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To determine the characteristics of pediatric patients 0-19 years of age who died after onset of SARS-CoV-2 infection in Japan during January 1-September 30, 2022, we reviewed multiple sources. We identified 62 cases, collected detailed information from medical records and death certificates, and conducted interviews, resulting in 53 patients with detailed information for our study. Among 46 patients with internal causes of death (i.e., not external causes such as trauma), 15% were <1 year of age, 59% had no underlying disease, and 88% eligible for vaccination were unvaccinated. Nonrespiratory symptoms were more common than respiratory symptoms. Out-of-hospital cardiac arrest affected 46% of patients, and time from symptom onset to death was <7 days for 77%. Main suspected causes of death were central nervous system abnormalities (35%) and cardiac abnormalities (20%). We recommend careful follow-up of pediatric patients after SARS-CoV-2 infection during the first week after symptom onset, regardless of underlying diseases.
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COVID-19 , SARS-CoV-2 , Humanos , COVID-19/mortalidad , COVID-19/epidemiología , Preescolar , Lactante , Niño , Japón/epidemiología , Femenino , Masculino , Adolescente , Recién Nacido , Adulto JovenRESUMEN
BACKGROUND: Worldwide, children, newborns, and pregnant or postpartum women are vulnerable to disasters and emergency situations, and providing support to this population is of great concern. Japan is located in a disaster-prone area, so disaster response and risk reduction strategies are important priorities. METHODS: We introduce a system called the Disaster Liaison for Pediatric and Perinatal Medicine (DLPPM). This was created with a specific focus on perinatal children and pregnant women in Japan. We report the details of its activities, discuss its challenges, and draw on lessons learned for the further development of perinatal support systems, particularly for children. RESULTS: The lessons learned from the activities of the DLPPM include the following: (1) establish a support system for emergency specialists beyond those with pediatric and perinatal specialties; (2) mitigate the risk of indirect damage caused by primary disasters; and (3) establish a networking function linked to existing pediatric and perinatal medicine facilities. CONCLUSIONS: By establishing similar systems, we believe that it will be feasible to address pediatric and perinatal care needs in disaster response contexts in other countries and regions around the world.
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Planificación en Desastres , Atención Perinatal , Humanos , Japón , Femenino , Embarazo , Recién Nacido , Atención Perinatal/métodos , Planificación en Desastres/organización & administración , Pediatría , Niño , Perinatología , DesastresRESUMEN
Skin lesions, cataracts, and congenital anomalies have been frequently associated with inherited deficiencies in enzymes that synthesize cholesterol. Lanosterol synthase (LSS) converts (S)-2,3-epoxysqualene to lanosterol in the cholesterol biosynthesis pathway. Biallelic mutations in LSS have been reported in families with congenital cataracts and, very recently, have been reported in cases of hypotrichosis. However, it remains to be clarified whether these phenotypes are caused by LSS enzymatic deficiencies in each tissue, and disruption of LSS enzymatic activity in vivo has not yet been validated. We identified two patients with novel biallelic LSS mutations who exhibited congenital hypotrichosis and midline anomalies but did not have cataracts. We showed that the blockade of the LSS enzyme reaction occurred in the patients by measuring the (S)-2,3-epoxysqualene/lanosterol ratio in the forehead sebum, which would be a good biomarker for the diagnosis of LSS deficiency. Epidermis-specific Lss knockout mice showed neonatal lethality due to dehydration, indicating that LSS could be involved in skin barrier integrity. Tamoxifen-induced knockout of Lss in the epidermis caused hypotrichosis in adult mice. Lens-specific Lss knockout mice had cataracts. These results confirmed that LSS deficiency causes hypotrichosis and cataracts due to loss-of-function mutations in LSS in each tissue. These mouse models will lead to the elucidation of the pathophysiological mechanisms associated with disrupted LSS and to the development of therapeutic treatments for LSS deficiency.
