RESUMO
Mutations in the protein kinase PINK1 lead to defects in mitophagy and cause autosomal recessive early onset Parkinson's disease1,2. PINK1 has many unique features that enable it to phosphorylate ubiquitin and the ubiquitin-like domain of Parkin3-9. Structural analysis of PINK1 from diverse insect species10-12 with and without ubiquitin provided snapshots of distinct structural states yet did not explain how PINK1 is activated. Here we elucidate the activation mechanism of PINK1 using crystallography and cryo-electron microscopy (cryo-EM). A crystal structure of unphosphorylated Pediculus humanus corporis (Ph; human body louse) PINK1 resolves an N-terminal helix, revealing the orientation of unphosphorylated yet active PINK1 on the mitochondria. We further provide a cryo-EM structure of a symmetric PhPINK1 dimer trapped during the process of trans-autophosphorylation, as well as a cryo-EM structure of phosphorylated PhPINK1 undergoing a conformational change to an active ubiquitin kinase state. Structures and phosphorylation studies further identify a role for regulatory PINK1 oxidation. Together, our research delineates the complete activation mechanism of PINK1, illuminates how PINK1 interacts with the mitochondrial outer membrane and reveals how PINK1 activity may be modulated by mitochondrial reactive oxygen species.
Assuntos
Proteínas de Insetos , Pediculus , Proteínas Quinases , Animais , Microscopia Crioeletrônica , Proteínas de Insetos/metabolismo , Mitocôndrias , Mitofagia , Fosforilação , Conformação Proteica , Proteínas Quinases/metabolismo , Ubiquitina/metabolismoRESUMO
Yersinia pestis, the causative agent of plague, is a highly lethal vector-borne pathogen responsible for killing large portions of Europe's population during the Black Death of the Middle Ages. In the wild, Y. pestis cycles between fleas and rodents; occasionally spilling over into humans bitten by infectious fleas. For this reason, fleas and the rats harboring them have been considered the main epidemiological drivers of previous plague pandemics. Human ectoparasites, such as the body louse (Pediculus humanus humanus), have largely been discounted due to their reputation as inefficient vectors of plague bacilli. Using a membrane-feeder adapted strain of body lice, we show that the digestive tract of some body lice become chronically infected with Y. pestis at bacteremia as low as 1 × 105 CFU/ml, and these lice routinely defecate Y. pestis. At higher bacteremia (≥1 × 107 CFU/ml), a subset of the lice develop an infection within the Pawlowsky glands (PGs), a pair of putative accessory salivary glands in the louse head. Lice that developed PG infection transmitted Y. pestis more consistently than those with bacteria only in the digestive tract. These glands are thought to secrete lubricant onto the mouthparts, and we hypothesize that when infected, their secretions contaminate the mouthparts prior to feeding, resulting in bite-based transmission of Y. pestis. The body louse's high level of susceptibility to infection by gram-negative bacteria and their potential to transmit plague bacilli by multiple mechanisms supports the hypothesis that they may have played a role in previous human plague pandemics and local outbreaks.
Assuntos
Pediculus , Peste , Yersinia pestis , Animais , Yersinia pestis/patogenicidade , Yersinia pestis/fisiologia , Pediculus/microbiologia , Pediculus/fisiologia , Humanos , Peste/transmissão , Peste/microbiologia , Insetos Vetores/microbiologia , Insetos Vetores/parasitologia , Mordeduras e Picadas de Insetos/microbiologia , Feminino , MasculinoRESUMO
Insects have repeatedly forged symbioses with heritable microbes, gaining novel traits. For the microbe, the transition to symbioses can lead to the degeneration of the symbiont's genome through transmission bottlenecks, isolation, and the loss of DNA repair enzymes. However, some insect-microbial symbioses have persisted for millions of years, suggesting that natural selection slows genetic drift and maintains functional consistency between symbiont populations. By sampling in multiple countries, we examine genomic diversity within a symbiont species, a heritable symbiotic bacterium found only in human head lice. We find that human head louse symbionts contain genetic diversity that appears to have arisen contemporaneously with the appearance of anatomically modern humans within Africa and/or during the colonization of Eurasia by humans. We predict that the observed genetic diversity underlies functional differences in extant symbiont lineages, through the inactivation of genes involved in symbiont membrane construction. Furthermore, we find evidence of additional gene losses prior to the appearance of modern humans, also impacting the symbiont membrane. From this, we conclude that symbiont genome degeneration is proceeding, via gene inactivation and subsequent loss, in human head louse symbionts, while genomic diversity is maintained. Collectively, our results provide a look into the genomic diversity within a single symbiont species and highlight the shared evolutionary history of humans, lice, and bacteria.
