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Early-onset breast cancer is known for its aggressive clinical characteristics and high prevalence in East Asian countries, but a comprehensive understanding of its molecular features is still lacking. In this study, we conducted a proteogenomic analysis of 126 treatment-naïve primary tumor tissues obtained from Korean patients with young breast cancer (YBC) aged ≤40 years. By integrating genomic, transcriptomic, and proteomic data, we identified five distinct functional subgroups that accurately represented the clinical characteristics and biological behaviors of patients with YBC. Our integrated approach could be used to determine the proteogenomic status of HER2, enhancing its clinical significance and prognostic value. Furthermore, we present a proteome-based homologous recombination deficiency (HRD) analysis that has the potential to overcome the limitations of conventional genomic HRD tests, facilitating the identification of new patient groups requiring targeted HR deficiency treatments. Additionally, we demonstrated that protein–RNA correlations can be used to predict the late recurrence of hormone receptor-positive breast cancer. Within each molecular subtype of breast cancer, we identified functionally significant protein groups whose differential abundance was closely correlated with the clinical progression of breast cancer. Furthermore, we derived a recurrence predictive index capable of predicting late recurrence, specifically in luminal subtypes, which plays a crucial role in guiding decisions on treatment durations for YBC patients. These findings improve the stratification and clinical implications for patients with YBC by contributing to the optimal adjuvant treatment and duration for favorable clinical outcomes.

ABSTRACTBy employing the platformization of cultural production from a critical political economy approach, this article analyzes the transition of the Korean cultural industries to the platform-driven phase of Hallyu. By discussing the highly transnationalized and platformized Korean Wave in the shifting global media environment, it examines how Netflix platformizes and appropriates the Korean broadcasting industry through various strategies, such as investing in original content creation, licensing Korean content, and subcontractualization of Korean production. These strategies reveal that Korean cultural industry firms have become subordinated to, and rely on, global OTT platforms. In light of the growing influences of Netflix and other global platforms, the article explores the implications of the platformization of cultural production for the transnational cultural flows of Hallyu.

ABSTRACTThis study examines the discourse surrounding the transnational flows of South Korean popular culture, known as Hallyu (the Korean Wave), and its relationship to the country’s soft power through a discourse analysis of Korean news and social media. Specifically, the study explores how Hallyu was addressed as Korea’s soft power tool during the COVID-19 pandemic, when it gained even greater popularity overseas through digital means. The study questions how local cultural intermediaries, such as journalists, critics and YouTubers, have engaged with the Hallyu phenomenon. Although Hallyu is often considered a core component of Korea’s soft power, aimed at increasing its influence in overseas reception points, there is a lack of studies on the meanings of Hallyu as a discursive construct in the Korean mediascape. Therefore, this study explores how Korean news and social media perceive and represent the global circulation of their local cultural content.

Transnational fans of South Korean pop music (K-pop) are known for their cosmopolitan sense of belonging and community beyond geocultural boundaries. Academics who are also fans (i.e. aca-fans) and who have conducted recent ethnographic studies have developed a favorable perspective on the potential of global K-pop fandom. While acknowledging the alternative force generated by the grassroots K-pop universe, this article suggests that transnational fans do not constitute a homogeneous group; rather, they inevitably have to negotiate their own positionalities, such as race and gender, when engaging with K-pop’s virtual fan universe. Drawing on qualitative interviews with K-pop fans in Canada, this study comparatively analyzes how young people of White and Asian backgrounds experience K-pop as an emerging cultural genre whose meaning is not yet clearly situated in their local contexts. The study suggests that transnational fans’ experiences reveal the gap between the socially divided realuniverse and the cosmopolitan virtualK-pop universe.

