Diffusion-weighted MR imaging: diagnosing atypical or malignant meningiomas and detecting tumor dedifferentiation

BACKGROUND AND PURPOSE

Atypical and malignant meningiomas are uncommon tumors with aggressive behavior and higher mortality, morbidity, and recurrence compared with benign tumors. We investigated the utility of diffusion-weighted (DW) MR imaging to differentiate atypical/malignant from benign meningiomas and to detect histologic dedifferentiation to higher tumor grade.

MATERIALS AND METHODS

We retrospectively compared conventional and DW MR images (b-value 1000 s/mm(2)) acquired on a 1.5T clinical scanner between 25 atypical/malignant and 23 benign meningiomas. The optimal cutoff for the absolute apparent diffusion coefficient (ADC) and normalized ADC (NADC) ratio to differentiate between the groups was determined by using receiver operating characteristic (ROC) analysis.

RESULTS

Irregular tumor margins, peritumoral edema, and adjacent bone destruction occurred significantly more often in atypical/malignant than in benign meningiomas. The mean ADC of atypical/malignant meningiomas (0.66 +/- 0.13 x 10(-3) mm(2)/s) was significantly lower compared with benign meningiomas (0.88 +/- 0.08 x 10(-3) mm(2)/s; P < .0001). Mean NADC ratio in the atypical/malignant group (0.91 +/- 0.18) was also significantly lower than the benign group (1.28 +/- 0.11; P < .0001), without overlap between groups. ROC analysis showed that ADC and NADC thresholds of 0.80 x 10(-3) mm(2)/s and 0.99, respectively, had the best accuracy: at the NADC threshold of 0.99, the sensitivity and specificity were 96% and 100%, respectively. Two patients had isointense benign tumors on initial DW MR imaging, and these became hyperintense with the decrease in ADC and NADC below these thresholds when they progressed to atypical and malignant meningiomas on recurrence.

CONCLUSIONS

ADC and NADC ratios in atypical/malignant meningiomas are significantly lower than in benign tumors. Decrease in ADC and NADC on follow-up imaging may suggest dedifferentiation to higher tumor grade.

Wearable EDA sensor gloves using conducting fabric and embedded system

We developed wearable EDA sensor gloves using conducting fabric and embedded system. EDA(Electro-dermal Activity) signal is an electric response on the skin of the human body. There are SCL(Skin Conductance Level) and SCR(Skin Conductance Response) in EDA. Mostly, SCL consists of DC elements. On the other hand, SCR consists of AC elements. We use the relationship between the drowsiness condition and EDA signal We made EDA sensors using conducting fabric instead of Agcl electrode for a more suitable wearable device. And we used an embedded system for EDA signal acquisition and processing instead of a personal computer, which is connected to the EDA sensor gloves through conducting fabric lines. Also, the embedded system is linked to a Notebook PC that shows the results of EDA signal processing analysis and gives proper feedback to the user. This system, for example, can be used in detecting and preventing drowsiness driving accidents for automobile drivers.

Phase I study of troxacitabine administered by continuous infusion in subjects with advanced solid malignancies

BACKGROUND

Troxacitabine is a novel L-nucleoside analogue. Preclinical studies showed improved activity with infusions of at least 3 days compared with bolus regimens, especially at concentrations >20 ng/ml. This phase I study tested the feasibility of achieving a troxacitabine steady-state concentration of 20 ng/ml for at least 72 h in patients with solid tumors.

PATIENTS AND METHODS

Patients with solid tumors received troxacitabine as a progressively longer infusion on days 1-4 of a 28-day cycle. The initial length of infusion and infusion rate were 48 h and 3 mg/m(2)/day.

RESULTS

Twenty-one patients were treated at infusion lengths that increased from 48 to 72 h and then 96 h. The infusion rate was decreased from 3 to 1.88 mg/m(2)/day due to toxicity. Dose-limiting toxicities consisted of grade 4 neutropenia (three) and grade 3 constipation (one). The maximum tolerated dose of continuous infusion troxacitabine in patients with solid tumors is 7.5 mg/m(2) administered over 96 h. This dose level resulted in steady-state drug concentration of at least 20 ng/ml for 72 h.

CONCLUSIONS

Administration of troxacitabine by continuous infusion achieved the prospectively defined target plasma concentration. Pharmacokinetics (PK) modeling coupled with real-time PK assessment was an efficient approach to conduct hypothesis-driven phase I trials.

