Effect of the compound bacterial agent on microbial community of the aerobic compost of food waste

In our study, we used 16SrRNA and ITS to investigate the microbial community composition and the effect of compound bacterial agent on the microbial community composition in the aerobic composting process of food waste (FW). At the bacterial level, the main phyla of Group A (compost naturally) were Proteobacteria and Firmicutes, and the main species were Pseudomonas_sp._GR7, Bacillus licheniformis and Pediococcus acidilactici. The main phyla of Group B (compost with compound bacterial agent) were Proteobacteria, Firmicutes and Streptophyta, and the main species were Klebsiella pneumoniae, Cronobacter sakazakii, Macrococcus caseolyticus, Enterococcus faecalis, Citrobacter freundii and Bacillus velezensis. It is worth noting that M. caseolyticus may be able to improve the effect of odour which is an important sensory index during aerobic composting. At the fungal level, the main phylum of both Groups A and B was Ascomycota, and the main species of Group A were Paecilomyces variotii, Byssochlamys spectabilis and Aspergillus fumigatus. The main species of Group B were Ogataea polymorpha and Millerozyma farinosa. Finally, the degradation rate of Group B was 81% that was about 15% higher than that of Group A, indicating that the compound bacterial agent could effectively improve the degradation rate and the composting process, while the low abundance of the compound bacterial agent in the composting process might be due to the small initial addition or the inhibition of other bacteria or fungi in the composting process.

Thermal therapy induced fluid pressure and stress reductions in a solid tumor

This paper presents an investigation on the interstitial fluid pressure and stress reductions in a vascularized solid tumor using a thermal therapy approach. The solid tumor is modeled as a fluid infiltrated poroelastic medium with a pressure source subjected to spatial heating. The distributions of temperature, interstitial fluid pressure, strains and stresses in a spherical tumor are obtained using a thermoporoelasticity theory in which the extracellular solid matrix and the interstitial fluid have different coefficient of thermal expansion (CTE). The numerical results for a solid tumor subjected to uniform spatial heating indicate that the CTE of the solid matrix of the tumor plays a crucial role in the reductions in the fluid pressure and effective stresses caused by the thermal therapy. The pore pressure and effective stresses are reduced when the CTE of the solid matrix is higher than that of the interstitial fluid. The reductions in fluid pressure and stresses may become significant depending on the difference between the CTEs of the solid matrix and interstitial fluid. The reductions reach the maximum at the tumor center and decrease with increasing radial distance from the tumor center. Finally, the thermally induced fluid flow is directed from the surface towards the center thereby potentially improving the microcirculation in the solid tumor.

A Chemo-poroelastic Analysis of Mechanically Induced Fluid and Solute Transport in an Osteonal Cortical Bone

It is well known that transport of nutrients and wastes as solute in bone fluid plays an important role in bone remodeling and damage healing. This work presents a chemo-poroelastic model for fluid and solute transport in the lacunar-canalicular network of an osteonal cortical bone under cyclic axial mechanical loading or vascular pressure. Analytical solutions are obtained for the pore fluid pressure, and fluid and solute velocities. Numerical results for fluid and calcium transport indicate that under a cyclic stress of 20 MPa, the magnitudes of the fluid and calcium velocities increase with an increase in the loading frequency for the frequency range considered (≤ 3 Hz) and peak at the inner boundary. The peak magnitude of calcium velocity reaches 18.9 μm/s for an osteon with a permeability of 1.5 × 10^-19 m² under a 3 Hz loading frequency. The magnitude of calcium velocity under a vascular pressure of 50 mmHg is found to be two orders of magnitude smaller than that under the mechanical load. These results have the potential to be important in understanding fundamental aspects of cortical bone remodeling as transport characteristics of calcium and other nutrients at the osteon scale influence bone metabolism.

Zoledronic acid accelerates osteogenesis of bone marrow mesenchymal stem cells by attenuating oxidative stress via the SIRT3/SOD2 pathway and thus alleviates osteoporosis

OBJECTIVE

The aim of this study was to clarify the potential effect of zoledronic acid on alleviating oxidative stress and promoting bone marrow mesenchymal stem cells (BMSCs) osteogenesis through the SIRT3/SOD2 pathway, thus alleviating the progression of osteoporosis.