Development of selenium (Se)-enriched agricultural products can increase human daily dietary Se intake in Se-deficient areas. Canadian oat (Avena sativa L. cv. Saddle) is one of the common cereal grains in the world. Previous studies have shown that Se accumulation in oat can be significantly affected by soil Se, but few have dealt with different chemical forms of Se, including emerging nanoscale elemental Se particles (SeNPs). Because SeNPs have unique chemical and physical properties in comparing with bulk elemental Se, this laboratory study determined the effects of soil SeNP treatments of 0, 1, 5, and 10mg/kg on Se bioconcentration in oat grain, compared with bulk elemental Se or selenate (Na2 SeO4 ). The results showed that the soil SeNP treatments significantly increased Se concentrations in oat grain with an increase in the treatment level from 1 to 10mg/kg (P husk>stem and leaf. While the grain yield was reduced with the higher soil selenate treatments of 5–10mg/kg, the soil SeNP treatment of 1–10mg/kg significantly enhanced the oat grain yield, compared with the control. Concentrations of Se in oat grains in the soil SeNP treatments were approximately 7–20-fold higher than were the concentrations of those in the soil bulk elemental Se treatments, but were about 7–26% of the concentrations in oat grains in the soil selenate treatments. This study demonstrated that nanoscale elemental Se particles could be used for development of soil Se-amended fertilisers for Se-biofortified oat.

AbstractTransitional cell carcinoma (TCC) is the most common malignant tumor of the canine urinary tract. In this case study, a dog with metastatic urethral TCC was treated with sorafenib. The tumor expression levels of receptor tyrosine kinase genes, including VEGFR-1, VEGFR-2, PDGFR-α, PDGFR-β, ALK, EGFR, ErbB2, and B-RAF, were analyzed. VEGFR was overexpressed in tumor tissues compared to the normal tissues. Considering the high frequency of B-RAF mutation in canine urological tumors, the B-RAFgene was examined, and the B-RAF V595E mutation was detected in the tumor tissue. Therefore, the antitumor effect of sorafenib, a multi-tyrosine kinase inhibitor, on unresectable metastatic urethral TCC characterized by B-RAF V595E was evaluated and circulating cell-free tumor DNA (ctDNA) was assessed for monitoring the treatment response. After the initiation of oral sorafenib therapy (4 mg/kg/day escalated to 10 mg/kg/day), the dysuria was alleviated gradually, and the patient remained stable for 3 months. During that treatment period, the patient showed various levels of changes associated with B-RAF V595E mutation in ctDNA as evident from longitudinal plasma samples after initiation of sorafenib therapy. The findings of this study suggest that ctDNA may serve as a useful non-invasive tool for monitoring the treatment response to anticancer drugs.

The effect of inactivity and undernutrition after acute ischemic stroke on mass, myofibrillar protein content, and Type I and II fiber cross-sectional areas of rat hindlimb muscles are examined. Hindlimb muscle atrophy occurs in both affected and unaffected sides after acute stroke, with Type I muscle changes more apparent than Type II changes.

Drawing on qualitative interviews conducted in Toronto, Canada, this study examines how the young adult children of Korean immigrants, also known as 1.5-generation immigrants, explore multicultural senses of belonging and identity through digital media practices. This study reveals that although young immigrants’ capabilities to choose from different forms of cultural content may be enhanced by digital media, they may be subject to structural forces, such as offline ethnic segregation. That is, young immigrants may enjoy digital media as a multicultural facilitator in one sense but question its contribution to multicultural senses of identity in another.