Molecular characteristics of the porcine DLK1 and MEG3 genes

Imprinted genes play important roles in embryo survival and postnatal growth regulation. The DLK1 and MEG3 (previously GTL2) genes are linked and reciprocally imprinted in several mammals, but their imprinting status is still unknown in pigs. In this study, we report polymorphisms, imprinting status and QTL analyses of the porcine DLK1 and MEG3 genes. Muscle and adipose DNA and RNA samples from 30-day-old animals generated with reciprocal crosses between the Korean native pig (KNP) and Yorkshire breeds were used to analyse DLK1 and MEG3 variation and expression. The samples exhibited paternal expression of DLK1 and maternal expression of MEG3 in pigs. These results indicated that the imprinting status of the DLK1 and MEG3 genes is conserved across mammalian species. By linkage analyses, we assigned the DLK1 and MEG3 genes to the telomeric region of SSC7. By QTL analyses, we confirmed a significant polar overdominance (POD) effect in DLK1, which was previously detected for several growth traits in pigs. However, no significant POD effect was found with the MEG3 locus.

Effect of a new infrared light device (1100-1800 nm) on facial lifting

Laser skin resurfacing procedures can be classed into two categories - invasive and non-invasive. The last several decades have witnessed a host of advancements in ablative laser therapy and other ablative modalities for the rejuvenation of skin, including the CO(2) laser, the erbium : yttrium aluminum garnet laser, chemical peels, and dermabrasion. Despite the excellent results that can result from the practice of these techniques by experienced surgeons, the invasive nature of these devices is associated with inherent risks and patient discomfort. Therefore, much of the focus has been on non-ablative lasers and intense-pulsed light devices. We evaluated the efficacy and safety of treatment with the new infrared light device (1100-1800 nm), Titan, and assessed the degree of improvement associated with two-time laser treatments, as compared to one-time laser treatment.

Enhancing intensity of emitted light from a ring by incorporating a circular groove

We fabricated a ring containing a single circular groove (RCG) on silver film and which was supported on a glass substrate. We found that by changing the mean radius of the circular groove, the light intensity emitted from the RCG can be modulated by using the scattering light from the circular groove. In addition, we also fabricated circular grooves with the same depth but of different widths so that we could examine the scattering light behavior of the grooves. Herein, we propose a theoretical model which takes into account the amplitude modulation of the cylindrical waves. Our results showed that our proposed model agreed well with the experimental results.

Removal of basic and reactive dyes using ethylenediamine modified rice hull

Wastewaters from textile industries may contain a variety of dyes that have to be removed before their discharge into waterways. Rice hull, an agricultural by-product, was modified using ethylenediamine to introduce active sites on its surface to enable it to function as a sorbent for both basic and reactive dyes. The sorption characteristics of Basic Blue 3 (BB3) and Reactive Orange 16 (RO16) by ethylenediamine modified rice hull (MRH) were studied under various experimental conditions. Sorption was pH and concentration dependent. Simultaneous removal of BB3 and RO16 occurred at pH greater than 4. The kinetics of dye sorption fitted a pseudo-second order rate expression. Increase in agitation rate had no effect on the sorption of BB3 but increased uptake of RO16 on MRH. Decreasing particle size increased the uptake of dyes in binary dye solutions. Equilibrium data could be fitted into both the Langmuir and Freundlich isotherms. Maximum sorption capacities calculated from the Langmuir model are 14.68 and 60.24 mg/g for BB3 and RO16, respectively in binary dye solutions. This corresponds to an enhancement of 4.5 and 2.4 fold, respectively, compared to single dye solutions. MRH therefore has the potential of being used as an efficient sorbent for the removal of both dyes in textile wastewaters.

Successful management of recurrent coccygeal hernia with the de-epithelialised rectus abdominis musculocutaneous flap

OBJECTIVE

Little data exist about the optimal management of the rare coccygeal hernia. A novel method of repair is reported.

METHODS

A 46-year-old woman presented with a symptomatic coccygeal hernia after resection of the coccyx for a tumour. She had previously been reconstructed with an on-lay polytetrafluorethylene (PTFE) mesh but subsequently developed a hernia. A de-epithelialised vertical rectus abdominis musculocutaneous flap was elevated and passed through the hernia defect. The de-epithelialised dermis was secured to the levator ani and to the periosteum of the sacrum via access through a posterior approach. The gluteal skin was closed primarily over the inset flap.

