Obesity during childhood and beyond may have its origins during fetal or early postnatal life. At present, there are no suitable in vivo experimental models to study factors that modulate or perturb human fetal white adipose tissue expansion, remodeling, development, adipogenesis, angiogenesis, or epigenetics. We have developed such a model. It involves the xenotransplantation of mid-gestation human white adipose tissue into the renal subcapsular space of immunocompromised SCID-beige mice. After an initial latency period of approximately two weeks, the tissue begins expanding. The xenografts are healthy and show robust expansion and angiogenesis for at least two months following transplantation. Data and cell size and gene expression are consistent with active angiogenesis. The xenografts maintain the expression of genes associated with differentiated adipocyte function. In contrast to the fetal tissue, adult human white adipose tissue does not engraft. The long-term viability and phenotypic maintenance of fetal adipose tissue following xenotransplantation may be a function of its autonomous high rates of adipogenesis and angiogenesis. Through the manipulation of the host mice, this model system offers the opportunity to study the mechanisms by which nutrients and other environmental factors affect human adipose tissue development and biology.
Habitat loss and over collection have caused North American pitcher plants to become rare, including U.S. federally endangered Sarracenia alabamensis and S. oreophila, and S. leucophylla, S. psittacina and S. purpurea spp. venosa, endangered in several states.
Herpes simplex virus is a common virus that causes a variety of clinical presentations ranging from mild to life-threatening. Orolabial and genital herpes are common disorders that can often be managed in an outpatient setting; however, some patients do present to the emergency department with those conditions, and emergency clinicians should be aware of possible complications in the pediatric population. Neonatal herpes is a rare disorder, but prompt recognition and initiation of antiviral therapy is imperative, as the morbidity and mortality of the disease is high. Herpes encephalitis is an emergency that also requires a high index of suspicion to diagnose. Herpes simplex virus is also responsible for a variety of other clinical presentations, including herpes gladiatorum, herpetic whitlow, eczema herpeticum, and ocular herpes. This issue reviews the common clinical presentations of the herpes simplex virus, the life-threatening infections that require expedient identification and management, and recommended treatment regimens.
Human population-based genome-wide association (GWA) studies identify low penetrance breast cancer risk alleles; however, GWA studies alone do not definitively determine causative genes or mechanisms. Stringent genome- wide statistical significance level requirements, set to avoid false-positive associations, yield many false-negative associations. Laboratory rats (Rattus norvegicus) are useful to study many aspects of breast cancer, including genetic susceptibility. Several rat mammary cancer associated loci have been identified using genetic linkage and congenic strain based-approaches. Here, we sought to determine the amount of overlap between GWA study nominated human breast and rat mammary cancer susceptibility loci.
Enterobius vermicularis is a parasite that inhabits the human digestive tract. We present two pediatric patients with symptoms mimicking acute appendicitis who were found to have E. vermicularis infection. The first case is a 5-year-old female who presented with flank and abdominal pain associated with low-grade fever and anorexia. She had localized tenderness in the right lower quadrant and a leukocytosis with left shift. Intraoperative findings included a normal-appearing appendix, but ex vivo examination revealed Enterobius vermicularis. The second case is a 7-year-old female who presented with periumbilical abdominal pain, anorexia, and emesis. She had tenderness at McBurneys point, and ultrasound revealed a small echogenic focus within the appendix. Intraoperatively, the distal tip of the appendix appeared inflamed. Again, ex vivo examination revealed E. vermicularis. Enterobius vermicularis infection of the appendix can present with a clinical picture similar to acute appendicitis. In at-risk populations, it should be included in the differential diagnosis for children with right lower quadrant abdominal pain. Complete therapy requires treatment with mebendazole.
