[The value of dynamic contrast-enhanced MRI in the differentiation between benign and malignant lacrimal epithelial tumors]

Objective: To investigate the diagnostic performance of multiparametric dynamic contrast-enhanced MRI(DCE-MRI) for the differentiation between benign and malignant larcrimal gland epithelial tumors. Methods: The clinical and imaging data of 104 patients with epithelial tumors of the lacrimal gland who underwent orbital MRI scan and met the inclusion criteria in Beijing Tongren Hospital from January 2011 to December 2017 were retrospectively collected, including 48 males and 56 females, aged from 12 to 77 (43±7) years. Sixty-three cases of benign epithelial tumors and 41 cases of malignant epithelial tumors were examined by DCE-MRI. The parameters of semiquantitative analysis including: time to peak enhancement (Tpeak), maximum enhancement ratio (ERmax), Slope, washout ratio (WR) and time-signal intensity curve (TIC) types. The parameters of quantitative analysis including: volume transfer constant (Ktrans), the extravascular extracellular volume fraction (Ve) and rate constant (Kep). Receiver operating characteristic (ROC) curve analysis was performed for DCE-MRI parameters with statistically significant differences, the area under the curve (AUC) was calculated, the diagnostic threshold was determined, and the diagnostic performance was evaluated. Logistic regression analysis was used to determine the best parameters for differential diagnosis of benign and malignant epithelial tumors of the lacrimal gland. Results: For the semiquantitative analysis of DCE-MRI, malignant lacrimal gland epithelial tumor had a significantly shorter Tpeak than benign masses [(103.77±57.87) s vs (187.80±77.01) s,P<0.001)], while had a higher value in ERmax, Slope [M(Q1,Q3)] and WR in malignant masses compared with benign one [1.55±0.39 vs 1.36±0.33; 1.76 (0.97,2.27) vs 0.62 (0.50,0.93); 7.70%(1.40%, 21.60%)% vs 0(0, 0),all P<0.05)].The TICs of benign lacrimal tumors mainly showed a persistent type (49/63),while most malignant lacrimal tumors mainly showed a plateau type (25/41). For the quantitative analysis of DCE-MRI, the values of Ktrans and Kep[M(Q1,Q3)] in malignant tumors were significantly greater than those of benign tumors (0.99±0.52/min vs 0.43±0.23/min, P<0.001; 1.33(0.83, 1.55)/min vs 0.55(0.46, 0.68)/min, P<0.001). No significant difference in Ve was found between the groups (0.76±0.20 vs 0.73±0.22,P=0.467). Through the statistical analysis, TIC types (OR=3.887,95%CI: 1.409-10.725) and Ktrans(OR=50.979,95%CI: 6.046-429.830) can provide superior diagnostic performance for predicting malignant lacrimal gland epithelial tumors, with a sensitivity of 78.05%, specificity of 77.78%,and sensitivity of 70.73%, specificity of 95.24%, respevtively. Furthermore, the comprehensive diagnostic performance of Ktrans in AUC was proven to be significantly better than that of TIC [0.875 (0.796-0.932) vs 0.798 (0.708-0.870),P=0.049]. Conclusions: Multiparametric DCE-MRI is helpful for the differential diagnosis of benign and malignant epithelial tumors of lacrimal gland. TIC type and Ktrans have higher diagnostic value, and the diagnostic performance of Ktrans is better than that of TIC.

The β-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 axis promotes adult T-cell lymphoblastic lymphoma progression and chemoresistance

BACKGROUND

High-intensity chemotherapy regimens are often used in adult T-cell lymphoblastic lymphoma (T-LBL) patients. Nevertheless, the response rate remains unsatisfactory due to emergence of chemoresistance. Growing evidence has shown that long non-coding RNAs (lncRNAs) are involved in tumor progression and chemoresistance. Herein, we investigated the potential role of lncRNAs in T-LBLs.

METHODS

RNAseq was used to screen and identify candidate lncRNAs associated with T-LBL progression and chemoresistance. Luciferase reporter assay was used to examine the binding of miR-371b-5p to the 3'UTR of Smad2 and LEF1, and the binding of TCF-4/LEF1 to the promoter of LINC00183. Chromatin immunoprecipitation assay was undertaken to analyze the connection between LEF1 and the LINC00183 promoter region. RNA immunoprecipitation assays were used to explore the mechanism whereby LINC00183 regulated miR-371b-5p. MTT and flow cytometry assays were used to measure apoptosis of T-LBL cells.

RESULTS

LINC00183 was upregulated in T-LBL progression and chemoresistant tissues in both the Sun Yat-sen University Cancer Center dataset and the First Affiliated Hospital of Anhui Medical University dataset. High expression of LINC00183 was correlated with poorer overall survival and progression-free survival of T-LBL patients compared to those with low expression of LINC00183. Furthermore, miR-371b-5p was negatively regulated by LINC00183. In vivo and in vitro assays showed that LINC00183-mediated T-LBL chemoresistance depended on miR-371b-5p expression. The direct binding of miR-371b-5p to Smad2 and LEF1 was verified by luciferase assays. It was shown that TCF4/LEF1 could bind to the LINC00183 promoter site and increase its transcript level. Downregulation of miR-371b-5p led to increased expression of Smad2/LEF1, and in turn increased LINC00183 expression. Additionally, phospho-Smad2 promotes nuclear translocation of β-catenin, LINC00183 downregulation decreased chemoresistance induced by β-catenin and TGF-β1 in T-LBL cells.

CONCLUSION

We unraveled a β-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 feedback loop that promotes T-LBL progression and chemoresistance, indicating that LINC00183 may serve as a potential therapeutic target in T-LBLs.

Measurement of the ^{18}O(α, γ)^{22}Ne Reaction Rate at JUNA and Its Impact on Probing the Origin of SiC Grains

The ^{18}O(α,γ)^{22}Ne reaction is critical for AGB star nucleosynthesis due to its connection to the abundances of several key isotopes, such as ^{21}Ne and ^{22}Ne. However, the ambiguous resonance energy and spin-parity of the dominant 470 keV resonance leads to substantial uncertainty in the ^{18}O(α,γ)^{22}Ne reaction rate for the temperature of interest. We have measured the resonance energies and strengths of the low-energy resonances in ^{18}O(α,γ)^{22}Ne at the Jinping Underground Nuclear Astrophysics experimental facility (JUNA) with improved precision. The key 470 keV resonance energy has been measured to be E_{α}=474.0±1.1  keV, with such high precision achieved for the first time. The spin-parity of this resonance state is determined to be 1^{-}, removing discrepancies in the resonance strengths in earlier studies. The results significantly improve the precision of the ^{18}O(α,γ)^{22}Ne reaction rates by up to about 10 times compared with the previous data at typical AGB temperatures of 0.1-0.3 GK. We demonstrate that such improvement leads to precise ^{21}Ne abundance predictions, with an impact on probing the origin of meteoritic stardust SiC grains from AGB stars.

