Automated Estimation of Quantitative Lesion Water Uptake as a Prognostic Biomarker for Patients with Ischemic Stroke and Large-Vessel Occlusion

BACKGROUND AND PURPOSE

Net water uptake is qualified as an imaging marker of brain edema. We aimed to investigate the ability of net water uptake to predict 90-day functional outcome in patients with acute ischemic stroke and large-vessel occlusion.

MATERIALS AND METHODS

A total of 295 consecutive patients were retrospectively enrolled. Automated ASPECTS-net water uptake was calculated on the admission CT. The relationship between ASPECTS-net water uptake and 90-day neurologic outcome was assessed. The independent predictors of favorable outcome (mRS score ≤2) were assessed using multivariate logistic regression analysis and receiver operating characteristic curves and stratified by the ASPECTS.

RESULTS

Favorable 90-day outcomes were observed in 156 (52.9%) patients. ASPECTS-net water uptake (OR, 0.79; 95% CI, 0.70-0.90), NIHSS scores (OR, 0.91; 95% CI, 0.87-0.96), age (OR, 0.96; 95% CI, 0.94-0.99), and vessel recanalization (OR, 7.78; 95% CI, 3.96-15.29) were independently associated with favorable outcomes at 90 days (all, P < .01). A lower ASPECTS-net water uptake independently predicted a good prognosis, even in the subgroup of patients with low ASPECTS (≤5) (P < .05). An outcome-prediction model based on these variables yielded an area under the receiver operating characteristic curve of 0.856 (95% CI, 0.814-0.899; sensitivity, 76.3%; specificity, 81.3%).

CONCLUSIONS

ASPECTS-net water uptake could independently predict 90-day neurologic outcomes in patients with acute ischemic stroke and large-vessel occlusion. Integrating ASPECTS-net water uptake with clinical models could improve the efficiency of outcome stratification.

[Later approach sinus floor elevation using deproteinized bovine bone mineral with staged implant placement: follow-up for more than 3 years in a prospective clinical study]

Objective: To evaluate clinical effect of deproteinized bovine bone for delayed implantation after fenestration. Methods: This trial is a continuation of a prospective clinical trial. From May 2011 to February 2015 in Department of Implantology, School of Stomatology, The Fourth Military Medical University after planting division of 55 cases of maxillary teeth missing area of residual alveolar bone height ≤5 mm patients. There were 21 female and 34 male patients, their average age were (55.2±7.1) years. A total of 62 side fenestration of maxillary sinus floor lift, clinical and imaging examination, evaluation of implant retention rate, complications, peripheral soft tissue health and marginal bone resorption. Results: A total of 82 implants were followed up in 41 patients. The average follow-up time was (51.8±14.3) months (36-78 months). The follow-up rate of the maxillary sinus was 75.8% (47/62), the follow-up rate of the implant was 73.9% (82/111), and the implant survival rate was 98.8% (81/82). The bone resorption results at the implant margins were (0.64±0.63) mm (-0.28 mm, 1.47 mm) in the near and (0.49±0.73) mm (-0.51 mm, 1.21 mm) in the far, the improved hemorrhage index was 0.46±0.72, the improved plaque index was 0.60±0.87, and the keratinized mucosa width was (2.14±1.22) mm. The incidence rate of peri-implant mucositis was 28.4% (23/81) among 23 implants, and there was no complication of peri-implant inflammation. Conclusions: This study shows that under the condition of insufficient sinus ridge spacing in the maxillary posterior area, it is feasible to use bovine bone alone to remove protein for delayed implantation of maxillary sinus floor elevation by windowing, and the clinical effect is reliable.

[Establishment of animal model of bacterial microleakage at implant-abutment interface]

Objective: To study the bacterial microleakage at the interface between dental implant and abutment in rats. Methods: Under aseptic conditions, suspension of 0.25 μl of Porphyromonas gingivalis (Pg) (10(9) CFU/ml) was added into the customized implant. After the abutment was connected, the suspension was cultured in an Ep (eppendorf) tube containing 1 ml brain heart infusion (BHI) culture medium. After 7 days and 14 days, the liquid in the Ep tube was taken and inoculated, and the growth of bacteria was observed. Six male SD rats with 12 implants were divided into experimental group (4 implants), negative control group (4 implants) and blank control group (4 implants). All 6 rats had two implants implanted in their bilateral upper jaws. During the second operation, suspension of 0.25 μl Pg (10(9) CFU/ml) was added to the inner part of the implant of the experimental group, culture solution of 0.25 μl was added to the control group and nothing was added to the blank control group. The amount of Pg and total bacteria in each group were evaluated by quantitative real-time PCR (qPCR). The inflammatory cell infiltrate in the peri-implant mucosa was evaluated histomorphometrically. Results: The in vitro model directly verified the presence of bacterial microleakage at implant-abutment interface (IAI), and the animal model confirmed the existence of microleakage through the infiltrate of inflammatory cells near the micro-gap in the experimental group indirectly. In vitro experiments found that Pg had penetrated from the implant within a week by observation and culture. In animal study, the presence of 10(2)-10(4) Pg was detected in the experimental group and it was not detected in the negative control group and the blank control group. At the same time, under the light microscope, in the experimental group, there were inflammatory cells aggregation in the connective tissue around the micro-gap and the density of inflammatory cells gradually decreased from the micro-gap to coronal and the apical of the connective tissue, while there were only scattered inflammatory cells in the connective tissue around the blank control group and the negative control group. In the experimental group, inflammatory cells density in area of 0.25-0.50 mm, 0-0.25 mm coronal to the micro-gap and 0-0.25 mm, 0.25-0.50 mm apical to the mico-gap was respectively, 976 (655), 1 673 (1 245), 2 267 (819) and 895 (162) cells/mm(2),which was significantly more than the blank control group in the corresponding position [respectively 201 (180), 321 (351), 309 (236) and 218 (272) cells/mm(2)] (P<0.05). Conclusions: Pg in the dental implants of rats can be found in the microleakage through implant-abutment interface, and cause the soft tissue inflammation around the implant, and the inflammation has certain distribution characteristics.

THE PI3K/Akt/mTOR Signaling Pathway Plays a Role in Regulating Autophagy in Mouse Oocytes During Vitrification-warming and in vitro Maturation

BACKGROUND

It has been shown that vitrified-warmed oocytes exhibit autophagic activation. However, its regulatory molecular mechanism of autophagy needs to be clarified.

OBJECTIVE

To determine the role of signaling pathway of PI3K/Akt/mTOR in the regulation of autophagy in oocytes during vitrification-warming and IVM.

MATERIALS AND METHODS

Oocytes from mice were vitrified-warmed and IVM. The expressions of LC3-II, Beclin-1, PI3K, Akt, and mTOR protein were determined. Moreover, the ATP level, viability of vitrified-warmed oocytes, and their developmental potential were measured.

RESULTS

At 6 h of incubation of warmed oocytes, the LC3-II and Beclin-1 expressions were markedly up-regulated, whereas PI3K, Akt, and mTOR proteins expressions were significantly down-regulated. In addition, autophagy inhibition significantly decreased ATP level, viability of oocytes, and their developmental potential.