ObjectiveOesophageal squamous cell carcinoma (ESCC) is a heterogeneous disease with variable outcomes that are challenging to predict. A better understanding of the biology of ESCC recurrence is needed to improve patient care. Our goal was to identify small non-coding RNAs (sncRNAs) that could predict the likelihood of recurrence after surgical resection and to uncover potential molecular mechanisms that dictate clinical heterogeneity.DesignWe developed a robust prediction model for recurrence based on the analysis of the expression profile data of sncRNAs from 108 fresh frozen ESCC specimens as a discovery set and assessment of the associations between sncRNAs and recurrence-free survival (RFS). We also evaluated the mechanistic and therapeutic implications of sncRNA obtained through integrated analysis from multiple datasets.ResultsWe developed a risk assessment score (RAS) for recurrence with three sncRNAs (microRNA (miR)-223, miR-1269a and nc886) whose expression was significantly associated with RFS in the discovery cohort (n=108). RAS was validated in an independent cohort of 512 patients. In multivariable analysis, RAS was an independent predictor of recurrence (HR, 2.27; 95% CI, 1.26 to 4.09; p=0.007). This signature implies the expression of ΔNp63 and multiple alterations of driver genes like PIK3CA. We suggested therapeutic potentials of immune checkpoint inhibitors in low-risk patients, and Polo-like kinase inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and histone deacetylase inhibitors in high-risk patients.ConclusionWe developed an easy-to-use prognostic model with three sncRNAs as robust prognostic markers for postoperative recurrence of ESCC. We anticipate that such a stratified and systematic, tumour-specific biological approach will potentially contribute to significant improvement in ESCC treatment.

Although the biological functions of tumor-originated cell-free DNA have not been previously clarified, such molecular characteristics as mutations, hypermethylation, and microsatellite instability have confirmed its tumor origin. Therefore, to investigate the use of plasma DNA level as a biomarker of lung cancer, we compared plasma DNA concentrations in 102 patients with lung cancer and 105 healthy individuals using quantitative PCR analyses. The median plasma DNA concentrations for the healthy and cancer groups were 10.4 and 22.6 ng/ml, respectively (P< 0.0001), and elevated plasma DNA levels were also detected in patients with either stage I or II disease. Neither smoking status nor the number of packs per year had an effect on the level of circulating cell-free DNA. Increased concentrations of circulating cell-free DNA showed the potential power to discriminate lung cancer (area under the receiver operating characteristic curve = 0.86, 95% CI = 0.81 to 0.91). When subjects were classified into three groups based on their plasma DNA concentrations, subjects in the upper tertile (ie, those with the highest concentration) had a significantly increased risk of lung cancer as compared with those in the lowest tertile (adjusted odds ratio = 50.6, P< 0.001). These results suggest that elevated circulating plasma DNA levels may serve as a potential diagnostic indicator and be an important risk factor for lung cancer.

Histone H3 lysine 9 (H3-K9) methylation and DNA methylation are important features of mammalian heterochromatin. Suppressor of variegation 3-9 homolog 2 (SUV39H2) is the histone methyltransferase that is required to methylate H3-K9, leading to transcriptional repression or silencing of target genes. In this study, we investigated the association of SUV39H2 polymorphisms and the risk of lung cancer. From the results of PCR direct sequencing, eight single nucleotide polymorphisms (SNPs) of SUV39H2 were identified in Korean population. In a hospital-based study of 346 lung cancer patients and 423 healthy controls, a novel SNP in the 3′-UTR of SUV39H2 (1624 G→C) was associated with a statistically significant increase in lung cancer risk. Compared to the G/G genotype, genotypes with 1624C allele (G/C + C/C) significantly increased the susceptibility to lung cancer with adjusted odds ratio (AOR) of 2.63 (95% confidence interval (CI)= 1.10–6.29) for ever-smokers, especially in the older age group (age ≥55 years). Specifically, the variant genotype of 1624SNP was significantly associated with an increased risk of squamous cell carcinoma (AOR, 3.52; 95% CI = 1.13–9.45) in the older age group, while no significant association was found in patients with other histology. This study provided the first evidence that a novel SUV39H2 polymorphism may be an important predictive marker for lung cancer susceptibility for the smokers.