RESULTS

The de-epithelialised rectus abdominis musculocutaneous flap is a viable option for the treatment of coccygeal hernia.

RELEVANCE

The de-epithelialised rectus abdominis flap has several advantages over other techniques including mesh repair and anterior or posterior flap repairs of the coccygeal hernia. The transposed muscle blocks herniation through the pelvic floor and does not create the dead space that is associated with posterior flap repairs such as the bilateral gluteal advancements. It also has the advantages of the posterior approach mesh repair, as the de-epithelialised dermis provides significant strength when secured like mesh to healthy local tissue.

Enzymatic deinking of laser printed office waste papers: some governing parameters on deinking efficiency

The protocol for the enzymatic deinking of laser printed waste papers on a laboratory scale using cellulase (C) and hemicellulase (H) of Aspergillus niger (Amano) was developed as an effective method for paper recycling. A maximum deinking efficiency of almost 73% by the enzyme combination of C:H was obtained using the deinking conditions of pulping consistency of 1.0% (w/v) with the pulping time of 1.0min, temperature of 50 degrees C, pH=3.5, agitation rate of 60rpm, pulp concentration of 4% (w/v), concentration of each enzyme of 2.5U/g air dried pulp and the enzyme ratio of 1:1. The deinking efficiency was further enhanced to 95% using the optimized flotation system consisting of pH=6.0, Tween 80 of concentration 0.5% (w/w), working air flow rate of 10.0L/min and temperature of 45 degrees C. The deinked papers were found to exhibit properties comparable to the commercial papers suggesting the effectiveness of the enzymatic process developed.

Portable microscopic cell counter for the determination of residual leucocytes in blood components

BACKGROUND AND OBJECTIVES

The accurate determination of residual white blood cell (WBC) in blood components is of considerable clinical importance, and a variety of methods have been devised for the counting of low levels of residual WBC. In this study, we evaluated the performance of microscopic cell counter with microchannel plastic chip (C-reader) with regard to its ability to quantify WBC in WBC-reduced red cell concentrates.

MATERIALS AND METHODS

In order to quantify residual WBC with the microscopic cell counter, WBC-reduced red cell concentrate was stained using propidium iodide. Three studies were performed: linearity, precision and correlation compared to those of manual Nageotte chamber counting and automatic flow cytometric methods.

RESULTS

Dilution experiments, conducted over a range of 0.7-712 WBC/microl, showed a linearity of r(2) > 0.999, with coefficient of variation values of < or = 15.6% and accuracy of 93.8% over all tested ranges. In comparison with the Nageotte chamber counting and flow cytometric methods, the correlation coefficients were r(2) > 0.995. The detection limit of this method was 0.24 WBC/microl. Total analysis time per sample was approximately 5 min.

CONCLUSION

The microscopic cell counter for residual WBC counting was determined to be efficient at the level of currently defined standards, with acceptable precision and accuracy. This method may prove useful for the quality assurance and control of WBC-depleted blood products.

Predicting potential drop-out and future commitment for first-time donors based on first 1·5-year donation patterns: the case in Hong Kong Chinese donors

BACKGROUND AND OBJECTIVES

Adequate blood supply is crucial to the health-care system. To maintain a stable donor pool, donation-promotion strategies should not only be targeted in recruitment but also focus on retaining donors to give blood regularly. A study using statistical modelling is conducted to understand the first 4-year donation patterns for drop-out and committed first-time blood donors and to build model for the donor-type identification based on their first 1.5-year donation patterns.

SUBJECTS AND METHODS

First-time whole blood (n= 20 631) adult donors recruited in year 2000 and 2001 in Hong Kong were observed for more than 4 years. Cluster analysis was first applied to group donor type by their similarities in donation behaviour under the surveillance period. A decision tree model based on a shorter surveillance period (1.5 years) is then built to predict the donor type.

RESULTS

Three donation patterns - one-time, drop-out, and committed donor behaviour - were identified in cluster analysis. Three variables - donation frequencies in the first-year and in the half-year period after first year, and the number of donation centre visits in the following half year after first year, were able to predict drop-out donors with potential to become committed and committed donors with relatively lower donation frequency.

