C3ar1, C4a, CFD and C5ar1 were seen to be different at each time point. The expression levels of C1q, C4, C1s, C2, C3, C5, C7, CFD, C3ar1, C4a and C5ar1 were significantly up-regulated at 7 d and the gene expression of levels of C3, CD93 and C5ar1 were seen to be different at each time point. The results confirmed that all the complement-associated genes were expressed in chicken erythrocytes and showed the H9N2 virus interaction with chicken erythrocytes and subsequent regulation of chicken erythrocyte complement-associated genes expression. This study reported, for the first time, the relationship between H9N2 and complement system of chicken erythrocytes, which will provide a foundation for further research into the prevention and control of H9N2 infection.

[Study of the inhibitory effect of cell entry inhibitory ezetimibe on hepatitis B virus in vitro]

Objective: To study the inhibitory effect of ezetimibe in an experimental model of human hepatoma cell line (HepaRG) infected with hepatitis B virus (HBV) positive human serum in vitro. Methods: Mature HepaRG cells were divided into a treatment group (received drugs) and a control group (did not receive drugs). In the ezetimibe prevention experiment, the cells in the treatment group was treated with drugs 2 h before infection and 24 h during infection. In the ezetimibe treatment experiment, the cells in the treatment group were treated with drugs for 6 ~ 10 days continuously after 24 hours of HBV infection. The expression of HBV DNA and intracellular cccDNA in the supernatant was detected by fluorescence quantitative PCR. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) content in the cell supernatant were detected by chemiluminescence. Analysis of variance was used to compare the differences between multiple groups. Pairwise comparisons among groups were followed by t- test with normal distribution. P < 0.05 was considered as statistically significant. Results: Ezetimibe prevention experiment showed that compared with control group, the treatment group was added with 20, 60, and 100 μmol/L ezetimibe before and during infection, and the HBV DNA content in the supernatant 2 days before was significantly reduced (P < 0.05) in the treatment group. Compared with the control group, the HBsAg expression level 2 days before was significantly reduced (P < 0.05) with the addition of 60 μmol/L ezetimibe in the treatment group. Compared with the control group, the expression level of intracellular cccDNA was significantly reduced (P < 0.05) after 10 days with the addition of 100μmol/L ezetimibe in the treatment group. Ezetimibe treatment experiment showed that cccDNA content in the cells were significantly lowered with the immediate addition of 60μmol/L ezetimibe 24 hours after infection for 10 days when compared to control group (P < 0.05). Conclusion: Ezetimibe, as a cytosolic inhibitor, has a certain inhibitory effect on hepatitis B virus infection in both prevention and treatment experiment.

Inhibition of Notch1-mediated inflammation by intermedin protects against abdominal aortic aneurysm via PI3K/Akt signaling pathway

The Notch1-mediated inflammatory response participates in the development of abdominal aortic aneurysm (AAA). The vascular endogenous bioactive peptide intermedin (IMD) plays an important role in maintaining vascular homeostasis. However, whether IMD inhibits AAA by inhibiting Notch1-mediated inflammation is unclear. In this study, we found Notch intracellular domain (NICD) and hes1 expression were higher in AAA patients’ aortas than in healthy controls. In angiotensin II (AngII)-induced AAA mouse model, IMD treatment significantly reduced AAA incidence and maximal aortic diameter. IMD inhibited AngII-enlarged aortas and -degraded elastic lamina, reduced NICD, hes1 and inflammatory factors expression, decreased infiltration of CD68 positive macrophages and the NOD-like receptor family pyrin domain containing 3 protein level. IMD inhibited lipopolysaccharide-induced macrophage migration in vitro and regulated macrophage polarization. Moreover, IMD overexpression significantly reduced CaCl₂-induced AAA incidence and down-regulated NICD and hes1 expression. However, IMD deficiency showed opposite results. Mechanically, IMD treatment significantly decreased cleavage enzyme-a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) level. Pre-incubation with IMD_17-47 (IMD receptors blocking peptide) and the phosphatidylinositol 3-kinase/protein kinase b (PI3K/Akt) inhibitor LY294002 reversed ADAM10 level. In conclusion, exogenous and endogenous IMD could inhibit the development of AAA by inhibiting Notch1 signaling-mediated inflammation via reducing ADAM10 through IMD receptor and PI3K/Akt pathway.