Assuntos
Hominidae , Pediculus , Animais , Humanos , Pediculus/genética , Filogenia , Genoma Bacteriano , Evolução Molecular , Bactérias/genética , Genômica , Hominidae/genética , Insetos/genética , Simbiose/genéticaRESUMO
Coherent fluorescence imaging with two objective lenses (4Pi detection) enables single-molecule localization microscopy with sub-10 nm spatial resolution in three dimensions. Despite its outstanding sensitivity, wider application of this technique has been hindered by complex instrumentation and the challenging nature of the data analysis. Here we report the development of a 4Pi-STORM microscope, which obtains optimal resolution and accuracy by modeling the 4Pi point spread function (PSF) dynamically while also using a simpler optical design. Dynamic spline PSF models incorporate fluctuations in the modulation phase of the experimentally determined PSF, capturing the temporal evolution of the optical system. Our method reaches the theoretical limits for precision and minimizes phase-wrapping artifacts by making full use of the information content of the data. 4Pi-STORM achieves a near-isotropic three-dimensional localization precision of 2-3 nm, and we demonstrate its capabilities by investigating protein and nucleic acid organization in primary neurons and mammalian mitochondria.
Assuntos
Lentes , Imagem Individual de Molécula , Animais , Artefatos , Mamíferos , Microscopia , Imagem ÓpticaRESUMO
We analyzed body lice collected from persons experiencing homelessness in Winnipeg, Manitoba, Canada, during 2020-2021 to confirm vector species and ecotype and to identify louseborne pathogens. Of 556 lice analyzed from 7 persons, 17 louse pools (218 lice) from 1 person were positive for the louseborne bacterium Bartonella quintana.
Assuntos
Pessoas Mal Alojadas , Infestações por Piolhos , Pediculus , Humanos , Animais , Pediculus/microbiologia , Infestações por Piolhos/epidemiologia , Infestações por Piolhos/parasitologia , Bartonella quintana/genética , Canadá/epidemiologia , Manitoba/epidemiologia , Masculino , FemininoRESUMO
Tissue-clearing techniques have revolutionized the field of biological imaging by rendering biological specimens transparent and enabling inside optical detection. Light-sheet fluorescence microscopy (LSFM) is a powerful tool for three-dimensional imaging of large biological samples. Combining tissue-clearing techniques with LSFM has advanced the efficient 3D visualization of these samples. A crucial challenge with LSFM is the requirement for the objective to operate within the clearing reagent, which can cause aberrations. To address this issue, we introduce a novel, to our knowledge, approach for the flexible design of the solid immersion refractive meniscus lens (SIMlens), facilitating the use of air objectives with cleared samples. Compared to the previous SIMlens, this method not only eliminates aberrations but also offers customized options for enhancing the numerical aperture and working distance of the objective lens, achieving at least a 10% improvement. We have demonstrated the feasibility of this new method using mouse brain samples.
Assuntos
Lentes , Microscopia de Fluorescência , Animais , Camundongos , Microscopia de Fluorescência/métodos , Encéfalo/diagnóstico por imagem , Imageamento TridimensionalRESUMO
We present a versatile extended depth-of-field (EDOF) wide-field fluorescence microscopy using a new, to the best of our knowledge, active device, micro-mirror array lens system (MALS) for calibration-free and orientation-insensitive EDOF imaging. The MALS changed the focal plane during image acquisition, and the system could be operated in any orientation. Two EDOF imaging modes of high-speed accumulation and low-speed surface sectioning were implemented. The performance was demonstrated in non-contact imaging of conjunctival goblet cells in live mice and depth-resolved cellular examination of ex-vivo human cancer specimens. MALS-based EDOF microscopy has potential for versatile cellular examination.