MATERIALS AND METHODS

Relative expression levels of osteogenesis-related genes (ALP, RUNX2, and Bglap) were determined. Meanwhile, ALP activity and capacity of mineralization in BMSCs treated with different doses of zoledronic acid were measured. Subsequently, viability and ROS level in H2O2-induced BMSCs influenced by zoledronic acid treatment were assessed. The regulatory effect of zoledronic acid on the SIRT3/SOD2 pathway was detected by Western blot. Furthermore, the involvement of the SIRT3/SOD2 pathway in zoledronic acid-mediated BMSCs osteogenesis was evaluated.

RESULTS

Zoledronic acid treatment significantly up-regulated the levels of ALP, RUNX2, and Bglap. Meanwhile, it improved ALP activity and capacity of mineralization in BMSCs dose-dependently. H2O2 induction markedly suppressed viability and enhanced ROS level in BMSCs, which were reversed by zoledronic acid treatment. Besides, zoledronic acid protected H2O2-induced SIRT3 down-regulation and AC-SOD2/SOD2 up-regulation in BMSCs. In addition, silence of SIRT3 reversed the protective effects of zoledronic acid on osteogenesis of BMSCs.

CONCLUSIONS

Zoledronic acid alleviates the progression of osteoporosis. Meanwhile, it accelerates BMSCs osteogenesis by inhibiting oxidative stress via the SIRT3/SOD2 pathway.

[Effects of N-(4-hydroxyphenyl) retinamide lipid microbubble combined with ultrasound on human keloid fibroblasts]