Direct Measurement of the Astrophysical ^{19}F(p,αγ)^{16}O Reaction in the Deepest Operational Underground Laboratory

Fluorine is one of the most interesting elements in nuclear astrophysics, where the ^{19}F(p,α)^{16}O reaction is of crucial importance for Galactic ^{19}F abundances and CNO cycle loss in first generation Population III stars. As a day-one campaign at the Jinping Underground Nuclear Astrophysics experimental facility, we report direct measurements of the essential ^{19}F(p,αγ)^{16}O reaction channel. The γ-ray yields were measured over E_{c.m.}=72.4-344  keV, covering the Gamow window; our energy of 72.4 keV is unprecedentedly low, reported here for the first time. The experiment was performed under the extremely low cosmic-ray-induced background environment of the China JinPing Underground Laboratory, one of the deepest underground laboratories in the world. The present low-energy S factors deviate significantly from previous theoretical predictions, and the uncertainties are significantly reduced. The thermonuclear ^{19}F(p,αγ)^{16}O reaction rate has been determined directly at the relevant astrophysical energies.

Role of manganese superoxide dismutase (Mn-SOD) against Cr(III)-induced toxicity in bacteria

The toxicity of Cr(VI) was widely investigated, but the defense mechanism against Cr(III) in bacteria are seldom reported. Here, we found that Cr(III) inhibited bacterial growth and induced reactive oxygen species (ROS). After exposure to Cr(III), loss of sodA not only led to the excessive generation of ROS, but also enhanced the level of lipid peroxidation and reduced the GSH level, indicating that the deficiency of Mn-SOD decreased the bacterial resistance ability against Cr(III). The adverse effects of oxidative stress caused by Cr(III) could be recovered by the rescue of Mn-SOD in the sodA-deficient strain. Besides the oxidative stress, Cr(III) could cause the bacterial morphology variation, which was distinct between the wild-type and the sodA-deficient strains due to the differential expressions of Z-ring division genes. Moreover, Mn-SOD might prevent Cr(III) from oxidation on the bacterial surface by combining with Cr(III). Taken together, our results indicated that the Mn-SOD played a vital role in regulating the stress resistance, expression of cell division-related genes, bacterial morphology, and chemistry valence state of Cr. Our findings firstly provided a more in-depth understanding of Cr(III) toxicity and bacterial defense mechanism against Cr(III).

A gene-expression-based signature predicts survival in adults with T-cell lymphoblastic lymphoma: a multicenter study

We aimed to establish a discriminative gene-expression-based classifier to predict survival outcomes of T-cell lymphoblastic lymphoma (T-LBL) patients. After exploring global gene-expression profiles of progressive (n = 22) vs. progression-free (n = 28) T-LBL patients, 43 differentially expressed mRNAs were identified. Then an eleven-gene-based classifier was established using LASSO Cox regression based on NanoString quantification. In the training cohort (n = 169), high-risk patients stratified using the classifier had significantly lower progression-free survival (PFS: hazards ratio 4.123, 95% CI 2.565-6.628; p < 0.001), disease-free survival (DFS: HR 3.148, 95% CI 1.857-5.339; p < 0.001), and overall survival (OS: HR 3.790, 95% CI 2.237-6.423; p < 0.001) compared with low-risk patients. The prognostic accuracy of the classifier was validated in the internal testing (n = 84) and independent validation cohorts (n = 360). A prognostic nomogram consisting of five independent variables including the classifier, lactate dehydrogenase levels, ECOG-PS, central nervous system involvement, and NOTCH1/FBXW7 status showed significantly greater prognostic accuracy than each single variable alone. The addition of a five-miRNA-based signature further enhanced the accuracy of this nomogram. Furthermore, patients with a nomogram score ≥154.2 significantly benefited from the BFM protocol. In conclusion, our nomogram comprising the 11-gene-based classifier may make contributions to individual prognosis prediction and treatment decision-making.

A CpG Methylation Classifier to Predict Relapse in Adults with T-Cell Lymphoblastic Lymphoma

PURPOSE

Adults with T-cell lymphoblastic lymphoma (T-LBL) generally benefit from treatment with acute lymphoblastic leukemia (ALL)-like regimens, but approximately 40% will relapse after such treatment. We evaluated the value of CpG methylation in predicting relapse for adults with T-LBL treated with ALL-like regimens.

EXPERIMENTAL DESIGN

A total of 549 adults with T-LBL from 27 medical centers were included in the analysis. Using the Illumina Methylation 850K Beadchip, 44 relapse-related CpGs were identified from 49 T-LBL samples by two algorithms: least absolute shrinkage and selector operation (LASSO) and support vector machine-recursive feature elimination (SVM-RFE). We built a four-CpG classifier using LASSO Cox regression based on association between the methylation level of CpGs and relapse-free survival in the training cohort (n = 160). The four-CpG classifier was validated in the internal testing cohort (n = 68) and independent validation cohort (n = 321).

RESULTS

The four-CpG-based classifier discriminated patients with T-LBL at high risk of relapse in the training cohort from those at low risk (P < 0.001). This classifier also showed good predictive value in the internal testing cohort (P < 0.001) and the independent validation cohort (P < 0.001). A nomogram incorporating five independent prognostic factors including the CpG-based classifier, lactate dehydrogenase levels, Eastern Cooperative Oncology Group performance status, central nervous system involvement, and NOTCH1/FBXW7 status showed a significantly higher predictive accuracy than each single variable. Stratification into different subgroups by the nomogram helped identify the subset of patients who most benefited from more intensive chemotherapy and/or sequential hematopoietic stem cell transplantation.

CONCLUSIONS

Our four-CpG-based classifier could predict disease relapse in patients with T-LBL, and could be used to guide treatment decision.

Impact of water quality on the microbial diversity in the surface water along the Three Gorge Reservoir (TGR), China

The Three Gorges Reservoir (TGR), one of the world's largest reservoirs, has crucial roles in flood control, power generation, and navigation. The TGR is contaminated because of the human activities, and how the contaminated water influences the distribution of the microbial community have not been well studied. In this study, we collected 41 freshwater samples from 13 main dwelling districts along the TGR to investigate the water quality, the distribution of the microbial community, and how water quality affects the microbial community structure. The sampling sites cover the whole TGR along the stream, with 670 km distance. Our results show that both water quality and the compositions of bacterial community vary along the TGR. The distribution of bacterial community is closely related to the local water quality. There is the highest concentration of chemical oxygen demand (COD), the highest relative abundance of Firmicutes, and the highest relative abundance of Bacillus in the upstream, compared to the middle and down streams. Redundancy analysis (RDA) showed that PO₄^3- and COD were the main environmental factors influencing on the structure of bacterial community. The relative abundance of nitrification and denitrification functional genes also altered along the streams. These findings provide the basic data for water quality, the distribution of bacterial community, the link of environmental factors, and the bacterial community structure along the TGR, which guides the local environmental protection agency to launch protection strategy for maintaining the ecosystem health of the TGR.