CONCLUSION

Autophagy plays a protective role in the oocytes during vitrification-warming and IVM. The PI3K/Akt/mTOR pathway participated in regulating autophagy activity in oocyte during vitrification-warming and IVM.

Risk of Acute Kidney Injury with Consecutive, Multidose Use of Iodinated Contrast in Patients with Acute Ischemic Stroke

Currently, CTA is the imaging technique most frequently used to evaluate acute ischemic stroke, and patients with intracranial large-vessel occlusion usually undergo endovascular treatment. This single-center, prospective, cohort study showed that consecutive, multidose use of contrast during CTA and DSA does not increase the incidence of acute kidney injury in patients with acute ischemic stroke, though acute kidney injury tended to have a higher incidence in the contrast multiexposure group (P = .172).

[Analysis of epidermal growth factor receptor mutations and its clinico-pathologic characteristics of the primary lung adenocarcinoma in Xinjiang Uighur Autonomous Region]

OBJECTIVE

To clarify the relationship between epidermal growth factor receptor (EGFR) mutations and the clinicopathologic features of primary lung adenocarcinomas in Xinjiang.

METHODS

The mutations of EGFR gene at exons 18-21 in 59 cases (including 15 cases of Uighur and 44 cases of Han) of lung adenocarcinoma tissues, which were obtained from surgical resection, were detected by amplification refractory mutation system (ARMS) method. And the relationships among mutations, race and clinicopathologic features were analyzed.

RESULTS

The frequencies of EGFR mutations in lung adenocarcinoma were 20% for Uighur, which was lower than that in Han (54.5%), P<0.05. The deletion mutations at exon 19 were seen in 2 of 15 Uighur cases and 9 of 44 Han cases. EGFR mutations were present, including exon 21 L858R in one Uighur case and 12 Han cases, exon 18 G719X in two of 44 cases of Han, exon 21 L861Q in one of them. On histological type, the frequencies of EGFR mutation in alveolar predominant adenocarcinoma was 71% (22/31), which was higher than both that in solid predominant and mucinous carcinoma ( 6.7%, 20% respectively). According to statistic analysis, EGFR mutations were without correlation with the patient's gender, age, location, gross type, smoking status and lymph node metastasis(P>0.05). EGFR mutation was more frequent in well-differentiated cancer, mainly in acinar carcinoma, while poorly differentiated adenocarcinoma and mucous adenocarcinoma were lower.

CONCLUSION

There was a difference of EGFR mutation in primary lung adenocarcinoma between Uighur and Han in Xinjiang, perhaps reflecting ethnic genetic variation, which is worth further analyzing. EGFR mutation was commonly detected in well or middle differentiated adenocarcinoma, mainly in acinar carcinoma.

[Analysis of epidermal growth factor receptor mutations and its clinico-pathologic characteristics of the primary lung adenocarcinoma in Xinjiang Uighur Autonomous Region]

OBJECTIVE

To clarify the relationship between epidermal growth factor receptor (EGFR) mutations and the clinicopathologic features of primary lung adenocarcinomas in Xinjiang.

METHODS

The mutations of EGFR gene at exons 18-21 in 59 cases (including 15 cases of Uighur and 44 cases of Han) of lung adenocarcinoma tissues, which were obtained from surgical resection, were detected by amplification refractory mutation system (ARMS) method. And the relationships among mutations, race and clinicopathologic features were analyzed.

RESULTS

The frequencies of EGFR mutations in lung adenocarcinoma were 20% for Uighur, which was lower than that in Han (54.5%), P<0.05. The deletion mutations at exon 19 were seen in 2 of 15 Uighur cases and 9 of 44 Han cases. EGFR mutations were present, including exon 21 L858R in one Uighur case and 12 Han cases, exon 18 G719X in two of 44 cases of Han, exon 21 L861Q in one of them. On histological type, the frequencies of EGFR mutation in alveolar predominant adenocarcinoma was 71% (22/31), which was higher than both that in solid predominant and mucinous carcinoma ( 6.7%, 20% respectively). According to statistic analysis, EGFR mutations were without correlation with the patient's gender, age, location, gross type, smoking status and lymph node metastasis(P>0.05). EGFR mutation was more frequent in well-differentiated cancer, mainly in acinar carcinoma, while poorly differentiated adenocarcinoma and mucous adenocarcinoma were lower.

CONCLUSION

There was a difference of EGFR mutation in primary lung adenocarcinoma between Uighur and Han in Xinjiang, perhaps reflecting ethnic genetic variation, which is worth further analyzing. EGFR mutation was commonly detected in well or middle differentiated adenocarcinoma, mainly in acinar carcinoma.

[Study on detection methods of interstitial fluid glucose concentration based on infrared attenuated total reflection]

Measuring the glucose concentrations in the interstitial fluid is currently the main method to achieve the continuous blood glucose monitoring. The MIR-ATR(Mid-infrared, Attenuated Total Reflection)Spectroscopy has prominent advantage on the analysis of small biological molecule for composition information like the glucose, but it is still an unresolved problem that how to detect the subcutaneous glucose concentration by using the MIR-ATR Spectroscopy. In the present paper, we carry out the experiment based on MIR-ATR for the detection of subcutaneous glucose information on both the natural state and the penetration state based on the theoryanalysis of MIR penetration depth. Firstly, collect spectral data of the subcutaneous glucose concentration of human finger on the natural state were collected as the light shined the skin directly, and it was discussed whether the MIR can penetrate the skin to get the information of subcutaneous glucose. On this basis, collect spectral data of the subcutaneous glucose concentration of human finger at the penetration state were collected when the Interstitial fluid is permeated to the surface layer by using low-frequency ultrasound and vacuum, then it analyzed that whether it can detect the glucose-specific information or not. As the two-dimensional correlation spectroscopy has high resolution and good versatility, it is widely used to analyze the inter-molecular reaction and judge the absorption peaks information in many fields including the MIR spectroscopy field, so we choose the Two-dimensional correlation spectroscopy to analyze the information of subcutaneous glucose concentration at the natural state and the penetration state. The experiment result shows that the MIR-ATR spectroscopy can't be applied in the detection of subcutaneous glucose concentrationdirectly, and it is a promising direction to make the Interstitial fluid permeated to the surface layer by the physical methods or chemical methods.

[Identification of adulterated milk based on two-dimensional correlation near-infrared spectra parameterization and BP neural network]

Discriminant models of adulterated milk and pure milk were established using BP neural network combined with two-dimensional (2D) correlation near-infrared spectra parameterization. Forty pure milk samples, 40 adulterated milk samples with urea (1-20 g x L(-1)) and 40 adulterated milk samples with melamine (0.01-3 g x L(-1)) were prepared respectively. Based on the characteristics of 2D correlation near-infrared spectra of pure milk and adulterated milk, 5 apparent statistic parameters were calculated based on the parameterization theory. Using 5 characteristic parameters, discriminant models of urea adulterated milk, melamine adulterated milk and two types of adulterated milk were built by BP neural network The prediction rate of unknown samples were 95%, 100% and 96.7%, respectively. The results show that this method can extract effectively feature information of adulterant, reduce the input dimensions of BP neural network, and better realize qualitative analysis of adulterant in milk.

