Establishment of Primary Adult Skin Fibroblast Cell Lines from African Savanna Elephants (Loxodonta africana).

Following population declines of the African savanna elephant (Loxodonta africana) across the African continent, the establishment of primary cell lines of endangered wildlife species is paramount for the preservation of their genetic resources. In addition, it allows molecular and functional studies on the cancer suppression mechanisms of elephants, which have previously been linked to a redundancy of tumor suppressor gene TP53. This methodology describes the establishment of primary elephant dermal fibroblast (EDF) cell lines from skin punch biopsy samples (diameter: ±4 mm) of African savanna elephants (n = 4, 14-35 years). The applied tissue collection technique is minimally invasive and paves the way for future remote biopsy darting. On average, the first explant outgrowth was observed after 15.75 ± 6.30 days. The average doubling time (Td) was 93.02 ± 16.94 h and 52.39 ± 0.46 h at passage 1 and 4, respectively. Metaphase spreads confirmed the diploid number of 56 chromosomes. The successful establishment of EDF cell lines allows for future elephant cell characterization studies and for research on the cancer resistance mechanisms of elephants, which can be harnessed for human cancer prevention and treatment and contributes to the conservation of their genetic material.

DNA damage response of haematopoietic stem and progenitor cells to high-LET neutron irradiation.

The radiosensitivity of haematopoietic stem and progenitor cells (HSPCs) to neutron radiation remains largely underexplored, notwithstanding their potential role as target cells for radiation-induced leukemogenesis. New insights are required for radiation protection purposes, particularly for aviation, space missions, nuclear accidents and even particle therapy. In this study, HSPCs (CD34+CD38+ cells) were isolated from umbilical cord blood and irradiated with 60Co γ-rays (photons) and high energy p(66)/Be(40) neutrons. At 2 h post-irradiation, a significantly higher number of 1.28 ± 0.12 γ-H2AX foci/cell was observed after 0.5 Gy neutrons compared to 0.84 ± 0.14 foci/cell for photons, but this decreased to similar levels for both radiation qualities after 18 h. However, a significant difference in late apoptosis was observed with Annexin-V+/PI+ assay between photon and neutron irradiation at 18 h, 43.17 ± 6.10% versus 55.55 ± 4.87%, respectively. A significant increase in MN frequency was observed after both 0.5 and 1 Gy neutron irradiation compared to photons illustrating higher levels of neutron-induced cytogenetic damage, while there was no difference in the nuclear division index between both radiation qualities. The results point towards a higher induction of DNA damage after neutron irradiation in HSPCs followed by error-prone DNA repair, which contributes to genomic instability and a higher risk of leukemogenesis.

An Automated Microscopic Scoring Method for the γ-H2AX Foci Assay in Human Peripheral Blood Lymphocytes.

Ionizing radiation is a potent inducer of DNA damage and a well-documented carcinogen. Biological dosimetry comprises the detection of biological effects induced by exposure to ionizing radiation to make an individual dose assessment. This is pertinent in the framework of radiation emergencies, where health assessments and planning of clinical treatment for exposed victims are critical. Since DNA double strand breaks (DSB) are considered to be the most lethal form of radiation-induced DNA damage, this protocol presents a method to detect DNA DSB in blood samples. The methodology is based on the detection of a fluorescent labelled phosphorylated DNA repair protein, namely, γ-H2AX. The use of an automated microscopy platform to score the number of γ-H2AX foci per cell allows a standardized analysis with a significant decrease in the turn-around time. Therefore, the γ-H2AX assay has the potential to be one of the fastest and sensitive assays for biological dosimetry. In this protocol, whole blood samples from healthy adult volunteers will be processed and irradiated in vitro in order to illustrate the usage of the automated and sensitive γ-H2AX foci assay for biodosimetry applications. An automated slide scanning system and analysis platform with an integrated fluorescence microscope is used, which allows the fast, automatic scoring of DNA DSB with a reduced degree of bias.

The Impact of Dose Rate on DNA Double-Strand Break Formation and Repair in Human Lymphocytes Exposed to Fast Neutron Irradiation.