Assuntos
Lentes , Microscopia de Fluorescência , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Animais , Camundongos , Humanos , Células Caliciformes/citologia , Túnica Conjuntiva/citologia , Túnica Conjuntiva/diagnóstico por imagemRESUMO
BACKGROUND: Head lice infestation is a prevalent dermatological condition among adolescent girls, which has wide-ranging adverse physical, psychological, and emotional effects on their lives. However, these experiences have been sparsely documented. This study aimed to investigate the lived experiences of Iranian adolescent girls regarding head lice infestation. METHODS: In this phenomenological study, a purposive sampling technique was employed to select 15 adolescent girls who were experiencing head lice infestation. Collaboration was established with local schools to identify and recruit the participants. Subsequently, the purpose and nature of the study were explained to the identified participants and their guardians. Semi-structured in-depth interviews were conducted to gather the necessary data. The collected data underwent analysis using Colaizzi's seven-step method. To enhance the credibility of the findings, Lincoln and Guba's (2004) criteria were applied. The management of the data was facilitated through the utilization of MAXQDA software version 0.9.5. RESULTS: The average age of the participants, aged 12 to 17, was 14.5 (standard deviation = 1.7). In terms of education, the majority of them had completed upper secondary education (n = 8, 53.3%), followed by lower secondary education (n = 4, 26.6%). The participants' experiences were categorized into four main themes and 15 sub-themes. The main themes included living in the shadow of fear, torment of infestation, "struggling with head lice, and disturbing ramifications. The sub-themes encompassed social fear, fear of harm, fear of beauty decline, stigma, bullying behavior, self-blame, adversity, challenging struggle, effective coping, nonconforming behavior, family disruption, academic disruption, health threats, and confused mental state. CONCLUSION: During head lice infestation, adolescent girls endured negative experiences and extensive fears, considering it a significant ordeal. They encountered multiple challenges while dealing with lice and utilized both adaptive and maladaptive strategies to cope with the infestation. It is recommended to enhance public awareness regarding head lice infestation, and healthcare providers should offer emotional support and counseling services to affected girls and their families.
Assuntos
Infestações por Piolhos , Pediculus , Pesquisa Qualitativa , Humanos , Feminino , Adolescente , Infestações por Piolhos/psicologia , Animais , Criança , Irã (Geográfico)RESUMO
BACKGROUND: Head lice are a main public health problem and the most important human ectoparasites and the use of pediculicides is the most common way to control it. One of the possible causes of treatment failure is the lack of improper application of pediculicide. The aim of this study was to assess the effect of education on efficacy of 1% permethrin or 4% dimeticone lotion to treat head lice infestation. METHODS: This quasi-experimental study included 100 individuals with head lice infestation from comprehensive urban health centers in Ardabil as the intervention group, and 400 individuals from East Azerbaijan and West Azerbaijan provinces as the control group, from April to March 2019. The data collection tools included a demographic questionnaire and an examination recording sheet, which documented the presence of adult lice or nits. Due to the inability to perform random assignment and control for numerous observed covariates, propensity score matching (PSM) was used. RESULTS: The outcome of treatment included elimination of head lice infestation on is 7, and in the case of recurrence, it was considered on days 14 and 30 after treatment. The results showed that the educational intervention program had a significant positive effect on the efficacy of both treatments. The likelihood of improvement was approximately three times greater in the intervention group compared to the control group. CONCLUSION: Participants who received the training intervention (OR = 3.29; CI 95%: 2.21-4.88) were more likely to have a successful treatment than control group. In the case of providing proper training on the use of pediculicides and observing hygiene tips to patients with pediculosis, could help to successful treatment of pediculosis.
Assuntos
Inseticidas , Infestações por Piolhos , Pediculus , Animais , Adulto , Humanos , Infestações por Piolhos/tratamento farmacológico , Permetrina/uso terapêutico , Pontuação de Propensão , Dimetilpolisiloxanos/farmacologia , Inseticidas/uso terapêutico , Inseticidas/farmacologiaRESUMO
The human head lice Pediculus humanus capitis (De Geer) (Phthiraptera: Pediculidae) are strict, obligate human ectoparasites that spends their entire life cycle in the host and cause skin irritation and derived infections. Despite the health-related importance, few studies have evaluated the chemical communication among these insects. Here, we evaluate the response of lice of both sexes to cuticular extracts using two solvents of different polarity (hexane and methanol). Cuticular extracts that elicited an attraction response towards head lice were analysed by gas chromatography-mass spectrometry (GC-MS) to determine the cuticular lipid profile. Both lice sexes were attracted to the hexane extracts but not the methanol extracts, suggesting the non-polarity of the compounds present in the cuticle. Chemical analyses of hexane extracts from males and females showed high similarity in major compounds. This study provides the first evidence that lice respond to cuticle extracts, which may be important to understand aggregation behaviour.