A simple and reliable all-fiber-optic component for a first-order polarization mode dispersion compensator is presented and tested in a 10-Gbit/s transmission system. The proposed component incorporates tunable differential group delay (DGD) provided by several pieces of polarization maintaining (PM) fibers of different DGD that were spliced together with short lengths of single-mode fibers between them. The total DGD of the compensator is determined by the alignment of fast and slow axes of the PM fiber sections. Applying this component as a first-order polarization mode dispersion (PMD) compensator, we demonstrate that a component with seven pieces of PM fiber segments could possibly compensate the first-order PMD up to 63.5 ps with 1-ps steps and a switching time of 300 ms. We also optimize the number of PM fiber sections in this component for a first-order PMD compensation in a 10-Gbit/s system based on experimental results. © 2002 Society of Photo-Optical Instrumentation Engineers.

Juvenile polyposis is an uncommon condition characterized by the development of multiple (usually more than 5) juvenile polyps in the gastrointestinal tract, especially in the colon. This disease usually occurs during childhood, and is inherited in an autosomal dominant fashion. It has been suggested that the dpc4 (deleted in pancreatic carcinoma, locus 4) gene, which is located on chromosome 18q21.1, might cause juvenile polyposis. The dpc4 (smad4) gene is a candidate tumor-suppressor gene and may play a role in the TGF-β-signaling pathway. To confirm the idea that alterations of the dpc4 gene may result in juvenile polyposis, we screened 5 Korean juvenile-polyposis patients by PCR-SSCP (single-strand conformation polymorphism) analysis and bi-directional sequencing. There were germline mutations of the dpc4 gene in 3 out of the 5 patients: 2 had a genetic alteration in exon 9 and the third had a mutation in exon 8. These germline mutations occurred in the C-terminus of the dpc4 gene, similar to most published mutations. One patient exhibited a non-sense mutation (codon 388), which changed a glutamine codon (CAG) to a stop codon (TAG). The second patient harbored a mis-sense mutation (codon 390), causing a non-conservative amino-acid change 〈glutamate (GAA) to lysine (AAA)〉. The third patient had a mis-sense mutation in exon 8 (codon 361), which altered an arginine codon (CGC) into a histidine codon (CAC). Int. J. Cancer 86:529–532, 2000. © 2000 Wiley-Liss, Inc.

The present study examines the level of permethrin and malathion resistance in human head (Pediculosis capitis) and body (Pediculosis humanusL.) louse populations. Putatively insecticide-susceptible body and head louse populations were obtained from Israel (IS-BL) and Panama (PA-HL), respectively. Putatively insecticide-resistant populations of head lice were obtained from Florida (FL-HL) and Massachusetts (MA-HL), in the United States, and from Bristol (BR-HL), in the United Kingdom. Using knockdown and mortality bioassays, we confirmed permethrin resistance in the FL-HL and MA-HL populations. Resistance levels of the FL-HL and MA-HL populations were 132 and 223 times higher than that of the IS-BL population and 41 and 68 times higher than that of the PA-HL population when determined by knockdown resistance ratios. Resistance levels of the FL-HL and MA-HL populations were 4.3 and 4.9 times that of the IS-BL population and 3.8 and 4.3 times that of the PA-HL population when determined by mortality resistance ratios. The significantly higher levels of resistance determined using the knockdown ratios compared to the mortality ratios suggest that nerve insensitivity, most likely mediated by mutations within sodium channel genes, is a principal mechanism associated with resistance. None of these populations were resistant to malathion. The mortality response was significantly synergized by piperonyl butoxide in the PA-HL and MA-HL populations, indicating a possible role of oxidative metabolism in these strains. This apparent increase in oxidative metabolism is likely responsible for the lower permethrin sensitivity of the PA-HL versus the IS-BL and the MA-HL versus the FL-HL populations, respectively. Using a homology probing strategy, we have amplified para-orthologous louse sodium channel α-subunit cDNA fragments that span the ∼lIIS4–IIS6 region, where most of the sodium channel gene mutations that are known to be associated with knockdown resistance are located. Through molecular cloning and sequencing, we have identified two point mutations, T929I and L932F, located in the IIS5 transmembrane segment of cDNAs from only the permethrin-resistant FL-HL and BR-HL populations. Using homologous primers from our initial sequencing analysis of the cDNA fragments, we obtained a 568-bp genomic DNA fragment and confirmed the presence of the two mutations associated with permethrin resistance. The availability of PCR primers that directly amplify the genomic DNA fragment containing the mutation sites that are widely found associated with knockdown resistance will greatly facilitate the development of DNA-based diagnostic protocols for use in monitoring programs.