Microsatellite markers (N = 5) were developed for analysis of genetic variation in 15 populations of the columnar cactus Stenocereus stellatus, managed under traditional agriculture practices in central Mexico. Microsatellite diversity was analyzed within and among populations, between geographic regions, and among population management types to provide detailed insight into historical gene flow rates and population dynamics associated with domestication. Our results corroborate a greater diversity in populations managed by farmers compared with wild ones (H E = 0.64 vs. 0.55), but with regional variation between populations among regions. Although farmers propagated S. stellatus vegetatively in home gardens to diversify their stock, asexual recruitment also occurred naturally in populations where more marginal conditions have limited sexual recruitment, resulting in lower genetic diversity. Therefore, a clear-cut relationship between the occurrence of asexual recruitment and genetic diversity was not evident. Two managed populations adjacent to towns were identified as major sources of gene movement in each sampled region, with significant migration to distant as well as nearby populations. Coupled with the absence of significant bottlenecks, this suggests a mechanism for promoting genetic diversity in managed populations through long distance gene exchange. Cultivation of S. stellatus in close proximity to wild populations has led to complex patterns of genetic variation across the landscape that reflects the interaction of natural and cultural processes. As molecular markers become available for nontraditional crops and novel analysis techniques allow us to detect and evaluate patterns of genetic diversity, genetic studies provide valuable insights into managing crop genetic resources into the future against a backdrop of global change. Traditional agriculture systems play an important role in maintaining genetic diversity for plant species.
Optical tweezers are exciting tools with which to explore liquid crystal (LC) systems; the motion of particles held in laser traps through LCs is perhaps the only approach that allows a low Ericksen number regime to be accessed. This offers a new method of studying the microrheology associated with micrometre-sized particles suspended in LC media--and such hybrid systems are of increasing importance as novel soft-matter systems. This paper describes the microrheology experiments that are possible in nematic materials and discusses the sometimes unexpected results that ensue. It also presents observations made in the inverse system; micrometre-sized droplets of LC suspended in an isotropic medium.
Bexarotene was evaluated in treating advanced non small cell lung cancer (NSCLC) in two phase III trials. Although a significant survival benefit was not observed for the overall bexarotene-treated population (617 patients), a third of bexarotene-treated patients who developed high-grade hypertriglyceridemia exhibited significantly longer survival.
Rapamycin is an inhibitor of the mammalian Target of Rapamycin, mTOR, a nutrient-sensing signaling kinase and a key regulator of cell growth and proliferation. While rapamycin and related compounds have anti-tumor activity, a prevalent characteristic of cancer cells is resistance to their anti-proliferative effects. Our studies on nutrient regulation of fetal development showed that hepatocyte proliferation in the late gestation fetal rat is resistant to rapamycin. Extension of these studies to other tissues in the fetal and neonatal rat indicated that rapamycin resistance is a characteristic of normal cell proliferation in the growing organism. In hepatic cells, ribosomal biogenesis and cap-dependent protein translation were found to be relatively insensitive to the drug even though mTOR signaling was highly sensitive. Cell cycle progression was also resistant at the level of cyclin E-dependent kinase activity. Studies on the effect of rapamycin on gene expression in vitro and in vivo demonstrated that mTOR-mediated regulation of gene expression is independent of effects on cell proliferation and cannot be accounted for by functional regulation of identifiable transcription factors. Genes involved in cell metabolism were overrepresented among rapamycin-sensitive genes. We conclude that normal cellular proliferation in the context of a developing organism can be independent of mTOR signaling, that cyclin E-containing complexes are a critical locus for rapamycin sensitivity, and that mTOR functions as a modulator of metabolic gene expression in cells that are resistant to the anti-proliferative effects of the drug.