Assuntos
Hexanos , Pediculus , Animais , Feminino , Masculino , Pediculus/efeitos dos fármacos , Pediculus/química , Hexanos/química , Cromatografia Gasosa-Espectrometria de Massas , Metanol/química , Comportamento Animal/efeitos dos fármacosRESUMO
The human cannot detect light with a wavelength exceeding 700 nm, primarily due to limitations in the physiological structure of the human eye. However, in certain specific scenarios, the ability to detect near-infrared (NIR) light proves to be extremely valuable. To attain this desired capability, NIR up conversion nanoparticles (UCNPs) were prepared and doped in the optical lens materials, aiming to obtain a NIR light "visible" optical lens. It is demonstrated that the doping of UCNPs in the optical lens materials does not significantly impact on their mechanical properties, optical properties, surface properties and it exhibits excellent biocompatibility in cell and animal experiments. More importantly, the UCNPs doping can convert NIR light into visible light within the material effectively and stably. The eyes can "see" the NIR light after wearing such UCNPs doped optical lens. Such NIR light visible optical lens could have great potential in actual applications.
Assuntos
Raios Infravermelhos , Nanopartículas , Nanopartículas/química , Animais , Humanos , Camundongos , Lentes , Materiais Biocompatíveis/química , Propriedades de SuperfícieRESUMO
Bio-inspired optical systems have recently been developed using polarizers and liquid or rigid lenses. In this work, we propose a bio-inspired opto-mechatronic system that imitates the accommodation and regulation of light intensity as the human eye does. The system uses a polymeric lens as a cornea, an adjustable diaphragm as an iris, a tunable solid elastic lens as a crystalline lens, and a commercial sensor as a retina. We also present the development of the electronic control system to accommodate and regulate the amount of light that enters the system, for which two stepper motors, an Arduino control system, and light and movement sensors are used. The characterization of the system is presented together with the results obtained, where it can be seen that the system works in an acceptable range as the human eye does.
Assuntos
Cristalino , Lentes , Dispositivos Ópticos , Humanos , Iluminação , CórneaRESUMO
INTRODUCTION: Head lice infestation remains a persistent public health concern among primary school children in resource-limited settings, affecting their well-being and academic performance. Despite previous studies, there is no consistent evidence on the prevalence and factors associated with head lice infestation. This study aimed to determine the prevalence and factors related to head lice infestation among primary school children in low and middle-income countries. METHODS: This review was conducted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Relevant electronic databases, including PubMed, Cochrane Library, Web of Science, Science Direct, AJOL, and Google Scholar, were used to retrieve articles. The study included only published articles written in English languages between December 01, 2014 to January 31, 2024 for studies reporting the prevalence of head lice infestation or associated factors among primary school children in low- and middle-income countries. This review has been registered on PROSPERO with Prospero registration number CRD42024506959. The heterogeneity of the data was evaluated using the I2 statistic. A meta-analysis was conducted using STATA 17 software, with a 95% confidence interval. Publication bias was evaluated using funnel plots and statistical tests, such as Egger's and Beggs's tests, to identify publication biases in the included studies. Meta-regression was also carried out to assess the source of publication of publication bias. RESULTS: The review included 39 studies involving 105,383 primary school children. The pooled prevalence of head lice infestation among primary school children in low- and middle-income countries was 19.96% (95% CI; 13.97, 25.95). This review also found out that being a girl was 3.71 times (AOR = 3.71; 95% CI: 1.22-11.26) more likely to have head lice infestation as compared to boys, while children with a previous history of infestation were 4.51 times (AOR = 4.51; 95% CI: 2.31-8.83) more likely to have head lice infestation as compared to their counterparts. CONCLUSION: The overall prevalence of head lice infestation among primary school children in low- and middle-income countries was found to be high. Female gender, children who had a previous history of infestation, and family size were significant predictors of head lice infestation. As a result, policymakers and program administrators should focus on the identified determinants.
