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Epithelial hyperplasia in human polycystic kidney diseases. Its role in pathogenesis and risk of neoplasia. 总被引:4,自引:2,他引:4 下载免费PDF全文
The importance of tubular epithelial hyperplasia in polycystic kidney diseases has become apparent during the last decade. Micropapillary hyperplasia occurs in autosomal dominant polycystic kidney disease, in localized cystic disease, and in acquired cystic disease. Neoplastic or severely dysplastic epithelial hyperplasia occurs in von Hippel-Lindau disease. A histopathologically distinctive epithelial hyperplasia occurs in tuberous sclerosis. In each of these conditions, epithelial hyperplasia may be related to cyst formation and may also impose an increased risk of malignancy--a risk that seems to be highest in patients under treatment with long-term hemodialysis for end-stage kidney disease. Although hyperplasia in some of these diseases may share a common pathway of development, it is more probable that the histopathologic differences reflect different pathogenetic pathways that converge on a common endpoint. 相似文献
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Selective hyperthermia can be a feasible treatment modality for deep tissue abnormalities. It is accomplished by using a laser or ultrasound noninvasively to transfer energy to a desired target causing tissue damage. This process has two potential benefits to medical professionals: simplicity of procedure and safety to patient. However, optimizing these selective interactions is difficult due to the number of variables. We propose an optimization coefficient relating the dynamic and geometric parameters of selective hyperthermia, and proceed to measure it in an experimental setup consisting of a near-infrared laser and laser-absorbing dye. To simulate tissue, gelatin phantoms are created using a combination of water, intralipid, and gelatin. Our experiments use a 1.00-cm-diam spherical phantom that is homogeneously enhanced with an indocyanine green (ICG) solution and placed inside a nontarget phantom and irradiated by an 805-nm diode laser. Temperature measurements taken at different locations are analyzed so optimization coefficients can be calculated for different parameters. This optimization coefficient compares the difference in temperatures from inside and outside the target. Analysis of the values after thermal equilibrium provides information about the best parameter selection. Our findings indicate that the optimal ICG concentration and power combination for our tested parameters are 0.083% and 0.97 W, respectively. Based on our analysis, optimization can be obtained by using this coefficient to compare the selectivity of several parameter combinations. 相似文献
14.
Morphogenetic clonal growth of kidney epithelial cell line MDCK 总被引:6,自引:0,他引:6
MDCK (Madin-Darby canine kidney) cells were cultured either dispersed within hydrated collagen gel (HCG) or seeded atop a collagen substrate and then immediately overlaid with HCG. Individual cells exhibited clonal growth in three dimensions to form spherical cysts made up of a simple epithelium enclosing a fluid-filled lumen. The cells of MDCK cysts were polarized with the basolateral surface in contact with the collagen gel and the apical surface bordering the lumen. The ultrastructure of MDCK cysts showed similarities to distal nephron. The cells bore apical microvilli and solitary cilia and had occluding junctions and a simple basolateral surface. MDCK cysts increased in size (greater than 800 microns diameter) with continued culture. MDCK cysts grown between layers of HCG were stripped free of the overlying collagen to give direct access to basolateral surface membrane. Unlike monolayer culture, morphogenetic clonal growth of cell line MDCK produces a polarized cell population with a true lumenal and basolateral surface. Collagen-gel-cultured MDCK cysts provide an easily manipulable in vitro cell system that may offer unique advantages for the study of renal cell structure and function. 相似文献
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Wood E Hogg RS Yip B Tyndall MW Sherlock CH Harrigan RP O'Shaughnessy MV Montaner JS 《Journal of acquired immune deficiency syndromes (1999)》2002,30(2):159-166
BACKGROUND: In HIV-positive persons receiving antiretroviral therapy, CD4 cell responses are associated with optimal suppression of viral replication. However, increases in CD4 cell counts in the absence of viral suppression have been reported. We characterized plasma viral load (pVL) and CD4 cell count increases in closely followed patients to evaluate determinants and the prevalence of CD4 cell responses at a populational level. METHODS: All HIV-positive patients in the province of British Columbia, Canada, who were antiretroviral naive and initiated therapy between August 1996 and May 1998 were eligible for the study. The selection criteria were that patients had to have CD4 cell counts and pVLs measured at baseline and at least once during eight 16-week periods after the initiation of therapy. We characterized CD4 cell responses and sought patients who had a "discordant" increase at 1 year, which was defined as an increase in CD4 cell count of >or=50/mm3 with a <1 log10 decrease in pVL. We also evaluated adherence and antiretroviral use. RESULTS: Overall, when baseline and 1-year pVLs and CD4 cell counts were compared, 6.2% of patients had CD4 cell count increases without pVL decreases of >or=1 log10. However, when all pVLs before 1 year were considered, 92% of the discordant increases could be attributed to prior transient or partial viral suppression. Furthermore, although substantial increases in CD4 cell counts were observed in transient virologic responders, the cumulative number of antiretroviral agents used by this group was significantly higher than that used by full virologic responders (p <.001). CONCLUSIONS: Our results demonstrate that virtually all CD4 cell count increases can be attributed to transient or partial pVL suppression. Unmeasured pVL suppression likely explains discordant responses that have been previously reported. Similarities between transient and full virologic responders also appear to be time limited and are often associated with greater cumulative use of antiretroviral therapy by transient virologic responders. 相似文献
17.