Objective: To explore the effects of N-(4-hydroxyphenyl) retinamide (4HPR), 4HPR liposome (4HPR-L), and 4HPR lipid microbubble (4HPR-LM) combined with ultrasound on proliferation, apoptosis, and cell cycle of human keloid fibroblasts (Fbs). Methods: (1) 4HPR-L and 4HPR-LM were prepared by hydration ultrasonic method. The appearance morphology, particle size distribution, Zeta potential, loading drug concentration, encapsulation efficiency, and drug loading rate of 4HPR-L were investigated by high performance liquid chromatography, dynamic light scattering, and transmission electron microscope. (2) Human keloid Fbs were cultured and divided into 13 groups by random number table (the same grouping method below), with 6 wells in each group. Cells in control group were given no treatment, while cells in 12 ultrasound groups including 0.5 W 30 s group, 0.5 W 60 s group, 0.5 W 120 s group, 0.7 W 30 s group, 0.7 W 60 s group, 0.7 W 120 s group, 1.0 W 30 s group, 1.0 W 60 s group, 1.0 W 120 s group, 1.5 W 30 s group, 1.5 W 60 s group, and 1.5 W 120 s group were treated by ultrasound with corresponding parameters. The cells viability was measured by a microplate reader after 24 hours of routine culture. Another batch of human keloid Fbs were divided into 5 groups, with 6 wells in each group. Cells in control group were given no treatment, while cells in 1, 10, 20, and 50 μg/mL blank lipid microbubble groups were treated with blank lipid microbubbles in corresponding mass concentration. The cells viability was measured as before after 24 hours of routine culture. Another batch of human keloid Fbs were divided into 6 groups, with 12 wells in each group. Cells in control group were given no treatment, while cells in 1, 10, 20, 50, and 100 μg/mL 4HPR-L groups were added with 4HPR-L carrying corresponding mass concentration of 4HPR. The cells viability in 6 wells of each group was detected after 24 and 48 hours of routine culture, respectively. Another batch of human keloid Fbs were divided into 4 groups, with 6 wells in each group. Cells in control group were given no treatment, while cells in 4HPR, 4HPR-L, and 4HPR-LM+ ultrasound groups were treated with 4HPR, 4HPR-L, and 4HPR-LM (all the mass concentration of 4HPR was 20 μg/mL), respectively, and cells in 4HPR-LM+ ultrasound group were given 0.5 W 60 s ultrasound treatment immediately after drug administration. The cells viability was measured as before after 24 hours of routine culture. (3) Another batch of human keloid Fbs were divided into control group, 4HPR group, 4HPR-L group and 4HPR-LM+ ultrasound group, with 3 wells in each group, and the cells in each group were treated as before. Apoptosis of the cells was detected by flow cytometer after 24 hours of routine culture. (4) Another batch of human keloid Fbs were grouped and treated as in (3), and then the cell cycle distribution was detected by flow cytometer after 24 hours of routine culture. Data were processed with one-way analysis of variance and t test. Results: (1) 4HPR-L particles had a spherical or spheroidal structure and were uniform in size, with particle size of (100.1±1.3) nm and Zeta potential of (-34.3±2.3) mV. The mass concentration of 4HPR in 4HPR-L solution was about 1 400 μg/mL, with the encapsulation efficiency of (95.8±1.2)% and drug loading rate of (8.3±0.4)%. (2) The viability of cells in the 12 ultrasound groups was higher than 93.0%, and the viability of cells in 1, 10, 20, and 50 μg/mL blank lipid microbubble groups was higher than 95.0%. The viability of cells in 1 μg/mL 4HPR-L group at administration hour 24 was similar to that at 48 (t=0.393, P>0.05). The viability of cells in 10, 20, 50, and 100 μg/mL 4HPR-L groups at administration hour 24 was significantly higher than that at administration hour 48 (t=44.593, 22.961, 32.224, 35.337, P<0.01). The viability of cells in 4HPR group, 4HPR-L group, and 4HPR-LM+ ultrasound group was (47.3±0.7)%, (42.3±1.7)%, and (38.6±0.8)%, respectively. The viability of cells in 4HPR group was significantly higher than that in 4HPR-L group and 4HPR-LM+ ultrasound group (t=4.551, 15.895, P<0.05 or P<0.01). The viability of cells in 4HPR-L group was significantly higher than that in 4HPR-LM+ ultrasound group (t=-3.360, P<0.05). (3) The percentages of total apoptotic cells in 4HPR group, 4HPR-L group, and 4HPR-LM+ ultrasound group were (32.8±2.4)%, (42.5±2.4)%, and (58.5±6.3)%, respectively, which were significantly higher than the percentage of control group [(14.9±1.6)%, t=8.748, 13.637, 9.500, P<0.01]. The percentages of total apoptotic cells in 4HPR-L group and 4HPR-LM+ ultrasound group were significantly higher than the percentage in 4HPR group (t=4.049, 5.393, P<0.05 or P<0.01), and the percentage of total apoptotic cells in 4HPR-LM+ ultrasound group was significantly higher than that in 4HPR-L group (t=3.371, P<0.01). (4) The percentage of G2/M phase cells in 4HPR group was higher than that in control group, but there was no statistically significant difference (t=2.107, P>0.05). The percentage of G2/M phase cells in 4HPR-L group was significantly higher than that in 4HPR group or control group (t=18.169, 30.026, P<0.01). The percentage of G2/M phase cells in 4HPR-LM+ ultrasound group was significantly higher than that in 4HPR-L group, 4HPR group, and control group (t=4.932, 25.854, 66.231, P<0.01). Conclusions: 4HPR can inhibit proliferation, induce apoptosis, and arrest G2/M phase of human keloid Fbs, and the effects of 4HPR-LM combined with ultrasound are better than those of 4HPR-L and free 4HPR.

Paracrine regulation of melanogenesis

Melanocytes are generally characterized by the basic ability of melanin synthesis and transfer to adjacent keratinocytes. This constitutes an individual skin phenotype and provides epidermal protection from various stimuli, such as ultraviolet irradiation, through a complex process called melanogenesis, which can be regulated by autocrine or paracrine factors. Recent evidence has revealed the paracrine effects of keratinocytes on melanogenesis by secreting cytokines, including α-melanocyte stimulating hormone and endothelin-1. In addition to keratinocytes, there are other types of cells in the skin, such as fibroblasts and immune cells, which are also actively involved in the regulation of melanocyte behaviour through the production of paracrine factors. In addition, extracellular matrix proteins, which are secreted mainly by skin-resident cells, not only play direct roles in regulating melanocyte morphology and functions but also provide structural support between the epidermis and dermis to control the distribution of various secreted cytokines from keratinocytes and/or fibroblasts, which are potentially involved in the regulation of melanogenesis. Moreover, understanding the origin of melanocytes (neural crest cells) and the presence of nerve endings in the epidermis can reveal the intimate contact between melanocytes and cutaneous specific nervous system proteins. Melanocytes are associated with all these networks with corresponding receptors expressed on the cell surface. In this review, we provide an overview of recent advances in determining the intimate relationships between melanocytes and their surrounding elements, which provide insights into the complex nature of the regulation of melanogenesis.