Only a portion of the estimated heritability of breast cancer susceptibility has been explained by individual loci. Comparative genetic approaches that first use an experimental organism to map susceptibility QTLs are unbiased methods to identify human orthologs to target in human population-based genetic association studies. Here, overlapping rat mammary carcinoma susceptibility (Mcs) predicted QTLs, Mcs6 and Mcs2, were physically confirmed and mapped to identify the human orthologous region. To physically confirm Mcs6 and Mcs2, congenic lines were established using the Wistar-Furth (WF) rat strain, which is susceptible to developing mammary carcinomas, as the recipient (genetic background) and either Wistar-Kyoto (WKy, Mcs6) or Copenhagen (COP, Mcs2), which are resistant, as donor strains. By comparing Mcs phenotypes of WF.WKy congenic lines with distinct segments of WKy chromosome 7 we physically confirmed and mapped Mcs6 to ~33 Mb between markers D7Rat171 and gUwm64-3. The predicted Mcs2 QTL was also physically confirmed using segments of COP chromosome 7 introgressed into a susceptible WF background. The Mcs6 and Mcs2 overlapping genomic regions contain multiple annotated genes, but none have a clear or well established link to breast cancer susceptibility. Igf1 and Socs2 are two of multiple potential candidate genes in Mcs6. The human genomic region orthologous to rat Mcs6 is on chromosome 12 from base positions 71,270,266 to 105,502,699. This region has not shown a genome-wide significant association to breast cancer risk in pun studies of breast cancer susceptibility.
Sarracenia species (pitcher plants) are carnivorous plants which obtain a portion of their nutrients from insects captured in the pitchers. Sarracenia species naturally hybridize with each other, and hybrid swarms have been identified. A number of the taxa within the genus are considered endangered. In order to facilitate evolutionary, ecological and conservation genetic analyses within the genus, we developed 25 microsatellite loci which show variability either within species or between species. Three S. purpurea populations were examined with 10 primer sets which showed within population variability.
We investigated mTOR regulation of gene expression by studying rapamycin effect in two hepatic cell lines, the non-tumorigenic WB-F344 cells and the tumorigenic WB311 cells. The latter are resistant to the growth inhibitory effects of rapamycin, thus providing us with an opportunity to study the gene expression effects of rapamycin without confounding effects on cell proliferation.
The mTOR inhibitor rapamycin has anti-tumor activity across a variety of human cancers, including hepatocellular carcinoma. However, resistance to its growth inhibitory effects is common. We hypothesized that hepatic cell lines with varying rapamycin responsiveness would show common characteristics accounting for resistance to the drug.
A Chilean flamingo (Phoenicopterus chilensis) was presented to the veterinary clinic at the North Carolina Zoological Park for evaluation of acute weakness of the right wing. Results of a physical examination revealed a lack of a palpable pulse in the radial artery, which suggested occlusion or obstruction of the vessel. Radiography, thermography, and fluorescein angiography confirmed right wing injury and vascular compromise. Based on the poor prognosis for return to function associated with irreversible vascular damage, the wing was amputated. After a period of observation and treatment, the bird was returned to public exhibit.
Multiple human breast and rat mammary carcinoma susceptibility (Mcs) alleles have been identified. Wistar Kyoto (WKY) rats are resistant to developing mammary carcinomas, while Wistar Furth (WF) females are susceptible. Gene transcripts at Mcs5a1, Mcs5a2, and Mcs5c are differentially expressed between resistant WKY and susceptible WF alleles in immune-system tissues. We hypothesized that immune-related gene transcript profiles are genetically determined in mammary carcinoma resistant and susceptible mammary glands. Low-density QPCR arrays were used to compare inflammation related genes between mammary carcinoma resistant WKY and susceptible WF females. Mammary gland gene transcript levels predicted to be different based on arrays were tested in independent samples. In total, 20 females per strain were exposed to 7,12-dimethylbenz(a)anthracene (DMBA) to induce mammary carcinogenesis. Twelve age-matched controls per strain without DMBA were included to determine main effects of DMBA-exposure. Significant (ANOVA P ? 0.01) effects of strain on mammary gland transcript level were observed for Cx3cl1, Il11ra, Il4, C3, Ccl20, Ccl11, Itgb2, Cxcl12, and Cxcr7. Significant effects of DMBA-exposure were observed for Cx3cl1, Il11ra, Cxcr4, Il4ra, and Il4. Strain and DMBA-exposure interaction effects were significant for Cx3cl1. Transcript levels of Cxcr7 relative to Cxcr4 were modified differently by DMBA in mammary carcinoma resistant and susceptible strains. In conclusion, several genetically-determined differences in cytokine, chemokine, and receptor gene transcript levels were identified between mammary carcinoma susceptible and resistant mammary glands, which may be indicative of cell populations and activities that suppress mammary carcinogenesis in resistant genotypes.