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Catarata/genética , Epidermis/patología , Hipotricosis/genética , Transferasas Intramoleculares/genética , Cristalino/patología , Adolescente , Animales , Catarata/congénito , Catarata/patología , Colesterol/metabolismo , Análisis Mutacional de ADN , Modelos Animales de Enfermedad , Epidermis/enzimología , Salud Holística , Humanos , Hipotricosis/congénito , Hipotricosis/patología , Transferasas Intramoleculares/metabolismo , Lanosterol/análisis , Lanosterol/metabolismo , Cristalino/enzimología , Masculino , Ratones , Ratones Noqueados , Mutación , Linaje , Sebo/química , Secuenciación del ExomaRESUMEN
This study examines 4ß-Hydroxycholesterol (4ß-HC), which is considered to be a potential marker for the CYP3A4 induction of new chemical entities (NCEs) in drug development. To ensure the use of 4ß-HC as a practical biomarker, it is necessary to accurately measure 4ß-HC and demonstrate that CYP3A4 induction can be appropriately assessed, even for weak inducers. In clinical trials of NCEs, plasma is often collected with various anticoagulants, in some cases, the plasma is acidified, then stored for an extended period. In this study, we examined the effects of these manipulations on the measurement of 4ß-HC, and based on the results, we optimized the plasma collection and storage protocols. We also found that a cholesterol oxidation product is formed when plasma is stored, and by monitoring the compound, we were able to identify when plasma was stored inappropriately. After evaluating the above, clinical drug-drug interaction (DDI) studies were conducted using two NCEs (novel retinoid-related orphan receptor γ antagonists). The weak CYP3A4 induction by the NCEs (which were determined based on a slight decline in the systemic exposure of a probe substrate (midazolam)), was detected by the significant increase in 4ß-HC levels (more specifically, 4ß-HC/total cholesterol ratios). Our new approach, based on monitoring a cholesterol oxidation product to identify plasma that is stored inappropriately, allowed for the accurate measurement of 4ß-HC, and thus, it enabled the evaluation of weak CYP3A4 inducers in clinical studies without using a probe substrate.
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Citocromo P-450 CYP3A , Hidroxicolesteroles , Colesterol , BiomarcadoresRESUMEN
BACKGROUND: The COVID-19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms. METHODS: We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID-19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society. RESULTS: Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID-19-positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID-19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively). CONCLUSIONS: COVID-19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID-19 among children.
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COVID-19 , Adolescente , Adulto , Niño , Humanos , Japón/epidemiología , Pandemias , SARS-CoV-2 , Instituciones AcadémicasRESUMEN
Although the rate of preterm birth has increased in recent decades, a number of preterm infants have escaped death due to improvements in perinatal and neonatal care. Antenatal glucocorticoid (GC) therapy has significantly contributed to progression in lung maturation; however, its potential effects on other organs remain controversial. Furthermore, the effects of antenatal GC therapy on the fetal heart show both pros and cons. Translational research in animal models indicates that constant fetal exposure to antenatal GC administration is sufficient for lung maturation. We have established a premature fetal rat model to investigate immature cardiopulmonary functions in the lungs and heart, including the effects of antenatal GC administration. In this review, we explain the mechanisms of antenatal GC actions on the heart in the fetus compared to those in the neonate. Antenatal GCs may contribute to premature heart maturation by accelerating cardiomyocyte proliferation, angiogenesis, energy production, and sarcoplasmic reticulum function. Additionally, this review specifically focuses on fetal heart growth with antenatal GC administration in experimental animal models. Moreover, knowledge regarding antenatal GC administration in experimental animal models can be coupled with that from developmental biology, with the potential for the generation of functional cells and tissues that could be used for regenerative medical purposes in the future.
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Glucocorticoides , Nacimiento Prematuro , Animales , Metabolismo Energético , Femenino , Corazón Fetal , Glucocorticoides/farmacología , Humanos , Recién Nacido , Recien Nacido Prematuro , Embarazo , RatasRESUMEN
Despite the importance of the insight about the oxidation mechanisms (i.e., radical and singlet oxygen (1O2) oxidation) in extra virgin olive oil (EVOO), the elucidation has been difficult due to its various triacylglycerol molecular species and complex matrix. This study tried to evaluate the mechanisms responsible for EVOO oxidation in our daily use by quantitative determination of triacylglycerol hydroperoxide (TGOOH) isomers using LC-MS/MS. The standards of dioleoyl-(hydroperoxy octadecadienoyl)-triacylglycerol and dioleoyl-(hydroperoxy octadecamonoenoyl)-triacylglycerol, which are the predominant TGOOHs contained in EVOO, were prepared. Subsequently, fresh, thermal-, and photo-oxidized EVOO were analyzed. The obtained results mostly agreed with the previously reported characteristics of the radical and 1O2 oxidation of linoleic acid and oleic acid. This suggests that the methods described in this paper should be valuable in understanding how different factors that determine the quality of EVOO (e.g., olive species, cultivation area, cultivation timing, and extraction methods) contribute to its oxidative stability.