CONCLUSIONS

The present statistical modelling is able to identify those donors with potential to become committed donors and those committed donors who can donate more frequently. This information is useful for development of targeted donor retention strategies.

Tissue microarrays characterise the clinical significance of a VEGF-A protein expression signature in gastrointestinal stromal tumours

A tissue microarray analysis of 22 proteins in gastrointestinal stromal tumours (GIST), followed by an unsupervised, hierarchical monothetic cluster statistical analysis of the results, allowed us to detect a vascular endothelial growth factor (VEGF) protein overexpression signature discriminator of prognosis in GIST, and discover novel VEGF-A DNA variants that may have functional significance.

Evaluation of surface and superficial dose for head and neck treatments using conventional or intensity-modulated techniques

With increased use of intensity-modulated radiation therapy (IMRT) for head and neck treatment questions have arisen as to selection of an optimum treatment approach when either superficial sparing or treatment is desired. Other work has pointed out the increased superficial dose resulting from obliquity effects when multiple tangential beams are applied to head and neck treatment, as is the general case in IMRT planning. Helical tomotherapy might be expected to result in even further enhanced superficial dose compared with conventional bilateral field treatment. We have designed a typical right oropharynx target volume in an anthropomorphic head and neck phantom. Three different treatment techniques have been used to optimally treat this target, including bilateral static fields, eight-field IMRT and helical tomotherapy. The phantom was immobilized in a standard treatment position and treated on a Varian 2300cd linear accelerator and on a Hi-Art Helical Tomotherapy unit. 1 mm3 lithium-fluoride thermoluminescent dosimeters (TLDs) were placed on the surface of the phantom at a number of axial test positions. Film strips (Kodak EDR2) were either wrapped around the surface or sandwiched within the phantom. Measured doses at the surface and as a function of depth are compared with the planning system predictions for each treatment technique. The maximum surface doses on the proximal treatment side, averaged from TLDs and films, were measured to be 69-82% of the target dose with the bilateral fields yielding the lowest surface doses (69%), tomotherapy about 2% more than that (71%) and IMRT 13% more (82%). Anterior to the target volume, doses are always low for bilateral treatment. In this case the minimum anterior surface dose (chin area) was 6% of the prescription dose from that technique as compared with 26% and 35% from the IMRT and tomotherapy methods, respectively. The Eclipse and Tomotherapy planning systems both modelled deep and superficial doses well. Surface doses were better modelled by Eclipse at the test points, while the tomotherapy plans consistently overestimated the measured doses by 10% or more. Depth dose measurements, extracted from embedded films, indicated the depth of dose build-up to >99% to be the shallowest for IMRT (2-5 mm) followed by tomotherapy (5-8 mm) and bilateral fields (10-15 mm). The amount of surface dose is clearly technique dependent and should be taken into account in the planning stage.

Congenitally missing maxillary primary canines: report of three cases

BACKGROUND

Hypodontia is uncommon in the primary dentition and lateral incisors are the most commonly missing primary teeth in the patients affected. Studies have found that hypodontia in the primary dentition involving only maxillary canine is rare.

CASE REPORTS

Three cases of hypodontia in the primary dentition involving only maxillary canine are presented. Two of them were affected by hypodontia and hyperdontia in the permanent dentitions respectively, yet all the permanent canines developed normally in these three cases.

CONCLUSION

In children with congenitally missing maxillary canines, the permanent dentitions may show diverse anomalies in tooth numbers, ranging from hypodontia to hyperdontia.

[A field epidemiological study on the risk factors of injury caused by typhoon]

OBJECTIVE

To determine the risk factors involved in the typhoon episodes and to put forward and evaluate the intervention measures.

METHODS

We defined a confirmed injury case as: 'a person with fall,scalpel and stab, collision, drowning, injuries and trauma due to flying debris and building collapse, asphyxiation due to entrapment in collapsed buildings by typhoon from 0 am,August 12 to 6 pm, August 14 2004' and a death case as: 'a person with fall, scalpel and stab, collision, drowning, injuries and trauma due to flying debris and building collapse, asphyxiation due to entrapment in collapsed buildings by typhoon from 0 am, August 12 to 12 am, August 18 2004'. We investigated all hospitalized injured cases in ten hospitals and telephoned to those who were not hospitalized and the cases of death. We did case-control study with 1 pair versus 2 cases. 74 cases were selected in ten hospitals. The controls were neighbors of the controls matched by occupation, sex, village, and within 5 years of age without injury in this typhoon. We asked the cases and the controls on their alertness regarding typhoon and what actions taken when typhoon arrived.