[Outline of Song's works on the gynecology of traditional Chinese medicine]

Because of long history and excellent medical skills, the Song gynecology is regarded as one of the "four great masters" of the gynecology in Zhejiang province. The monographs survived of Song gynecology are at least four, besides the earliest one Songshi Nüke Cuoyao(, Synopsis of Song's Gynecology)(1612), there is Songshi Bochuan Chanke Quanshu(, Complete Treatise on Gynecology of Song Bochuan), Songshi Nüke Chanhou Pian(, Chapter of Puerperal Disease from Song's Gynecology), which are formed in Qing dynasty, and Linzheng Lu(, Clinical Records) formed in the Republic of China era.And Jingli Songshi Nüke(, Meticulously Sort Out Song's Gynecology), which might belong to School of Song's gynecology, and Nüke Milu(, Secretive Records of Gynecology) were found in records. This paper excavates and sorts these 6 Song's gynecological monographs, carries out in-depth research on the changes of editions, spread and origins, and clarify the general situation of song's gynecological monographs.

A facile solid-phase synthesis of Baylis–Hillman products from polymeric selenium reagents

Treatment of lithio derivatives of polystyrene-supported methyl α-selenopropionate, 2-selenopropiophenone, 1-selenoethyl phenyl sulfone and diethyl 1-selenoethylphosphonate with aldehydes respectively, followed by cleavage from the polymer by oxidation-elimination with 30% hydrogen peroxide efficiently afforded Baylis–Hillman products in good yields and high purities.

[Value of the apparent diffusion coefficient in diffusion weighted imaging at 3.0T MR for differentiating lacrimal gland tumors]

Objective: To investigate the diagnostic value of apparent diffusion coefficient in diffusion weighted imaging at 3.0 T MR for the differentiation in the larcrimal gland tumors. Methods: A total of 73 cases, 36 males and 37 female; mean age 14-81(44±15)years, with lacrimal gland tumors confirmed by pathology in Beijing Tongren Hospital were retrospectively analyzed between January 2011 and April 2016.All cases underwent the preoperative routine MRI and DWI scan, the ADC values were measured in region of interest within the solid zone. The cases were divided into benign and malignant group by the histopathology, according the different pathological categories, the malignant cases were further divided into the epithelial and non-epithelial malignacy. The receiver operating characteristic curve (ROC) was constructed using various cut points of ADC for different parameters to confirm the diagnostic threshold value and evaluate the diagnostic efficacy. Results: There were totally 77 lesions in 73 cases, of which 69 involved unilateral lacrimal gland,4 bilateral lacrimal glands. The mean ADC value of malignant and benign masses in lacrimal gland was (1.36±0.16) and (0.90±0.30)×10(-3) mm(2)/s respectively. There was significantly statistical difference between the both(t=-8.319, P<0.01). The mean ADC value of epithelial and non-epithelial malignacy in lacrimal gland was (1.08±0.18) and (0.54±0.09)×10(-3) mm(2)/s respectively. There was significantly statistical difference between the both(t=11.988, P<0.01). The area under the ROC for distinguishing malignant from benign lesions was 0.940. Using an ADC value of 1.275×10(-3) mm(2)/s as the threshold value, the best result obtained had a sensitivity of 94.4%(34/36), specificity of 82.9%(34/41), accuracy of 88.3%(68/77). The area under the ROC for differentiating non-epithelial from epithelial malignacy was 1.0. Using an ADC value of 0.736×10(-3) mm(2)/s as the threshold value, the best result obtained had a sensitivity of 100%, specificity of 100%, accuracy of 100%. Conclusion: The ADC value is helpful in differentiation among different kinds of tumors in lacrimal masses.

[Limonoids from seeds of Azadirachta indica and their cytotoxic activity]

Eight limonoids were isolated from 95% ethanol extracts of neem(Azadirachta indica) seeds by various chromatographic methods. By comparison of their spectroscopic data with those reported in the literatures, these limonoids were determined as salannin(1), 1-detigloyl-1-isobutylsalannin(2), salannol-3-acetate(3), salannol(4), spirosendan(5), 1-detigloyloxy-3-deacetylsalannin-1-en-3-one(6), nimbin(7) and 6-deacetylnimbin(8). Compounds 2 and 5 were firstly isolated from this genus and 5 represented the only example of its type. And 6 is a new natural product. 6 showed inhibitory activity against HeLa and HL-60 cells, with IC₅₀ of(21.61±4.37) and(27.33±5.74) μmol·L⁻¹, respectively. Both 7 and 8 mildly inhibited the growth of HeLa cells, with IC₅₀ of (33.15±5.24) and (38.56±6.41) μmol·L⁻¹, respectively.

[Chemical constituents from Pteris dispar and their anti-tumor activity in vitro]

The dried whole plant of Pteris dispar were milled and extracted with 95% EtOH. The resulting dried extract was isolated by kinds of chromatographic column, including polyamide, Sephadex LH-20, preparative HPLC. As a result, ten diterpenes were isolated from the plant. By analyzing of ESI-MS and NMR spectroscopic data, the structures were established as geopyxin B(1), geopyxin E(2), ent-11α-hydroxy-18-acetoxykaur-16-ene(3), ent-14β-hydroxy-18-acetoxykaur-16-ene(4), neolaxiflorin L(5), ent-3β,19-dihydroxy-kaur-16-ene(6), ent-3β-hydroxy-kaur-16-ene(7), 7β,17-dihydroxy-16α-ent-kauran-19-oic acid 19-O-β-D-glucopyranoside ester(8), crotonkinin C(9)and crotonkinin C(10). Compounds 1-10 were obtained from P. dispar for the first time. Compounds 1 and 2 showed moderate activities against Bel-7402 with IC₅₀ values of 7.50 and 10.60 μmol•L⁻¹, and against HepG2 with IC₅₀ values of 6.68,11.80 μmol•L⁻¹, respectively.

[Nitrification and Denitrification Rates in a Small Tributary, Nanhe River, of Three Gorge Dam Reservoir During Water Collection and Release Events]

Three Gorge Dam Reservoir (TGDR) is a new forming ecosystem and its sediments dynamics remains unknown. Investigation on the nitrification and denitrification dynamics of sediments of TGDR during water collection and release events-anti-seasonal actions-is critical for nitrogen management in TGDR. In this study, we sampled sediments in three locations (upstream, center, and downstream along water flow) of South River, located in a typical small tributary, Nanhe, in TGDR during 2015 water collection and release events to characterize its physiochemical property and determine its nitrification and denitrification rates using acetylene inhabitation method. The results showed that the concentrations of physiochemical parameters of sediments (total carbon, total nitrogen, nitrate, and ammonia) were significantly higher (P<0.05) in water collection event than those in water release event, suggesting there were external materials (e. g., soil) entering into TGDR. Furthermore, the nitrification rate of sediments in water collection event[194.06 μmol·(m²·h)^-1] was significantly higher than that in water release event[16.52 μmol·(m²·h)^-1]. Sediments nitrification rate was positively correlated to the physiochemical parameters. In contract, the denitrification rate of sediments was higher in water release event[647.20 μmol·(m²·h)^-1] than that in water collection event[24.04 μmol·(m²·h)^-1). Accordingly, the denitrification rate of sediments was negatively correlated to the physiochemical parameters.