Disaster nursing experiences of Chinese nurses responding to the Sichuan Ya'an earthquake

AIM

The aim of this study was to investigate the disaster experiences of nurses called to assist survivors one month after the 2013 Ya'an earthquake.

BACKGROUND

China has experienced an increasing number of earthquake disasters in the past four decades. Although a health and disaster management system was initiated after the 2008 Wenchuan earthquake, nurses' roles and experiences in a disaster have been overlooked.

METHODS

The researchers used qualitative descriptive design that included 16 participants. Data were collected using semi-structured interviews and observation notes, after which a qualitative content analysis was conducted.

FINDINGS

Three major themes emerged: the process of being dispatched from hospitals to the disaster zone, the effort involved in getting to and working in the affected site and reflecting on the challenges they encountered.

DISCUSSION

About half of the participants had received disaster nursing training before deploying to the disaster site, but they consistently expressed a lack of physical and psychological preparedness regarding the process of being dispatched from their hospitals to the disaster zone.

LIMITATIONS

This was a single-incident experience. Caution should be taken when trying to extend the findings to other parts of China.

CONCLUSION

These findings highlighted the need for disaster in-service training as well as for having disaster plans in place.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

Hospital and nursing leaders should provide disaster training opportunities that included topics such as compiling resource inventories, formulating disaster drills and simulations, managing emergencies, and using emergency communication methods. Health policy-makers should be required to prioritize capacity-building training for front-line nurses as well as to develop and implement disaster management plans to better prepare nurses for future disasters.

[DNA shuffling of ptr resistance gene leads to improved pristinamycin production in Streptomyces pristinaespiralis]

In order to enhance pristinamycin production, six homologous ptr genes from high pristinamycin-producing strains of Streptomyces pristinaespiralis were selected for DNA shuffling, and the reason for the altered activities of the shuffled ptr gene was speculated by sequence alignment. The highest pristinamycin yield of 0.12 g/L was achieved with a sixfold increase in strain sps16 obtained by DNA shuffling when compared to ancestral strain ATCC 25486. Sequence analysis of theptr gene variant from the sps16 strain indicated that five mutations (H16P, N63D, T75P, Q107R, and P435A) were introduced into the gene, two of them (N63D and T75P) located in the second of the 14 transmembrane segments (TMS). Prediction of the secondary structure of the gene product indicated that mutations at the N-terminus resulted in the shortening of the corresponding α-helix, while the mutation at the C-terminus lengthened the helix. In conclusion, combination of DNA shuffling with genome shuffling is an effective breeding strategy for increasing the antibiotic yield by directed evolution of target genes.

Effect of phytosterols on rumen fermentation in vitro

We investigated the effect of phytosterols on rumen fermentation in vitro using gas syringes as incubators. Phytosterols were dissolved in ethyl acetate (8.3%) and added at various concentrations to the common diet in rumen fluid. In vitro gas production (GP) was recorded after 3, 6, 12, 18, and 24 h incubation. Incubation was stopped at 6, 12, and 24 h and the inoculants were then tested for pH, dry matter digestibility (DMD), microbial protein yield (MCP), lactic acid, NH3-N, and volatile fatty acids (VFAs). GP was consistently higher than the control; particularly, treatments at 12, 18, and 24 h reached extremely significant levels (P < 0.01). Compared to the control group, the pH of ruminal fluid was slightly lower after incubation, and DMD and MCP increased with increasing phytosterol level except for the content of MCP at 6 h, which changed only minimally. Lactate was significantly lower after treatment compared to the control at 12 h (P < 0.01) and 24 h (P < 0.05), while NH3-N at 12 h (P < 0.05) and 24 h (P < 0.01) after treatment decreased significantly. Acetate, propionate, butyrate, and total VFA for all treatments were higher than those of the control, particularly for butyrate at 6 h (P < 0.01). These results suggest that phytosterols modify rumen fermentation by inhibiting released harmful products and promoting the release of beneficial product, which may be useful for improving nutrient utilization and animal health.

Developmental regulation of embryonic genes in plants

Somatic embryogenesis from cultured carrot cells progresses through successive morphogenetic stages termed globular, heart, and torpedo. To understand the molecular mechanisms underlying plant embryogenesis, we isolated two genes differentially expressed during embryo development. The expression of these two genes is associated with heart-stage embryogenesis. By altering the culture conditions and examining their expressions in a developmental variant cell line, we found that these genes were controlled by the developmental program of embryogenesis and were not directly regulated by 2,4-dichlorophenoxyacetic acid, the growth regulator that promotes unorganized growth of cultured cells and suppresses embryo morphogenesis. These genes are also expressed in carrot zygotic embryos but not in seedlings or mature plants.