Intermedin alleviates pathological cardiac remodeling by upregulating klotho

Cardiac remodeling is accompanied by cardiac hypertrophy, fibrosis, dysfunction, and eventually leading to heart failure. Intermedin (IMD), as a paracrine/autocrine peptide, has a protective effect in cardiovascular diseases. In this study, we elucidated the role and the underlying mechanism of IMD in pathological remodeling. Pathological remodeling mouse models were induced by abdominal aorta constriction for 4 weeks or angiotensin II (Ang II) infusion for 2 weeks in wildtype, IMD-overexpression, IMD-knockout and klotho-knockdown mice. Western blot, real-time PCR, histological staining, echocardiography and hemodynamics were used to detect the role of IMD in cardiac remodeling. Cardiac hypertrophy, fibrosis and dysfunction were significantly aggravated in IMD-knockout mice versus wildtype mice, and the expression of klotho was downregulated. Conversely, cardiac remodeling was alleviated in IMD-overexpression mice, and the expression of klotho was upregulated. Hypertension induced by Ang II infusion rather than abdominal aorta constriction was mitigated by IMD. However, the cardioprotective effect of IMD was blocked in klotho-knockdown mice. Similar results were found in cultured neonatal rat cardiomyocytes, which was pretreated with IMD before Ang II stimulation. Mechanistically, IMD inhibited the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) and the activity of calcineurin to protect against cardiac hypertrophy through upregulating klotho in vivo and in vitro. Furthermore, peroxisome proliferator-activated receptor γ (PPARγ) might mediate IMD upregulating klotho. In conclusion, pathological remodeling may be alleviated by endogenous IMD, which inhibits the expression of calcineurin and p-CaMKII by upregulating klotho via the PPARγ pathway. It suggested that IMD might be a therapeutic target for heart disease.

Intermedin1-53 attenuates aging-associated vascular calcification in rats by upregulating sirtuin 1

Vascular calcification is a common phenomenon in older adults. Intermedin (IMD) is a cardiovascular bioactive peptide inhibiting vascular calcification. In this study, we aimed to investigate whether IMD_1-53 attenuates aging-associated vascular calcification. Vascular calcification was induced by vitamin D3 plus nicotine (VDN) in young and old rats. The calcification in aortas was more severe in old rats treated with VDN than young control rats, and IMD expression was lower. Exogenous administration of IMD_1-53 significantly inhibited the calcium deposition in aortas and the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) in VDN-treated old rats. Moreover, levels of aging-related p16, p21 and β-galactosidase were all greatly decreased by IMD_1-53. These results were further confirmed in rat and human VSMCs in vitro. In addition, IMD-deficient mouse VSMCs showed senescence features coinciding with osteogenic transition as compared with wild-type mouse VSMCs. Mechanistically, IMD_1-53 significantly increased the expression of the anti-aging factor sirtuin 1 (sirt1); the inhibitory effects of IMD_1-53 on calcification and senescence were blocked by sirt1 knockdown. Furthermore, preincubation with inhibitors of PI3K, AMPK or PKA efficiently blunted the upregulatory effect of IMD_1-53 on sirt1. Consequently, IMD_1-53 could attenuate aging-associated vascular calcification by upregulating sirt1 via activating PI3K/Akt, AMPK and cAMP/PKA signaling.

Intermedin1-53 Ameliorates Homocysteine-Promoted Atherosclerotic Calcification by Inhibiting Endoplasmic Reticulum Stress

Aim:

Vascular calcification (VC) is thought to be an independent predictor of cardiovascular morbidity and mortality. Intermedin1-53 (IMD) is a cardiovascular protective peptide and can inhibit vascular medial calcification in rats. In this study, we investigated the effect of IMD on atherosclerotic calcification induced by a high-fat diet plus homocysteine (Hcy) and the potential mechanisms.

Methods:

ApoE−/− mice were fed a high-fat diet with Hcy in drinking water to induce atherosclerotic calcification.