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Peróxido de Hidrógeno , Espectrometría de Masas en Tándem , Cromatografía Liquida , Aceite de Oliva/análisis , TriglicéridosRESUMEN
BACKGROUND: Cor a 9 and Cor a 14 are effective markers for predicting hazelnut allergy. However, there have been no reports on the component-resolved diagnostics (CRD) of hazelnut allergy using an oral food challenge (OFC) for diagnosis in Asia. We hypothesized that CRD would improve the accuracy of diagnosing hazelnut allergies in Japanese children. METHODS: We recruited 91 subjects (median age: 7.3 years) who were sensitized to hazelnuts and had performed a hazelnut OFC at the National Hospital Organization Sagamihara National Hospital between 2006 and 2017. All subjects were classified as allergic or asymptomatic to 3 g of hazelnuts. The sIgE levels (hazelnut/Cor a 1/Cor a 8/Cor a 9/Cor a 14/alder pollen) were measured using ImmunoCAP. We aimed to determine the predictive factors of hazelnut allergy. RESULTS: Nine subjects (10%) were allergic to ≤3 g of hazelnuts. Levels of sIgE for Cor a 9 in hazelnut-allergic subjects were significantly higher than those in asymptomatic subjects (4.47 vs. 0.76 kUA/L, p = 0.039). Levels of sIgE to alder pollen and Cor a 1 in hazelnut-allergic subjects were significantly lower than those in asymptomatic subjects (<0.10 vs 13.0 kUA/L, p = 0.004; <0.10 vs 5.03 kUA/L, p = 0.025). The area under the receiver operating characteristics curve for hazelnut/alder/Cor a 1/Cor a 9 was 0.55/0.78/0.72/0.71, respectively, with p = 0.651/0.006/0.029/0.040, respectively. CONCLUSIONS: The findings of a high sIgE level for Cor a 9 and a low sIgE level for Cor a 1 can improve the diagnostic accuracy to better identify Japanese children sensitized to hazelnuts.
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Corylus/inmunología , Hipersensibilidad a la Nuez/diagnóstico , Proteínas de Plantas/inmunología , Administración Oral , Niño , Reacciones Cruzadas , Femenino , Humanos , Inmunización , Inmunoglobulina E/metabolismo , Japón , Masculino , Polen/inmunología , Curva ROCRESUMEN
The International Liaison Committee on Resuscitation has initiated a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation science. This is the second annual summary of International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations that includes the most recent cardiopulmonary resuscitation science reviewed by the International Liaison Committee on Resuscitation. This summary addresses the role of antiarrhythmic drugs in adults and children and includes the Advanced Life Support Task Force and Pediatric Task Force consensus statements, which summarize the most recent published evidence and an assessment of the quality of the evidence based on Grading of Recommendations, Assessment, Development, and Evaluation criteria. The statements include consensus treatment recommendations approved by members of the relevant task forces. Insights into the deliberations of each task force are provided in the Values and Preferences and Task Force Insights sections. Finally, the task force members have listed the top knowledge gaps for further research.
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Reanimación Cardiopulmonar , Paro Cardíaco Extrahospitalario/terapia , Amiodarona/uso terapéutico , Antiarrítmicos/uso terapéutico , Consenso , Servicios Médicos de Urgencia , Humanos , Lidocaína/uso terapéutico , Magnesio/uso terapéutico , Paro Cardíaco Extrahospitalario/tratamiento farmacológicoRESUMEN
The International Liaison Committee on Resuscitation has initiated a near-continuous review of cardiopulmonary resuscitation science that replaces the previous 5-year cyclic batch-and-queue approach process. This is the first of an annual series of International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations summary articles that will include the cardiopulmonary resuscitation science reviewed by the International Liaison Committee on Resuscitation in the previous year. The review this year includes 5 basic life support and 1 pediatric Consensuses on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Each of these includes a summary of the science and its quality based on Grading of Recommendations, Assessment, Development, and Evaluation criteria and treatment recommendations. Insights into the deliberations of the International Liaison Committee on Resuscitation task force members are provided in Values and Preferences sections. Finally, the task force members have prioritized and listed the top 3 knowledge gaps for each population, intervention, comparator, and outcome question.