Medium optimization based on statistical methodologies for pristinamycins production by Streptomyces pristinaespiralis

The optimization of nutrient levels for the production of pristinamycins by Streptomyces pristinaespiralis CGMCC 0957 in submerged fermentation was carried out using the statistical methodologies based on the Plackett-Burman design, the steepest ascent method, and the central composite design (CCD). First, the Plackett-Burman design was applied to evaluate the influence of related nutrients in the medium. Soluble starch and MgSO4 x 7H2O were then identified as the most significant nutrients with a confidence level of 99%. Subsequently, the concentrations of the two nutrients were further optimized using response surface methodology of CCD, together with the steepest ascent method. Accordingly, a second-order polynomial regression model was finally fitted to the experimental data. By solving the regression equation from the model and analyzing the response surface, the optimal levels for soluble starch and MgSO4 x 7H2O were determined as 20.95 and 5.67g/L, respectively. Under the optimized medium, the yield of pristinamycins in the shake flask and 5-L bioreactor could reach 1.30 and 1.01 g/L, respectively, which is the highest yield reported in literature to date.

Production of teicoplanin by valine analogue-resistant mutant strains of Actinoplanes teichomyceticus

Teicoplanin is a glycopeptide antibiotic produced by Actinoplanes teichomyceticus. A strain improvement to increase the productivity of the major component, teicoplanin A2-2, was carried out. As the fatty moiety of teicoplanin A2-2 is derived from L-valine, L-valine analogue (valine hydroxamate)-resistant mutants were derived. One of the mutants, 98-1-227, overproduced valine and produced a higher titer of total teicoplanin with higher A2-2 content. In a pilot fermentor (7 m3), the total productivity of teicoplanin was 1,800 units/ml and the A2-2 content was 58%.

Modification of thermosensitivity and chemosensitivity induced by combined treatments with hyperthermia and adriamycin

Both adriamycin (ADM) and hyperthermia show thermal chemo-enhancement. Tolerance induction against ADM in heated cells has been reported resulting in clinical difficulty of cancer therapy. We investigated thermo-enhancement induced with ADM (0.2 microg/ml) treatment alone or combined with ADM and 42 degrees C hyperthermia in Chinese hamster V79 cells in vitro. Intracellular accumulation of hsc70 and hsp72 proteins after hyperthermia or ADM was observed to examine the possible relationship between cell killing effect and their accumulations. Thermosensitivity of V79 cells at 42 degrees C after the simultaneous treatments with ADM showed marked thermo-enhancement within the short-term treatments for less than 1 h, while the combined treatments for longer than 1 h, the cells showed reduced thermosensitivity. Survival from the simultaneous treatments for less than 1 h was reduced markedly less than the single treatment both with ADM or 42 degrees C hyperthermia alone. Thermotolerance was markedly induced in a step-up hyperthermia (42 degrees C 2 h-44 degrees C). The combined treatments with ADM and 44 degrees C hyperthermia following the 42 degrees C preheating alone does not inhibit thermotolerance development. The combined treatments with ADM and 42 degrees C preheating showed markedly interactive cell killing, but no thermo-enhancement to the following 44 degrees C hyperthermia was shown. The leveling slope of the 44 degrees C heating period-survival curve was drawn. In the Western blot analyses, hsc70 existed constitutively in the V79 cells. Following the 42 or 44 degrees C hyperthermia alone, intracellular accumulation of hsp72 was determined. ADM treatment alone did not induce any accumulation of hsp72. In the simultaneous treatments with ADM and hyperthermia, the accumulation of hsp72 was markedly reduced. The accumulation of hsp72 after the combined treatment with ADM and hyperthermia was not observed as markedly as that after hyperthermia alone.