Results:

As compared to the high-fat diet alone, Hcy treatment significantly increased atherosclerotic lesion areas and the number of calcified nodules in aortic roots and was reduced by IMD infusion or 4-phenylbutyric acid (PBA) treatment. In vitro, as compared to calcifying medium alone, Hcy treatment further increased alkaline phosphatase activity, calcium content, and calcium nodule number in human aorta vascular smooth muscle cells (HA-VSMCs), all blocked by IMD or PBA pretreatment. Mechanistically, IMD or PBA significantly alleviated endoplasmic reticulum stress (ERS) activation compared with Hcy treatment. In parallel, IMD or PBA attenuated the messenger RNA levels of osteogenic markers and inflammatory cytokines in aortas and their protein levels in lesions of aortic roots. In vitro, Hcy treatment significantly increased the protein levels of osteoblast-like cell markers in primary rat VSMCs and inflammation markers in mouse peritoneal macrophages, all decreased with IMD or PBA pretreatment. Intermedin1-53 pretreatment also markedly reduced the protein levels of ERS markers in rat VSMCs and mouse peritoneal macrophages.

Conclusions:

Intermedin1-53 protects against Hcy-promoted atherosclerotic calcification in ApoE−/− mice by inhibiting ERS.

Endogenous intermedin protects against intimal hyperplasia by inhibiting endoplasmic reticulum stress

Extensive proliferation of vascular smooth muscle cell (VSMC) contributes to intimal hyperplasia following vascular injury, in which endoplasmic reticulum stress (ERS) plays a critical role. Intermedin (IMD) is a vascular paracrine/autocrine peptide exerting numerous beneficial effects in cardiovascular diseases. IMD overexpression could alleviate intimal hyperplasia. Here, we investigated whether endogenous IMD protects against intimal hyperplasia by inhibiting endoplasmic reticulum stress. The mouse left common carotid-artery ligation-injury model was established to induce intimal hyperplasia using IMD^-/-mice and C57BL/6 J wild-type (WT) mice. Platelet-derived growth factor-BB (PDGF-BB) was used to stimulate the proliferation of VSMC. IMD^-/- mice displayed exacerbated intimal hyperplasia induced by complete ligation of the left carotid artery at 14 d and 28 d compared to WT mice. However, IMD-deficiency had no effect on blood pressure, plasma triglyceride, and fasting blood glucose levels in mice. Furthermore, VSMCs derived from IMD^-/- mice showed increased cell proliferation and dramatically elevated levels of glucose regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), ATF6 mRNA under PDGF-BB treatment compared to WT mice-derived VSMCs. In addition, exogenous administration of IMD significantly attenuated PDGF-BB-induced cell proliferation and GRP78, phosphorylase-inositol requiring enzyme 1α, ATF4, and ATF6 protein levels. Thus, endogenous IMD may counteract ERS to exert protective role in response to vascular injury and IMD is expected to be a therapeutic target for the prevention and treatment of restenosis.

Inhibition of endoplasmic reticulum stress by intermedin1-53 attenuates angiotensin II-induced abdominal aortic aneurysm in ApoE KO Mice

Endoplasmic reticulum stress (ERS) is involved in the development of abdominal aortic aneurysm (AAA). Since bioactive peptide intermedin (IMD)1-53 protects against AAA formation, here we investigated whether IMD1-53 attenuates AAA by inhibiting ERS. AAA model was induced by angiotensin II (AngII) in ApoE KO mouse background. AngII-treated mouse aortas showed increased ERS gene transcription of caspase12, eukaryotic translation initiation factor 2a (eIf2a) and activating transcription factor 4(ATF4).The protein level of ERS marker glucose regulated protein 94(GRP94), ATF4 and C/EBP homologous protein 10(CHOP) was also up-regulated by AngII. Increased ERS levels were accompanied by severe VSMC apoptosis in human AAA aorta. In vivo administration of IMD1-53 greatly reduced AngII-induced AAA and abrogated the activation of ERS. To determine whether IMD inhibited AAA by ameliorating ERS, we used 2 non-selective ERS inhibitors phenyl butyrate (4-PBA) and taurine (TAU). Similar to IMD, PBA, and TAU significantly reduced the incidence of AAA and AAA-related pathological disorders. In vitro, AngII infusion up-regulated CHOP, caspase12 expression and led to VSMC apoptosis. IMD siRNA aggravated the CHOP, caspase12-mediated VSMC apoptosis, which was abolished by ATF4 silencing. IMD infusion promoted the phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in aortas in ApoE KO mice, and the AMPK inhibitor compound C abolished the protective effect of IMD on VSMC ERS and apoptosis induced by AngII. In conclusion, IMD may protect against AAA formation by inhibiting ERS via activating AMPK phosphorylation.

