Molecular characterization of the full-length genome of the Japanese encephalitis viral strain K87P39

We have determined the complete nucleotide and deduced amino acid sequences of the Japanese encephalitis virus (JEV) strain K87P39, isolated from a pool of circulating Culex tritaeniorhynchus mosquitoes in Korea. In comparison with 27 fully sequenced JEV genomes currently available, we found that the 10968-nucleotide RNA genome of K87P39 has a nine-nucleotide deletion in the 3' nontranslated variable region and that its single open reading frame has a total of eight amino acid substitutions. The K87P39 isolate is highly similar to other JEV isolates, and homology ranges from 97.9 to 89.0% at the nucleotide level, and 99.1 to 96.7% at the deduced amino acid level. Phylogenetic analyses using the full-length sequence of the 27 available JEV genomes showed that the K87P39 strain is most closely related to six Chinese SA14 derivatives and that it is distantly related to the Australian FU, Korean K94P05 and Japanese Ishikawa strains. In addition, we also found that phylogenetic relationships based on the full-length genome are highly similar to those based on the E gene, indicating that phylogenetic analysis of the E gene will be useful for studying the genetic relationships among JEV isolates. We therefore performed a more extensive E gene-based phylogenetic analysis on a selection of 70 JEV isolates available from GenBank, which represent a temporally and geographically wide variety of JEV strains.     

Brain tumor in the first year of life: a single institute study.

Brain tumors in infants present special diagnostic and therapeutic challenges. To figure out the clinical features, pathological classification of the tumors and the treatment outcome of infantile brain tumors, 458 children (age<16) with brain tumors were reviewed retrospectively. Among them 21 cases (4.6%) were diagnosed during the first 12 months of life. Two tumors were definitely of congenital origin. The majority of infants with brain tumors presented with increased intracranial pressure. Fourteen tumors were located at the supratentorial area. Sixteen cases had neuroepithelial tumors; astrocytoma (optic pathway), supratentorial primitive neuroectodermal tumor (PNET) and medulloblastoma were found in three cases each. There were two treatment-related mortalities. Compared with the outcomes in older children, the treatment outcome was poorer in medulloblastoma and the optic pathway glioma which showed a higher growth potential. Because of the limited application of postoperative adjuvant therapy, radical surgical removal played a more important role in this age group. The prognosis of patients in whom the tumors could not be totally removed, largely depended on the pathological malignancy of the tumors. Though the treatment outcome was not always dismal, immaturity of the brain, higher growth potential, perioperative risks, limitations in adjuvant therapy, and pessimistic attitude on the part of parents made management more challenging.     

REM sleep deprivation inhibits LTP in vivo in area CA1 of rat hippocampus

Rapid eye movement (REM) sleep deprivation has previously been shown to interfere with normal learning and memory and to inhibit long-term potentiation (LTP) in vitro. Previous studies on REM sleep deprivation and LTP have relied on in vitro analysis in isolated brain slices taken from animals following several days of sleep deprivation. LTP in the hippocampus in situ may differ from LTP in vitro due to modulatory inputs from other brain regions, which are altered after REM sleep deprivation. Here, we examined LTP in unanesthetized, behaving animals on the first and second recovery days following REM sleep deprivation to determine if similar effects are seen in vivo as previously reported in vitro. We found that LTP was significantly impaired in REM sleep-deprived animals on the second recovery day but not the first recovery day. Our results extend previous findings by showing that REM sleep deprivation continues to affect hippocampal function for more than 24h following the end of deprivation. Our results also suggest the presence of a modulatory process not present in vitro. Our findings are not explained by stress during REM sleep deprivation because equivalent circulating corticosterone levels (an index of stress) were found during both REM sleep deprivation and control treatment.     

Cardiac pathology in the hypertensive diabetic rat. Biventricular damage with right ventricular predominance.