[Study on specificity of noninvasive glucose measurements based on two-dimensional correlation mid-infrared spectroscopy]

Glucose specificity is the premise of spectroscopic measurements of blood glucose concentration, and it is also paramount for feasibility study of a spectral measurement method. Two-dimensional correlation spectroscopy technology is widely used in many fields such as inter-/intra-molecular reaction, material phase transition and information extraction because of its high resolution and effective Noda's rule. In the present paper, the glucose specificity for noninvasive glucose measurements by mid-infrared spectra based on the 2D correlation spectroscopy was investigated. First, the feasibility of this method was validated by a series of in vitro experiments of glucose. Then the in vivo experiments of four volunteers were conducted and the characteristic information of glucose by mid-infrared spectra collected from human fingers was confirmed by 2D correlation spectroscopy analysis.

Development of a targeted topoisomerase I inhibitor for anticancer therapy

Abstract #2146

Background:&#x2028; DNA topoisomerase I (Top1) has been identified as the molecular target of a variety of drugs, due to the important roles that they play in biological systems. Studies show that breast cancer cell lines are sensitive to Top1 agents such as camptothecin. Recent clinical trials have suggested that breast cancer patients may respond to drugs which target Top1. This suggests that some breast cancers may have elevated expression of the enzyme.&#x2028; Thus, development of Top1 inhibitors may be a good target for anticancer therapy. To better target cancer cells, the drugs can be linked to a pH-sensitive linker such as the N-Ethoxybenzylimidazoles (NEBIs) developed in our lab. The NEBIs are designed to undergo hydrolysis in slightly acidic aqueous solutions at physiological temperature, comparable to the environment found in endosomes, lysosomes, and the extracellular environment of tumors. The hydrolysis of the NEBI causes the dissociation of the drug from a carrier (e.g. Herceptin), and the rates can be tuned by modifying the electron withdrawing and donating groups on the NEBI ring. It was demonstrated that the rates can be tuned to give half-lives ranging from 36 minutes to 9 months.&#x2028; Materials and Methods:&#x2028; We have developed a new class of imidazole-containing drugs which may inhibit Top1 activity. These compounds have a 4-ring, indenoisoquinoline structure and were synthesized by a simple condensation reaction which gives good yield. Ring substituents were modified to achieve molecules of optimal potency. The resulting drugs were subsequently linked to the NEBI, and hydrolysis studies were performed to determine the rate of active drug release.&#x2028; &#x2028; Cytotoxicity of cleaved drugs was screened using the sulforhodamine B (SRB) assay and topoisomerase inhibition assays will be performed in the near future.&#x2028; Results:&#x2028; Cytotoxicity studies showed that the hydrolyzed drugs are toxic to the 10μM range in cancer cells. One of the compounds has recently been approved for the National Cancer Institute screen, in which the activity will be evalutated with 60 different cancer cell lines of diverse tumor origins. Ongoing studies will assess the topoisomerase I inhibition activity of these compounds.&#x2028; Discussion:&#x2028; We have developed a novel prodrug which comprises of a toxic Top1 inhibiting drug attached to a pH-sensitive linker. This may prove to be an effective approach to anticancer therapy. Future studies will be pursued in using folic acid as the drug carrier to target breast cancer cells. Studies show that folate receptor overexpression is associated with poor outcome in women with breast cancer. Furthermore, it has been shown that folate receptors may undergo endocytosis, which will trigger the release of the active drug from the linker.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2146.

Simultaneous Fluorometric Resolution of Pyridoxal, Pyridoxamine and 4-Pyridoxic Acid Using Chemometric Methods

An alternatively minimizing covariant matrix error (AMCME) algorithm, newly proposed by the present authors, was applied to the simultaneous fluorometric determination of pyridoxal, pyridoxamine and 4-pyridoxic acid without loss of sensitivity. The experimental results illustrate that the profiles of spectra and concentration can be accurately resolved using the AMCME algorithm with a high sensitivity and stable repeatability. That is to say, the closely overlapping problem of the spectra could be resolved owing to the characteristic features of the AMCME algorithm.

An algorithm for three-way data analysis that alternatively minimizes coupled vector (COV) resolution error and PARAFAC error

A novel algorithm, alternatively minimizing coupled vector (COV) resolution error and PARAFAC error algorithm, is proposed in this paper. This algorithm can overcome the problem of slow convergence and is insensitive to the estimation of component number, such problems are unavoidable while using the traditional parallel factors analysis (PARAFAC) algorithm. In other words, this algorithm is capable of improving the computing speed and providing accurate resolutions provided that the number of factors used in the computation is no less than that of the actual underlying ones. The characteristic performances were demonstrated with a novel fluorescence data array.

Oxidant stress enhances Lyso-PAF-AcT activity by modifying phospholipase D and phosphatidic acid in aortic endothelial cells

Oxidant stress, as a consequence of selenium (Se) deficiency, alters production of vasoactive compounds including platelet-activating factor (PAF). Recent studies report that enhanced PAF production during Se deficiency is a consequence of increased lyso-PAF:acetyl-coenzyme A acetyltransferase (Lyso-PAF-AcT) activity. To elucidate the mechanism behind increased Lyso-PAF-AcT activity during oxidant stress, phospholipase D (PLD) activity and phosphatidic acid (PA) production were examined. Increased PLD activity and PA production were exhibited in bovine aortic endothelial cells using a Se-deficient model of oxidant stress. The direct effects of PLD and PA on Lyso-PAF-AcT activity were assessed using selective inhibitors and repletion experiments. Following the inhibition of PLD and addition of exogenous PA, Lyso-PAF-AcT activity significantly decreased and increased, respectively. Therefore, Se deficiency enhances Lyso-PAF-AcT activity in part by modifying PLD and PA. This suggests a novel link between Se status and PAF production, providing potential upstream therapeutic targets for PAF regulation under conditions of oxidant stress.

Spectrofluorometric resolution of closely overlapping drug mixtures using chemometrics methods

A modified parallel factors analysis (PARAFAC) algorithm with a penalty diagonalization error (PDE), newly proposed by the present authors, was utilized to simultaneously resolve drug mixtures of propranolol (PRO), dipyridamole (DIP) and amiloride (AMI) without any loss of sensitivity. The analyses were performed in aqueous solution. The experimental results demonstrated that the profiles of the spectra and the concentrations could be accurately resolved using the PDE algorithm with a high sensitivity and stable repeatability. That is to say, the closely overlapping problem of the spectra could be easily solved. Furthermore, simultaneous determinations of three kinds of tablets, which contain PRO, AMI and DIP, respectively, were successfully performed with satisfactory results.