Assuntos
Países em Desenvolvimento , Infestações por Piolhos , Pediculus , Humanos , Infestações por Piolhos/epidemiologia , Prevalência , Criança , Animais , Instituições Acadêmicas , Fatores de Risco , Dermatoses do Couro Cabeludo/epidemiologia , Masculino , FemininoRESUMO
SIGNIFICANCE: This study provides a faster method for objectively measuring accommodative amplitude with an open-field autorefractor in a research setting. PURPOSE: Objective measures of accommodative amplitude with an autorefractor take time because of the numerous stimulus demands tested. This study compares protocols using different amounts and types of demands to shorten the process. METHODS: One hundred participants were recruited for four age bins (5 to 9, 10 to 14, 15 to 19, and 20 to 24 years) and monocular amplitude measured with an autorefractor using three protocols: proximal, proximal-lens (letter), and proximal-lens (picture). For proximal, measurements were taken as participants viewed a 0.9 mm "E" placed at 13 demands (40 to 3.3 cm = 2.5 to 30 D). The other protocols used a target (either the "E" or a detailed picture) placed at 33 and 12.5 cm followed by 12.5 cm with a series of lenses (-2, -4, and -5.5 D). Adjustments were made for lens effectivity for the three lens conditions, which were thus 9.6, 11.1, and 12.0 D for individuals without additional spectacle lenses. Accommodative amplitude was defined as the greatest response measured with each technique. One-way analysis of variance was used to compare group mean amplitudes across protocols and differences between letter protocols by age bin. RESULTS: Amplitudes were significantly different between protocols (p < 0.001), with proximal having higher amplitudes (mean ± standard deviation, 8.04 ± 1.70 D) compared with both proximal-lens protocols (letter, 7.48 ± 1.42 D; picture, 7.43 ± 1.42 D) by post hoc Tukey analysis. Differences in amplitude between the proximal and proximal-lens (letter) protocol were different by age group (p = 0 .003), with the youngest group having larger differences (1.14 ± 1.58 D) than the oldest groups (0.17 ± 0.58 and 0.29 ± 0.48 D, respectively) by post hoc Tukey analysis. CONCLUSIONS: The proximal-lens protocols took less time and identified the maximum accommodative amplitude in participants aged 15 to 24 years; however, they may underestimate true amplitude in younger children.
Assuntos
Acomodação Ocular , Lentes , Criança , HumanosRESUMO
The intracapsular accommodation mechanism (IAM) may be understood as an increase in the lens equivalent refractive index as the eye accommodates. Our goal was to evaluate the existence of an IAM by analysing observed changes in the inner curvature gradient of the lens. To this end, we fitted a gradient index and curvature lens model to published experimental data on external and nucleus geometry changes during accommodation. For each case analysed, we computed the refractive power and equivalent index for each accommodative state using a ray transfer matrix. All data sets showed an increase in the effective refractive index, indicating a positive IAM, which was stronger for older lenses. These results suggest a strong dependence of the lens equivalent refractive index on the inner curvature gradient.
Assuntos
Cristalino , Lentes , Humanos , Refração Ocular , Acomodação Ocular , Refratometria/métodosRESUMO
This study evaluates the pediculicidal activity of nanoformulations containing different binary essential oil component mixtures (eugenol:linalool, 1,8 -cineole:linalool, and eugenol:thymol) using immersion bioassays. These have allowed us to evaluate the knockdown time affecting 50% of the individuals (KT50). In addition, the type of interaction between the components in each mixture was established in terms of the combination index (IC). The KT50 values were 6.07; 8.83; 7.17 and 27.23 h for linalool, 1,8 -cineole, eugenol, and thymol, respectively. For the eugenol:linalool mixtures, the efficacy was lower or equal to that obtained for the nanoformulations of the pure compounds, with values of KT50 about 13.33, 8.16 and 6.71 h for mixtures with ratios 3:1, 1:1 and 1:3, respectively. These mixtures present IC > 1, evidencing antagonistic interaction, which is enhanced with eugenol content. In the case of the binary mixtures of 1,8 -cineole: linalool, KT50 values were similar to those obtained for eugenol:linalool mixtures with similar ratios. In this case, IC assumes values close to unity, suggesting additive interactions independently of the mixture composition. On the other side, mixtures of eugenol:thymol with 1:1 and 1:3 ratios showed values of 9.40 and 32.93 h, while the mixture with a 3:1 ratio showed the greatest effectiveness (KT50 of 4.42 h). Eugenol:thymol mixtures show synergistic interaction (IC < 1) for combinations 3:1 and 1:1, while no interaction was observed for 1:3 combination. This indicates that eugenol enhances thymol activity. These results must be considered an important step forward to the development of effective pediculicidal nanoformulations based on botanical compounds.
