128 research outputs found

    Effects of density-dependence, environment and species interaction during spawning and incubation on population dynamics of pink and sockeye salmon in the Auke Lake system, southeast Alaska

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    Thesis (Ph.D.) University of Alaska Fairbanks, 1996Mechanisms that regulate or influence fry and smolt production of pink and sockeye salmon in the Auke Lake system, southeast Alaska, were studied with special emphases on effects of: (1) density-dependence; (2) environmental effects; and (3) species interaction. There has been an increasing trend in the residuals of spawner-recruit models for pink and sockeye salmon since the late 1970's. A strong positive influence of precipitation was found in sockeye smolt production. Estimated spawner capacity of pink salmon was 15 times greater than sockeye salmon in the system. Pink salmon spawners varied in stream life (5-11 days), spawning efficiency (30-70% of daily cohorts of females retained less than 500 eggs at death), and habitat selection (30-70% spawned in Auke Creek rather than Lake Creek, the inlet stream). Variation of these attributes in female pink salmon was explained by various environmental variables using generalized linear models. Repeated use of limited spawning grounds by Pacific salmon, i.e., redd superimposition, can cause density-dependent mortality. Pink salmon egg loss from part of Auke Creek, estimated by a series of mark and recapture experiments, was roughly proportional to spawner abundance and not related to discharge. The maximum daily egg loss was estimated to be 3-400,000 eggs. Eggs in samples were more advanced in development later in the season. Eggs were washed out from the streambed due to redd superimposition; eggs spawned by early pink salmon spawners suffered higher mortality than eggs spawned by later spawners. The peak sockeye spawning preceded the peak pink spawning by approximately one week in Lake Creek, and the major spawning areas of sockeye salmon occurred approximately 250-350 m upstream from those of pink salmon. Microhabitat selection measured by four variables differed significantly between the species, but discrimination between the species was impossible because of large overlaps. Habitat variation was greater among different runs of sockeye salmon than between the two species. Sockeye salmon shifted spawning sites from riffles to pools as the season progressed

    Analysis of spontaneous regeneration of olfactory structures with emphasis on myelination and re-innervation of cortical areas

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    Regeneration of the lateral olfactory tract (LOT) occurs spontaneously after transection in developing rats. In neonatally LOT-transected rats, we observed a newly formed myelinated tract near the rhinal sulcus. The aim of this study was to analyze the precise re-innervated cortical areas and to demonstrate ectopic LOT myelination in neonatally LOT-transected rats. Neonatal rats were subjected to unilateral LOT transection and simultaneous injection of a retrograde fluorescent tracer into the posterior olfactory cortex to evaluate the degree of transection. After 8 weeks, bilateral olfactory bulbs of the rats were subjected to multiple injections of an anterograde neuronal tracer to determine the extent of the regenerated fibers. In the completely LOT-transected rats, the regenerated fibers were distributed in the anterior olfactory cortices: the anterior olfactory nucleus, the olfactory tubercle, and the rostral part of the piriform cortex. Ectopic myelination of LOT was evident immediately below the rhinal sulcus in the completely and incompletely LOT-transected rats. We concluded that the regenerated bulbar fibers were confined to the regions of the anterior olfactory cortices and that ectopic myelination of the regenerated LOT occurred only at a specific site near the rhinal sulcus.ArticleNEUROSCIENCE LETTERS. 537:35-39 (2013)journal articl

    Frequent Consumption of Vegetables and The Decreased Risk of Ovarian Cancer

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    A case-control study was conducted to assess the relationship of dietary habits to ovarian cancer. A uniform questionnaire was filled out by 44 ovarian cancer cases hospitalized at Sapporo Medical University or 2 other hospitals in Sapporo between August and norember, 1990. Two hundred twenty individually locality-matched controls were selected from telephone books and sent the same questionnaire ; 156 (70.9%) responded. The conditional logistic regression anal-ysis was used to compare the data of 44 ovarian cancer cases and the 156 individ-ually age-matched controls. Univariate analysis revealed that single marital sta-tus was significantly associated with the increased risk of ovarian cancer (odds ratio, or OR=3.45, 95% confidence interval, or 95%CI 1.13-10.84). Frequent intake of midnight meals was also significantly related to the increased risk (trend, OR=1.56, 95%CI 1.01-2.41), and frequent intake of vegetables other than yellow or red was significantly related to the decreased risk (trend, OR= 0.58, 95%CI 0.37-0.91). These odds ratios concerning dietary habits were not substantially altered even after adjustment for potentially distorting variables such as marital status, the number of parities, and family history for uterine, ovarian, or breast cancer with the multivariate analysis. No other dietary habits, including frequent consumption of meat, fish, or milk, were associated with the increase or decrease of the risk of ovarian cancer

    Gluonic phase in neutral two-flavor dense QCD

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    In the Ginzburg-Landau approach, we describe a new phase in neutral two-flavor quark matter in which gluonic degrees of freedom play a crucial role. We call it a gluonic phase. In this phase gluonic dynamics cure a chromomagnetic instability in the 2SC solution and lead to spontaneous breakdown of the color gauge symmetry, the electromagnetic U(1), and the rotational SO(3). In other words, the gluonic phase describes an anisotropic medium in which the color and electric superconductivities coexist. Because most of the initial symmetries in this system are spontaneously broken, its dynamics is very rich.Comment: Revtex4, 11 pages, clarifications and new section added, references added, to appear in Phys. Lett.

    Structural and Expressional Alterations of Episomal and Integrated Human Papillomavirus Type 16 in Precancerous Lesions and Carcinomas of the Cervix.

