Residues of hexachlorocyclohexane isomers and their distribution characteristics in soils in the Tianjin area, China

Hexachlorocyclohexane (HCH) has a history of use in China. This paper presents the results of an investigation of HCH residue isomers and their distribution characteristics in soils near Tianjin, China. One hundred eighty-eight soil samples were collected from the Tianjin area. Four HCH isomers-alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH-were detected using gas chromatography for all samples. Concentrations of the sum HCH ranged from 1.3 to 1095 ng g(-1), among which beta-HCH accounted for 52.5%. In addition, residues of HCH within Tianjin's urban areas were found to be higher. No significant differences were found between the residues of HCH in soils from waste irrigation areas and those in other areas. Total organic carbon content was determined to impact the residue levels of HCH in soils, while pH value and clay content were not related to concentrations of HCH. In general, all HCH isomers in soil samples had abnormally high residue levels, possibly the result of continuous use of HCH in this area.

Sample purification for analysis of organochlorine pesticides in sediment and fish muscle

The methods of sample purification for determinations of organochlorine pesticides (OCPs) in sediment and fish muscle were investigated in this study. A two-step procedure with preliminary cleanup and florisil column fraction was adopted. The working conditions of florisil column were firstly optimized. As to preliminary cleanup, liquid-liquid extraction by mixture of dimethyl formamide (DMF) and hexane and sulphonation by concentrated sulfuric acid were applied respectively and compared for the studied samples. The results indicated that liquid-liquid distribution could effectively separate lipids from fish muscle extracts, while failed in elimination of chlorophyll extracted from the relicts of hydrophytes in the sediment sample. In view of the sample appearance and clarity of gas chromatogram, sulphonation was more suitable to purify the sediment sample, however, the recoveries of the spiked standards were poor. The use of eluting solvent with stronger polarity could improve the corresponding recoveries significantly. Due to complete loss of Dieldrin, Endrin, and Endrin aldehyde after sulphonation, this pretreatment was improper to the three components. Sulfur, as the particular disturbing element in sediment, could be removed sufficiently by addition of activated copper powder. The relevant detection limits of the selected methods for OCPs in the studied substrates were also provided.

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.

Level and distribution of DDT in surface soils from Tianjin, China

One hundred and eighty eight surface soil samples were collected from the Tianjin area to study the contamination of DDT and its metabolites. Measurements were taken for p,p'-DDE, p,p'-DDD, p,p'-DDT, o,p'-DDE, o,p'-DDD and o,p'-DDT for all samples. The results indicated that p,p'-DDT and p,p'-DDE were the predominant contaminant compounds in the surface soil samples, with mean concentrations of 27.5 and 18.8 ng g(-1) respectively. No significant differences in DDT concentrations were found between the soils from wastewater treated irrigated areas and other areas, suggesting that wastewater irrigation is not an important source of DDT in the area. However, the spatial distribution of soil DDTs levels in the area did correlate well with early direct application rates of pesticides. In addition, both pH level and organic carbon content are also known factors affecting the level of DDT and its metabolites. Although it was assumed that the use of these chemicals was banned in the early 1980s, the current concentration levels appear to be too high to be mere residuals after 20 years degradation.

From hemorheology to vascular mechanobiology: An overview

Almost all of the cells of the human body are subjected to mechanical stresses. In endothelial cells, mechanical stresses can vary from some milli-Pascal (shear stress) to one ore more Pascal (hydrostatic pressure). Now it is know that mechanical stresses have a decisive part cellular physiology. However, if the main biological effects of mechanical stress are well related, the mechanisms allowed the relation between mechanical stress to physiological phenomenon remain nearly unknown (mechanotransduction phenomenon). In this work, through personal results and published works, the authors considers all the effects of mechanical stresses and the possible hypothesis.

