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.

HPLC-MS identification and expression of Candida drug-resistance proteins from African HIV-infected patients.

The objective of this study was to elucidate the proteomic mechanisms of drug resistance in HIV-infected African patients. Cell membrane fractions from forty oral Candida isolates isolated from African HIV-positive patients were analysed using HPLC-MS with the aim of identifying proteins associated with their pathogenicity and drug resistance. Heat shock proteins that mediate the fungicidal activity of salivary peptides were found in all tested Candida fractions, with pH-responsive proteins associated with increased pathogenicity only being present in the three most commonly isolated species. ABC multidrug transporter efflux pumps and estrogen binding proteins were only found in C. albicans fractions, while ergosterol biosynthesis proteins were identified in four species. The combination of various adherence, invasion, upregulation and efflux pump mechanisms appear to be instrumental for the Candida host colonization and drug resistance emergence in HIV-infected individuals.

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.

Next generation sequencing improves detection of drug resistance mutations in infants after PMTCT failure.

BACKGROUND: Next generation sequencing (NGS) allows the detection of minor variant HIV drug resistance mutations (DRMs). However data from new NGS platforms after Prevention-of-Mother-to-Child-Transmission (PMTCT) regimen failure are limited. OBJECTIVE: To compare major and minor variant HIV DRMs with Illumina MiSeq and Life Technologies Ion Personal Genome Machine (PGM) in infants infected despite a PMTCT regimen. STUDY DESIGN: We conducted a cross-sectional study of NGS for detecting DRMs in infants infected despite a zidovudine (AZT) and Nevirapine (NVP) regimen, before initiation of combination antiretroviral therapy. Sequencing was performed on PCR products from plasma samples on PGM and MiSeq platforms. Bioinformatic analyses were undertaken using a codon-aware version of the Smith-Waterman mapping algorithm and a mixture multinomial error filtering statistical model. RESULTS: Of 15 infants, tested at a median age of 3.4 months after birth, 2 (13%) had non-nucleoside reverse transcriptase inhibitor (NNRTI) DRMs (K103N and Y181C) by bulk sequencing, whereas PGM detected 4 (26%) and MiSeq 5 (30%). NGS enabled the detection of additional minor variant DRMs in the infant with K103N. Coverage and instrument quality scores were higher with MiSeq, increasing the confidence of minor variant calls. CONCLUSIONS: NGS followed by bioinformatic analyses detected multiple minor variant DRMs in HIV-1 RT among infants where PMTCT failed. The high coverage of MiSeq and high read quality improved the confidence of identified DRMs and may make this platform ideal for minor variant detection.

Deep sequencing reveals minor protease resistance mutations in patients failing a protease inhibitor regimen.

Standard genotypic antiretroviral resistance testing, performed by bulk sequencing, does not readily detect variants that comprise <20% of the circulating HIV-1 RNA population. Nevertheless, it is valuable in selecting an antiretroviral regimen after antiretroviral failure. In patients with poor adherence, resistant variants may not reach this threshold. Therefore, deep sequencing would be potentially valuable for detecting minority resistant variants. We compared bulk sequencing and deep sequencing to detect HIV-1 drug resistance at the time of a second-line protease inhibitor (PI)-based antiretroviral regimen failure. Eligibility criteria were virologic failure (HIV-1 RNA load of >500 copies/ml) of a first-line nonnucleoside reverse transcriptase inhibitor-based regimen, with at least the M184V mutation (lamivudine resistance), and second-line failure of a lopinavir/ritonavir (LPV/r)-based regimen. An amplicon-sequencing approach on the Roche 454 system was used. Six patients with viral loads of >90,000 copies/ml and one patient with a viral load of 520 copies/ml were included. Mutations not detectable by bulk sequencing during first- and second-line failure were detected by deep sequencing during second-line failure. Low-frequency variants (>0.5% of the sequence population) harboring major protease inhibitor resistance mutations were found in 5 of 7 patients despite poor adherence to the LPV/r-based regimen. In patients with intermittent adherence to a boosted PI regimen, deep sequencing may detect minority PI-resistant variants, which likely represent early events in resistance selection. In patients with poor or intermittent adherence, there may be low evolutionary impetus for such variants to reach fixation, explaining the low prevalence of PI resistance.

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.

Alternative dosage of zidovudine in infants exposed to maternal human immunodeficiency virus infection.