[Bioactive lignans from Silybum marianum]

The seeds of Silybum marianum were extracted by hot water, and the extract was isolated by D101 macroporous resin, MCI resin, MPLC, HPLC, et al. As a result, 7 compounds including tricin 4'-O-[threo-β-guaiacyl-(7″-O-methyl)-glyceryl] ether(1), tricin 4'-O-[erythro-β-guaiacyl-(7″-O-methyl)-glyceryl] ether(2), 5'-methoxyhydnocarpin-D(3),palstatin(4),(8R,7'S,8'R)-5,5'-dimethoxy-7-oxolariciresinol 9'-O-D-xylopyranoside(5), 9-O-D-glucopyranoside(6), and(-)-haplomyrtoside(7) were isolated and identified for the first time. Compounds 1, 3, 4, and 5 exhibited activity against influenza A(H5N1)with IC₅₀ value of 0.65, 0.21, 0.32, and 0.56 μmol•L⁻¹, respectively. Compounds 1, 2, 6, and 7 exhibited cytotoxity against HepG-2 with IC₅₀ value of 0.35, 0.25, 0.53, 0.66 μmol•L⁻¹, respectively.

[Clinical outcomes of early repair for open orbital fracture]

OBJECTIVE

To investigate the clinical outcomes following early repair for orbital fracture and soft tissue simultaneously for open orbital fractures.

METHODS

Retrospective clinical study. This study comprised of 19 patients(20 eyes) with open orbital fracture who underwent surgery within 48 hours in the Second Hospital of Dalian Medical University between August 2011 and August 2014. The wounds were evaluated at the same time and the surgical debridement was done. The surgical exposure was achieved through direct approach and auxiliary cosmetic incisions. Titanium mesh and plate was used for orbital reconstruction. Local flaps or island flaps were used for soft tissue repair. With the post-operative CT scan, the condition of the soft tissue which was herniated, the orbital rim and orbital wall were observed. The measurement of the exophthalmos of both eyes was performed using Hertel exophthalmometer. Compared with the intact eye, the globe displacement (upward or downward) of the reconstructed eye was measured. The follow up duration was 12-24 months. The eye movement, diplopia, restriction of mouth opening, depression of midface, the condition of soft tissue and scar as well as post-operative complications were recorded. Comparison of the reconstructed eye's globe displacement before and after operation were analyzed with wilcoxon signed ranks test. Comparison of the exophthalmos of the reconstructed eye relative to the intact eye were analyzed with t-paired test.

RESULTS

In all 19 cases (20 eyes), fractures were anatomically reconstructed, and no cases of infection, titanium mesh and plate migration and rejection occured during the follow-up. Seven cases had eyeball hypoglobus with median 3.0 mm (min 2.0 mm, max 4.0 mm) pre-operatively. The Reconstructed eye globe were corrected in 6 cases and 1 case had residual hypoglobus of 1.0 mm ,median 0.0 mm (min 0.0 mm, max 1.0 mm). The amount of the eye globe displacement between pre-and post-operation was statistically significant(z=-2.40, P<0.05). Enophthalmos was corrected in 16 cases (the mean of posterior globe displacement in reconstructed orbit relative to intact orbit was less than or equal to 2.0mm), but in 2 patients the residual enophthalmos was 3.0 mm. The difference of the exophthalmos of both eyes was not obvious (t=-0.46,P>0.05). Among 20 eyes, 16 patients had restrictive eye movement. After 12 months follow-up, 13 eyes with restrictive eye movement were corrected while the other 3 showed improvement. Eight patients of restriction of mouth opening or midface depression were corrected and no infection complications were noted. There was no flap necrosis in 13 patients of soft tissue defect.

CONCLUSION

Surgical treatment of open orbital fractures with simultaneous repair of orbital fracture and soft tissue within 48 hours after trauma could correct enophthalmos, hypoglobus and eye movement function effectively and improve periorbital aesthetics. (Chin J Ophthalmol, 2016, 52: 273-277).

Production and characterization of high efficiency bioflocculant isolated from Klebsiella sp. ZZ-3

In this study, a new bioflocculant (ZZ-3) is isolated and evaluated. This novel flocculant was derived Klebsiella, which was identified by 16S rDNA sequencing as well as biochemical and physiological analyses. The composition of ZZ-3 was found to be 84.6% polysaccharides and 6.1% protein. More specifically, the amount (moles) of the polysaccharides rhamnose, mannose, and galactose were found to be 6.48, 2.47, and 1.74 greater than glucose, respectively. Results show ZZ-3 has a relatively high molecular weight (603-1820 kDa) and contains many functional groups (hydroxyl, amide, carboxyl, and methoxyl) that likely contribute to flocculation. The results of microscopic observation, zeta potential measurements, and ZZ-3 bioflocculant structure suggested that bridging was the main mechanism for flocculation with kaolin. Based on a high flocculation efficiency, thermal stability, pH tolerance and the ability to flocculate without additional cations, ZZ-3 shows potential for industrial application.

Investigation of microbial community structure of a shallow lake after one season copper sulfate algaecide treatment

In present work we described, for the first time, the phylogenic structure of the microbial community in a shallow freshwater lake (Hawk Island Lake, located in the Lower Peninsula of the State of Michigan, U.S.A.) after one season (four times during May to August 2007) of CuSO₄ treatment for algae growth control. The microbial community structure was characterized by terminal restriction fragment length polymorphism (TRFLP), clone library and 454 pyrosequencing. The similar structure of water chemistry measured across three sampling sites suggested that the lake was well mixed. The concentration of chlorophyll a (chl-a) and turbidity was low, 3.35 ± 1.62 μg/L and 2.5 ± 1.9 NTU, respectively, implying that photosynthesis was suppressed. TRFLP profiles showed that the lake was dominated by 16 terminal fragments (TFs), accounting for 85.5-92.6% abundance. Analysis of similarity (ANOSIM) showed that the difference in microbial community structure between upper and lower depths of the water column was not significant (P=0.101). These results suggested that the microbial community structure within the lake was similar. Clone library and 454 pyrosequencing indicated that the lake was dominated by freshwater phyla, Proteobacteria, Bacteroides, and Actinobacteria. Moreover, the large number of unclassified bacteria (27.4% of total 2090,454 sequences) suggested a complex microbial community structure in the lake.

Isolation and purification of two antioxidant peptides from alcalase hydrolysate of Arca subcrenata

OBJECTIVE

To investigate the constituents with antioxidant activities from alcalase hydrolysate of Arca subcrenata.

METHODS

The consecutive chromatographic methods were employed,including ion-exchange chromatography, gel filtration chromatography, and reverse phase high-performance liquid chromatography (RP-HPLC). The amino acid sequences of the purified antioxidant peptides were determined by automated Edman degradation.

RESULTS

Under the guidance of the assay of scavenging free radicals, two peptides with antioxidant activities, termed as A-Bg1 and A-Bh, were isolated and purified from the alcalase hydrolysate of Arca subcrenata.

CONCLUSION

Constituents from the hydrolysate of Arca subcrenata might be a new potential resource of antioxidants.