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Cardiología/normas , Reanimación Cardiopulmonar/normas , Servicios Médicos de Urgencia/normas , Medicina de Emergencia/normas , Medicina Basada en la Evidencia/normas , Paro Cardíaco/terapia , Factores de Edad , Consenso , Paro Cardíaco/diagnóstico , Paro Cardíaco/mortalidad , Humanos , Paro Cardíaco Extrahospitalario/diagnóstico , Paro Cardíaco Extrahospitalario/mortalidad , Paro Cardíaco Extrahospitalario/terapia , Resultado del TratamientoRESUMEN
OBJECTIVES: Catheter-associated urinary tract infections account for 30% of healthcare-associated infections. To date, few studies have addressed pediatric catheter-associated urinary tract infection in PICUs. The aim of our study was to assess the risk of catheter-associated urinary tract infection in relation to the duration of catheterization in the PICU. DESIGN: Retrospective cohort study. SETTING: PICU at a tertiary children's hospital. PATIENTS: Our study was conducted between April 2012 and June 2015 at Tokyo Metropolitan Children's Medical Center in Japan. Children in the PICU with an urethral catheter were included. Catheter-associated urinary tract infection cases were defined according to the National Healthcare Safety Network criteria. The patients' demographic data and isolated organisms were reviewed. Duration of catheterization and the catheter-associated urinary tract infection occurrence rate were analyzed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 1,890 catheterizations, 23 catheter-associated urinary tract infection cases were identified. The overall occurrence rate was 2.35/1,000 catheter-days. Among the patients with catheter-associated urinary tract infection, 13 were boys. The median age was 11 months (interquartile range, 7-35 mo), and the median duration of catheterization was 7 days (interquartile range, 5-12 d). The isolated bacteria were Escherichia coli (26.5%), Enterococcus faecalis (17.6%), and Klebsiella pneumoniae (11.8%). Two species were isolated in each of 11 cases (47.8%). Each additional day of catheterization increased the risk of catheter-associated urinary tract infection (odds ratio, 1.06; 95% CI, 1.02-1.10, and odds ratio adjusted for contact precaution status and surgical procedures was 1.05; 95% CI, 1.01-1.09). CONCLUSIONS: Longer duration of catheterization increased the risk of catheter-associated urinary tract infection by 5% each day at the PICU. Prompt removal of the urethral catheter is strongly recommended whenever feasible.
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Infecciones Relacionadas con Catéteres/epidemiología , Catéteres de Permanencia/efectos adversos , Cateterismo Urinario/efectos adversos , Infecciones Urinarias/epidemiología , Niño , Preescolar , Infección Hospitalaria/prevención & control , Femenino , Humanos , Lactante , Unidades de Cuidado Intensivo Pediátrico , Masculino , Estudios Retrospectivos , Factores de Tiempo , Cateterismo Urinario/estadística & datos numéricosRESUMEN
Telomerase is expressed in ~90% of human cancer cell lines and tumor specimens, whereas its enzymatic activity is not detectable in most human somatic cells, suggesting that telomerase represents a highly attractive target for selective cancer treatment. Accordingly, various classes of telomerase inhibitors have been screened and developed in recent years. We and other researchers have successfully found that some dietary compounds can modulate telomerase activity in cancer cells. Telomerase inhibitors derived from food are subdivided into two groups: one group directly blocks the enzymatic activity of telomerase (e.g., catechin and sulfoquinovosyldiacylglycerol), and the other downregulates the expression of human telomerase reverse transcriptase (hTERT), the catalytic subunit of human telomerase, via signal transduction pathways (e.g., retinoic acid and tocotrienol). In contrast, a few dietary components, including genistein and glycated lipid, induce cellular telomerase activity in several types of cancer cells, suggesting that they may be involved in tumor progression. This review summarizes the current knowledge about the effects of dietary factors on telomerase regulation in cancer cells and discusses their molecular mechanisms of action.