In this article, we describe the characteristics of 12 human colorectal-carcinoma cell lines established from 6 primary tumors and 6 metastatic sites of 11 Korean colorectal-carcinoma patients, including the morphology in vivo and in vitro and mutations of K-ras2, p15, p16, p53, APC, β-catenin, hMLH1 and hMSH2 genes in vitro. No lines were contaminated with Mycoplasma or bacteria. All lines were proven to be unique by DNA-fingerprinting analysis. All lines expressed the surface carcino-embryonic antigen and secreted it into the supernatant fluid. The morphological correlation between the original tumors and cultured cells suggested that the original tumors showing mucinous adenocarcinoma correlated with floating aggregates in culture, and degree of desmoplasia in the original tumor correlated with attached growth in culture. Five of the cell lines showed mutations in the K-ras2 gene, and 6 of the cell lines showed mutations in the p53 gene. The p15 gene was deleted in 2 cell lines, and the p16 gene was hypermethylated in 3 cell lines. The mutation of mismatch-repair genes (hMLH1 and hMSH2) was found in 4 lines, the APC gene and β-catenin gene were mutated in 9 and 2 lines respectively. These well-characterized colorectal-cancer cell lines should serve as useful tools for investigating the biological characteristics of colorectal cancer. Int. J. Cancer 81:902–910, 1999. © 1999 Wiley-Liss, Inc.

In this article, the author cites the expectations for new Economic Secretary Choi Joong-Kyung in South Korea. The author asserts that some foreign exchange traders anticipate that the appointment of Choi as a senior presidential secretary will decrease the value of the won. The author also predicts the new Economic Secretary to display his prowess in overall economic fields.

Pediculosis is a prevalent parasitic infestation of humans, which is increasing due, in part, to the selection of lice resistant to either the pyrethrins or pyrethroid insecticides by the knockdown resistance (kdr) mechanism. To determine the extent and magnitude of the kdr-type mutations responsible for this resistance, lice were collected from 138 collection sites in 48 U.S. states from 22 July 2013 to 11 May 2015 and analyzed by quantitative sequencing. Previously published data were used for comparisons of the changes in the frequency of the kdr-type mutations over time. Mean percent resistance allele frequency (mean % RAF) values across the three mutation loci were determined from each collection site. The overall mean % RAF (±SD) for all analyzed lice was 98.3 ± 10%. 132/138 sites (95.6%) had a mean % RAF of 100%, five sites (3.7%) had intermediate values, and only a single site had no mutations (0.0%). Forty-two states (88%) had a mean % RAF of 100%. The frequencies of kdr-type mutations did not differ regardless of the human population size that the lice were collected from, indicating a uniformly high level of resistant alleles. The loss of efficacy of the Nix formulation (Prestige Brand, Tarrytown, NY) from 1998 to 2013 was correlated to the increase in kdr-type mutations. These data provide a plausible reason for the decrease in the effectiveness of permethrin in the Nix formulation, which is the parallel increase of kdr-type mutations in lice over time.

The human head louse is a cosmopolitan ectoparasite and frequently infests many people, particularly school-age children. Due to widespread pyrethroid resistance and the lack of efficient resistance management, there has been a considerable interest in the protection of uninfested people and prevention of reinfestation by disrupting lice transfer. In this study, two nonclinical model systems (in vitro and in vivo) were used to determine the efficacy of the infestation deterrents, Elimax lotion and Elimax shampoo, against human head lice or poultry chewing lice, respectively. With in vitro assessments, female head lice exhibited significantly higher avoidance responses to hair tufts treated with either of the test formulations, which led to significantly higher ovipositional avoidance when compared with female lice on control hair tufts. Additionally, both formulations were determined to be competent infestation deterrents in a competitive avoidance test in the presence of a known attractant (head louse feces extract). In in vivo assessments using a previously validated poultry model, Elimax shampoo was determined to be an efficacious deterrent against poultry chewing lice within Menopon spp. and Menacanthus spp.