[The expression and significance of CD(276) and CD(133) in colorectal cancer and precancerous lesions]

In order to study the significance of CD(276) and CD(133) in the development and progression of colorectal cancer (CRC), the expression of CD(276) and CD(133) was detected by immunohistochemistry in CRC and precancerous lesions. The results showed that the intensity of CD(276) and CD(133) in CRC samples was higher than that in adenoma group and non-adenoma group. CD(276) and CD(133) single and double positive expression were significantly correlated with CRC lymph node metastasis, distant metastasis and survival. CD(276) and CD(133) are significantly correlated to the development and progression of CRC and associated with poor prognosis.

Intermedin reduces neointima formation by regulating vascular smooth muscle cell phenotype via cAMP/PKA pathway

BACKGROUND AND AIMS

Vascular smooth muscle cell (VSMC) dedifferentiation contributes to neointima formation, which results in various vascular disorders. Intermedin (IMD), a cardiovascular paracrine/autocrine polypeptide, is involved in maintaining circulatory homeostasis. However, whether IMD protects against neointima formation remains largely unknown. The purpose of this study is to investigate the role of IMD in neointima formation and the possible mechanism.

METHODS

IMD_1-53 (100ng/kg/h) or saline water was used on rat carotid-artery balloon-injury model. The mouse left common carotid-artery ligation-injury model was established using IMD-transgenic and C57BL/6J mice. Immunohistochemistry and immunofluorescence staining was used to detect the protein expression in rat carotid arteries. Radioimmunoassay was used to determine the serum IMD level. The hematoxylin andeosin staining was used for carotid arteries morphological testing. In vitro, for rat primary cultured VSMC phenotype transition, proliferation and migration assays, platelet-derived growth factor-BB (PDGF-BB) reagent and IMD_1-53 peptide were added to the culture media at the final concentration of 20 ng/mL and 10^-7mol/L respectively. Quantification of VSMC proliferation involved MTT and BrdU assay and migration was detected by wound-healing assay. Western blot and realtime PCR were used to detect the protein and mRNA levels of tissues or cells.

RESULTS

With the rat carotid-artery balloon-injury model, IMD was significantly downregulated in injured arteries and plasma. Exogenous IMD_1-53 greatly inhibited neointima formation and prevented VSMC from switching to a synthetic phenotype. With the left common carotid-artery ligation-injury model, IMD-transgenic mice showed less neointima formation than C57BL/6J mice. PDGF-BB reduced IMD mRNA expression in rat primary cultured VSMCs but increased that of its receptors, calcitonin receptor-like receptor or receptor activity-modifying proteins. Furthermore, PDGF-BB promoted VSMC proliferation and migration and transformed VSMCs to the synthetic phenotype, which was reversed with IMD_1-53 treatment. Mechanistically, IMD_1-53 maintained the contractile VSMC phenotype via the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway.

CONCLUSIONS

IMD attenuated neointima formation both in the rat model of carotid-artery balloon injury and mouse model of common carotid-artery ligation injury. IMD protection may be mediated by maintaining a VSMC contractile phenotype via the cAMP/PKA pathway.

Loading-rate-independent delay of catastrophic avalanches in a bulk metallic glass

The plastic flow of bulk metallic glasses (BMGs) is characterized by intermittent bursts of avalanches, and this trend results in disastrous failures of BMGs. In the present work, a double-side-notched BMG specimen is designed, which exhibits chaotic plastic flows consisting of several catastrophic avalanches under the applied loading. The disastrous shear avalanches have, then, been delayed by forming a stable plastic-flow stage in the specimens with tailored distances between the bottoms of the notches, where the distribution of a complex stress field is acquired. Differing from the conventional compressive testing results, such a delaying process is independent of loading rate. The statistical analysis shows that in the specimens with delayed catastrophic failures, the plastic flow can evolve to a critical dynamics, making the catastrophic failure more predictable than the ones with chaotic plastic flows. The findings are of significance in understanding the plastic-flow mechanisms in BMGs and controlling the avalanches in relating solids.

