Cytogenetic diversity in primary human tumors

Cytogenetic patterns from primary short-term culture of breast cancer, renal carcinoma, and tumors of the central nervous system are presented to illustrate the range of karyotypic diversity of human solid tumors as well as their biologic differences in culture systems that support their growth. These studies have illustrated several major issues. 1) Results vary with the tissue of origin: primary cultures from breast are almost uniformly diploid, while renal tumors are near-diploid, mosaic, and show clonal aberrations; and CNS tumors are heterogeneous: some diploid, some near-diploid and some highly aneuploid. 2) Results after short-term culture are selective, representing subpopulations from the heterogeneous cells that are detected on direct analysis of fresh tumors by cytogenetics or flow cytometry (FCM). It is not yet clear whether prognosis depends on the dominant population of the primary tumor or alternatively should be influenced by detection of small aneuploid subpopulations. 3) Evidence from all three tumor types supports the interpretation that cytogenetically normal diploid cells constitute part of some tumor populations, and may be better adapted to routine growth in culture than aneuploid subpopulations from the same primary tumors. These cells may also compose a major portion of the viable population of tumors in vivo and, therefore, could represent a useful model for studies of tumorigenesis and therapeutic regimens.     

Study of the anatomy of the living human heart using echocardiography

For studying anatomy of the alive human heart, a new method of ultrasonic echography has been used. With its assistance it is possible to see all the cardiac chambers, interventricular and interatrial septa, tricuspidal and mitral valves, their chordae, papillary muscles, myocardium and pericardium. Not only their statics, but also their dynamics are investigated, when the heart contracts and its valves make movements. Owing to this, possibilities for studying cardiac anatomy in the alive people.     

Epididymal cribriform hyperplasia with nuclear atypia in p53 homozygous knockout mice on a mixed 129/Sv-FVB/N background

Epididymal cribriform hyperplasia (ECH) is a variant of normal epididymal histologic features in men, and has also been reported in rats, mice, dogs, cats, and bulls. The epididymal change has been associated with aging, testicular atrophy, cryptorchidism, and germ cell tumors. Epididymal cribriform hyperplasia was observed in p53 homozygous knockout mice on a mixed 129/Sv-FVB/N background, but not in wild-type or heterozygous mice. The aim of the study reported here was to determine the prevalence and characterize the morphologic, immunohistochemical, and ultrastructural features of ECH in these mice. Epididymal cribriform hyperplasia was present in 88% (72/82) of male mice ranging in age from seven to 65 weeks. The lesion was characterized microscopically by epithelial cells with atypical hyperchromatic nuclei, vacuolization, intratubular lumina formation, infrequent apoptosis, and rare mitotic figures. In contrast to germ cells, the cells of ECH did not express alpha-fetoprotein, carcinoembryonic antigen, or S-100. Ultrastructurally, the cells were pleomorphic with stereocilia at their apical borders and within intratubular lumina, and were supported by a basement membrane. Although 14% (10/72) of mice had concomitant testicular neoplasia, ECH did not appear to be a preneoplastic change. Investigators using these mice for modeling human disease should be aware of the background prevalence of this lesion.     

Pancreaticoduodenal arterial rupture and hemoabdomen in ACI/SegHsd rats with polyarteritis nodosa

Many lesions associated with aging have been well-characterized in various strains of rats. Although documented in Sprague-Dawley and spontaneously hypertensive rats, polyarteritis nodosa has not previously been reported in ACI/SegHsd rats. ACII SegHsd rats were maintained on high-fat (40.5%), low-fat (11.6%), and high-fat to low-fat dietary protocols to examine the correlation between dietary fat and the regulation of prostate 5alpha-reductase gene expression and prostate cancer. Seven rats died unexpectedly with hemoabdomen and rupture of the pancreaticoduodenal artery secondary to polyarteritis nodosa (PAN). The purpose of this study was to analyze the pathologic findings in these and the remaining ACI/SegHsd rats and to correlate the level of dietary fat with the presence of PAN, arterial rupture, and hemoabdomen. Approximately 65% of the rats had evidence of PAN by histopathology, with a 24% incidence of arterial rupture. Additional lesions noted included an 88% incidence of chronic progressive nephropathy (CPN) and a 32% incidence of cartilaginous foci in the aortic valve. We found no association between the percentage of dietary fat and incidence of PAN, CPN, or cardiac cartilage. Although arterial rupture is a known complication of polyarteritis nodosa in humans, this case series is the first to document arterial rupture and hemoabdomen in rats with PAN.     