Human bed bug infestations have dramatically increased worldwide since the mid-1990s. A similar phenomenon was also observed in Israel since 2005, when infestations were reported from all over the country. Two single nucleotide polymorphisms (V419L and L925I) in the bed bug voltage-sensitive sodium channel confer kdr-type resistance to pyrethroids. Using quantitative sequencing (QS), the resistance allele frequencies of Israeli bed bug populations from across the country were determined. Genomic DNA was extracted from samples of 12 populations of bed bugs collected from Israel and DNA fragments containing the V419L or L925I and I936F mutations sites were PCR amplified. The PCR products were analyzed by QS and the nucleotide signal ratios calculated and used to predict the resistance allele frequencies of the unknown populations. Results of the genetic analysis show that resistant nucleotide signals are highly correlated to resistance allele frequencies for both mutations. Ten of the 12 tested populations had 100% of the L925I mutation and 0% of the V419L mutation. One population was heterogeneous for the L925I mutation and had 0% of the V419L mutation and another population was heterogeneous for the V419L mutation and had 100% of the L925I mutation. I936F occurred only at low levels. These results indicate that bed bugs in Israel are genetically resistant to pyrethroids. Thus, pyrethroids should only be used for bed bug management with caution using effective application and careful monitoring procedures. Additionally, new and novel-acting insecticides and nonchemical means of controlling bed bugs should be explored.

The study examines the extent and frequency of a knockdown-type resistance allele (kdr type) in North American populations of human head lice. Lice were collected from 32 locations in Canada and the United States. DNA was extracted from individual lice and used to determine their zygosity using the serial invasive signal amplification technique to detect the kdr-type T917I (TI) mutation, which is most responsible for nerve insensitivity that results in the kdr phenotype and permethrin resistance. Previously sampled sites were resampled to determine if the frequency of the TI mutation was changing. The TI frequency was also reevaluated using a quantitative sequencing method on pooled DNA samples from selected sites to validate this population genotyping method. Genotyping substantiated that TI occurs at high levels in North American lice (88.4%). Overall, the TI frequency in U.S. lice was 84.4% from 1999 to 2009, increased to 99.6% from 2007 to 2009, and was 97.1% in Canadian lice in 2008. Genotyping results using the serial invasive signal amplification reaction (99.54%) and quantitative sequencing (99.45%) techniques were highly correlated. Thus, the frequencies of TI in North American head louse populations were found to be uniformly high, which may be due to the high selection pressure from the intensive and widespread use of the pyrethrins- or pyrethroid-based pediculicides over many years, and is likely a main cause of increased pediculosis and failure of pyrethrins- or permethrin-based products in Canada and the United States. Alternative approaches to treatment of head lice infestations are critically needed.