Silencing ECHS1 attenuates the proliferation and induces the autophagy of hepatocellular carcinoma via impairing cell metabolism and activating AMPK

Hepatocellular carcinoma (HCC) is among the most common cancers in the world with a low survival rate. Our previous study showed Short chain enoyl-CoA hydratase (ECHS1) could bind to HBsAg (HBs) and that ECHS1's localization in mitochondria induced HepG2 cell apoptosis. However, the role of the ECHS1 in energy metabolism and autophagy during hepatocellular carcinoma development remains undefined. We aimed to determine what ECHS1 does to energy metabolism and its effects on HCC progression. We performed CCK-8, EdU assays in hepatocellular carcinoma cell lines (HepG2 and HuH7) with stable ECHS1 knock-down. ATP and NADP+/NADPH levels were measured using an colorimetric assay. Our data demonstrated that ECHS1 silencing inhibited cell proliferation and induced autophagy. ECHS1 knockdown did not increase fatty acid synthesis, but decreased cellular ATP. This resulted in AMP-activated protein kinase (AMPK) activation and induced HCC cell autophagy. Our results showed that silencing ECHS1 to attenuate proliferation and induce autophagy may make it a novel cancer therapy target.

Succinoylation of sugarcane bagasse under ultrasound irradiation

The chemical modification of sugarcane bagasse with succinic anhydride using pyridine as solvent after ultrasound irradiation was studied. The optimized parameters included ultrasound irradiating time 0-50 min, reaction time 30-120 min, succinic anhydride concentration by the ratio of dried sugarcane bagasse to succinic anhydride from 1:0.25 to 1:1.50, and reaction temperature 75-115 degrees C are required in the process. The extent of succinoylation was measured by the weight percent gain (WPG), which increased with increments of reaction time, succinic anhydride concentration, and reaction temperature. The ultrasound irradiation has a positive effect on bagasse succinoylation process. On the other hand, the ultrasonic pre-treatment application broke down the cell wall polymers, resulting in, therefore, a negative effect on the WPG. Evidences of succinoylation were also provided by FT-IR and CP MAS (13)C NMR and the results showed that the succinoylation at C-2 and C-3 occurred. The thermal stability of the succinylated bagasse decreased upon chemical modification.

Homogeneous modification of sugarcane bagasse cellulose with succinic anhydride using a ionic liquid as reaction medium

The homogeneous chemical modification of sugarcane bagasse cellulose with succinic anhydride using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as a reaction medium was studied. Parameters investigated included the molar ratio of succinic anhydride/anhydroglucose units in cellulose in a range from 2:1 to 14:1, reaction time (from 30 to 160min), and reaction temperature (between 60 and 110 degrees C). The succinylated cellulosic derivatives were prepared with a low degree of substitution (DS) ranging from 0.071 to 0.22. The results showed that the increase of reaction temperature, molar ratio of SA/AGU in cellulose, and reaction time led to an increase in DS of cellulose samples. The products were characterized by FT-IR and solid-state CP/MAS (13)C NMR spectroscopy, and thermal analysis. It was found that the crystallinity of the cellulose was completely disrupted in the ionic liquid system under the conditions given. The data also demonstrated that homogeneous modification of cellulose with succinic anhydride in AmimCl resulted in the production of cellulosic monoester. The thermal stability of the succinylated cellulose decreased upon chemical modification.

Physicochemical characterization of cellulose from perennial ryegrass leaves (Lolium perenne)

In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.

Fractional and structural characterization of hemicelluloses from perennial ryegrass (Lolium perenne) and cocksfoot grass (Dactylis glomerata)