Up-Regulation of FPR2, a Chemotactic Receptor for Amyloid β 1–42 (Aβ42), in Murine Microglial Cells by TNFα

Human FPRL1 and its mouse homologue FPR2 are functional receptors for several exogenous and host-derived chemotactic peptides, including amyloid beta(42) (A beta(42)), a critical pathogenic factor in Alzheimer's disease. We investigated the effect of TNF alpha on the expression and function of FPR2 in mouse microglial cells, a crucial inflammatory cell type in the CNS. Primary murine microglia and a cell line N9 in resting state expressed low levels of FPR2 gene and lacked the response to chemotactic agonists for this receptor. Incubation with TNF alpha, however, increased microglial expression of FPR2 gene, in association with potent chemotactic responses to FPR2-specific agonists including A beta(42). The effect of TNF alpha was dependent on the p55 TNF alpha receptor and activation of MAP kinase p38. TNF alpha concomitantly down-regulated microglial response to the chemokine SDF-1 alpha. Thus, by selectively up-regulating FPR2 in microglia, TNF alpha has the capacity to amplify host response in inflammatory diseases in the CNS.

Nuclear translocation of PDCD5 (TFAR19): an early signal for apoptosis?

The programmed cell death 5 (PDCD5) protein is a novel protein related to regulation of cell apoptosis. In this report, we demonstrate that the level of PDCD5 protein expressed in cells undergoing apoptosis is significantly increased compared with normal cells, then the protein translocates rapidly from the cytoplasm to the nucleus of cells. The appearance of PDCD5 in the nuclei of apoptotic cells precedes the externalization of phosphatidylserine and fragmentation of chromosome DNA. This phenomenon is parallel to the loss of mitochondrial membrane potential, independent of the feature of apoptosis-inducing stimuli and also independent of the cell types and the apoptosis modality. In conclusion, the nuclear translocation of PDCD5 is a universal earlier event of the apoptotic process, and may be a novel early marker for apoptosis.

Intraoperative management of posterior capsule tears in phacoemulsification and intraocular lens implantation

OBJECTIVE

This paper presents the incidence, causes, and management of posterior capsule (PC) tears and their postoperative outcomes in a large series of eyes that underwent cataract removal and intraocular lens (IOL) implantation, operated on by one surgeon.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Eighteen thousand four hundred seventy consecutive eyes (1992-1999) were reviewed with the assistance of electronic medical records for incidence of PC tears in patients seeking treatment at an outpatient cataract surgery clinic.

INTERVENTION

Eyes in this series underwent continuous curvilinear capsulorrhexis (CCC), nucleofractis phacoemulsification, and IOL implantation under topical anesthesia. Different intraoperative surgical strategies such as posterior continuous curvilinear capsulorrhexis (PCCC) were used in the management of PC tears.

MAIN OUTCOME MEASURES

Routine preoperative and postoperative visual and refractive outcomes were recorded, including incidence of lens capsule tears, IOL position, and postoperative complications.

RESULTS

Posterior capsule tears occurred in 83 of 18,470 eyes, resulting in an overall incidence of 0.45%. Of these 83 eyes with PC tears, 49% received vitrectomy. Fifty-one of 83 PC tears (61.4%) were amenable to be converted to PCCC. Of these 51 procedures, 50 eyes had PC IOL in-the-bag fixation. One eye had PCCC with optic capture. There were no eyes with dropped nuclei or nuclear fragments requiring pars plana vitrectomy. Seventeen eyes (20.5%) had Neuhann anterior capsule rhexis fixation with the haptics placed in the sulcus and IOL securely in the bag. Ten eyes (12.1%) had the IOL placed in the sulcus, and 5 eyes (6.0%) required anterior chamber IOL fixation. None of the 83 PC tears resulted in clinically evident cystoid macular edema, retinal detachment, or endophthalmitis.

CONCLUSIONS

With an intact CCC and with conversion of PC tears to PCCC, in-the-bag fixation of IOLs can be achieved in most eyes.

[Significance of the unbalanced expression of Th1/Th2 type cytokines in human glioma]

OBJECTIVE

To study the significance of the unbalanced expression of Th1/Th2 type cytokines in human glioma.