The purpose of this special issue of Stem Cell Reviews is to address some of the most difficult ethical debates surrounding the derivation of pluripotent stem cell lines. The possible benefits of stem cells are widely discussed, but the scientific community is particularly aware that research in this area is still at an early, but essential, stage of development. With this research at such an early stage, it is noteworthy that the media, the public, religious leaders, politicians, policy makers, and regulators have had as much interest in stem cell research as for any other area of scientific inquiry. The central issue that has made this area so controversial has been the use of the human embryo for deriving stem cell lines. 相似文献
18.
Two- to four-day-old beagle puppy kidneys were preapred for transmission and scanning electron microscopy and compared to similarly prepared adult tissues. Proximal tubules of puppy kidneys which contained nephrons in various stages of differentiation were examined and maturational changes were described. Lateral surface contours of proximal tubular cells were initially smooth and relatively unfolded, but progressively acquired complex processes that may be recognized as lateral ridges and lateral-basal processes. Basal projections began as short, stubby processes and gradually took on either a narrow, plate-like or finger-like appearance. Mitochondria lysosomes and apical vacuoles increased in number as the tubules matured. Mitochondria lacked orientation in outer cortical tubules, but exhibited some vertical arrangement within basal processes in inner cortical tubules. Despite features indicating advanced maturation of tubules in the inner cortex, puppy kidneys lacked the lipid droplets characteristic of the adult. Thus, differentiation of this portion of the developing nephron into S1, S2 and S3 segments was not possible at day 4. Morphometric analyses of the lateral and basal membrane surface concentration of proximal convulted tubules from the puppy revealed all cells to have a significantly smaller membrane area than that of the adult. However, the inner cortical cells of the puppy had a greater surface concentration than those of the outer cortex. The reduced transport capacity of the puppy proximal tubule may be realted to the lack of segmentation and/or reduced lateral-basal surface area. 相似文献
19.
The role of unhealthy dietary pattern in the association between socio-economic factors and obesity is unclear. The aim was to examine the association between socio-economic disadvantage and obesity and to assess mediation effect of unhealthy dietary pattern defined using the Mediterranean diet criteria. The data source was the Australian National Nutrition and Physical Activity Survey. The study sample included 7744 participants aged 18 years and over, 28% of whom had obesity. We used the Australian Socio-Economic Indexes for Areas (SEIFA) classification system for categorizing socio-economic disadvantage; calculated the Mediterranean Diet Score (MDS) using standard criteria; and used measured body mass index to define obesity. We conducted a mediation analysis using log–binomial models to generate the prevalence ratio for obesity and the proportion mediated by the MDS. The most disadvantaged group was associated with higher level of obesity after controlling for covariates (1.40, 95% CI 1.25, 1.56) compared to the least disadvantaged group, and in a dose–response way for each decreasing SEIFA quintile. The relationship between socio-economic disadvantage and obesity was mediated by the MDS (4.0%, 95% CI 1.9, 8.0). Public health interventions should promote healthy dietary patterns, such as the Mediterranean diet, to reduce obesity, especially in communities with high socio-economic disadvantage. 相似文献
20.
Unsafe injection practices in a cohort of injection drug users in Vancouver: Could safer injecting rooms help? 总被引:10,自引:6,他引:4 下载免费PDF全文