The hypertensive-diabetic rat is a new small animal model of cardiomyopathy characterized by ventricular damage. To determine the extent of pathology in this model, quantitation of light microscopic changes in hearts from 15 hypertensive-diabetic rats and 15 age-matched controls was performed. The fraction of myocardium involved by interstitial fibrosis, myocyte necrosis, replacement fibrosis, vascular sclerosis and perivascular fibrosis was computed separately for right and left ventricles. Spontaneously dying as well as deliberately killed hypertensive-diabetic rats were studied. Spontaneously dying animals had higher systolic blood pressures compared with rats killed deliberately. Body weights were lower and lung weights higher in the former group. Left and right ventricular necrosis and fibrosis were increased in spontaneously dying compared with deliberately killed rats. The degree of right ventricular necrosis and fibrosis paralleled that in the left ventricle, but was, unexpectedly, several times greater in magnitude. Thus, quantitative histology in the hypertensive-diabetic rat reveals more cardiac necrosis and fibrosis, in either ventricle, from spontaneously dying animals compared with deliberately killed rats. This damage, coupled with major functional alterations in the viable myocardium, may lead to congestive heart failure or arrhythmia.     

GSTP1 polymorphism,cigarette smoking and cervical cancer risk in Korean women

Previous studies have suggested that glutathione S-transferase (GST) genotypes may play a role in determining susceptibility to cervical cancer, though the data have often been conflicting. The objective of this study was to examine the effect of GSTP1 polymorphism on cervical carcinogenesis. The studied subjects, patients who were pathologically diagnosed with invasive cervical cancer yielding positive results for human papillomavirus (HPV) (n=342), were compared to healthy, normal, female controls (n=707). DNA from peripheral blood samples from studied subjects whose GSTP1 specific sequences had been determined by PCR with allele-specific primers were reviewed in comparison with the normal controls. The genetic susceptibility of GSTP1 (11q 13.1) in cervical carcinogenesis was determined by examining the effect of gene and environmental factors by the different histopathologic types of invasive cervical cancers. In assessing polymorphism GSTP1, the percentages of individuals homozygous for the A allele, homozygous for the G allele, and heterozygous for the two alleles were 66.8%, 3.9%, and 29.3%, respectively, in the control group, and 64.3%, 4.1%, and 31.6%, respectively, among in women with cervical cancer. Compared with GSTP1 G allele positive (GA or G/G), the odds ratio (OR) (95% confidence interval) for GSTP1 A/A was 1.0 (0.7 - 1.4) for invasive cervical cancer. However, the risk increased with GSTP1 A/A among ever smokers (3.9, 1.7 - 8.9, p-value=0.0012) compared with GSTP1 G allele positive among nonsmokers. In particular, this risk was higher among women with squamous cell carcinoma (4.7, 2.0 - 10.8, p=0.0003). Polymorphism of GSTP1 among smoking women was associated with a higher risk of developing cervical cancer.     

Determining optimal two-beam axial orientations for heart sparing in left-sided breast cancer patients

BACKGROUND AND PURPOSE: The optimal intensity fluence profile of a beam depends on the profiles of other beams but most optimizations assume fixed beam orientations, a priori. Breast cancer radiotherapy attempts to cover the target and to spare critical structures such as the heart and lungs. The study aims are (1) to determine and document the optimal two-beam orientation that best spares the heart for left-sided breast cancer patients and (2) to investigate the influence of the treatment technique (i.e., conformal versus intensity modulation) on the optimal objective cost function. MATERIAL AND METHODS: Ten left-sided breast cancer patients were planned using a conformal (3DCRT) and a simplified intensity modulated (sIMRT) technique using predefined segments and different two-beam orientations. Optimal segment weights were determined exhaustively for all axial two-beam combinations, in 5 degree increments, by minimizing a quadratic objective cost function. The resulting objective cost function was analyzed with respect to target geometry and treatment technique. RESULTS: The sIMRT plans are generally less sensitive to beam orientation compared to 3DCRT plans. Optimal two-beam orientations for 3DCRT and sIMRT plans exist and they correspond to a hinge angle of approximately 188 degrees and 160 degrees or 210 degrees (the latter is bimodal), respectively. CONCLUSIONS: The optimization software is a useful tool that can test many different beam combinations and estimate their associated objective cost values. Afterwards, the most promising beam orientations could be re-optimized under the TPS to fine-tune and verify the dose distributions. Optimal uniform two-beam orientations for the breast consist of opposing tangential medial and lateral beams. Optimal nonuniform two-beam orientations for left-sided breast cancers are bimodal, containing hinge angles around 160 degrees and 210 degrees. Nonuniform beam techniques are less sensitive to beam orientation compared to uniform beam techniques and result in significantly improved heart sparing but at a cost of slightly compromised planning target volume coverage.     