[Advances in molecular mechanism of bacterial reduction of hexavalent chromium]

Cr(VI) has been causing serious environmental pollution due to its carcinogenicity, teratogenicity and strong migration. Reduction of Cr( VI) to Cr(III), a precipitation that is much less toxic, is an efficient strategy to control Cr pollution. Within the strategy, bacterial reduction of Cr(VI) to Cr(III) has been considered as one of the best bioremediation methods because of its efficiency, environment friendly, and low cost; however, the molecular mechanism remains large unknown. This review summarizes Cr(VI) reduction bacterial species and its application in pollution control, elaborates the pathways of Cr( VI) reduction and functional proteins involved, concludes the molecular mechanism of baterial reduction Cr(VI), and discusses the orientation of the future research.

[Normative research on bacteriostasis and relieving itching external therapeutic function of kochiae fructus]

OBJECTIVE

To normalize bacteriostasis and relieving itching external therapeutic function of Kochiae Fructus.

METHODS

Itching guinea pig model caused by histamine, itching mice model, eczema guinea pig model caused by OVA, and inhibitory effect on pathogens in vitro were used to observe the itching threshold, symptoms and other related physiological index, as well as the inhibitory effect on the normal skin fungi by water extraction of Kochiae Fructus to evaluate the external therapeutic function of Kochiae Fructus.

RESULTS

The itching threshold of guinea pig itching model treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly increased when compared with negative control group (P < 0.05 or P < 0.01); Red speckle of OVA guinea pig model treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly decreased when compared with negative control group (P < 0.05 or P < 0.01); The number of itching and total time of itching within 30 minutes of mice model caused by R-glycose anhydride treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly decreased when compared with negative control group (P < 0.05 or P < 0.01); Several common skin fungi could be significantly inhibited by the water extraction of Kochiae Fructus. MIC of the water extraction of Kochiae Fructus on Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis, Trichophyton violaceum, and Trichophyton schoenleini were 3.12%, 0.78%, 0.78%, 0.78%, 0.78%, respectively.

CONCLUSION

Kochiae fructus has the effect of bacteriostasis and relieving itching.

Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.

Structure characterization and antioxidant activity of a novel polysaccharide isolated from pulp tissues of Litchi chinensis

A novel polysaccharide (LCP50S-2) with antioxidant activity was isolated from Litchi chinensis Sonn. The structure of LCP50S-2 was elucidated on the basis of physicochemical and instrumental analyses, and its average molecular weight was determined by gel permeation chromatography to be 2.19 × 10(2) kDa. The backbone of LCP50S-2 was composed of (1→3)-linked β-L-rhamnopyranosyl residues, (1→4)-linked α-D-xylopyranosyl residues, (1→4)-linked β-D-glucopyranosyl residues, and (1→4)-linked α-D-glucopyranosyl residues which branched at O-6. The two branches consisted of α-L-arabinopyranosyl residues and (1→6)-linked β-D-galactopyranosyl residues terminated with α-L-arabinopyranosyl residues, respectively. In the in vitro antioxidant assay, LCP50S-2 was found to possess DPPH radical-scavenging activity and hydroxyl radical-scavenging activity with IC(50) values of 220 and 266 μg/mL, respectively.

Chemotherapeutic effects of bioassay-guided extracts of the American cockroach, Periplaneta americana

The organic extract of Periplaneta americana L. (Dictyoptera; Blattidae) has been traditionally used in southwestern China as an alternative medicine against disorders such as hepatitis, trauma, gastric ulcers, burns, and heart disease. The present study describes bioassay-guided purification and chemotherapeutic evaluation of the 60% ethanolic fraction of P americana organic extracts (PAE60). The most effective cytotoxic fraction was determined by way of repeated in vitro screenings against 12 distinct cultured human carcinoma cell lines: Eca 109, BGC823, HO8910, LS174T, CNE, HeLa, K562, PC-3, A549, BEL 7404, HL-60, and KB, followed by in vivo antitumor assays of the lead fraction (PAE60). The complexity of enriched active fraction was qualitatively evaluated using thin layer chromatography. Reconstituted PAE60 was effective at inhibiting HL-60, KB, CNE, and BGC823 cell growth with IC(50) values <20 µg mL-(1). PAE60 reduced tumor growth in S180-bearing immunocompetent mice by 72.62% after 10 days following oral doses of 500 mg kg d-(1) compared with 78.75% inhibition following 40 mg kg d-(1) of cyclophosphamide (CTX). Thymus and spleen indices of S180-bearing mice treated with PAE60 were significantly greater (P < .05) than CTX treatment groups, suggesting potential immunomodulation of antitumor host defenses by PAE60. Antiviral activity was also investigated and PAE60 inhibited herpes simplex type-2 replication (IC(50) = 4.11 ± 0.64 µg mL-(1)) with a selectivity index (CC(50) to IC(50) ratio) of 64.84 in Vero cells but was less effective on type-1 virus (IC(50) of 25.6 ± 3.16 µg mL-(1)). These results support future clinical trials on P. americana as an alternative or complementary medicinal agent.

[Review on investigations related to chemical constituents and biological activities of Periplaneta americana]

With the fast development of medicinal animals as new drugs, research on Periplaneta americana become hot recently. Several drugs which mainly consisted of P. americana were approved for clinical applications. The chemical constituents and pharmacological bioactivities of this insect were summarized herein, which provides informativon for further researches on this medicinal animal.

The performance and application of fly ash modified by PDMDAAC

Fly ash modification by polydimethydiallylammonium chloride (PDMDAAC) in laboratory scale was explored in this work and the adsorption performance of modified fly ash and its application in dyeing wastewater treatment were also studied. The key factors (concentration and temperature) for PDMDAAC to affect the adsorption properties of fly ash (FA) were revealed using the orthogonal test with four factors. The results indicated that the adsorption magnitude of fly ash to PDMDAAC increased due to its favorable specific surface causing the change of the surface charge nature. Hence, adsorption performance of modified fly ash on organic molecules and its ion exchange capacity are strengthened. The maximum color removal efficiency was obtained as 88.2% by modified fly ash with 2.0 g/100 mL dosage in dyeing wastewater, which is much higher than 12.5% color removal efficiency by raw fly ash with the same dosage. And, the used modified fly ash could be used for cement production as additive agent. The intensity of cement produced with 15% the modified fly ash in weight reached the Chinese Cement Standard (GB/T17671-1999), blazing a promising novel way in fly ash utilization.

