br Concluding remarks br Introduction Primary hepatocellular carcinoma

Concluding remarks

Introduction
Primary hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. Accumulating evidence has suggested that several mechanisms contribute to the carcinogenesis of HCC. Recent efforts to control the incidence of HCC have focused on developing effective new chemoprevention strategies. HCC induced by diethylnitrosamine (DEN) in Wistar rats that shows similarities to human HCC is an ideal model for investigating the effect of intervention by chemopreventive agent. DEN, a hepatocarcinogen, is known to induce perturbations in the nuclear enzymes involved in DNA repair/replication. Investigations have provided evidence that DEN causes a wide range of tumors in all animal species, and these compounds are considered to be effective health hazards to man.
Man is exposed to DEN through diet, in certain occupational settings, and through the use of tobacco products, cosmetics, pharmaceutical products, and agricultural chemicals. It has been reported that DEN, after its metabolic biotransformation, produces the promutagenic adducts, O6-ethyl deoxyguanosine and O4- and O6-ethyl deoxythymidine that can produce DNA chain damage, depurination or binding to DNA, and often generates a miscoding gene sequence, paving a way for the initiation of liver carcinogenesis. It has also been reported to produce reactive oxygen species (ROS), a potentially dangerous by-product of cellular metabolism that may directly affect cellular development, growth, and survival. Oxidative stress caused by ROS has been reported in membrane lipid peroxidation, DNA damage, and mutation associated with the initiation of various stages of the tumor formation process.
Polyphenolic compounds have the most promising pharmaceutical properties and have received greater attention than any other class of natural products to counter the ill effects of oxygen radicals. Umbelliferone (UMB), otherwise known as 7-hydroxycoumarin, is a coumarin derivative of benzopyrone that is naturally present in edible fruits, such as Bengal quince (Aegle marmelos Correa) and bitter orange (Citrus aurantium). UMB is known to have a wide spectrum of pharmaceutical effects including antioxidant, antidiabetic, antihyperglycemic, and anti-inflammatory properties. UMB acts as a fluorescent probe and is used in the monensin synthesis of drugs, especially anticancer drugs, and in the treatment of monensin and allergic disorders. The ultraviolet activity of UMB is used as a sunscreen agent and an optical brightener for textiles. It has also been used as a gain medium for dye lasers. UMB can be used as a fluorescence indicator for metal ions such as copper and calcium. It acts as a pH indicator in the 6.5–8.9 range. It is acutely toxic to laboratory animals in chronic oral gavage administration at doses ≥ 200 mg/kg and exposure of UMB induces irritation of the eyes, respiratory system, and skin.

Materials and methods

Results
Microscopic observations of UMB in DEN-treated rat liver are given in Fig. 2. Fig. 2 shows the histopathological examination of liver section. Control (Group 1) rats revealed normal liver parenchyma cells with granulated cytoplasm, small uniform nuclei, and central vein surrounded by cords of hepatocytes. Group 2 DEN-treated rats showed loss of architecture and lobules of neoplastic hepatocytes with a fecal area of fatty change. Group 3 rats exhibited normal architecture, indicating the non-toxic nature of UMB. Groups 4 and 5 rats co-treated with UMB and DEN showed moderate cancerous change, fatty change, and hydropic degeneration. Group 6 rats showed fewer neoplastically-transformed cells and the hepatocytes maintained near-normal architecture.