This study establishes deltamethrin resistance in a common bed bug, Cimex lectularius L., population collected from New York City (NY-BB). The NY-BB population was 264-fold more resistant to 1% deltamethrin in contact bioassay compared with an insecticide-susceptible population collected in Florida (FL-BB). General esterase, glutathione S-transferase, and 7-ethoxycoumarin O-deethylase activities of NY-BB were not statistically different from those of FL-BB. cDNA fragments that encoded the open reading frame of voltage-sensitive sodium channel a-subunit genes from the FL-BB and NY-BB populations, respectively, were obtained by homology probing polymerase chain reaction (PCR) and sequenced. Sequence alignment of the internal and 5' and 3' rapid amplification of cDNA ends (RACE) fragments generated a 6,500-bp cDNA sequence contig, which was composed of a 6,084-bp open reading frame (ORF) encoding 2,027 amino acid residues and 186-bp 5' and 230-bp 3' untranslated regions (5' and 3' UTRs, respectively). Sequence comparisons of the open reading frames of the a-subunit genes identified two point mutations (V419L and L925I) that were presented only in the NY-BB population. L925I, located the intracellular loop between IIS4 and IIS5, has been previously found in a highly pyrethroid-resistant populations of whitefly (Bemisia tabaci). V419L, located in the IS6 transmembrane segment, is a novel mutation. A Val to Met mutation at the corresponding position of the bed bug V419, however, has been identified in the tobacco budworm as a kdr-type mutation. This evidence suggests that the two mutations are likely the major resistance-causing mutations in the deltamethrin-resistant NY-BB through a knockdown-type nerve insensitivity mechanism.

A quantitative sequencing (QS) protocol that detects the frequencies of sodium channel mutations (M815I, T917I, and L920F) responsible for knockdown resistance in permethrin-resistant head lice (Pediculus humanus capitis De Geer) was tested as a population genotyping method for use as a preliminary resistance monitoring tool. Genomic DNA fragments of the sodium channel a-subunit gene that encompass the three mutation sites were polymerase chain reaction (PCR)-1 amplified from individual head lice with either resistant or susceptible genotypes, and combined in various ratios to generate standard DNA template mixtures for QS. After sequencing, the signal ratios between resistant and susceptible nucleotides were calculated and plotted against the corresponding resistance allele frequencies. Quadratic regression coefficients of the plots were close to 1, demonstrating that the signal ratios are highly correlated with the resistance allele frequencies. Resistance allele frequencies predicted by QS, using either "pooled DNA" (DNA extracted from individual louse specimens and pooled) or "pooled specimen DNA" (DNA simultaneously extracted from multiple louse specimens), agreed well with those determined by individual sequencing, confirming the reliability and accuracy of QS as a population genotyping method and validating our approach of using the pooled specimen DNA as the DNA template for QS. Our protocol for QS was determined to be highly reliable for the prediction of resistance allele frequencies higher than ≈7.4% at the 95% confidence level. According to the resistance allele frequencies determined by QS, pyrethroid resistance varies substantially among different geographical regions, emphasizing the importance of early resistance detection and proper management strategies.

This study examines the effectiveness of a new ivermectin formulation for the topical treatment of the human head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae). Permethrin-resistant lice originally obtained from south Florida and maintained on an in vitro rearing system were 100% susceptible to ivermectin formulations by using a semiclinical hair tuft bioassay. The formulation was 100% effective at killing lice using 1, 0.5, and 0.25% ivermectin concentrations after 10-min exposures. As judged by the lethal time (LT)50 and LT95 values, 0.5% formulated ivermectin was 3.8 and 3.2 times faster at killing lice, respectively, than 0.5% nonformulated ivermectin, indicating that the formulation may facilitate the penetration of ivermectin into the louse. The hair tuft-based bioassay in conjunction with the in vitro rearing system provides a standardized method to assess the comparative efficacy of pediculicide formulations in a reproducible format that mimics the exposure scenario that occurs on the human scalp.

The human body louse, Pediculus humanus humanus L. (Anoplura: Pediculidae), is a vector of several diseases, including louse-borne epidemic typhus, relapsing fever, and trench fever, whereas the head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae), is more a pest of social concern. Sequencing of the body louse genome has recently been proposed and undertaken by National Human Genome Research Institute. One of the first steps in understanding an organism's genome is to determine its genome size. Here, using flow cytometry determinations, we present evidence that body louse genome size is 104.7 ± 1.4 Mb for females and 108.3 ± 1.1 Mb for males. Our results suggest that head lice also have a small genome size, of similar size to the body louse. Thus, Pediculus lice have one of the smallest genome sizes known in insects, suggesting it may be a suitable choice as a minimal hemimetabolous genome.