METHODS

The gene expressions of Th1/Th2 type cytokines in 62 specimens of human glioma tissues, 4 glioma cell lines, peripheral blood mononuclear cell (PBMC) of 15 glioma patients, 5 specimens of normal adult brain tissue and 5 brain meningioma tissues were detected by semiquantitative reverse transcription polymerase chain reaction. IFN-gamma and IL-2 represent Th1 type cytokines. IL-4, IL-6, IL-10 and IL-13 represent Th2 type cytokines.

RESULTS

There were obviously predominant expression of Th2 type cytokines in glioma cell lines (P < 0.01) and specimens of human glioma tissues (P < 0.01). The tendency of distinct expression of Th2 type cytokines in PBMC was also existent. There wasn't obvious discrepancy of the expression of two type cytokines in normal adult brain tissues and meningioma tissues.

CONCLUSIONS

It is likely that the switching of Th1/Th2 type cytokines in gliomas as predominant expression of Th2 type cytokine genes is related to the origination of gliomas and the evasion of glioma cells from immune surveillance.

Connectionist inference models

The performance of symbolic inference tasks has long been a challenge to connectionists. In this paper, we present an extended survey of this area. Existing connectionist inference systems are reviewed, with particular reference to how they perform variable binding and rule-based reasoning and whether they involve distributed or localist representations. The benefits and disadvantages of different representations and systems are outlined, and conclusions drawn regarding the capabilities of connectionist inference systems when compared with symbolic inference systems or when used for cognitive modelling.

[Influence of adjustment of balance of Th1/Th2 type cytokines on proliferation of glioma cells]

OBJECTIVE

To study the influence of adjustment of balance of Th1/Th2 by external cytokines on proliferation of glioma cells.

METHODS

The gene expressions of Th1/Th2 type cytokines in C6, 9L, U251 and SHG44 glioma cells were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). After the cells were induced with IFN-gamma + IL-4 McAb and IL-4 + IFN-gamma McAb respectively, we isolated the total RNA to proceed RT-PCR again. The evaluation of cell proliferation was proceeded by MTT assay method.

RESULTS

There was obviously predominant expression of Th2 type cytokines in glioma cell lines (P < 0.01). The expression intensity of IFN-gamma was improved in IFN-gamma + IL-4 McAb groups and Th2 type cytokines were enhanced in IL-4 + IFN-gamma McAb groups. IFN-gamma and IL-4 McAb could cause the switch from Th2 to Th1, and could remarkably inhibit the proliferation of glioma cells in a dose-dependent way (P < 0.01). On the other hand, IL-4 and IFN-gamma McAb could strengthen the switch of Th2, and might stimulate the glioma cell growth, also in a dose-dependent way (P < 0.01).

CONCLUSIONS

There is a Th2 preponderance in glioma cells. IFN-gamma and IL-4 McAb could regulate the switch from Th2 to Th0 or Th1, and inhibit the proliferation of glioma cells.

Bioactive aromatic compounds from leaves and stems of Vanilla fragrans

Alcoholic extracts of leaves and stems of Vanilla fragrans were fractionated with ethyl acetate and aqueous butanol. All three fractions of ethyl acetate, butanol, and water were screened for toxic bioactivity against mosquito larvae. The results of these experiments showed that the fractions from the ethyl acetate and butanol phases were both active in the bioassay. Bioactivity of the ethyl acetate fraction was found to be much greater than that from the butanol fraction in mosquito larvae toxicity. The water phase appeared to contain no substances that impaired mosquito larval growth. Repeated column chromatography of the ethyl acetate fraction on silica gel led to the isolation of 4-ethoxymethylphenol (1), 4-butoxymethylphenol (2), vanillin (3), 4-hydroxy-2-methoxycinnamaldehyde (4), and 3,4-dihydroxyphenylacetic acid (5). Compounds 4 and 5 were isolated from Vanilla species for the first time and 2 has not been reported to have been found in a natural form. 4-Ethoxymethylphenol (1) was the predominant compound, but 4-butoxymethylphenol (2) showed the strongest toxicity to mosquito larvae. The structures of the compounds were determined on the basis of their mass spectra and (1)H or (13)C NMR data.