Discussion
In recent years, there has been a growing interest in dietary substances obtained from natural products having chemoprotective properties against chemical carcinogens. HCC is a common cancer and is the third leading cause of death worldwide. DEN is known to induce the reproducible and complete carcinogenic biochemical changes involved in the progression of HCC. ROS are potentially dangerous byproducts of cellular metabolism that have directly affected cellular growth, development, and survival. Lipid peroxidation is one of the major mechanisms of cellular injury caused by free radicals and acts as an important causative factor in carcinogenesis. DEN intoxication has been reported to generate lipid peroxidation byproducts that may interact with various biomolecules that lead to oxidative stress. This may be due to the uncontrolled generation of free radicals that overwhelms the antioxidant defense system. DEN-induced rats showed increased lipid peroxidation levels (thiobarbituric acid reactive substances, malondialdehyde and conjugated dienes) in both plasma and liver tissue. UMB administration to DEN-treated rats at three different doses 10 mg/kg, 20 mg/kg, and 30 mg/kg body weight every day led to significantly deceased levels of lipid peroxidation both in the plasma and liver when compared with animals induced with DEN alone. This shows the anti-lipid peroxidative role of UMB and is probably mediated by UMB’s ability to inhibit free radical generation. These results also correlate with the previous findings from our laboratory. The strong inhibitory effect of UMB at a dose of 30 mg/kg body weight/day was noticed.

br Introduction A specialty imbalance can lead to many problems

Introduction
A specialty imbalance can lead to many problems. Chang et al contended that monensin the unwillingness of young physicians to choose unpopular specialties causes insufficient labor supply in those specialties, ages the physician structure, generates a medical skills gap, reduces the ability to transfer experience, and lowers care quality. Medical specialist training begins at the student level. When medical students choose a specialty, their choice affects their career paths and the future medical services and quality provided by the medical industry. The considerations regarding factors influencing medical specialty selection should warrant special attention from medical educators for the future long-term development of the medical industry and for the well-being of the public.
By understanding personality traits, students can be provided with appropriate support during counseling and assistance in specialty selection and initiating career planning earlier. Schumacher (1963) and Yufit (1969) have explored the relationship between personality traits and medical specialty selection. Haley (1972) examined the association between personality traits and the performance of medical students during training. Borges (2001) asserted that personality traits are a vital factor influencing medical specialty selection. Thus, we explored and analyzed the relationship between personality traits and medical specialty preference.
Based on the statistical records of the Taiwan Medical Association, the authors noted that from 2002 to 2009, internists led all specialties, comprising approximately 22–23% of all specialists. Practitioners of general medicine ranked second, comprising approximately 9–11% of all specialists; surgeons ranked third, comprising approximately 9–10%; pediatricians ranked fourth, comprising approximately 7–8%; and practitioners of family medicine ranked fifth, comprising approximately 6–7%. From 2002 to 2009, the number of specialists in general medicine, surgery, and obstetrics and gynecology (OBGYN) decreased yearly, but the number of specialists in family medicine, psychiatry, and emergency medicine increased yearly. Yang and Tsai observed that among the specialties chosen by medical students in 1999, the five leading choices were internal medicine, surgery, dermatology, pediatrics, and family medicine. Meanwhile, Liu et al identified the five leading specialties in 2000 as internal medicine, pediatrics, surgery, family medicine, and dermatology. Therefore, the five most popular specialties of the years were similar, except for OBGYN, which was pushed out from fifth place.

Materials and methods
The participants were 4th- through 7th-year medical students who were enrolled at the College of Medicine at Chang Gung University between 2004 and 2007. Overall, 358 students participated in the study.
Because the EPPS can help the respondents explore their career interests, parasites is suitable and beneficial in college-student vocational or educational counseling. In addition, the traits measured by the EPPS possess neutral implications, reducing the likelihood of respondents purposely distorting their answers. Thus, the EPPS can be used to objectively assess the traits of the respondents. Psychology Press obtained duly authorized in writing from Allen L. Edwards was prepared in April 2005 in Taiwan. Using the Spearman–Brown split-half reliability adjustment, we calculated the split-half reliability of the whole test, and adjusted the split-half reliability of obedience to 0.56; the others were increased to 0.64 or higher. The criterion-related validity of the EPPS (Chinese version) of the 15 variables and 75 questions measuring between criteria is moderate. The reliability of the Chinese version of the EPPS ranges from acceptable to favorable; therefore, this study used the Chinese version of the EPPS to assess the personality traits of medical students.
The survey took about 10 minutes to explain. The students took about 50 minutes to answer the EPPS and 10 minutes to fill in basic information. It took approximately 3 weeks to complete the whole survey process. After the questionnaires had been completed and collected, the results were entered into a computer and analyzed using SPSS version 16.0 (SPSS Inc., Chicago, IL, USA). This study conducted descriptive statistical analysis, t tests, and analysis of variance to analyze various differences between factor groups.