Selenium modulates 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (PAF) biosynthesis in bovine aortic endothelial cells

Selenium (Se) deficiency has been reported to increase platelet-activating factor (PAF) production in human endothelial cells; however, the mechanism is unclear. This study demonstrated that tumor necrosis factor-alpha (TNF-alpha) stimulated Se-deficient bovine aortic endothelial cells (BAEC) produced significantly more PAF than Se-supplemented cells. Moreover, the increase in the level of PAF was associated with enhanced activity of two anabolic enzymes in the remodeling pathway: phospholipase A2 and Lyso-PAF:acetyl-coenzyme A acetyltransferase (Lyso-PAF-AcT). In contrast, the activity of the PAF catabolic enzyme, PAF-acetylhydrolase, was not affected by Se status. Interestingly, prostacyclin, a potent vasodilator and inhibitor of platelet aggregation, inhibited the activity of Lyso-PAF-AcT and reduced the PAF production in TNF-alpha-stimulated BAEC. Therefore, we conclude that Se deficiency alters PAF production in TNF-alpha-stimulated BAEC by altering the activity of anabolic enzymes involved in the remodeling pathway partially through the inhibition of prostacyclin production.

Determination of clopidol residues in chicken tissues by liquid chromatography: part II. Distribution and depletion of clopidol in chicken tissues

A study was made of the distribution and depletion of clopidol residues at different tissue locations in chickens fed with feeds incurred with clopidol. Experiments showed that the residue levels were not identical at 5 different tissue locations in each chicken. The sequence of residue levels from high to low was livers, kidneys, upper breast, lower breast, and leg meat. The maximum residue values after suspension of the drug for 8 h were (mg/kg): livers, 4.600; kidneys, 3.619; upper breast, 1.742; lower breast, 1.641; leg meat, 1.525. The averages were taken after values for 10 chickens were determined. After suspension of the drug for 3 days, >80% residue clopidol was depleted, and the depletion was nearly completed within 7 days. The speed of depletion varied at different tissue locations in each chicken, with the sequence from fast to slow being equivalent to that of the residue levels. Analytical results of 350 samples during 7 days showed that the proposed method is specific for determination of clopidol in chickens.

Determination of clopidol residues in chicken tissues by liquid chromatography: part III. Quality control analysis of export chickens

A summary is presented of the liquid chromatographic (LC) determination of clopidol residues in export chickens from 1992 to 1999. Over the past 8 years, we analyzed >7000 chicken samples. A total of 0.66% of samples contained clopidol residues, ranging from 0.005 to 0.79 mg/kg; however, none exceeded 3 mg/kg, the Chinese maximum residue limit. In comparison with 1992, the number of samples multiplied 70-fold, and the frequency of clopidol found in samples decreased 148-fold in 1999. The chickens inspected were exported to foreign countries; all were cleared by the buyers with no disputes. This report also introduces the critical control points of the proposed LC method as well as identification of false-positive procedures by both experience and LC/mass spectrometric confirmation. Our experiences over the past 8 years have demonstrated that the ruggedness of the proposed LC method is quite good.

Determination of clopidol residues in chicken tissues by liquid chromatography: part I. Optimization of analytical conditions and comparison with AOAC gas chromatography method

A simple and specific liquid chromatographic method was developed for determination of clopidol in chicken tissues. Samples were extracted with acetonitrile. The extracts were cleaned up on an alumina column and an anion exchange column. The clopidol was separated on a column (30 cm x 3.9 mm) of microBondapak C18 (10 microm) by using acetonitrile-water (20 + 80, v/v) as mobile phase, and determined quantitatively at 270 nm. Recoveries were 86.0-97.6%, with relative standard deviations of 2.14-9.42% at 0.010-2.0 mg/kg from 4 spiked matrixes of chicken muscle, egg, liver, and kidney. The limit of detection was 0.005 mg/kg. Compared with the modified AOAC gas chromatographic method, the present method is simple and fast to operate. Its results are accurate and reliable, making it favorable for environmental protection and meeting requirements for human safety. Thus, it is suitable for routine analysis of large quantities of samples.

Inhibiting effect of antisense oligonucleotides phosphorthioate on gene expression of TIMP-1 in rat liver fibrosis

AIM

To observe the inhibition of antisense oligonucleotides (asON) phosphorthioate to the tissue inhibitors metalloproteinase-1 (TIMP-1) gene and protein expression in the liver tissue of immunologically induced hepatic fibrosis rats. The possibility of reversing hepatic fibrosis through gene therapy was observed.

METHODS

Human serum albumin (HSA) was used to attack rats, as hepatic fibrosis model, in which asONs were used to block the gene and protein expressing TIMP-1. According to the analysis of modulator, structure protein, coding series of TIMP-1 genome, we designed four different asONs. These asONs were injected into the hepatic fibrosis models through coccygeal vein. The results was observed by RT-PCR for measuring TIMP-1 mRNA expression, immunohistochemistry and in situ hybridization for collagen I, II, special staining of collagen fiber, and electron microscopic examination.

RESULTS

Hepatic fibrosis could last within 363 days in our modified model. The expressing level of TIMP-1 was high during hepatic fibrosis process. It has been proved by the immunohistochemical and the electron microscopic examination that the asON phosphorthioate of TIMP-1 could exactly express in vivo. The effect of colchicine was demonstrated to inhibit the expressing level of mRNA and the content of collagen I, III in the liver of experimental hepatic fibrosis rats. However, the electron microscopy research and the pathologic grading of hepatic fibrosis showed that there was no significant difference between the treatment group and the model group (P> 0.05).

CONCLUSION

The experimental rat model of hepatic fibrosis is one of the preferable models to estimate the curative effect of anti-hepatic fibrosis drugs. The asON phosphorthioate of TIMP-1 could block the gene and protein expression of TIMP-1 in the liver of experimental hepatic fibrosis rats at the mRNA level. It is possible to reverse hepatic fibrosis, and it is expected to study a new drug of antihepatic fibrosis on the genetic level. Colchicine has very limited therapeutic effect on hepatic fibrosis, furthermore, its toxicity and side effects are obvious.

Increased 15-HPETE production decreases prostacyclin synthase activity during oxidant stress in aortic endothelial cells

Selenium (Se) is an integral component of glutathione peroxidase and is able to detoxify peroxides that can affect arachidonic acid (AA) metabolism, thereby influencing eicosanoid biosynthesis. This study investigated the effects of oxidant stress, a consequence of Se deficiency, on eicosanoid formation and important key enzyme expression in bovine aortic endothelial cells (BAEC). Bovine aortic endothelial cells cultured in Se-deficient media and stimulated with tumor necrosis factor alpha or H2O2 produced significantly less prostacyclin (PGI(2)) and more 15-hydroxyeicosatetraenoic acid, 15-hydroperoxyeicosatetraenoic acid (15-HPETE), and thromboxane than Se-supplemented BAEC. Additionally, reverse transcription polymerase chain reaction and immunoblotting determined that the mRNA and protein levels of the eicosanoid forming enzymes cyclooxygenase-1 (COX1), cyclooxygenase-2 (COX2), and PGI synthase were not significantly changed. The addition of 15-HPETE to Se-supplemented BAEC inhibited the production of PGI(2) suggesting that the accumulation of lipid hydroperoxides during Se-deficiency may be the underlying factor in the altered eicosanoid production during Se deficiency. Furthermore, inhibition of COX and addition of PGH(2) to Se-deficient or Se-supplemented BAEC still resulted in lower PGI(2) formation by Se-deficient cells. Together, these results suggest that Se deficiency modifies eicosanoid production by affecting the activity of key enzymes, particularly PGI synthase, rather than their transcription or translation.