Assuntos
Monoterpenos Acíclicos , Eucaliptol , Eugenol , Monoterpenos , Monoterpenos/farmacologia , Monoterpenos/química , Animais , Eugenol/farmacologia , Eugenol/química , Eucaliptol/farmacologia , Monoterpenos Acíclicos/farmacologia , Monoterpenos Acíclicos/química , Pediculus/efeitos dos fármacos , Inseticidas/farmacologia , Inseticidas/química , Timol/farmacologia , Timol/química , Micelas , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Nanopartículas/química , Infestações por Piolhos/tratamento farmacológicoRESUMO
OBJECTIVE: This scoping review aimed to identify and describe the available evidence on the effect of magnifying devices (loupe or microscope) on the performance of restorative dental preparations. MATERIALS AND METHODS: This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the INPLASY database. An electronic search was performed in four databases and Grey literature for articles published until November 2023. Eligibility criteria were determined using the PICOS strategy and comprised studies that evaluated the performance of magnification devices for restorative dental preparations. A bibliographic mapping of the evidence was conducted. RESULTS: Sixteen studies met the inclusion criteria. Most of the studies (n = 12) compared the performance of dental preparations using magnification loupes vs. no magnification. The magnification for loupes and microscopes ranged from 2.5x to 4.0x and 6.4x to 10x, respectively. The use of magnifying loupes improved the performance of restorative preparations in 66.6% of the evaluated studies. However, when the magnifications were compared, the greater magnification provided by microscopes did not improve preparation performance compared to magnification loupes. Regarding the place of publication, the American continent concentrates the most significant number of evidence. CONCLUSIONS: Although evidence for magnification improving the performance of dental preparations has increased over the last decade, basically only in vitro studies (most of which have taken place in the Americas) have been reported in the literature. The evidence suggests that magnification significantly improves restorative preparation performance when compared to non-magnification. However, higher magnifications (e.g., microscopes) do not appear to improve tooth preparation performance compared with lower magnification devices (e.g., magnification loupes). CLINICAL RELEVANCE: Available evidence supports that using magnification can improve the performance of restored tooth preparations. However, high magnifications have no advantages over lower magnifications.
Assuntos
Lentes , Humanos , Microscopia/instrumentação , Restauração Dentária Permanente/métodos , Preparo da Cavidade Dentária/métodosRESUMO
Transient terahertz time-domain spectroscopy (THz-TDS) imaging has emerged as a novel non-ionizing and noninvasive biomedical imaging modality, designed for the detection and characterization of a variety of tissue malignancies due to their high signal-to-noise ratio and submillimeter resolution. We report our design of a pair of aspheric focusing lenses using a commercially available lens-design software that resulted in about 200 × 200-µm2 focal spot size corresponding to the 1-THz frequency. The lenses are made of high-density polyethylene (HDPE) obtained using a lathe fabrication and are integrated into a THz-TDS system that includes low-temperature GaAs photoconductive antennae as both a THz emitter and detector. The system is used to generate high-resolution, two-dimensional (2D) images of formalin-fixed, paraffin-embedded murine pancreas tissue blocks. The performance of these focusing lenses is compared to the older system based on a pair of short-focal-length, hemispherical polytetrafluoroethylene (TeflonTM) lenses and is characterized using THz-domain measurements, resulting in 2D maps of the tissue refractive index and absorption coefficient as imaging markers. For a quantitative evaluation of the lens effect on the image resolution, we formulated a lateral resolution parameter, R2080, defined as the distance required for a 20-80% transition of the imaging marker from the bare paraffin region to the tissue region in the same image frame. The R2080 parameter clearly demonstrates the advantage of the HDPE lenses over TeflonTM lenses. The lens-design approach presented here can be successfully implemented in other THz-TDS setups with known THz emitter and detector specifications.