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Dieta , Neoplasias/genética , Neoplasias/metabolismo , Telomerasa/metabolismo , Animales , Proteínas de Unión al ADN/metabolismo , Suplementos Dietéticos , Activación Enzimática/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Regiones Promotoras Genéticas , Unión Proteica , Telomerasa/genética , Transcripción GenéticaRESUMEN
This manuscript provides a global perspective on physician and nursing education and training in paediatric cardiac critical care, including available resources and delivery of care models with representatives from several regions of the world including Africa, Israel, Asia, Australasia, Europe, South America, and the United States of America.
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Cardiología/educación , Cuidados Críticos , Pediatría/educación , Cuidados Críticos/organización & administración , Salud Global , Cardiopatías/diagnóstico , Cardiopatías/terapia , Humanos , Enfermeras y Enfermeros/normas , Médicos/normas , Recursos HumanosRESUMEN
UNLABELLED: Approximately one-third of Lassa virus (LASV)-infected patients develop sensorineural hearing loss (SNHL) in the late stages of acute disease or in early convalescence. With 500,000 annual cases of Lassa fever (LF), LASV is a major cause of hearing loss in regions of West Africa where LF is endemic. To date, no animal models exist that depict the human pathology of LF with associated hearing loss. Here, we aimed to develop an animal model to study LASV-induced hearing loss using human isolates from a 2012 Sierra Leone outbreak. We have recently established a murine model for LF that closely mimics many features of human disease. In this model, LASV isolated from a lethal human case was highly virulent, while the virus isolated from a nonlethal case elicited mostly mild disease with moderate mortality. More importantly, both viruses were able to induce SNHL in surviving animals. However, utilization of the nonlethal, human LASV isolate allowed us to consistently produce large numbers of survivors with hearing loss. Surviving mice developed permanent hearing loss associated with mild damage to the cochlear hair cells and, strikingly, significant degeneration of the spiral ganglion cells of the auditory nerve. Therefore, the pathological changes in the inner ear of the mice with SNHL supported the phenotypic loss of hearing and provided further insights into the mechanistic cause of LF-associated hearing loss. IMPORTANCE: Sensorineural hearing loss is a major complication for LF survivors. The development of a small-animal model of LASV infection that replicates hearing loss and the clinical and pathological features of LF will significantly increase knowledge of pathogenesis and vaccine studies. In addition, such a model will permit detailed characterization of the hearing loss mechanism and allow for the development of appropriate diagnostic approaches and medical care for LF patients with hearing impairment.
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Modelos Animales de Enfermedad , Pérdida Auditiva Sensorineural/patología , Fiebre de Lassa/complicaciones , Animales , Nervio Coclear/patología , Brotes de Enfermedades , Oído Interno/patología , Pérdida Auditiva Sensorineural/epidemiología , Histocitoquímica , Humanos , Fiebre de Lassa/epidemiología , Virus Lassa/aislamiento & purificación , Ratones , Microscopía , Sierra Leona/epidemiología , VirulenciaAsunto(s)
Anorexia Nerviosa , Legionella , Neumonía , Anorexia Nerviosa/complicaciones , Femenino , HumanosAsunto(s)
Aneurisma Coronario , Trombosis Coronaria , Síndrome Mucocutáneo Linfonodular , Trombosis , Aneurisma Coronario/diagnóstico por imagen , Aneurisma Coronario/etiología , Angiografía Coronaria , Trombosis Coronaria/diagnóstico por imagen , Trombosis Coronaria/etiología , Humanos , Síndrome Mucocutáneo Linfonodular/complicaciones , Síndrome Mucocutáneo Linfonodular/diagnóstico , Trombosis/diagnóstico por imagen , Trombosis/etiologíaRESUMEN
OBJECTIVE: Assessment of abnormal vital signs in triage is a challenge in the paediatric emergency department (PED), since vital signs may reflect anxiety, fever or pain rather than the clinical deterioration of the child. We aimed to evaluate the efficacy of subjective 'down-triage' (change of the initially determined acuity levels) of Japanese Triage and Acuity Scale (JTAS). METHODS: This is a retrospective cohort study of patients in PED up to 15â years of age at a tertiary paediatric medical centre in Japan during a 1-year period. At the end of every JTAS triage process, PED nurses were allowed to 'down-triage' acuity levels of well-appearing patients with abnormal HR or RR, which were presumably attributable to fever, crying or being upset. We compared predictive performance of the triage system before and after 'down-triage' using admission rate as the primary outcome. RESULTS: Among 37â 961 PED visits during the study period, we analysed 37â 219 records. A total of 17â 089 patients (45.9%) were 'down-triaged' after their initial triage allocation upon arrival. Admission rates after 'down-triage' (83%, 33%, 7%, 1% and 3% for levels 1-5, respectively), compared with those of unmodified initial level (16%, 11%, 6%, 2% and 6% for levels 1-5, respectively), had a better apparent relevance with the anticipated admission rates of Canadian Triage and Acuity Scale. CONCLUSIONS: Modification of JTAS through 'down-triage' by experienced staff improves prediction of disposition in a PED. Further research is needed to determine an objective protocol for 'down-triage' to ensure safe practice in a PED.