A PARAFAC algorithm using penalty diagonalization error (PDE) for three-way data array resolution

A modified parallel factors analysis (PARAFAC) algorithm with the penalty diagnolization error (PDE) was developed. This algorithm can overcome the slow convergence problem of the traditional PARAFAC method and is insensitive to the number of components, i.e., it is much faster than PARAFAC and insensitive to overestimation of the dimensionality of the model. The characteristic performance was demonstrated by treating simulated and real excitation-emission fluorescence data for samples of naphthalene, 1-naphthol and 2-naphthol with satisfactory results.

Determination of clopidol residues in chicken tissues by high-performance liquid chromatography-mass spectrometry

A high-performance liquid chromatographic-mass spectrometric (HPLC-MS) method has been developed for determination of clopidol residues in chicken tissues. Samples are extracted with acetonitrile. The extracts are cleaned up on an alumina column followed by an anion-exchange column. The clopidol is separated on a column (150 cmx4.6 mm) of Intertsil by using acetonitrile-water (20:80) as mobile phase. The clopidol was qualitatively identified by molecule mass and determined quantitatively by selected ion monitoring mode at 190 m/z. The recoveries with RSDs ranged from 91.6+/-10.1 to 97.3+/-5.7 at 0.010 to 10.0 mg/kg by spiking three matrices (chicken muscle, liver, and kidney). The limit of detection was 0.005 mg/kg, and the limit of quantification was 0.010 mg/kg.

Altered eicosanoid biosynthesis in selenium-deficient endothelial cells

Selenium (Se) is an integral part of the Se-dependent glutathione peroxidase (Se-GSH-Px) catalytic domain. By modulating the cellular levels of fatty acid hydroperoxides, Se-GSH-Px can influence key enzymes of arachidonic acid cascade, in this case cyclooxygenase (COX) and lipoxygenase (LOX). To investigate this phenomenon, the effects of cellular Se status on the enzymatic oxidation of arachidonic acid were investigated in bovine mammary endothelial cells (BMEC), which were cultured in either Se-deficient (-Se) or Se-adequate (+Se) media. When stimulated with calcium ionophore A23187, BMEC produced eicosanoids of both COX and LOX pathways. Compared with the Se-adequate cells, the production of prostaglandin I(2) (PGI(2)), prostaglandin F(2) (PGF(2alpha)), and prostaglandin E(2) (PGE(2)) was significantly decreased in Se-deficient cells, whereas the production of thromboxane A(2) (TXA(2)) was markedly increased in the -Se BMEC cultures. Although the enzymatic oxidation of arachidonic acid by the LOX pathway was found to be relatively less than by the COX pathway, the BMEC cultured in -Se media produced significantly more 15-hydroperoxyeicosatetraenoic acid (15-HPETE) than the +Se cells produced. Based on these results, we postulate that cellular Se status plays an important regulatory role in the enzymatic oxidation of arachidonic acid by the COX and LOX pathways. The altered eicosanoid biosynthesis, especially the overproduction of 15-HPETE, in -Se BMEC may be one of the underlying biochemical phenomena responsible for vascular dysfunction during Se deficiency.

Multiresidue gas chromatographic method for determining synthetic pyrethroid pesticides in agricultural products: collaborative study

Fourteen laboratories from 6 countries and regions participated in an international collaborative study to evaluate a multiresidue gas chromatographic (GC) method for determining 8 synthetic pyrethroid pesticides in grains, fruits, and vegetables. The study design was based on Youden's matched-pairs principle for collaborative tests of analytical methods. Each laboratory analyzed 12 collaborative samples of wheat, oranges, and tomatoes as blind samples. Wheat samples were extracted with acetonitrile-water (2 + 1), while orange and tomato samples were extracted with acetone. Residues were partitioned into hexane, evaporated to dryness with a rotary evaporator, and then dissolved in hexane. The hexane extract was partitioned with acetonitrile and cleaned up on a 5% water-deactivated Florisil column with 6% ethyl ether in hexane as eluant. Residue concentrations were determined by GC with electron capture detection with splitless injection by comparison with single-point calibration standards. The appropriate standard concentration was determined by screening sample extracts before analysis. The multiresidue method was tested over the concentration range of 0.095-1.909 mg/kg depending on the 8 different of pesticides and agricultural products analyzed in the collaborative study. Statistical analysis of data from 13 laboratories showed weighted average recoveries for 8 pyrethroids in wheat, oranges, and tomatoes at 0.105-1.909, 0.095-1.909, and 0.105-0.954 mg/kg, respectively, ranging from 91.8 to 100.2%, from 88.1 to 100.6%, and from 88.2 to 101.5%, respectively. Reproducibility relative standard deviation values ranged from 6.46 to 17.74%, from 5.94 to 18.13%, and from 5.59 to 10.48%, respectively. Repeatability relative standard deviation values ranged from 6.34 to 10.84%, from 5.19 to 11.72%, and from 3.20 to 8.09%, respectively. The multiresidue GC method for determining synthetic pyrethroid pesticides in agricultural products has been adopted first action by AOAC INTERNATIONAL.

Modification of AOAC multiresidue method for determining synthetic pyrethroid residues in fruits, vegetables, and grains. Part III: Studies of analyte stability and method ruggedness

The stability of 8 synthetic pyrethroids in 9 crops during storage for 90 days were studied. The 8 pyrethroid insecticides were highly persistent in the 6 grains during storage. But their stabilities in 3 kinds of fruits and vegetables were different from those in the 6 grains: Most of them were degraded. Florisil purification conditions were studied with 6 batches of Florisil from 3 countries at various extents of deactivation and amounts. The best conditions of Florisil purification found in this present research agree with those found 1 year ago. The efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruit and vegetable samples were compared. The extraction efficiency of acetone was competitive with that of acetonitrile for the 6 fruit and vegetable samples. Method performance was evaluated by 6 analysts from different areas. The ruggedness tests demonstrate further that the proposed method is simple, accurate with good precision, and suitable for multiresidue analysis of pyrethroids in various agriculture products.

Evidence for G-protein-dependent and G-protein-independent activation of phospholipase D in lymphocytes

Previously we reported that tumor-promoting phorbol esters stimulate phospholipase D (PLD) independent of protein kinase C (PKC) activation in bovine lymph node lymphocytes. (Cao et al., Biochem. Biophys. Res. Commun. 171, 955-962, 1990; 217, 908-915, 1995). In the present study, we examined the effects of prostagladins (PGs), E2, F2 alpha, D2, and H2 on PLD activity as measured by conversion of [1-14C] arachidonic acid-labeled phospholipids into phosphatidylethanol (PEt) in bovine lymph node lymphocytes. Prostaglandins stimulated the formation of PEt at an optimal concentration of 10 microM with relative stimulatory effect on the order of PGE2 > PGF2 alpha > PGH2 > PGD2. The PGE2-stimulated formation of PEt was dose-dependent in the range of 0.1 to 10 microM and was not inhibited by PKC inhibitors staurosporine and K252a. When both PGE2 and 12-0-tetradecanoylphorbol-13-acetate (TPA) were included, their effect on the PLD activation was additive. Furthermore, NaF, a G-protein activator, stimulated the PEt formation. Interestingly, the stimulatory effects of PGE2 and NaF were not additive; however, the formation of PEt by NaF and TPA was additive. These results suggest that similar to TPA, PGs increase PLD activity independent of PKC and the stimulation by PGs and TPA in lymphocytes may involve both G-protein-dependent and G-protein-independent signaling pathways.