Function of Rta is essential for lytic replication of murine gammaherpesvirus 68

Rta, encoded primarily by open reading frame 50, is well conserved among gammaherpesviruses. It has been shown that the Rta proteins of Epstein Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV, or HHV-8), and murine gammaherpesvirus 68 (MHV-68; also referred to as gamma HV68) play an important role in viral reactivation from latency. However, the role of Rta during productive de novo infection has not been characterized in gammaherpesviruses. Since there are cell lines that can support efficient productive de novo infection by MHV-68 but not EBV or KSHV, we examined whether MHV-68 Rta plays a role in initiating viral lytic replication in productively infected cells. Rta, functioning as a transcriptional activator, can activate the viral promoter of early lytic genes. The amino acid sequence alignments of the Rta homologues suggest that the organizations of their functional domains are similar, with the DNA binding and dimerization domains at the N terminus and the trans-activation domain at the C terminus. We constructed two mutants of MHV-68 Rta, Rd1 and Rd2, with deletions of 112 and 243 amino acids from the C terminus, respectively. Rd1 and Rd2 could no longer trans-activate the promoter of MHV-68 gene 57, consistent with the deletions of their trans-activation domains at the C terminus. Furthermore, Rd1 and Rd2 were able to function as dominant-negative mutants, inhibiting trans-activation of wild-type Rta. To study whether Rd1 and Rd2 blocked viral lytic replication, purified virion DNA was cotransfected with Rd1 or Rd2 into fibroblasts. Expression of viral lytic proteins was greatly suppressed, and the yield of infectious viruses was reduced up to 10(4)-fold. Stable cell lines constitutively expressing Rd2 were established and infected with MHV-68. Transcription of the immediate-early gene, rta, and the early gene, tk, of the virus was reduced in these cell lines. The presence of Rd2 also led to attenuation of viral lytic protein expression and virion production. The ability of Rta dominant-negative mutants to inhibit productive infection suggests that the trans-activation function of Rta is essential for MHV-68 lytic replication. We propose that a single viral protein, Rta, governs the initiation of MHV-68 lytic replication during both reactivation and productive de novo infection.

Cold adaptive thermogenesis in small mammals from different geographical zones of China

The mechanisms of thermogenesis and thermoregulation were studied in the tree shrew (Tupaia belangeri) and greater vole (Eothenomys miletus) of the subtropical region, and Brandt's vole (Microtus brandti), Mongolian gerbil (Meriones unguiculatus), Daurian ground squirrel (Spermophilus dauricus) and plateau pika (Ochotona curzoniae) of the northern temperate zone. Resting metabolic rate (RMR) and non-shivering thermogenesis (NST) increased significantly in T. belangeri, E. miletus, M. brandti and M. unguiculatus after cold acclimation (4 degrees C) for 4 weeks. In T. belangeri, the increase in RMR and thermogenesis at liver cellular level were responsible for enhancing the capacity of enduring cold stress, and homeothermia was simultaneously extended. Stable body temperature in M. brandti, E. miletus, M. unguiculatus and O. curzoniae was maintained mainly through increase in NST, brown adipose tissue (BAT) mass and its mitochondrial protein content, and the upregulation of uncoupling protein (UCP1) mRNA, as well as enhancement of the activity of cytochrome C oxidase, alpha-glycerophosphate oxidase and T(4) 5'-deiodinase in BAT mitochondria. The RMR in O. curzoniae and euthermic S. dauricus was not changed, while NST significantly increased during cold exposure; the former maintained their stable body temperature and mass, while body temperature in the latter declined by 4.8 degrees C. The serum T(3) concentration or ratio of T(3)/T(4) in all the species was enhanced after cold acclimation. Results indicated that: (1) the adaptive mechanisms of T. belangeri residing in the subtropical region to cold are primarily by increasing RMR and secondly by increasing NST, and the mechanisms of thermogenesis are similar to those in tropical mammals; (2) in small mammals residing in northern regions, the adaptation to cold is chiefly to increase NST; (3) the mechanism of cold-induced thermogenesis in E. miletus residing in subtropical and high mountain regions is similar to that in the north; (4) a low RMR in warm environments and peak RMR and NST in cold environments enabled M. unguiculatus to tolerate a semi-desert climate; (5) O. curzoniae has unusually high RMR and high NST, acting mainly via increasing NST to adapt to extreme cold of the Qinghai-Tibet Plateau; (6) the adaptation of euthermic S. dauricus to cold is due to an increase in NST and a relaxed homeothermia; and lastly (7) the thyroid hormone is involved in the regulation of cold adaptive thermogenesis in all the species studied.