As part of the 076 protocol, ZDV was given to HIV-exposed neonates for the first 6 weeks of life. The dosage was 2 mg/kg every 6 hours. Frequent dosing can be a deterrent to regimen adherence. We report our experience, using 3 mg/kg every 8 hours in 155 eligible HIV-exposed neonates, none of whom became HIV infected. Maximum risk of transmission that could be missed by this cohort is approximately 2%, which is consonant with current transmission rates. ZDV at 3 mg/kg every 8 hours is noninferior to 2 mg/kg every 6 hours and easier to administer.

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.

Hypochlorite killing of community-associated methicillin-resistant Staphylococcus aureus.

We tested in vitro hypochlorite (bleach) killing of community-associated methicillin-resistant Staphylococcus aureus isolates to determine optimal concentration and duration. For all isolates maximal killing, >3-log decrease in colony forming units (CFU), was found after 5 minutes in 2.5 microL/mL bleach. We estimate that 2.5 microL/mL bleach is approximately one-half cup of bleach in one-quarter tub of water.

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.

Local anesthetic and stylet styles: factors associated with resident lumbar puncture success.

OBJECTIVE: To assess the effects of procedural techniques, local anesthetic use, and postgraduate training level on lumbar puncture (LP) success rates. METHODS: In this prospective observational study, medical students and residents ("trainees") reported techniques used for infant LPs in an urban teaching emergency department. Data on postgraduate year, patient position, draping, total and trainee numbers of attempts, local anesthetic use, and timing of stylet removal were collected. Logistic regression analysis was used to identify predictors of successful LP, with success defined as the trainee obtaining cerebrospinal fluid with <1000 red blood cells per mm3. RESULTS: We collected data on 428 (72%) of 594 infant LPs performed during the study period. Of 377 performed by trainees, 279 (74%) were successful. Local anesthesia was used for 280 (74%), and 225 (60%) were performed with early stylet removal. Controlling for the total number of attempts, LPs were 3 times more likely to be successful among infants >12 weeks of age than among younger infants (odds ratio [OR]: 3.1; 95% confidence interval [CI]: 1.2-8.5). Controlling for attempts and age, LPs performed with local anesthetic were twice as likely to be successful (OR: 2.2; 95% CI: 1.04-4.6). For infants < or =12 weeks of age, early stylet removal improved success rates (OR: 2.4; 95% CI: 1.1-5.2). Position, drape use, and year of training were not significant predictors of success. CONCLUSIONS: Patient age, use of local anesthetic, and trainee stylet techniques were associated with LP success rates. This offers an additional rationale for pain control. Predictors identified in this study should be considered in the training of physicians, to maximize their success with this important procedure.

Very low prevalence of endophthalmitis in very low birthweight infants who survive candidemia.

OBJECTIVE: Candida species often cause sepsis in very low birthweight (VLBW) infants, leading to formal ophthalmologic evaluation for endophthalmitis. Our experience suggests that endophthalmitis is rare in this setting, and retinal vascular compromise in extreme prematurity may decrease the risk. We studied the prevalence of endophthalmitis in surviving VLBW infants with candidemia. STUDY DESIGN: Epidemiologic data and presence of ROP and endophthalmitis were ascertained for all VLBW infants with candidemia at our institution from 1994 to 2001. RESULTS: A total of 123 infants were included. Median EGA was 25 weeks (range, 23 to 32) and median birthweight was 735 g (range, 426 to 1460). Of these 123, only one had transient retinal findings (prevalence 0.8%; 95% confidence interval 0 to 4%), which resolved during therapy. In no case was either the duration of therapy or the outcome of candidemia altered by retinal examination. CONCLUSIONS: Aggressive treatment of candidemia has made endogenous endophthalmitis rare in candidemic VLBW infants.

Facial cellulitis in childhood: a changing spectrum.

BACKGROUND: Before conjugated Haemophilus influenzae type b (Hib) vaccination, a syndrome known as buccal cellulitis, usually caused by Hib and often accompanied by bacteremia, was seen. We investigated the incidence and cause of facial cellulitis at our hospital during the 10 years before and the 10 years after introduction of the vaccine. METHODS: Records of patients discharged with a diagnosis of facial cellulitis or infections of the oral cavity were reviewed. Fisher's exact test was used to compare rates of cellulitis during the two decades. RESULTS: Trauma was the most common antecedent to facial cellulitis in both eras. Buccal cellulitis accounted for 7/25 (28%) of cases before Hib vaccination and 0/19 cases since. Pneumococcal buccal cellulitis was not seen in either decade. CONCLUSIONS: Buccal cellulitis due to Hib is a disappearing disease. Eighty-nine percent of recent inpatient cases of childhood facial cellulitis were related to trauma, tooth problems, or severe sinusitis. Facial cellulitis due to S pneumoniae is rare.