Melting mechanisms at the limit of superheating

The atomic-scale details during melting of a surface-free Lennard-Jones crystal were monitored using molecular dynamics simulations. Melting occurs when the superheated crystal spontaneously generates a sufficiently large number of spatially correlated destabilized particles that simultaneously satisfy the Lindemann and Born instability criteria. The accumulation and coalescence of these internal local lattice instabilities constitute the primary mechanism for homogeneous melt nucleation inside the crystal, in lieu of surface nucleation for equilibrium melting. The vibrational and elastic lattice instability criteria as well as the homogeneous nucleation theory all coincide in determining the superheating limit.

Superheating of confined Pb thin films

In this work we report, for the first time, an experimental observation of a superheating phenomenon in metal thin films. By means of cold rolling, Pb thin films of about 20 nm thick were sandwiched by Al layers, and between them semicoherent epitaxial Pb/Al interfaces were formed. In situ x-ray diffraction analysis indicated that the confined Pb thin films could be superheated for at least 6 degrees C. Thermodynamic analysis indicated that such a substantial superheating in the confined two-dimensional thin films may originate from suppression of growth of the molten droplets by the epitaxial Al/Pb/Al confinement, instead of suppression of melt nucleation for the confined particle superheating.

Photodynamic therapy based on combined use of 5-aminolevulinic acid with a pheophorbide-a derivative for murine tumors

BACKGROUND

5-Aminolevulinic acid (5-ALA)-based photodynamic therapy (PDT) appears to be a promising cancer treatment modality. Here, we investigated whether enhancement of 5-ALA-PDT by combining another photosensitizer, a pheophorbide-a derivative (PH-1126), is an option.

MATERIALS AND METHODS

PH-1126 (2.5, 5 or 10 mg/kg.bw) and 5-ALA (168 mg/kg.bw) were injected i.p. into C3H/HeN mice bearing squamous cell carcinoma (SCC) or BALB/c nude mice bearing L5178Y lymphoma. Afterwards, these mice received laser irradiations (630 nm for 5-ALA and 650 nm for PH-1126) with a total dose of 88 J/cm2. The results showed that PDT with 5-ALA plus PH-1126 at a low dose (2.5 mg/kg.bw) were well tolerated by both animal models, with resultant synergistically enhanced inhibition of tumor growth and/or survival advantage for the treated animals.

CONCLUSION

This study demonstrated the usefulness of the combination of a low dose PH-1126 with 5-ALA for PDT of experimental tumors in vivo.

Combination effect of photodynamic and sonodynamic therapy on experimental skin squamous cell carcinoma in C3H/HeN mice

We studied a combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT) for improving tumoricidal effects in a transplantable mouse squamous cell carcinoma (SCC) model. Two sensitizers were utilized: the pheophorbide-a derivative PH-1126, which is a newly developed photosensitizer, and the gallium porphyrin analogue ATX-70, a commonly used sonosensitizer. Mice were injected with either PH-1126 or ATX-70 i.p. at doses of 5 or 10 mg/kg.bw. At 24 (ATX-70) or 36 hr (PH-1126) (time of optimum drug concentration in the tumor) after injection, SCCs underwent laser light irradiation (88 J/cm2 of 575 nm for ATX-70; 44J/cm2 of 650 nm for PH-1126) (PDT), ultrasound irradiation (0.51 W/cm2 at 1.0 MHz for 10 minutes) (SDT), or a combination of the two treatments. The combination of PDT and SDT using either PH-1126 or ATX-70 as a sensitizer resulted in significantly improved inhibition of tumor growth (92-98%) (additive effect) as compared to either single treatment (27-77%). The combination using PH-1126 resulted in 25% of the treated mice being tumor free at 20 days after treatment. Moreover, the median survival period (from irradiation to death) of PDT + SDT-treated mice (> 120 days) was significantly greater than that in single treatment groups (77-95 days). Histological changes revealed that combination therapy could induce tumor necrosis 2-3 times as deep as in either of the single modalities. The combination of PDT and SDT could be very useful for treatment of non-superficial or nodular tumors.

A case of combined nevus: compound nevus and spindle cell Spitz nevus

Combined nevi consisting of a Spitz nevus and an acquired nevus are unusual, and, to our knowledge, the combination of a spindle cell Spitz nevus and an overlying compound nevus has not been previously reported. We report a 17-year-old girl with a nodule on the left anterior lower extremity. The nodule was asymptomatic, firm, brown, symmetrical, dome-shaped, 8 mm in diameter, and not found with ulceration. Histological findings showed proliferation of spindle-shaped cells with an overlying compound nevus. The spindle-shaped cells were large, non-pigmented, uniform in size and shape, with rare mitoses and without nuclear atypia, and arranged in a storiform pattern in thick collagen bundles. They stained positively for S-100 and negatively for HMB-45. The lesion was considered to be a new type of combined nevus consisting of a spindle cell Spitz nevus and an overlying compound nevus.