Symbiosis of Mycoplasma hominis in Trichomonas vaginalis may link metronidazole resistance in vitro

Fourteen of 28 Trichomonas vaginalis isolates collected from patients in Guangzhou, China from 2003 to 2004 were found to be naturally infected with Mycoplasma hominis, as determined by PCR using specific primers. In vitro metronidazole sensitivity assay of the 28 isolates revealed four displaying low susceptibility [minimum lethal concentration (MLC)= approximately 13-25 microg/ml] and another four displaying high resistance (MLC=50-100 microg/ml). The overwhelming majority of these resistant isolates (7/8) were mycoplasma-infected. The mean of MLCs of mycoplasma-infected isolates is approximately 10-fold higher than the mean of noninfected isolates (p=0.029). Sequence analyses of PCR-amplified small subunit-large subunit rRNA interspacer regions (ITS1/5.8S/ITS2) revealed that 23 of the 28 samples are identical, the remaining five being separable into two groups, each with a single point mutation. These internal transcribed spacer sequence variants are associated neither with mycoplasma infection nor with drug resistance. In contrast, random amplified polymorphic DNA analyses of DNAs using 10 different primers showed that the drug-resistant isolates are clustered together in association with mycoplasma infection, albeit more loosely. Taken together, the results obtained from this study suggest that in vitro metronidazole resistance of T. vaginalis is related to mycoplasma infection of this protozoan.

Characterization of the inhibitory effect of PEG-lipid conjugates on the intracellular delivery of plasmid and antisense DNA mediated by cationic lipid liposomes

Poly(ethylene glycol)-lipid (PEG-lipid) conjugates are widely used in the field of liposomal drug delivery to provide a polymer coat that can confer favorable pharmacokinetic characteristics on particles in the circulation. More recently these lipids have been employed as an essential component in the self-assembly of cationic and neutral lipids with polynucleic acids to form small, stable lipid/DNA complexes that exhibit long circulation times in vivo and accumulate at sites of disease. However, the presence of a steric barrier lipid might be expected to inhibit the transfection activity of lipid/DNA complexes by reducing particle-membrane contact. In this study we examine what effect varying the size of the hydrophobic anchor and hydrophilic head group of PEG-lipids has on both gene and antisense delivery into cells in culture. Lipid/DNA complexes were made using unilamellar vesicles composed of 5 mole% PEG-lipids in combination with equimolar dioleoylphosphatidylethanolamine and the cationic lipid dioleyldimethylammonium chloride. Using HeLa and HepG2 cells we show that under the conditions employed PEG-lipids had a minimal effect on the binding and subsequent endocytosis of lipid/DNA complexes but they severely inhibited active gene transfer and the endosomal release of antisense oligodeoxynucleotides into the cytoplasm. Decreasing the size of the hydrophobic anchor or the size of the grafted hydrophilic PEG moiety enhanced DNA transfer by the complexes.

Effect of combination therapy including protease inhibitors on mortality among children and adolescents infected with HIV-1

BACKGROUND

Combination therapy including protease inhibitors has been shown to be effective in treating adults infected with human immunodeficiency virus type 1 (HIV-1), but there are only limited data regarding the treatment of children and adolescents.

METHODS

A cohort of 1028 HIV-1-infected children and adolescents, from birth through 20 years of age, who were enrolled in research clinics in the United States before 1996 was followed prospectively through 1999. We used proportional-hazards regression models to estimate the effect on mortality of combination therapy including protease inhibitors.

RESULTS

Seven percent of the subjects were receiving combination therapy including protease inhibitors in 1996; by 1999, 73 percent were receiving such therapy. In univariate analyses, a higher base-line percentage of lymphocytes that were CD4-positive, a higher weight for age, a higher height for age, black race, Hispanic ethnic background, younger age, and perinatally acquired infection were associated with a longer median time to the initiation of this type of therapy (P<0.001). After adjustment for covariates, the differences among racial and ethnic groups in the time to initiation were not statistically significant. Mortality declined from 5.3 percent in 1996 to 2.1 percent in 1997, 0.9 percent in 1998, and 0.7 percent in 1999 (P for trend <0.001). There were reductions in mortality in all subgroups defined according to age, sex, percentage of CD4+ lymphocytes, educational level of the parent or guardian, and race or ethnic background. In adjusted analyses, the initiation of combination therapy including protease inhibitors was independently associated with reduced mortality (hazard ratio for death, 0.33; 95 percent confidence interval, 0.19 to 0.58; P<0.001).

CONCLUSIONS

The use of combination therapy including protease inhibitors has markedly reduced mortality among children and adolescents infected with HIV-1.

The social functioning of persons with chronic mental illness: an empirical typology of consumers and correlates of social functioning

This study examined the typology of consumers and correlates of their social functioning using the Social Functioning Scale (SFS). Data were obtained from 244 outpatients of two psychiatric hospitals and psychiatric ward inpatients in two general hospitals through a structured in-person interview. The typology was generated using Cluster Analysis, and the profile of each group was further examined. The results indicated that there were four distinct groups of consumers. Multiple regression analysis revealed that consumers' sex, age, education, diagnosis, behavioral problems, family caregivers' age, employment status, and overall social support were significantly associated with consumers' social functioning. The implications for previous research findings and psychiatric rehabilitation service are discussed.

Violence exposure and emotional trauma as contributors to adolescents' violent behaviors

OBJECTIVE

To investigate the degree to which violence exposure and symptoms of psychological trauma are related to adolescents' own violent behaviors.

DESIGN AND SETTING

Anonymous self-report questionnaire administered to students in 6 public high schools (grades 9-12).

PARTICIPANTS

Sixty-eight percent of the students attending the participating schools during the survey participated in the study (N=3735). Ages ranged from 14 to 19 years; 52% were female; and 35% were African American, 33% white, and 23% Hispanic.

RESULTS

Multiple regression analysis determined that violence exposure and symptoms of psychological trauma together explained more than 50% of the variance in both male and female self-reported violent behavior. The independent effects of exposure to violence explained about one quarter of the variance in both male and female adolescents' violent behaviors. Anger was found to be the leading trauma symptom.

CONCLUSION

Our findings suggest that health clinicians and other professionals who encounter adolescents should routinely screen them for both exposure to violence and symptoms of anger.

Functional binding between Gbeta and the LIM domain of Ste5 is required to activate the MEKK Ste11

BACKGROUND

In the budding yeast Saccharomyces cerevisiae, the pheromones that induce haploid cells of opposite cell types to mate activate the Gbeta and Ggamma subunits of a heterotrimeric G protein. These subunits signal through the PAK kinase Ste20 to activate a mitogen-activated protein (MAP) kinase cascade comprising the MEKK Ste11, the MEK Ste7 and two MAP kinases, Fus3 and Kss1. The pathway requires Ste5, a scaffold protein that tethers the MAP kinase cascade enzymes into a high molecular weight complex. Ste5 is thought to associate with Gbeta in a pheromone-independent manner, but it is not known if this interaction affects signaling.

RESULTS

A ste5C180A mutant - which expresses Ste5 disrupted in the LIM domain, a putative metal-binding motif that has been proposed to be essential for Ste5 oligomerization - could not transmit the pheromone signal from Gbeta through Ste20 to Ste11. The Ste5C180A protein was impaired in binding Gbeta, although it could oligomerize, bind Ste11, Ste7 and Fus3, facilitate the basal activation of Ste11, and relay the Ste11 signal to MAP kinases. Ste5 bound to Gbeta in a pheromone-dependent manner and preferentially associated with a phosphorylated form of Gbeta in wild-type and ste20Delta, but not in ste5C180A, strains.