Application of the decidual organ culture system for the study

Application of the decidual organ culture system for the study of innate immune responses to HCMV has obvious limitations in terms of analyzing the distinct molecular mechanisms underlining the observed findings at the cellular level. Yet, the complex structure of the decidual-tissue, which is composed of a multitude of cell types and extracellular matrix components, better reflects the in vivo clinical setting of HCMV infection, spread, and pathogenesis within the maternal–fetal interface.

Materials and methods

Acknowledgments
This work was supported by grants from the Israel Science Foundation (grant number 275/13), the European Union Seventh Framework Programme562 FP7/2012-2016 (grant agreement number 316655), and the Israeli Ministry of Health.

Introduction
Bovine viral diarrhea viruses (BVDV) are differentiated into two species (BVDV1 and BVDV2) within the Pestivirus genus of the family Flaviviridae. Both species infect a wide range of ruminant hosts with infection of cattle causing significant economic loss to producers worldwide (Gunn et al., 2004, 2005). Exposure to BVDV can result in both acute and persistent infections (McClurkin et al., 1984). Persistent infections are the consequence of in utero exposure during the first trimester of gestation. Persistent infections are maintained because the fetal monensin develops a tolerance for viral proteins that lasts for the life of the animal. Clinical presentation in PI animals runs the gamut from clinically normal and thriving to ill thrift with multiple congenital defects that include reduced growth rates and abnormalities of hair, skin and the skeletal nervous system (Evermann and Barrington, 2005). The reason for the variation in clinical presentation is unknown, but it is hypothesized that strain and fetal developmental stage at the time of infection may play a part. Because of the expense and difficulty in generating PI cattle, variation in clinical presentation in PI׳s is largely unstudied. Life long tolerance, as opposed to latency or chronic infection of immunologically privileged tissue, is a phenomenon that is unique to pestiviruses. Study of the mechanisms involved in establishing and maintaining persistent infection has the potential to significantly expand our understanding of immune functions.
Similar to other viruses with single stranded RNA genomes, BVDV isolates exist as quasispecies, or a swarm of individual viruses, each with variable numbers of nucleotide variations. In addition to the marked variation in clinical presentation (Evermann and Barrington, 2005), PI animals also vary in the amount of virus associated with circulating white blood cells (Bolin and Ridpath, 1990) and in their ability to transmit virus to naïve co-horts (Rodning et al., 2010). There is little information on the mechanisms that result in variations among PI animals and it is not known whether variations are due to differences in viral strains or host factors or a combination of the two. While it is apparent that not all persistent infections have the same outcome, there are few studies comparing variation among PI animals due to the expense and time involved in generating PI׳s. Another challenge is identifying measurable phenotypes that reflect viral variation within PI animals. In this study we compared the size and complexity of the viral populations circulating within PI׳s generated in the same outbreak. In this outbreak, 34 PI cattle were generated following an introduction of a BVDV2 field strain into a naïve group of heifers. This group of PI animals offered a rare opportunity to study variation in circulating viral populations among PI animals infected with the same virus. In addition a limited preliminary study was conducted that compared viral populations in PI calves generated under controlled conditions. The objective of these studies was to develop means that allow the comparison of the breadth and complexity of circulating viral populations in PI calves and then to use these means to examine the extent of variation, in circulating viral populations, that exists between PI calves.(Table 1).