Assuntos
Lentes , Imagem Terahertz , Animais , Camundongos , Polietileno , Politetrafluoretileno , Temperatura BaixaRESUMO
BACKGROUND: Fogging and staining of a laparoscope lens negatively impact surgical visualization. We hypothesized that the disposable hot pack could not only warm but also clean laparoscopes. Hence, this study verified and developed the disposable hot pack with anti-fogging and cleaning function. MATERIAL AND METHODS: The laparoscope was inserted into a swine abdominal cavity for five minutes. Then, the laparoscopic tip was heated with 65 °C saline or the folded disposable hot pack with nonwoven fabric coated surfactant for ten seconds (n = 15). Also, a laparoscopic tip with dirt was wiped with the prototype or conventional gauze for 10 s (n = 10). The dirt, fogging, and temperature of the laparoscopic tip were respectively evaluated after the laparoscope was inserted into the abdominal cavity. RESULTS: The laparoscopic tip temperature five minutes after insertion into the abdominal cavity was similar (31.1 °C vs 31.2 °C, p = 0.748) and there was no fogging in both methods. The conventional gauze had significantly less temperature of the laparoscopic tip after cleaning and higher fogging occurrence than the prototype (29.5 °C vs 34.0 °C, p < 0.001, 30% vs 0%, p = 0.030, respectively), although there was no dirt left after both methods. CONCLUSION: The disposable hot pack has a strong potential as an anti-fogging and cleaning device for use during laparoscopic surgery.
Assuntos
Laparoscopia , Lentes , Animais , Suínos , Laparoscopia/métodos , Laparoscópios , Temperatura , Temperatura AltaRESUMO
Analysis of lens changes in Marfan syndrome (MS), in addition to assessing the position of the lens itself, should include the possibility of examining its supporting and accommodative components (ciliary zonule and ciliary body), or what can be called the entire anatomical complex of the lens. Optical methods of studying the structures of the anterior segment of the eye, due to iris opacity, allow only to analyze the state of the lens within the natural or medically enlarged pupil width. Visualization of the structures located behind the iris is possible with the use of radiation diagnostic methods, in particular ultrasound biomicroscopy (UBM). PURPOSE: This study assesses the state of the anatomical complex of the lens in MS using UBM. MATERIAL AND METHODS: The study was carried out on clinical material previously used by us to analyze changes in the fibrous membrane of the eye in MS. At the first stage, the main (19 patients with MS, 38 eyes) and the control (24 patients with myopia, 48 eyes) groups were formed for comparative evaluation. The formed groups were standardized according to the age of the patients and the axial length of the eye. At the second stage, patients with MS were divided into subgroups depending on the absence or presence of biomicroscopic signs of ectopia lentis (22 and 16 eyes, respectively). For UBM, an ultrasound linear sensor with a scanning frequency of 50 MHz was used (Aviso device, Quantel Medical, France). Various biometric UBM indicators were determined: lens thickness, diameter of the lens, lens-axial length factor, iris-lens angle, iris-lens contact distance, posterior chamber depth, length of the fibers of ciliary zonule, thickness of the ciliary body, sclera-ciliary process angle. RESULTS: There are changes in the anatomical complex of the lens as a whole in MS (in the lens itself, the ciliary zonule, and the ciliary body), which are characterized by an increase in lens thickness and a decrease in the diameter of the lens, an increase in the length of the fibers of the ciliary zonule and a decrease in the thickness of the ciliary body. At the same time, the displacement of the lens detected by optical biomicroscopy (ectopia lentis) can be considered as an advanced stage of changes in the anatomical complex of the lens. CONCLUSION: UBM provides the possibility of full-fledged visualization of all components of the anatomical complex of the lens in terms of both diagnostics, and monitoring of changes in MS. The question of the advisability of including this method in the algorithm for diagnosing ocular manifestations in order to verify the MS remains open. Possible obstacles may be, on the one hand, related to the need for special and expensive equipment, and on the other hand, the absence of a generally accepted «normal¼ values of UBM indicators of the anatomical complex of the lens.