The lack of information on how biological systems respond to low-dose and low dose-rate exposures makes it difficult to accurately assess the carcinogenic risks. This is of critical importance to space radiation, which remains a serious concern for long-term manned space exploration. In this study, the γ-H2AX foci assay was used to follow DNA double-strand break (DSB) induction and repair following exposure to neutron irradiation, which is produced as secondary radiation in the space environment. Human lymphocytes were exposed to high dose-rate (HDR: 0.400 Gy/min) and low dose-rate (LDR: 0.015 Gy/min) p(66)/Be(40) neutrons. DNA DSB induction was investigated 30 min post exposure to neutron doses ranging from 0.125 to 2 Gy. Repair kinetics was studied at different time points after a 1 Gy neutron dose. Our results indicated that γ-H2AX foci formation was 40% higher at HDR exposure compared to LDR exposure. The maximum γ-H2AX foci levels decreased gradually to 1.65 ± 0.64 foci/cell (LDR) and 1.29 ± 0.45 (HDR) at 24 h postirradiation, remaining significantly higher than background levels. This illustrates a significant effect of dose rate on neutron-induced DNA damage. While no significant difference was observed in residual DNA damage after 24 h, the DSB repair half-life of LDR exposure was slower than that of HDR exposure. The results give a first indication that the dose rate should be taken into account for cancer risk estimations related to neutrons.

Exploring the differential diagnosis of hemorrhagic vesicopustules in a newborn.

Hemorrhagic vesicles in a newborn present a challenging differential diagnosis including both infectious and neoplastic disorders. Patients should be evaluated in an efficient manner to arrive at the correct diagnosis as quickly as possible. We present here an interesting case that outlines the methodical workup that ultimately revealed the diagnosis of congenital Langerhans cell histiocytosis. After a diagnosis of Langerhans cell histiocytosis is made, it is important to evaluate the patient thoroughly for systemic involvement. Historically, the diagnosis of congenital self-healing Langerhans cell histiocytosis was used to delineate a benign self-limited disorder limited to the skin with spontaneous resolution during the first several months of life; this disorder may also be referred to as "self-regressive Langerhans cell histiocytosis." However, some newborns with initial skin-only Langerhans cell histiocytosis progress to have multisystem disease after spontaneous resolution has occurred. For this reason, the nomenclature is changing. We suggest using the term "skin-only Langerhans cell histiocytosis." Periodic long-term follow-up is recommended to monitor for relapse or progression to systemic disease.

Sweet syndrome in infancy.

Sweet syndrome, or acute febrile neutrophilic dermatosis, is characterized by the presence of fever, peripheral leukocytosis, painful erythematous plaques and nodules, and a predominately neutrophilic dermal infiltrate. We report a case occurring in a 10-week-old male child, with preceding upper respiratory tract, and gastrointestinal infection symptoms. Sweet syndrome occurring in an infant should prompt a work-up for immunodeficiency, as well as a review of the peripheral blood smear to rule out the rare case of malignancy.

Congenital herpes simplex virus infection: two unique cutaneous presentations associated with probable intrauterine transmission.

Cutaneous manifestations of congenital herpes simplex virus (HSV) have been classically described as grouped vesicles on an erythematous base. We report two cases of HSV infection wherein both infants presented at birth with widespread erosions and an absence of vesicles or vesicopustules. The presence of skin lesions at birth, neurologic changes seen on radiographic imaging, and a cesarean section delivery in one case suggests intrauterine transmission in both neonates.

Human papillomavirus vaccine: recommendations, issues and controversies.

PURPOSE OF REVIEW: The human papillomavirus vaccine is now Food and Drug Administration-approved for girls and young women ages 9-26 years and Advisory Committee on Immunization Practices-recommended for girls ages 11-12 years of age. Several issues have shrouded its debut and continue to provide controversy that may hinder effective delivery of this vaccine to young people in industrialized as well as third world countries. RECENT FINDINGS: The quadrivalent and divalent vaccines are compared, particularly with respect to juvenile recurrent respiratory papillomatosis. Recommendations for administration are summarized. Immunization of men and cost effectiveness are discussed. Issues regarding compulsory vaccination and attitudes of parents about human papillomavirus vaccination are reviewed. SUMMARY: Studies of the human papillomavirus vaccine are very promising, showing excellent efficacy and very few adverse events. It remains to be determined if it will be licensed in the United States for use in boys and men. Some stumbling blocks to implementing the vaccine in the United States need to be addressed in order to gain widespread acceptance.