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease that has deleterious consequences in muscle and bone, leading to decreased mobility, progressive osteoporosis, and premature death. Patients with DMD experience a higher-than-average fracture rate, particularly in the proximal and distal femur and proximal tibia. The dystrophin-deficient mdx mouse is a model of DMD that demonstrates muscle degeneration and fibrosis and osteoporosis. Parathyroid hormone, an effective anabolic agent for post-menopausal and glucocorticoid-induced osteoporosis, has not been explored for DMD. Black bear parathyroid hormone (bbPTH) has been implicated in the maintenance of bone properties during extended periods of disuse (hibernation). We cloned bbPTH and found 9 amino acid residue differences from human PTH. Apoptosis was mitigated and cAMP was activated by bbPTH in osteoblast cultures. We administered 28nmol/kg of bbPTH 1-84 to 4-week old male mdx and wild type mice via daily (5×/week) subcutaneous injection for 6 weeks. Vehicle-treated mdx mice had 44% lower trabecular bone volume fraction than wild type mice. No changes were found in femoral cortical bone geometry or mechanical properties with bbPTH treatment in wild type mice, and only medio-lateral moment of inertia changed with bbPTH treatment in mdx femurs. However, ?CT analyses of the trabecular regions of the distal femur and proximal tibia showed marked increases in bone volume fraction with bbPTH treatment, with a greater anabolic response (7-fold increase) in mdx mice than wild type mice (2-fold increase). Trabecular number increased in mdx long bone, but not wild type bone. Additionally, greater osteoblast area and decreased osteoclast area were observed with bbPTH treatment in mdx mice. The heightened response to PTH in mdx bone compared to wild type suggests a link between dystrophin deficiency, altered calcium signaling, and bone. These findings support further investigation of PTH as an anabolic treatment for DMD-induced osteoporosis.
Oval cell activation occurs under conditions of severe liver injury when normal hepatocyte proliferation is blocked. Recent studies have shown that a subset of hepatocellular carcinomas expresses oval cell markers, suggesting that these cells are targets of hepatocarcinogens. However, the signaling pathways that control oval cell activation and proliferation are not well characterized. Based on the role of the nutrient signaling kinase complex, mTORC1, in liver development, we investigated the role of this pathway in oval cell activation. Oval cell proliferation was induced in male Fisher rats by a modification of the traditional choline deficient plus ethionine model (CDE) or by 2-acetylaminoflourene treatment followed by 2/3 partial hepatectomy with or without initiation by diethylnitrosamine. To assess the role of mTOR in the oval cell response and development of preneoplastic foci, the effect of the mTORC1 inhibitor, rapamycin, was studied in all models. Rapamycin induced a significant suppression of the oval cell response in both models, an effect that coincided with a decrease in oval cell proliferation. Rapamycin administration did not affect the abundance of neutrophils or natural killer cells in CDE-treated liver or the expression of key cytokines. Gene expression studies revealed the fetal hepatocyte marker MKP-4 to be expressed in oval cells. In an experimental model of hepatic carcinogenesis, rapamycin decreased the size of preneoplastic foci and the rate of cell proliferation within the foci. mTORC1 signaling plays a key role in the oval cell response and in the development of preneoplastic foci. This pathway may be a target for the chemoprevention of hepatocellular carcinoma.
The transcription factor c-myc regulates genes involved in hepatocyte growth, proliferation, metabolism, and differentiation. It has also been assigned roles in liver development and regeneration. In previous studies, we made the unexpected observation that c-Myc protein levels were similar in proliferating fetal liver and quiescent adult liver with c-Myc displaying nucleolar localization in the latter. In order to investigate the functional role of c-Myc in adult liver, we have developed a hepatocyte-specific c-myc knockout mouse, c-mycfl/fl;Alb-Cre.
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