The mechanism of sphingosine enhancement of phorbol ester-mediated phospholipase D activation in lymphocytes

Tumor-promoting phorbol esters stimulate the production of phosphatidylethanol (PEt) in bovine lymph node lymphocytes through the activation of Phospholipase D (PLD). Sphingosine enhanced the 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated formation of PEt in lymphocytes, while it had no effect by itself. Interestingly, the incorporation of labeled arachidonic acid into phospholipids was increased by sphingosine. Examination of the effect of sphingosine along with TPA on the incorporation of [1-14C]labeled-arachidonic acid into individual phospholipids revealed that they enhanced significantly the specific activity of only PC and lyso-PC fractions. These observations indicate that sphingosine does not activate PLD directly as TPA does. It appears that sphingosine increases the specific radioactivity of the substrate pool for PLD which results in an apparent increase in PEt when both sphingosine and TPA are present.

Selenium deficiency alters the lipoxygenase pathway and mitogenic response in bovine lymphocytes

We investigated the effect of altered selenium (Se) nutrition on arachidonic acid oxidation in immune cells. Experiments were conducted with peripheral blood lymphocytes obtained from dairy cattle fed diets either supplemented with or deficient in Se. The results indicate that the concanavalin A-stimulated lymphocyte proliferation was significantly lower in Se-deficient cows. When stimulated by calcium ionophore A23187, the lymphocytes derived from Se-deficient cows produced significantly less 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4) than those obtained from Se-supplemented cows. When included in cell cultures from animals fed +Se diets, 5-HETE and LTB4 elicited a partial reversal of the inhibition of lymphocyte proliferation by either hydrocortisone or nordihydroguaiaretic acid. Based on this information, we postulate that dietary Se status, which in turn determines tissue Se concentration, plays an important role in the regulation of arachidonate metabolism by way of the 5-lipoxygenase pathway. This may be one of the biochemical mechanisms underlying the inhibition of lymphocyte proliferation and the decrease in resistance to infectious diseases observed in Se-deficient animals.

Identification and quantitation of HIV-1 in the liver of patients with AIDS

OBJECTIVE

To detect and quantify HIV-1 in the liver in vivo.

DESIGN

Fourteen liver biopsy samples and corresponding blood lymphocytes and monocytes from patients with AIDS were studied for HIV-1 using quantitative polymerase chain reaction (PCR). In addition, expression of HIV-1 antigen and messenger (m) RNA in 10 autopsy liver specimens was examined by immunohistochemistry and in situ hybridization.

RESULTS

The amount of HIV-1 DNA in nine liver samples ranged from 850 to 27,000 copies per 10(6) cells, with mean and median values of 8150 and 3500 copies per 10(6) cells, respectively. Five other samples had no detectable HIV-1 DNA by PCR. Intracellular expression of HIV-1 antigen and mRNA was also detected in both Kupffer cells and hepatocytes by in situ studies.

CONCLUSION

These findings strongly indicate that HIV-1 could replicate in the liver of a majority of patients with AIDS.

Increased 12-HETE production in bovine lymphocytes during selenium deficiency

When peripheral blood lymphocytes were incubated with arachidonic acid in the presence of Ca++ ionophore (A23187), the cells from the selenium-deficient dairy cows produced significantly greater quantities of 12-hydroxyeicosatetraenoic acid (12-HETE) than the cells from the selenium-supplemented animals. The major product of reaction was verified as 12-HETE by cochromatography with a 12-HETE standard on an HPLC and structural analysis by GC-MS. Additionally, concanavalin A-stimulated lymphocyte proliferation was significantly decreased in cells from the Se-deficient cows. Furthermore, 12-HETE generated by the A23187-stimulated lymphocytes inhibited lymphocyte proliferation when added to Se-supplemented cell cultures. These observations suggest that self-regulation of lymphocyte proliferation might be mediated by 12-HETE production, especially during an altered nutritional state such as Se deficiency.

Another discontinuous epitope on glycoprotein gp120 that is important in human immunodeficiency virus type 1 neutralization is identified by a monoclonal antibody

To define the domains in the envelope glycoprotein important for antibody neutralization of the human immunodeficiency virus type 1 (HIV-1), monoclonal antibodies (mAbs) were generated by immunizing mice with purified glycoprotein gp120 of the IIIB isolate. One mAb, G3-4, reacted with the gp120 of homologous (IIIB) and heterologous (RF) isolates. In addition, mAb G3-4 efficiently neutralized both IIIB and RF viruses in vitro, as well as four of nine primary HIV-1 isolates. In competition immunoassays, mAb G3-4 and soluble CD4 were found to inhibit one another in binding to gp120. However, no competition was seen between mAb G3-4 and mAbs directed to the third variable region or the fourth conserved region of gp120. In particular, mAb G3-4 did not compete with our human mAb 15e, which identifies a discontinuous epitope on gp120 involved in group-specific neutralization of HIV-1 and in gp120-CD4 binding. Epitope-mapping studies on mAb G3-4 with synthetic or unglycosylated recombinant peptides were negative, suggesting that its epitope may be discontinuous. Indeed, this hypothesis was confirmed by showing the loss of mAb G3-4 serologic reactivity when gp120 was first denatured. We conclude that the site recognized by mAb G3-4 represents another discontinuous epitope on gp120 important for neutralization of HIV-1.

Lysophosphatidate Acyltransferase in the Microsomes from Maturing Seeds of Meadowfoam (Limnanthes alba)

Lysophosphatidate (LPA) acyltransferase (EC 2.3. 1.51) in the microsomes from the maturing seeds of meadowfoam (Limnanthes alba), nasturtium (Tropaeolum majus), palm (Syagrus cocoides), castor bean (Ricinus communis), soybean (Glycine max), maize (Zea mays), and rapeseed (Brassica napus) were tested for their specificities toward 1-oleoyl-LPA or 1-erucoyl-LPA, and oleoyl coenzyme A (CoA) or erucoyl CoA. All the enzymes could use either of the two acyl acceptors and oleoyl CoA, but only the meadowfoam enzyme could use erucoyl CoA as the acyl donor to produce dierucoyl phosphatidic acid (PA). The meadowfoam enzyme was studied further. It had an optimal activity at pH 7 to 8, and its activity was inhibited by 1 millimolar MnCl(2), ZnCl(2), or p-chloromercuribenzoate. In a test of substrate specificity using increasing concentrations of either 1-oleoyl-LPA or 1-erucoyl-LPA, and either oleoyl CoA or erucoyl CoA, the enzyme activity in producing PA was highest for dioleoyl-PA, followed successively by 1-oleoyl-2-erucoyl-PA, dierucoyl-PA, and 1-erucoyl-2-oleoyl-PA. In a test of substrate selectivity using a fixed combined concentration, but varying proportions, of 1-oleoyl-LPA and 1-erucoyl-LPA, and of oleoyl CoA and erucoyl CoA, the enzyme showed a pattern of acyl preference similar to that observed in the test of substrate specificity, but the preference toward oleoyl moiety in the substrates was slightly stronger. The meadowfoam microsomes could convert [(14)C]glycerol-3-phosphate to diacylglycerols and triacylglycerols in the presence of erucoyl CoA. The meadowfoam LPA acyltransferase is unique in its ability to produce dierucoyl-PA, and should be a prime candidate for use in the production of trierucin oils in rapeseed via genetic engineering.