Molecular cloning and characterization of chemokine-like factor 1 (CKLF1), a novel human cytokine with unique structure and potential chemotactic activity

Cytokines are small proteins that have an essential role in the immune and inflammatory responses. The repertoire of cytokines is becoming diverse and expanding. Here we report the identification and characterization of a novel cytokine designated as chemokine-like factor 1 (CKLF1). The full-length cDNA of CKLF1 is 530 bp long and a single open reading frame encoding 99 amino acid residues. CKLF1 bears no significant similarity to any other known cytokine in its amino acid sequence. Expression of CKLF1 can be partly inhibited by interleukin 10 in PHA-stimulated U937 cells. Recombinant CKLF1 is a potent chemoattractant for neutrophils, monocytes and lymphocytes; moreover, it can stimulate the proliferation of murine skeletal muscle cells. These results suggest that CKLF1 might have important roles in inflammation and in the regeneration of skeletal muscle.

Topical transfection using plasmid DNA in a water-in-oil nanoemulsion

Expression plasmids encoding chloramphenicol acetyltransferase (CAT) or human interferon-alpha2 cDNA were formulated in water-in-oil nanoemulsions and applied to murine skin. The histological location of transfected cells was assessed by in situ DNA PCR and showed that the deposition of plasmid DNA was primarily in follicular keratinocytes. Transgene expression in the skin was monitored for 24-72 h, following topical application of either single or multiple daily doses by quantitative RT-PCR and ELISA. It was found that transgene expression was optimal at 24 h following topical application of a single dose of water-in-oil nanoemulsion containing plasmid DNA. Dose-response studies using a total dose of 3, 10 or 30 microg of plasmid DNA suggested that topical transfection using nanoemulsions is subject to both threshold and saturation effects. None of the cationic liposome formulations tested as controls mediated transgenic protein expression at levels higher than background values of the ELISAs used to assay transgenic protein. Single and multiple dose experiments using human interferon-alpha2 as a transgene indicated that the efficiency of nanoemulsion mediated transfection was most effective in the context of normal versus atrophic hair follicles. In addition, the total amount of human interferon-alpha2 present in skin appeared to accumulate as a consequence of multiple dosing. Histologic evaluation of treated skin showed no overt signs of toxicity or irritation associated with the short-term application of the nanoemulsions. The results suggest that water-in-oil nanoemulsions can be used to facilitate transfection of follicular keratinocytes in vivo.

[Study of the cytotoxity against human hepatocellular carcinoma cells induced by the MAGE-1 gene modified dendritic cells]

OBJECTIVE

To genetically modify dendritic cells (DC) with a tumor associated antigen gene MAGE-1 and to observe in vitro the cytotoxic effect induced by this genetically modified DC against human hepatocellular carcinoma (HCC) cell line SMMC7721, thus giving a primary verification of the possibility of this genetically modified DC to induce specific antitumor immunity against HCC and serving as a new type of vaccine.

METHODS

The MAGE-1 gene was inserted into the retrovirus vector LXSN to construct the recombinant retrovirus LMSN. The monocyte-derived DCs were transfected by LMSN and control virus LXSN respectively as well as a third group was set up as non-transfected control. The MAGE-1 gene expression in LMSN transfected DC was identified by Western blot and the in vitro cytotoxities against SMMC7721 induced by three groups of DC were tested by MTT assay.