RESULTS

There were 392 injury cases in all ten hospitals and 50 death cases. The attack rate of injury was 27.3 per 100 000. The fatal rate was 11.3% with the death rate 3.1 per 100 000. We investigated 209 injury cases and 31 death cases. The number of cases who were injured from 1 to 6 hours before typhoon landing accounted for 64.6% (155) of all cases. The peak of epidemic curve was 4 hours before the landing of typhoon. Data on the analysis of 74 cases and 148 controls revealed that 42% (31) of the cases were outside their homes before and during typhoon compared to 15% (22) of the controls (OR = 3.9, 95% CI: 1.9-7.7). Compared with 20% (30) control persons (OR = 17,95% CI: 4.2-68). 28% (21) cases did not receive the alert of typhoon before it arrived compared with 18% (27) control persons (OR = 3.3, 95% CI:1.3-8.6). 53% (39) of the cases did not pay attention to the alert of typhoon before typhoon arrived.

CONCLUSION

Staying outdoor, not receiving or did not take seriously about the alert of typhoon seemed to be the risk factors of injury by the typhoon episode, suggesting that the government should increase the emergency preparedness and to raise the awareness on risks associated with typhoon.

Similarities and differences for light-induced surface plasmons in one- and two-dimensional symmetrical metallic nanostructures

Two types of double-sided nanostructure, one possessing a slit aperture with parallel grooves and the other possessing a circular aperture with concentric grooves, were fabricated to examine the similarities and differences of their diffraction behavior in one-dimensional (1-D) and two-dimensional (2-D) nanostructures. Based on the projection-slice theory, we conjecture that the surface plasmons in these two different nano-scale grooves possess similar modes. A localized surface plasmon (LSP) was used to examine the transmission characteristics induced by the apertures. The transmission characteristics of the slitted nanostructure and the circular nanostructure aperture were then measured. We coupled the transmission spectra measured from these two apertures with a 1-D parallel groove transmission curve simulated by a 1-D rigorous coupled wave analysis. Measured spectra results show reasonable agreement with the simulated data. We propose that the apparent blueshift observed in the peak frequency of a 2-D nanostructure is due to the difference in the shape of the aperture and the spot transmission characteristics of 1-D and 2-D systems as induced by a LSP.

Association of melanocortin 4 receptor (MC4R) and high mobility group AT-hook 1 (HMGA1) polymorphisms with pig growth and fat deposition traits

The aim of this study was to analyse the combined effect of melanocortin 4 receptor (MC4R) and high mobility group AT-hook 1 (HMGA1) polymorphisms on growth and fatness traits in Duroc pigs. No significant interaction was observed between MC4R and HMGA1 for back-fat traits. An additive mode of inheritance of both gene effects was found for average daily gain and lean meat content. Maximum mean differences from combined genotypic effects were over 2 mm for back fat, 70 g/day for average daily gain and 2% for lean meat content. Therefore, utilization of polymorphisms in both MC4R and HMGA1 for marker-assisted selection could result in an economic benefit to the pig industry.

Oxidative Metabolism in Pediococcus pentosaceus III. Glucose Dehydrogenase System

Lee, Chin K. (North Carolina State of the University of North Carolina, Raleigh), and Walter J. Dobrogosz. Oxidative metabolism in Pediococcus pentosaceus. III. Glucose dehydrogenase system. J. Bacteriol. 90:653-660. 1965.-A method was developed for the purification of glucose dehydrogenase from Pediococcus pentosaceus Az-25-5. The procedures included treatments with protamine sulfate, ammonium sulfate, and heat in addition to acid precipitation, calcium phosphate adsorption and elution, and diethylaminoethyl-Sephadex column chromatography. The final preparation thus obtained was purified 255-fold and exhibited both similarities and dissimilarities to the same enzyme isolated from other sources. The enzyme is absolutely specific for nicotinamide adenine dinucleotide phosphate (NADP) as a cofactor, and oxidizes only glucose or its analogue 2-deoxyglucose via the following reversible reaction: beta-d-glucose + NADP right harpoon over left harpoon d-glucono-delta-lactone + NADPH(2) + H(+). K(m) values were 2.3 x 10(-2) for glucose and 2 x 10(-4) for NADP. Monovalent cations were required for stability of the enzyme and stimulated activity. The pH optimum was 7.0, and the equilibrium constant was determined to be 13.4 x 10(-7) at pH 6.4. Among the Lactobacillaceae, glucose dehydrogenase activity was found to be essentially limited to members of the genus Pediococcus. Studies on the enzymatic composition of P. pentosaceus viewed in conjunction with other available data led to the conclusion that this enzyme is not involved to any significant extent in the energy metabolism of this organism.