Evidence for protein kinase C independent activation of phospholipase D by phorbol esters in lymphocytes

Recently it was reported that tumor-promoting phorbol esters stimulate the production of phosphatidylethanol (PEt) in lymphocytes through the activation of phospholipase D (PLD). However, it remains unclear whether this activation is mediated through protein kinase (PKC). The study reported here shows that tumor promoters 12-0-tetradecanoylphorbol-13-acetate (TPA), phorbol dibutyrate (PDBU), 12-deoxyphorbol-13-phenylacetate (DOPP), 12-deoxyphorbol-13-phenylacetate-20-acetate (DOPPA) and mezerin activated PLD, as measured by the formation of PEt, whereas Concanavalin A (ConA) had no effect. Inhibitors of PKC, sphingosine (2 x 10(-6) M - 5 x 10(-6) M), H-7, HA1004 (5 x 10(-7) - 5 x 10(-6) M) and K252a (1 x 10(-7) - 1 x 10(-6) M) failed to block the PEt synthesis induced by TPA. In fact, sphingosine increased it. Other PKC activators, 1-oleoyl-2-acetylglycerol (OAG) and dioctanoylglycerol (DiC8) had no effect on lymphocyte PLD activity. Analysis of the phospholipid contents after stimulation by TPA showed that only phosphatidylcholine (PC) was significantly decreased. Interestingly, TPA activated PLD in intact cells but not in lysates or subcellular fractions. These observations suggest that stimulation of PLD-catalyzed PEt synthesis by TPA is not solely mediated through PKC activation.

CD4-independent, productive human immunodeficiency virus type 1 infection of hepatoma cell lines in vitro

Five hepatoma cell lines, including CZHC/8571, PLC/PRF/5, Hep3B, HepG2, and HUH7, were inoculated with three diverse isolates of human immunodeficiency virus type 1 (HIV-1). Productive infection was noted in all hepatoma cell lines, and expression of viral p24 antigen lasted for over 3 months, but its level decreased in proportion to the number of viable cells. HIV-1 antigens were also found in the cells by immunohistochemical staining and radioimmunoprecipitation assay, as were viral RNA by in situ hybridization and HIV-1-like particles by electron microscopy. Virus yield assays were also positive on supernatant fluids collected from hepatoma cultures inoculated with HIV-1. Despite their susceptibility to infection, all five hepatoma cell lines were negative for CD4 by immunofluorescence and for CD4 mRNA by slot-blot hybridization. In addition, HIV-1 infection of hepatoma cell lines was not blocked by anti-CD4 monoclonal antibody or soluble CD4. Together, these findings clearly demonstrate that all five hepatoma cell lines were susceptible to productive infection by HIV-1 in vitro via a CD4-independent mechanism.

Megakaryocytes of human immunodeficiency virus-infected individuals express viral RNA

The pathogenesis of thrombocytopenia associated with human immunodeficiency virus (HIV) infection is not fully understood. Immune mechanisms provide a partial explanation but fail to account for a lack of compensatory megakaryocytosis, the rapid reversal after treatment with azidothymidine, and the ultrastructural aberrations seen in the megakaryocytes of patients with acquired immunodeficiency syndrome. Therefore, a direct effect of HIV on megakaryocytes was investigated. The bone marrow of HIV seropositive individuals was analyzed ultrastructurally, and the megakaryocytes of 10 thrombocytopenic patients were subjected to in situ hybridization with a HIV RNA probe. The structural aberrations in HIV megakaryocytes were distinct from those in HIV-negative immune thrombocytopenias, and the megakaryocytes of 10 of 10 patients examined by in situ hybridization unambiguously expressed viral RNA. Therefore, it is likely that direct infection of megakaryocytes with HIV-1 is one mechanism for the decrease in platelet production.

Antibodies to human immunodeficiency virus type 1 in the urine specimens of HIV-1-seropositive individuals

Specific antibodies to human immunodeficiency virus type 1 (HIV-1) were detected in 200-fold concentrated urine samples, but none were detected in unconcentrated urine specimens, from 100 randomly selected HIV-1--seropositive individuals by enzyme-linked immunosorbent assay (ELISA) and Western blot techniques using the manufacturer's recommended procedures. Using modified methods for both the ELISA and Western blot tests, antibodies to HIV-1 have also been detected in the unconcentrated urine specimens from the same HIV-1--seropositive individuals. No difference in the frequency of antibodies to HIV-1 were found between unconcentrated and 200-fold concentrated urine samples when tested by the modified methods. HIV-1 core antigen (p24) was not detected in either the concentrated or the unconcentrated HIV-1--seropositive adult urine samples; none of these individuals showed overt clinical or laboratory evidence of renal dysfunction. The titer of the antibodies to HIV-1 found in the urine specimens was found to be parallel with the titer of antibodies to HIV-1 in the corresponding individual's serum. Further elucidation of the pathophysiology and the nature of the specific antibodies to HIV-1 observed in the urine of HIV-1--seropositive individuals is under investigation in our laboratories.

Acyl coenzyme a preference of the glycerol phosphate pathway in the microsomes from the maturing seeds of palm, maize, and rapeseed

The acyl coenzyme A (CoA) preference of the glycerol phosphate pathway in the microsomes from the maturing seeds of palm (Butia capitata Becc.), maize (Zea mays L.), and rapeseed (Brassica napus L.) was tested. Each microsomal preparation was incubated with [(14)C-U]-glycerol-3-phosphate and either lauroyl CoA, oleoyl CoA, or erucoyl CoA, and the (14)C-lipid products were separated and quantitated. In the presence of oleoyl CoA, the microsomes from each of the three species produced lysophosphatidic acid, phosphatidic acid, diacylglycerol, and triacylglycerol with kinetics consistent with the operation of the glycerol phosphate pathway. In the presence of erucoyl CoA, the microsomes from all the three species did not produce di- or tri-acyl lipids. In the presence of lauroyl CoA, only the microsomes from palm, but not those from maize or rapeseed, synthesized di- and tri-acyl lipids. This lack of reactivity of lauroyl CoA was also observed in the microsomes from maturing castor bean, peanut, and soybean. In maize seed and rapeseed, but not palm seed, the kinetics of labeling suggest that lauroyl and erucoyl moieties of the acyl CoAs were incorporated into lysophosphatidic acid but failed to enter into phosphatidic acid and thus the subsequent lipid products. We propose that the high degree of acyl specificity of lysophosphatidyl acyltransferase is the blocking step in the synthesis of triacylglycerols using lauroyl CoA or erucoyl CoA. The significance of the findings in seed oil biotechnology is discussed.