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Servicio de Urgencia en Hospital/organización & administración , Triaje/métodos , Signos Vitales , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Japón , Masculino , Estudios RetrospectivosRESUMEN
Genetically engineered mice are valuable models for elucidation of auditory and vestibular pathology. Our goal was to establish a comprehensive vestibular function testing system in mice using: (1) horizontal angular vestibulo-ocular reflex (hVOR) to evaluate semicircular canal function and (2) otolith-ocular reflex (OOR) to evaluate otolith organ function and to validate the system by characterizing mice with vestibular dysfunction. We used pseudo off-vertical axis rotation to induce an otolith-only stimulus using a custom-made centrifuge. For the OOR, horizontal slow-phase eye velocity and vertical eye position were evaluated as a function of acceleration. Using this system, we characterized hVOR and OOR in the caspase-3 (Casp3) mutant mice. Casp3 (-/-) mice had severely impaired hVOR gain, while Casp3 (+/-) mice had an intermediate response compared to WT mice. Evaluation of OOR revealed that at low-to-mid frequencies and stimulus intensity, Casp3 mutants and WT mice had similar responses. At higher frequencies and stimulus intensity, the Casp3 mutants displayed mildly reduced otolith organ-related responses. These findings suggest that the Casp3 gene is important for the proper function of the semicircular canals but less important for the otolith organ function.
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Caspasa 3/deficiencia , Nistagmo Patológico/genética , Nistagmo Patológico/patología , Membrana Otolítica/fisiología , Reflejo Vestibuloocular/genética , Canales Semicirculares/fisiopatología , Aceleración , Análisis de Varianza , Animales , Factor Apoptótico 1 Activador de Proteasas/genética , Factor Apoptótico 1 Activador de Proteasas/metabolismo , Fenómenos Biomecánicos , Caspasa 3/genética , Femenino , Movimientos de la Cabeza/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación/genética , Rotación , Pruebas de Función VestibularRESUMEN
High-frequency oscillatory ventilation (HFOV) at frequencies of approximately 15 Hz is associated with optimal CO2 excretion. Higher frequencies using a nitrogen-oxygen gas mixture worsen CO2 excretion. An in vitro experiment using HFOV and a helium-oxygen gas mixture showed a significant increase in CO2 transport, which increased with increases in ventilation frequency. We hypothesised that in HFOV, the change in the arterial partial pressure of CO2 (PaCO2) would be greater at frequencies above 15 Hz when combined with helium-oxygen gas mixture administration. We tested this hypothesis in a hypoventilated healthy rabbit model by administering a helium-oxygen gas mixture at 15, 25, 35, and 45 Hz frequencies. One-way repeated measures ANOVA showed a significant decrease in PaCO2 among the four ventilation frequency groups. Post-hoc analysis showed significant differences between 15 and 35 Hz frequencies and between 15 and 45 Hz frequencies. The mean (standard error) decrease of PaCO2 was 10.8 (2.2), 14.1 (2.3), 21.3 (3.3), and 23.1 (2.5) mmHg at 15, 25, 35, and 45 Hz, respectively. Combination therapy of helium-oxygen gas mixture and high-frequency oscillation using ultra/very high frequencies (35-45 Hz) was associated with a greater PaCO2 decrease than that using the standard frequency (15 Hz).