[A seroepidemiological study on hepatitis D virus (HDV) infection in Henan Province, China]

In order to investigate the distribution of HDV infection in Henan province, a seroepidemiological study on HDV infection was conducted. A total number of 1182 HBsAg positive serum samples was collected from 13 prefectures and cities between 1991 and 1993. HDV markers (HDAg, anti-HDV, anti-HDV-IgM) were tested with Enzyme Linked Immunosorbant Assay (ELISA). The prevalence rates of HDAg, anti-HDV, anti-HDV-IgM and HDV infection rate were 3.0%, 3.5%, 3.5% and 8.1%, respectively. There were no statistically significant differences in the prevalence rates of HDV infection in patients of different sexes but significant differences in the prevalence rates of HDV infection in patients of different ages, especially in age group above 60, were noticed. We also noticed that the infection rates of HDV were 8.7%, 4.6%, 7.7%, 6.3%, 11.9% and 0.0% in the groups of HBsAg carriers, acute hepatitis, chronic active hepatitis, chronic persistent hepatitis, liver cirrhosis and severe hepatitis, respectively. These findings indicated that HDV infection was important in the pathogenesis of chronic hepatitis B and in the exacerbation from liver disease to cirrhosis.

[Study on effect of emodin on the isolated intestinal smooth muscle of guinea-pigs]

Emodin is an active principle of Rheum palmatum. It is reported that emodin possesses antibiotic and antineoplastic functions. The effect of emodin action on the isolated intestinal smooth muscle of guinea-pigs were dose dependent. When the dose of emodin was less than 29.6 mumol/L, the contraction effect enhanced obviously with increasing dosage; but whenever the dose increased to more than 29.6 mumol/L, on the contrary, the effect decreased gradually and ceased finally. Emodin with appropriate concentration (14.8 mumol/L) strengthened the effect of acetylcholine (Ach) on the isolated ileum and large intestine of guinea-pigs (P < 0.05 and P < 0.01). But high concentration of emodin could reduce even completely antagonize the effect of Ach. Under such condition, CaCl2 could restore the effect of Ach on the smooth muscle. It is suggested that emodin has biphasic regulatory effect on the intestinal smooth muscle, and its effect is related to calcium ion.

[Liver and ductal remnants of porta hepatis in biliary atresia: histopathology and clinical significance]

We studied the relationship between the histopathology of biliary atresia and its clinical significance. Liver biopsies were made in 30 patients and ductal remnants of porta hepatis were studied in 20. The criteria for the pathological diagnosis of hepatic fibrosis were described. We think that judging the severity of hepatic fibrosis may be useful in selecting the mode of Kasai's operation and estimating the prognosis of patients with biliary atresia.

A study on the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927

A study of the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927 is reported. Intermediate hosts are Tenebrio obscurus, T. molitor, Carpophilus dimidiatus and Tribolium castaneum. The first three species are new host records. Development in the intermediate host takes 1-1.5 months. The completion of the life-cycle takes 2-2.5 months. Surveys of intermediate hosts, pigs, humans and rats were carried out. In Rattus norvegicus, the prevalence was as high as 22%. Epidemiological factors and suggestions for control measures are discussed.

An experimental transmission of woodchuck hepatitis virus to young Chinese marmots

Fourteen young Chinese marmots (Marmota bobak sibirica Radde) were randomly allocated to two groups of seven each. They were injected intrahepatically with a standard woodchuck hepatitis virus challenge pool or a negative pool, prepared from sera of woodchucks with and without woodchuck hepatitis virus infection, respectively. Marmot No. 2 in the experimental group experienced an episode of seroconversion from woodchuck hepatitis surface antigen to anti-woodchuck hepatitis antibody. Woodchuck hepatitis virus DNA was detected, and woodchuck hepatitis surface antigen particles of both spherical and filamentous forms and intact woodchuck hepatitis virus virions were found in its serum. By contrast, none of the control group animals (receiving the negative pool) produced any marker of woodchuck hepatitis virus. This suggests that young Chinese marmots can get woodchuck hepatitis virus infection.