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    HPV infection has long been implicated in the development of cervical car-cinoma. We have analyzed the HPV 16 genome structure and expression of the viral mRNA in cervical intraepithelial neoplasias (CINs) and cervical car-cinomas by using modified polymerase chain reaction (PCR) methods. Genome structure has been determined by PCR using multi-primer sets which are located in each open reading frames and then these results have been compared with the physical state of the viral DNA determined by two-dimensional electrophoresis. Furthermore, we have analyzed the expression of HPV 16 mRNA and genome structure using DNA and RNA simultaneously extracted from CINs and cervical carcinomas using PCR and reverse transcription (RT-) PCR. Our data showed that the DNA regions from the El to Ll region were delet-ed in two of three CINs containing episomal HPV 16 and three out of seven cervical carcinomas containing integrated HPV 16. However, the E6/E7 region was conserved in all the HPV 16-positive samples. RT-PCR analysis has determined the presence of mRNA species which could encode the E6, E6*I, E6*II, E7, E2, E2 ? C, E1^E4, E1^E2 ? C, E4, E2 ? C-E5 and L2 proteins. The overall results of DNA and mRNA analyses in cervical lesions indicated that the expression patterns of the early and late transcripts studied were not specifically related to the grade of malignancy and the physical state or the deletion of the viral genome. Furthermore, alterations in the splicing pat-terns of HPV 16 transcripts may not be involved in tumor progression

    The Double Polymerase Chain Reaction with Consensus Primers Permits Rapid and Sensitive Detection of Genital Human Papillomavirus Oncogenes

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    We have developed a sensitive procedure for the detection of relatively low copy numbers of multiple genital human papillomaviruses (HPVs) using the polymerase chain reaction (PCR). HPV DNAs were detected by agarose gel electrophoresis and ethidium bromide staining after 2 rounds of PCR amplification (double PCR) with outer and inner consensus primer pairs for HPV-6, 11, 16, 18, 31, 33, 52, and 58. The detection limit of this method (i. e., 10?? copy of HPV DNA per cell in 1 μg cell DNA) was sufficient for analysis of cervical intraepithelial neoplasia (CIN) specimens. Overall prevalence rate of HPV was 100% in 20 cases of CIN specimens. HPV typing by restriction enzyme analysis revealed that HPV-16 sequence was present in 11 cases, HPV-18 in 1 case, HPV-31 in 4 cases, HPV-33 in 1 case, HPV-52 in 2 cases, HPV-58 in 3 cases, and an unidentified type(s) in 3 cases. There were 4 cases of mixed infections. This procedure obviates the use of hybridization- based for-mat for identification of at least 8 types of HPV sequences present in a small fraction of cells within a heterogeneous population

    Diagnostic Performance of 11C-choline PET/CT and FDG PET/CT in Prostate Cancer

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    We compared 11C-choline and FDG PET/CT scan findings for the staging and restaging of prostate cancer. Twenty Japanese prostate cancer patients underwent 11C-choline and FDG PET/CT before (n=5) or after (n=15) treatment. Using a five-point scale, we compared these scanning modalities regarding patient- and lesion-based diagnostic performance for local recurrence, untreated primary tumor, and lymph node and bony metastases. Of the 20 patients, documented local lesions, and node and bony metastases were present in 11 (55.0%), 9 (45.0%), and 13 (65.0%), respectively. The patient-based sensitivity/specificity/accuracy/area under the receiver-operating-characteristic curve (AUC) values for 11C-choline-PET/CT for diagnosing local lesions were 90.9% /100%/ 95.0% / 1.0, whereas those for FDG-PET/CT were 45.5% /100%/ 75.0% / 0.773. Those for 11C-choline-PET/CT for node metastasis were 88.9% /100%/ 95.0% / 0.944, and those for FDG-PET/CT were 44.4%/100%/75.0%/0.722. Those for 11C-choline-PET/CT for bone metastasis were 84.6%/100%/90.0%/0.951, and those for FDG-PET/CT were 76.9% /100%/ 85.0% / 0.962. The AUCs for local lesion and node metastasis differed significantly (p=0.0039, p=0.011, respectively). The lesion-based detection rates of 11C-choline compared to FDG PET/CT for local lesion, and node and bone metastases were 91.7% vs. 41.7%, 92.0% vs. 32.0%, and 94.8% vs. 83.0% (p=0.041, p=0.0030, p<0.0001), respectively. 11C-choline-PET/CT is more useful for the staging and restaging of prostate cancer than FDG-PET/CT in Japanese men

    Tree of motility – A proposed history of motility systems in the tree of life

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    Motility often plays a decisive role in the survival of species. Five systems of motility have been studied in depth: those propelled by bacterial flagella, eukaryotic actin polymerization and the eukaryotic motor proteins myosin, kinesin and dynein. However, many organisms exhibit surprisingly diverse motilities, and advances in genomics, molecular biology and imaging have showed that those motilities have inherently independent mechanisms. This makes defining the breadth of motility nontrivial, because novel motilities may be driven by unknown mechanisms. Here, we classify the known motilities based on the unique classes of movement-producing protein architectures. Based on this criterion, the current total of independent motility systems stands at 18 types. In this perspective, we discuss these modes of motility relative to the latest phylogenetic Tree of Life and propose a history of motility. During the ~4 billion years since the emergence of life, motility arose in Bacteria with flagella and pili, and in Archaea with archaella. Newer modes of motility became possible in Eukarya with changes to the cell envelope. Presence or absence of a peptidoglycan layer, the acquisition of robust membrane dynamics, the enlargement of cells and environmental opportunities likely provided the context for the (co)evolution of novel types of motility
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