RESULTS

A recombinant retrovirus LMSN containing the tumor rejection antigen gene MAGE-1 was successfully constructed and the MAGE-1 gene expression in LMSN transfected human monocyte-derived DC was induced. The LMSN transfected DC could induce very high lytic activity against SMMC7721 in vitro with the lytic activity of 78.9%+/-3.6%. Nevertheless, the LXSN transfected DC and non-transfected DC only induced relatively lower lytic activity as 34.7%+/-4.3% and 3.9%+/-2.0%, respectively. The difference of the lytic activities between those three groups as statistically significant (P<0.01).

CONCLUSIONS

The MAGE-1 gene transfected DC can induce higher in vitro cytotoxicity against SMMC7721, suggesting the possibility of this genetically modified DC to induce specific antitumor activity and to serve as a new type of vaccine for HCC.

Macroscopic chirality of a liquid crystal from nonchiral molecules

The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment.

[Effects of interferon-alpha on recurrence and metastasis of hepatocellular carcinoma after curative resection in nude mice]

OBJECTIVE

To study the effect of interferon-alpha (IFN-alpha) on the recurrence and metastasis of hepatocellular carcinoma (HCC) in nude mice, and to clarify if there is synergistic effect treated by combination of IFN-alpha and all-trans retinoic acid (ATRA).

METHODS

The effect of IFN-alpha and/or ATRA on the proliferation of HCC cell lines was measured in vitro. The metastatic model of human HCC in nude mice LCI-D20 was used in present study. Curative resection was performed at 10th day after implantation in 44 nude mice. Drugs were given at the next day after resection. IFN-alpha was administered subcutaneously at doses of 3+/-10(5) U/day, 6+/-10(5) U/day, respectively. ATRA was administered p.o. at a dose of 20 mg/kg/day, and IFN-alpha 6+/-10(5)U/day combined with ATRA 20 mg/kg/day. The mice were sacrificed 35 days after treatment. The recurrent tumor size was measured and the presence of intrahepatic dissemination and lung metastases were recorded.

RESULTS

The effect of IFN-alpha and/or ATRA on the proliferation of HCC cells SMMC7721, BEL-7402, BEL-7405, and MHCC97 was not obvious. The combination of IFN-alpha and ATRA had no synergistic effect in vitro. The lung metastatic rate, the liver recurrent rate, the size of main recurrent lesions, the number of intrahepatic disseminating nodules and the largest disseminating nodule of the controlled group was 100%(12/12), 100%(12/12), (1346.3+/-4.2 ) mm(3), 8.2+/-4.4, 864 mm(3), respectively; whereas it was 0, 87.5%(7/8), (8.7+/-2.9) mm(3), 2.3+/-0.6, and 7.8mm(3), respectively in the IFN-alpha 3+/-10(5) U/day treated group(P<0.05); 0, 12.5%(1/8), 0.5mm(3), 2, 0.5 mm(3) in the IFN-alpha 6+/-10(5)U/day treated group(P<0.05); 0, 12.5%(1/8), 1 mm(3), 2.5+/-0.7, 8 mm(3) in the IFN-alpha 3+/-10(5) U/day and ATRA treated group(P<0.05); 87.5%, 100%, (1472.6+/-5.6) mm(3), 7.3+/-3.8, 768.5 mm(3) in the ATRA treated group (P>0.05).

CONCLUSIONS

IFN-alpha has an inhibitory effect on intrahepatic recurrence and lung metastasis of human HCC after curative resection in nude mice, and the effect is enhanced with increasing dose. IFN-alpha and ATRA have no synergistic effect according to in vivo and in vitro test. ATRA has no effect on recurrence and metastasis of HCC.

Performance characteristics of the COBAS AmpliScreen HIV-1 test, version 1.5, an assay designed for screening plasma mini-pools

BACKGROUND

The COBAS AmpliScreen HIV-1 test, version 1.5 (v1.5) (Roche Molecular Systems), is designed for screening pools composed of samples from 24 individual units of blood or plasma. A specimen-processing procedure (Multiprep) simultaneously concentrates and extracts HIV-1, HCV, and HBV particles from plasma and incorporates an HIV-1 internal control (IC) RNA. Processed samples are amplified by RT-PCR using HIV-1-specific primers and detected by hybridization of the amplified products to HIV-1- and IC-specific oligonucleotide probes.