Using stable isotope analysis to understand the migration and trophic ecology of northeastern Pacific white sharks (Carcharodon carcharias)

The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the trophic ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the trophic ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.     

A locus conferring tolerance to Theileria infection in African cattle

East Coast fever, a tick-borne cattle disease caused by the Theileria parva parasite, is among the biggest natural killers of cattle in East Africa, leading to over 1 million deaths annually. Here we report on the genetic analysis of a cohort of Bos indicus (Boran) cattle demonstrating heritable tolerance to infection with T. parva (h² = 0.65, s.e. 0.57). Through a linkage analysis we identify a 6 Mb genomic region on bovine chromosome 15 that is significantly associated with survival outcome following T. parva exposure. Testing this locus in an independent cohort of animals replicates this association with survival following T. parva infection. A stop gained variant in a paralogue of the FAF1 gene in this region was found to be highly associated with survival across both related and unrelated animals, with only one of the 20 homozygote carriers (T/T) of this change succumbing to the disease in contrast to 44 out of 97 animals homozygote for the reference allele (C/C). Consequently, we present a genetic locus linked to tolerance of one of Africa’s most important cattle diseases, raising the promise of marker-assisted selection for cattle that are less susceptible to infection by T. parva.     

Double knockout Nme1/Nme2 mouse model suggests a critical role for NDP kinases in erythroid development

Nm23/NDP kinases A and B encoded by the Nme1/Nme2 genes are multifunctional enzymes responsible for the majority of NDP kinase activity in mammals. This review summarizes recent studies on their physiological roles using a mouse model in which both Nme1 and Nme2 genes have been deleted. The double knockout mice are stunted in growth and die perinatally. Additionally, these mice display hematologic phenotypes, including severe anemia, abnormal erythroid cell development, loss of the iron transport receptor molecule TfR1, and reduced iron uptake by Nme1 ^?/? /Nme2 ^?/? erythroid cells. We hypothesize that Nm23/NDP kinases regulate TfR1 gene expression in erythroid cells in some manner, and that defective iron transport into these cells is responsible for the anemia and death. This Nme1/Nme2 mouse model also links nucleotide metabolism with erythropoiesis, suggesting alternative or additional mechanisms that may explain the observed phenomena.     

Dose-dependant hypothyroidism in mice induced by commercial trimethoprim-sulfamethoxazole rodent feed

Trimethoprim-sulfamethoxazole (TMP-SMX) medication in the feed or water is commonly administered to immunocompro mised mice to prevent the occurrence of Pneumocystis murina (formerly P. carinii) pneumonia. Therapeutic doses of SMX can cause decreased total and free thyroxine (T4) levels in dogs and thyroid hypertrophy and hyperplasia in mice, rats, and dogs. Our primary objective was to determine whether SMX at doses present in commercially available rodent TMP-SMX feed would pro duce hypothyroidism in mice. Plasma T4 levels were determined prior to and after placement of Brand A TMP-SMX feed (daily SMX dose, 240 mg/kg), Brand B TMP-SMX feed (daily SMX dose, 2400 mg/kg), and their respective controls (doses calculated for a 25-g mouse according to vendor's information). T4 levels in the mice fed Brand B TMP-SMX feed were significantly decreased by 2 wk after feed placement. Levels of thyroid stimulating hormone in male and female mice given Brand B TMP-SMX feed were significantly elevated compared with those of control groups at 6 wk after feed placement, when only these mice showed evidence of thyroid hypertrophy and hyperplasia. No significant change in T4 levels occurred over the course of 11 wk in mice given the Brand A TMP-SMX chow or either control feed. In light of the significant clinical hypothyroidism that occurred in our mice while receiving Brand B TMP-SMX diet, we recommend SMX levels more similar to that of Brand A to avoid such unwanted effects which could confound research data.