Sequential three-stage treatments with 80% EtOH containing 0.2% NaOH, 2.5% H2O2-0.2% EDTA containing 1.5% NaOH and 2.5% H2O2-0.2% TAED containing 1.0% NaOH at 75 degrees C for 3h released 8.0% and 10.4%, 79.1% and 77.0% and 12.9% and 12.5% of the original hemicelluloses from perennial grass and cocksfoot grass, respectively. It was found that the four alkaline peroxide-soluble hemicellulosic fractions contained higher amounts of xylose (33.4-38.2%), uronic acids (9.3-15.3%) and rhamnose (3.0-3.9%), but were lower in glucose (25.1-28.3%), galactose (13.3-15.3%) and mannose (0.4-1.5%) than those of the two alkaline EtOH-soluble hemicellulosic fractions in which glucose (32.9-36.0%), xylose (20.1-22.6%), arabinose (14.1-21.4%), galactose (16.6-19.9%), mannose (4.1-9.9%) and uronic acids (3.4-7.4%) were the major sugar components. 13C NMR spectroscopy confirmed that all the six hemicellulosic fractions were composed of galactoarabinoxylans, 4-O-methylglucuronoarabinoxylans and beta-glucan. In addition, the studies showed that the four alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic and had larger molecular weights (Mw, 28,400-38,650 g mol(-1)) than those of the two alkaline EtOH-soluble hemicellulosic fractions (Mw, 16,460-17,420 g mol(-1)).

Improved fluorimetric determination of dissolved aluminium by micelle-enhanced lumogallion complex in natural waters

A modification of the aluminium-lumogallion fluorescence measurement in the presence of the non-ionic surfactant Triton X-100 is presented. The detection limit for dissolved Al is 0.7 nM, with a relative standard deviation of 3.6% at an Al level of 5.0 nM. Compared with previously reported methods in the literature, the method described here is free from matrix effects and can be used for the determination of aluminium in fresh, estuarine and saline waters. The interferences from iron and fluoride were minimized by the addition of o-phenanthroline and Be2+, respectively. The analysis of NIST SRM 1643C and PRC standard 2430101 by the proposed method provides results consistent with the certified values. A successful inter-laboratory calibration exercise also demonstrates the merit of the proposed method for the determination of Al in environmental and marine sciences.

Successful recovery of 14 patients afflicted with full-thickness burns for more than 70 per cent body surface area

Fourteen cases suffering full-thickness burns of more than 70 per cent total body surface area (TBSA) have been successfully treated during the last 8 years (1988-1995). Among these patients, 10 cases suffered from burns of more than 90 per cent TBSA. Five cases had full-thickness burns of 80-90 per cent TBSA. Escharectomy, followed by coverage of wounds with a homograft to the lower surface of which, adjacent to the wound bed, microautoskin grafts had been attached was employed to close wounds in the early stages after burn. The remaining non-surgically treated wound was treated by exposure and topical silver sulfadiazine. The temperature and humidity of the ward was controlled by air conditioning and dehumidification. Aggressive excision of eschar and auto-skingrafting was carried out 3 weeks post-injury. Strictly limiting the uncovered wound to less than 5 per cent appeared to be the major effective measure in preventing burn infection.

Effect of increased intra-abdominal pressure on peristalsis in feline esophagus

Our aim in this study was to determine the effect of variations in intrabolus pressure on esophageal peristalsis. In five cats, intrabolus pressure was altered by increasing intragastric pressure to 20-45 mmHg by use of a pressure cuff to compress the abdomen. In each cat, increases in intragastric pressure were associated with comparable increases in pressure of the esophageal bolus while the bolus was in the distal esophagus during esophageal peristalsis. Secondary peristalsis induced by a 5-ml injection of barium into the proximal esophagus was recorded by synchronized videofluoroscopy and esophageal manometry. Graded increases in intrabolus pressure caused an increased prevalence of ineffective, incomplete peristaltic sequences that did not completely clear barium from the esophagus. At intragastric pressures greater than 45 mmHg, 63% of the peristaltic sequences were incomplete. Increases in intrabolus pressure elicited by increased intragastric pressure also caused 1) slowing of the peristaltic wave in the distal esophagus, 2) increased pressure wave duration in the distal esophagus, 3) increased esophageal diameter, and 4) increased duration of lower esophageal sphincter opening. The incidence of retrograde bolus escape was inversely related to the difference between peristaltic wave amplitude and intrabolus pressure. A pressure difference of greater than 20 mmHg prevented retrograde barium escape at all esophageal levels, whereas a difference of less than 20 mmHg was generally associated with retrograde escape of barium in the distal esophagus. We conclude that an increase in intrabolus pressure causes an increase in esophageal distension that is transduced into alterations of esophageal peristalsis by either a myogenic or neural mechanism.