STUDY DESIGN AND METHODS

Plasma samples containing known quantities of HIV-1 were used to evaluate analytical sensitivity and precision and to validate a pool testing algorithm. Analytical specificity was evaluated by adding various viruses and bacteria to HIV-1-negative plasma. Seroconversion panels were tested to estimate the window-period reduction achieved by RNA testing.

RESULTS

The analytical sensitivity of the test (concentration that yields > or = 95% positive results in a set of replicate tests) was 25 copies of HIV-1 RNA per mL of pooled plasma. Representative strains from all HIV-1 group M subtypes were reproducibly detected (> 95% positive results) at concentrations of 20 to 200 viral particles per mL. The test did not cross-react with a set of 31 viral and 5 bacterial isolates, and it yielded negative results on a panel of 500 blood samples from HIV-1-seronegative donors. Plasma samples containing abnormally high levels of Hb, albumin, triglycerides, or bilirubin did not interfere with the test. HIV-1 RNA was detected 2 to 14 days before HIV-1 antibody and 0 to 28 days before p24 antigen. The test specifically detected pools containing a single positive unit with 2400 HIV-1 RNA copies per mL and correctly identified the positive unit.

CONCLUSION

The COBAS AmpliScreen HIV-1 test, v1.5, has sufficient sensitivity to detect a single infected unit containing 600 copies of HIV-1 per mL in a pool with 23 uninfected units and should reduce the window period between infection and seroconversion by at least 2 to 14 days.

Uncoupling protein1 mRNA, mitochondrial GTP-binding, and T4 5'-deiodinase of brown adipose tissue in euthermic Daurian ground squirrel during cold exposure

Regulation of thermogenic activity and uncoupling protein1 (UCP1) expression in brown adipose tissue (BAT) were studied in euthermic Daurian ground squirrel after acute and chronic cold exposure at 4 degrees C. The UCP1 concentration was indirectly determined by titration with its specific ligand [3H]-labeled GTP, and Ucp1 mRNA was detected by using a [32P]-labeled antisense oligonucleotide probe. Both acute and chronic cold exposure stimulated up-regulation of Ucp1 mRNA. Although UCP1 concentration is not significantly increased after 24 h of cold exposure, it is markedly elevated by 75% in squirrels after 4-week cold adaptation compared with controls raised at 22 degrees C. Changes in T4 5'-deiodinase activity were closely associated with variations of Ucp1 mRNA level. Ucp1 gene expression is significantly affected by cold exposure in BAT from euthermic Daurian ground squirrels. In addition, the activation of T4 5'-deiodinase may be an important regulatory factor in cold-induced Ucp1 expression.

Accuracy and predictability of intraocular lens power calculation after laser in situ keratomileusis

PURPOSE

To study the accuracy and predictability of intraocular lens (IOL) power calculation in eyes that had laser in situ keratomileusis (LASIK).

SETTING

Gimbel Eye Centre, Calgary, Alberta, Canada.

METHODS

Refractive outcomes in 6 cataract surgery and lensectomy eyes after previous LASIK were analyzed retrospectively. Target refractions based on measured and refraction-derived keratometric values were compared with postoperative achieved refractions. Differences between target refractions calculated using 5 IOL formulas and 2 A-constants and achieved refractions were also compared.

RESULTS

The refractive error of IOL power calculation in postoperative LASIK eyes was significantly reduced when refraction-derived keratometric values were used for IOL power calculation. Persistent residual hyperopia still occurred in some cases; this was corrected by hyperopic LASIK. Refractive results appeared more accurate and predictable when the Holladay 2 or Binkhorst 2 formula was used for IOL power calculation.

CONCLUSION

Hyperopic error after cataract surgery in post-LASIK eyes was significantly reduced by using refraction-derived keratometric values for IOL power calculation. Persistent hyperopic error was corrected by hyperopic LASIK.