CONCLUSIONS

Pheromone induces binding of Gbeta to Ste5 through its LIM domain. This binding is essential for activation of Ste11 and is distinct from the ability of Ste5 to oligomerize or to serve as a scaffold and relay the signal from Ste11 to the MAP kinases. Pheromone also induces Ste5-dependent phosphorylation of Gbeta.

Low initial tau phosphorylation in human brain biopsy samples

A rapid reversible tau phosphorylation at Ser 396/404 was observed in adult human cortical biopsy tissue and rat primary cortical cell cultures. Tau phosphorylation increased usually during the first 20-30 min in phosphate-buffered saline, followed by a decrease. The time course of tau phosphorylation and dephosphorylation in biopsy tissue could be lengthened by culturing in defined, oxygenated medium, instead of in phosphate-buffered saline. Phosphorylation of total protein in biopsy tissue occurred in two phases, with peaks at 30 and 90 min. The first peak of total protein phosphorylation coincided with the peak of tau phosphorylation, although both the first and second peaks of total protein phosphorylation coincided with the first and second peaks of neurofilament-H phosphorylation.

Predictors of depressive symptomatology among lower social class caregivers of persons with chronic mental illness

This study examined the predictors of depressive symptomatology among caregivers of persons with chronic mental illness. Data were collected through in-person interviews with family caregivers of 103 adults with chronic mental illness who were served by mental health case management agencies. The results indicated that insufficiency of overall social support was the most powerful predictor of caregiver depressive symptomatology. In addition, caregiver burden had a significant unique contribution to caregiver depressive symptomatology, with higher levels of burden associated with greater levels of caregiver depressive symptomatology. Higher levels of client behavioral problems and insufficient support from family members and mental health professionals related to the caregiving role were associated with higher levels of caregiver depressive symptomatology through their associations with caregiver burden. Caregiver race was not significantly related to caregiver burden or to caregiver depressive symptomatology after controlling for other variables. Over two-fifth of White caregivers and over one-quarter of Black caregivers were at risk for clinical depression. Implications for practice and research are discussed.

Adolescents' exposure to violence and associated symptoms of psychological trauma

OBJECTIVE

To examine the extent to which adolescents are exposed to various types of violence as either victims or witnesses, and the association of such exposure with trauma symptoms; specifically, the hypotheses that exposure to violence will have a positive and significant association with depression, anger, anxiety, dissociation, posttraumatic stress, and total trauma symptoms.

DESIGN AND SETTING

The study employed a survey design using an anonymous self-report questionnaire administered to students (grades 9 through 12) in six public high schools during the 1992-1993 school year.

PARTICIPANTS

Sixty-eight percent of the students attending the participating schools during the survey participated in the study (N = 3735). Ages ranged from 14 to 19 years; 52% were female; and 35% were African American, 33% white, and 23% Hispanic.

RESULTS

All hypotheses were supported. Multiple regression analyses of the total sample revealed that violence exposure variables (and to a lesser extent, demographic variables) explained a significant portion of variance in all trauma symptom scores, including depression (R2 = .31), anger (R2 = .30), dissociation (R2 = .23), posttraumatic stress (R2 = .31), and total trauma (R2 = .37).

CONCLUSIONS

A significant and consistent association was demonstrated linking violence exposure to trauma symptoms within a diverse sample of high school students. Our findings give evidence of the need to identify and provide trauma-related services for adolescents who have been exposed to violence.

The psychosocial issues of women serving time in jail

Two hundred and one randomly selected female inmates incarcerated at a municipal jail were interviewed to establish the needs of this population and to formulate appropriate rehabilitative interventions. Measures of social support for this sample were uniformly low. Scores on the Global Severity Index of the Brief Symptom Inventory showed that 64 percent of the women were in the clinical range for mental health problems. Scores obtained from the Short Drug Abuse Screening Test indicated that 83 percent of the women were in the substance abuse range. When child and adult sexual abuse were combined, 81 percent of the women had been sexually victimized at some time in their lives. The data point to the need for improved programs and conditions within penal settings and for intermediate sanctions for nonviolent female offenders. Such sanctions could include both correctional day treatment and community-based correctional living sites.

Predictors of burden among lower socioeconomic status caregivers of persons with chronic mental illness

This study uses a stress-coping-support framework to examine the predictors of caregiver burden with a sample of 103 lower social class family caregivers of persons with chronic mental illness. Results of multiple regression analyses show that the greater the frequency of client behavioral symptoms and the lower the amount of perceived support from family members, the higher the level of overall caregiver burden. Examination of the predictors of specific types of burden-family disruption, stigma, strain, and dependency-reveal that different constellations of variables predict different types of burden. The need for mental health agencies to address caregiver and client concerns is addressed. Implications are presented for practice and future research.

Direct and indirect interactions of cocaine with childbirth outcomes

OBJECTIVE

To evaluate neonatal sequelae of maternal cocaine use during pregnancy.

METHODS

One hundred women positive for cocaine use during pregnancy were compared with 100 matched controls who did not use cocaine. Maternal characteristics and infant neonatal outcomes were compared. We used t tests, chi 2, and multiple regression analyses to evaluate the contributions of cocaine vs other drugs to outcome.

RESULTS

Cocaine was the best predictor of increased incidence of abortions, higher maternal gravidity, and poorer prenatal care. Cocaine was also the best predictor of preterm birth and of lower birth weight, after controlling for prematurity. Maternal use of cocaine and alcohol in combination was the best predictor of decreased linear growth, after controlling for prematurity.

CONCLUSIONS

Maternal cocaine use predicts negative birth outcomes directly, as well as through obstetric risk factors of abortion history and less prenatal care. Interactive effects of cocaine and alcohol should be considered in future studies of birth outcomes.

Sexual victimization and substance abuse in psychiatrically hospitalized adolescents

This article investigates the relationship between substance abuse and sexual abuse in a population of 260 psychiatrically hospitalized adolescents. Seven hypotheses are set forth to test a model that uses parental alcohol abuse, sexual abuse status, and gender as exogenous variables, perceived benefit of alcohol or drugs as an endogenous mediating variable, and substance abuse as the dependent variable. Using these variables, a path model was constructed and revised based on empirical testing. The revised model achieved an adjusted R2 of .38, thus explaining 38 percent of the variance in this sample's abuse of alcohol or drugs. The model suggests that within clinical populations, sexually abused adolescents should be screened for substance abuse, and attention should be given to parental alcohol abuse as well as the degree to which adolescents perceive benefits from their alcohol or drug use.