Expression of cytokeratins 7 and 20 in primary carcinomas of the stomach and colorectum and their value in the differential diagnosis of metastatic carcinomas to the ovary

The expressions of cytokeratin (CK) 7 and 20 have been studied in various primary and metastatic carcinomas, and their determination may help distinguish the site of origin of metastatic carcinomas. However, little is known about the factors that determine variations in their expression patterns in primary gastric and colorectal carcinomas. We investigated the expressions of CK7 and CK20 in 289 cases of gastric carcinoma and 225 cases of colorectal carcinoma using a tissue microarray. To evaluate CK7 and CK20 expression patterns of ovarian metastases from gastric or colorectal carcinomas, 54 cases of metastatic carcinomas to the ovary were examined. It was found that 71% (207 of 289) of the gastric carcinomas stained positively for CK7, whereas only 9% (21 of 225) of the colorectal carcinomas proved to be CK7 positive, and that 41% (117 of 289) of the gastric carcinomas and 73% (165 of 225) of the colorectal carcinomas were CK20 positive. The proportion of CK7+/CK20- was highest in the gastric carcinomas at 46% (132 of 289), and was independent of the histologic classification of Lauren (46% of the intestinal type, 45% of the diffuse type). The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histologic grade and location of the tumor. CK7-/CK20+ had the greatest proportion (68%) in colorectal carcinomas, and this was dependent on the tumor's histologic grade (75% of low-grade versus 52% of high-grade) and location (46% of right-sided versus 76% of left-sided). Moreover, 42% (18 of 43) of gastric carcinomas metastatic to the ovary were CK7+/CK20-, whereas 19% (8 of 43) were CK7-/CK20+. All colorectal cancers metastatic to the ovary were CK7-/CK20+, except 1 case that was CK7-/CK20-. In conclusion, the CK7 and CK20 expression patterns in primary gastric carcinomas vary considerably, and those in colorectal carcinomas are associated with histologic grade and tumor location. The CK7-/CK20+ expression pattern is specific for metastatic colorectal carcinomas to the ovary, but has low predictability for colorectal origin in metastatic ovarian carcinoma.     

Synthesis and characterization of polyanhydride for local BCNU delivery carriers

p-Carboxyphenoxy propane (CPP) prepolymer consisting of 4 units and sebacic acid (SA) prepolymer consisting of about 10 units were synthesized by reacting CPP and SA in the presence of excess acetic anhydride, respectively. Polyanhydride, poly(CPP-SA) copolymers were copolymerized by a melt polycondensation process with a mixture of CPP and SA prepolymer. Copolymers of average molecular weight up to 110,000 g/mol were achieved. The crystallinity of poly(CPP-SA) copolymers was decreased by the addition of the CPP homopolymer segment to SA homopolymer. Poly(CPP-SA) copolymers gradually degraded for period of 10 days. No large difference of weight loss observed according to molecular weight variation of poly(CPP-SA) copolymers. BCNU release from wafers fabricated by poly(CPP-SA) showed a sustained release pattern with no initial burst and delay of drug release.