The purification and characterization of a phospholipase A in hamster heart cytosol for the hydrolysis of phosphatidylcholine

Phospholipases A1 and A2 catalyze the hydrolysis of acyl groups of phospholipids at C-1 and C-2, respectively. These phospholipases are important in phospholipid catabolism and the remodeling of the acyl groups of phospholipids. Phospholipase A from hamster heart cytosol was purified by a combination of ion-exchange and gel filtration chromatography. The purity of the enzyme was assessed by nondenaturing polyacrylamide gel electrophoresis, two-dimension polyacrylamide gel electrophoresis, and immunological studies. The purified enzyme exhibited both phospholipase A1 and A2 activities toward phosphatidylcholine and had the ability to hydrolyze the acyl groups of phosphatidylethanolamine. However, the enzyme was not active toward lysophosphatidylcholine, diacylglycerol, or triacylglycerol. By Sepharose 6B chromatography, the molecular weight of the purified enzyme was estimated to be 140,000. Analysis of the purified enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the enzyme was composed of identical Mr 14,000 subunits. At least six subunits in the native enzyme could be cross-linked by dimethyl suberimidate. Both phospholipase A1 and A2 activities showed similar pH profiles, exhibited no absolute requirements for divalent metallic cations, but displayed a high degree of specificity for the acyl groups of phosphatidylcholine at both C-1 and C-2. The Km of phospholipases A1 and A2 for 1-palmitoyl-2-arachidon-ylglycerophosphocholine was found to be identical (0.5 mM).

Regulation by vitamin E of phosphatidylcholine metabolism in rat heart

Lysophosphatidylcholine is the major lysophospholipid in mammalian tissues and has been shown to be cytolytic at high concentrations. In the present study we demonstrated that the level of lysophosphatidylcholine was significantly increased in the heart of rats fed with a vitamin E-deficient diet. Moreover, the cardiac lysophosphatidylcholine level was decreased in rats fed with a high vitamin E diet. The alterations in cardiac lysophosphatidylcholine level by dietary vitamin E were attributed to the changes in the activity of cardiac phospholipase A. Dietary vitamin E affected both phospholipase A1 and A2 in the same manner, but had no effect on the other major enzymes which are responsible for the metabolism of lysophosphatidylcholine. Kinetic studies revealed that the inhibition of enzyme activity by vitamin E was essentially non-competitive. The accumulation of lysophosphatidylcholine in the rat heart may be one of the underlying biochemical causes of the observed cardiac dysfunctions produced during vitamin E deficiency.

Detection of HIV antigen and specific antibodies to HIV core and envelope proteins in sera of patients with HIV infection

The sera of well-characterized populations were examined for three markers of human immunodeficiency virus (HIV) infection; HIV antigen (HIV Ag), and antibodies to HIV envelope (gp41) and core (p24) proteins. Of 563 serum samples tested, 251 were from HIV-infected patients diagnosed as having AIDS manifested by opportunistic infections (AIDS-OI), AIDS-associated Kaposi's sarcoma (AIDS-KS), or AIDS-related complex (ARC). One hundred seventy-six specimens tested were from asymptomatic high-risk individuals, and 136 were from heterosexual control subjects or patients with non-AIDS-related disease. None of the 136 control individuals tested had HIV Ag or HIV antibodies to either p24 or gp41. Of the 427 HIV-seropositive individuals, 99% to 100% were positive for gp41 antibodies to HIV. In contrast, the seroprevalence of p24 antibodies to HIV varied from 23% to 83% and appeared to be inversely associated with the severity of the patients' clinical symptoms. When specimens were analyzed for the presence of HIV Ag, in seropositive individuals the prevalence rate for this marker was lowest (1.4%) in asymptomatic individuals and highest (50%) in the AIDS-OI diagnosed group. Also, 240 cases with AIDS-KS, AIDS-OI, and ARC and the group of asymptomatic high-risk individuals were analyzed for T helper/T lymphocytes (T4) cell number and T4/T8 ratio; only one (2.0%) HIV Ag-positive case showed a T4 cell number greater than 400 and a normal T4/T8 ratio. These studies appear to demonstrate a direct correlation between the presence of HIV Ag and the severity of clinical complications of HIV infection.

Acyl coenzyme a preference of diacylglycerol acyltransferase from the maturing seeds of cuphea, maize, rapeseed, and canola

In their seed triacylglycerols, Cuphea carthagenensis contains 62% lauric acid; maize possesses 50% linoleic acid and 30% oleic acid; rapeseed (Brassica napus L. var Dwarf Essex) has 40% erucic acid; and Canola (Brassica napus L. var Tower) holds 60% oleic acid and 23% linoleic acid. Diacylglycerol acyltransferase (EC 2.3.1.20) in the microsomal preparations from maturing seeds of the above species were tested for their preference in using different forms of acyl coenzyme A (CoA). Lauroyl CoA, oleoyl CoA, and erucoyl CoA individually or in equimolar mixtures at increasing concentrations were added to the assay mixture containing diolein, and the formation of triacylglycerols from the acyl groups at 24, 32, and 40 degrees C was analyzed. The Cuphea enzyme preferred lauroyl CoA to oleoyl CoA, and was inactive on erucoyl CoA. The maize enzyme had about equal activities on oleoyl CoA and lauroyl CoA, and was inactive on erucoyl CoA. Enzymes from both rapeseed and Canola had the same pattern of acyl CoA preference, with highest activities on lauroyl CoA. The two enzymes were more active on oleoyl CoA than on erucoyl CoA at high acyl CoA concentrations (10 and 20 micromolar) at 24 degrees C, but were more active on erucoyl CoA than on oleoyl CoA at low acyl CoA concentrations (1.36 micromolar or less) at 32 and 40 degrees C. These findings are discussed in terms of the contribution of the enzyme to the acyl specificity in storage triacylglycerols and the implication in seed oil biotechnology.

Diacylglycerol acyltransferase in maturing oil seeds of maize and other species

Diacylglycerol acyltransferase (EC 2.3.1.20) activity was detected in the microsomal fractions of maturing maize scutellum, soybean cotyledon, peanut cotyledon, and castor bean endosperm. The activity detected was high enough to account for the in vivo rate of triacylglycerol synthesis. The activity of the maize enzyme was characterized using diolein micelles prepared by sonication in Tween 20 as the substrate. The activity was highest at pH values of 6 to 7. The activity was proportional to the amount of enzyme added, and the reaction rate was linear for about 2 minutes. The enzyme was not inactivated by Tween 20, Zwitterion 3-08, Triton-X 100, and cholate, but was inactivated completely by sodium dodecyl sulfate. The enzyme was active on linoleoyl coenzyme A (CoA), palmitoyl CoA, and oleoyl CoA, although the activity was highest on linoleoyl CoA. Endogenous diacylglycerol was present in the microsomes, and the enzyme activity was only partially dependent on the addition of external diolein. Subcellular fractionation of the total scutellum extract in sucrose density gradients was performed. By comparing the migration of the enzyme between rate and equilibrium centrifugation, and between equilibrium centrifugation in the presence and absence of magnesium ions in the preparative media, the enzyme was shown to be associated with the rough endoplasmic reticulum. Some of the above findings on the maize enzyme were extended to the enzymes from castor bean, soybean, and peanuts.