Divalent cations, phospholipid asymmetry and osmotic swelling in electrically-induced lysis, cell fusion and giant cell formation with human erythrocytes

We have previously reported that acidic phospholipids are exposed at the surface of human erythrocytes when the cells are subjected to electrical breakdown. It has now been shown that the prothrombinase assay, which was used previously for the determination of acidic phospholipids, is specific for phosphatidylserine under the conditions of our experiments. In the light of this finding, we have investigated and characterised factors that govern cell lysis, cell fusion, and the formation of giant cells induced by electrical breakdown with human erythrocytes in media of low ionic strength. Divalent cations (1.1 mM) protected the cells against haemolysis, in the order Mn2+ > Ca2+ > Ba2+ > Mg2+ >> Zn2+, whereas about 99% of the cells lysed immediately on breakdown in the presence of Na+ or K+ (2.1 mM), or Al3+ (0.95 mM). The lengths of pearl chains of fused erythrocytes formed was similarly greatest with Mn2+ and decreased progressively with Ba2+, Zn2+, Ca2+ and Mg2+. No cell fusion occurred with Na+, K+, or Al3+. It is suggested that interactions with phosphatidylserine, which is exposed at the cell surface by electrical breakdown, may enable Mn2+, Ba2+ and Ca2+ ions to inhibit cell lysis (via membrane resealing) and facilitate cell fusion. Following electrically-induced cell fusion, erythrocytes round-up into giant cells. It has previously been proposed that Ca2+ ions accelerate the rounding-up process. However, data are presented which show that, as with erythrocytes treated with Sendai virus, the formation of rounded, giant cells following cell fusion depends on the osmotic swelling properties of permeabilised erythrocytes. Osmotic swelling may also have induced any hemi-fused cells present to fuse completely. Zn2+ ions anomalously enabled erythrocytes to round-up very rapidly into giant cells following electrical breakdown. This phenomenon may result from an interaction of Zn2+ ions with cysteine groups in membrane proteins, which decreases the immediate loss of ions that occurs when erythrocytes are subjected to electrical breakdown in low-ionic-strength media.

Relationships between the surface exposure of acidic phospholipids and cell fusion in erythrocytes subjected to electrical breakdown

The procoagulant activity of human erythrocytes, which provides a measure of the translocation of acidic phospholipids from the inner to the outer monolayer of the plasma membrane, has been compared with the percentage cell fusion in experiments on the effects of electrical breakdown pulses under differing experimental conditions. After treatment with breakdown pulses of 20 microseconds or longer (5 kV cm-1), the plasma membranes of erythrocytes in 250 mM sucrose exhibited an almost complete loss of asymmetry with respect to acidic phospholipids. As the breakdown voltage was increased from 2 to 5 kV cm-1 (with breakdown pulses of 99 microseconds), the surface exposure of acidic phospholipids and cell fusion increased approximately in parallel. Furthermore, with 99 microseconds pulses and a voltage of 3 kV cm-1, a decrease in the osmolarity from 250 to 150 mM of the sucrose medium was accompanied by an increase in both the surface exposure of acidic phospholipids and the extent of cell fusion. Breakdown pulses of 2-5 microseconds were sufficient to cause a marked loss of asymmetry, but no cell fusion was observed unless the pulse length was at least 20 microseconds. Kinetic experiments indicated that exposure of the acidic phospholipids at the cell surface was more likely to be due to a direct effect of the electric field pulses on plasma membrane structure than to secondary effects, such as the action of endogenous proteinases on the membrane skeleton. It seems possible that a localised, surface exposure of acidic phospholipids may contribute to the 'long-lived fusogenic state' (Sowers, A.E. (1986) J. Cell Biol. 102, 1358-1362) and the 'transient permeant structures' (Teissié, J. and Rols, M.P. (1986) Biochem. Biophys. Res. Commun. 140, 258-266) that enable cell fusion to occur when contact between cells is established after they have been subjected to field pulses. Our observations also provide circumstantial support for the concept that changes in the phospholipid asymmetry of membranes may be important in physiologically-occurring instances of biomembrane fusion.

Membrane fusion without cytoplasmic fusion (hemi-fusion) in erythrocytes that are subjected to electrical breakdown

There are many reports of hemi-fusion in phospholipid vesicles but few published studies on hemi-fusion in cells. We report evidence from both fluorescence microscopy and freeze-fracture electron microscopy for hemi-fusion in the electrofusion of human erythrocytes. We have also characterised the conditions that favour hemi-fusion as opposed to complete fusion, and discuss the possibility that hemi-fusion might precede complete electrically-induced cell fusion. A membrane probe (DiIC16) and a cytoplasmic probe (6-carboxyfluorescein) were used to investigate the behaviour of doubly-labelled human erythrocytes which were aligned in chains by dielectrophoresis and then exposed to high voltage breakdown pulses. Some of the cells were fused by the pulses, as shown by diffusion of both membrane and cytoplasmic probes from labelled to unlabelled cells. With other cells, the membrane probe diffused into unlabelled cells after the breakdown pulses, without the cytoplasmic probe diffusing into unlabelled cells or leaking into the medium. Membrane fusion (hemi-fusion) thus occurred without cytoplasmic fusion in these erythrocytes. Such cells were irreversibly, but fragilely, attached to their neighbours by the breakdown pulses. There was an inverse relationship between conditions that permit complete fusion and those that favour hemi-fusion, with respect to breakdown pulse length, breakdown voltage and, in particular, osmolarity and temperature. The incidence of hemi-fusion in 250 mM erythritol was twice that in 150 mM erythritol, and hemi-fusion was 5-fold greater at 25 degrees C than at 20 degrees C. Hemi-fused erythrocytes occasionally fused completely on heating to 50 degrees C, demonstrating that hemi-fusion can proceed to complete cell fusion. Freeze fracture electron micrographs of preparations of hemi-fused cells revealed long-lived, complementary depressions and protrusions on the E- and P-fracture faces, respectively, of tightly apposed cells that may mediate hemi-fusion. The possibility that the fusion of closely adjacent human erythrocytes by electrical breakdown pulses may involve an intermediate, shared bilayer structure, which is stable in certain conditions but which can be ruptured by osmotic swelling of the permeabilised cells, is discussed.

Stress and depression in mothers of failure-to-thrive children

Compared 30 mothers whose children were hospitalized for failure-to-thrive (FTT) to a normative group on standardized measures of perceived stress and depression. Child and maternal medical and demographic data were also taken. Standardized development and feeding assessments were done. Descriptive statistics, correlational analyses, and t tests were used to describe and examine group differences. FTT children were perceived overall as more stressful, less adaptable, more inconsolable, and more unhappy than were healthy children. Child characteristics associated with higher maternal stress levels were higher birth weight, absence of organic disease or behavioral feeding problems, and higher IQ. Maternal self-report of depression, attachment to her child, sense of competence in parenting, social isolation, and relationship to spouse were not different from the normative sample.

[Experimental study of the pathological mechanism of thromboxane A2 in alkaline ocular burn]

The authors investigated the pathological mechanism of thromboxane A2 in alkaline burn of the eye. Thromboxane B2 (metabolic product of thromboxane A2) in aqueous humor of the burned eye significantly increased in 30 minutes after the burn. The pathological change was the formation of thrombosis 2 hours after the alkaline burn, especially in the anterior segment. The role of thromboxane A2 in alkaline burn of the eye was ascertained.

Human artificial insemination: donors in Melbourne. From our medical schools

Donors are crucial to any artificial insemination by donor (AID) programme but information about them is limited. This paper discusses the sources, characteristics and processing of semen donors.