Beaming light from a subwavelength metal slit surrounded by dielectric surface gratings

In this article, we demonstrate that a subwavelength metal slit surrounded by dielectric surface gratings possesses a directional beaming effect. We propose a surface plasmon diffraction scheme to explain the three kinds of beaming conditions. The numerical simulations of the illustrative structures undertaken used a Finite Difference Time Domain (FDTD) Method and a Rigorous Coupled Wave Analysis (RCWA) Method. Our simulations were found to be consistent and in agreement with the experimental results. In comparison with other metal structures, we find that dielectric metal structures offer better performance as well as the advantage of being able to be efficiently mass produced for large volume industrial applications.

Accumulation of chromium (VI) from aqueous solutions using water lilies (Nymphaea spontanea)

This study describes an investigation using tropical water lilies (Nymphaea spontanea) to remove hexavalent chromium from aqueous solutions and electroplating waste. The results show that water lilies are capable of accumulating substantial amount of Cr(VI), up to 2.119 mg g(-1) from a 10 mg l(-1) solution. The roots of the plant accumulated the highest amount of Cr(VI) followed by leaves and petioles, indicating that roots play an important role in the bioremediation process. The maturity of the plant exerts a great effect on the removal and accumulation of Cr(VI). Plants of 9 weeks old accumulated the most Cr(VI) followed by those of 6 and 3 weeks old. The results also show that removal of Cr(VI) by water lilies is more efficient when the metal is present singly than in the presence of Cu(II) or in waste solution. This may be largely associated with more pronounced phytotoxicity effect on the biochemical changes in the plants and saturation of binding sites. Significant toxicity effect on the plant was evident as shown in the reduction of chlorophyll, protein and sugar contents in plants exposed to Cr(VI) in this investigation.

Implications of increased tumor blood flow and oxygenation caused by mild temperature hyperthermia in tumor treatment

In many past clinical studies in which hyperthermia enhanced the efficacy of radiotherapy, the tumor temperatures could be raised only to 40-42 degrees C range in most cases. The heat-induced cell death, cellular radiosensitization, and vascular damage induced by such mild temperature hyperthermia (MTH) are likely to be insignificant despite the increased response of tumors to radiotherapy. Heating rodent tumors at 40-42 degrees C was found to cause an enduring increase in blood flow and oxygenation in the tumors. Recent studies with canine soft tissue sarcoma and human tumor clinical studies also demonstrated that MTH improves tumor oxygenation, and enhances response of the tumors to radiotherapy or chemoradiotherapy. The increased blood flow and vascular permeability caused by MTH may also improve the delivery of various therapeutic agents such as chemotherapy drugs, immunotherapeutic agents and genetic constructs for gene therapy to tumor cells. MTH as a means to potentiate the efficacy of radiotherapy and others warrants further investigation.

Effects of growth factors and feeder cells on porcine primordial germ cells in vitro

As embryonic stem (ES) cells are not available in swine, embryonic germ (EG) cells derived from primordial germ cells (PGCs) are an alternate source of pluripotent embryonic cells for genetic modification through homologous recombination. Although morphological and biochemical characteristics are similar between ES and EG cells, culture conditions are quite different. To optimize the culture condition for the establishment of porcine EG cells, porcine PGCs were cultured in vitro with various combinations of growth factors (leukemia inhibitory factor [LIF], stem cell factor [SCF], and basic fibroblast growth factor [bFGF]) and on different kinds of feeder cells (STO, TM(4), Sl/Sl(4) m220, porcine embryonic fibroblasts, and COS-7 cells). Optimal results were obtained when all three growth factors (LIF, SCF, and bFGF) were present in the media. Also, feeder cells expressing membrane-bound SCF are required for survival and establishment of porcine EG cells. Therefore, a combination of growth factors and proper feeder cells are critical for the establishment of undifferentiated porcine EG cells.