A superior heterologous prime-boost vaccination strategy against COVID-19: A bivalent vaccine based on yeast-derived RBD proteins followed by a heterologous vaccine.

Various vaccines have been challenged by SARS-CoV-2 variants. Here, we reported a yeast-derived recombinant bivalent vaccine (Bivalent wild-type [Wt]+De) based on the wt and Delta receptor-binding domain (RBD). Yeast derived RBD proteins based on the wt and Delta mutant were used as the prime vaccine. It was found that, in the presence of aluminium hydroxide (Alum) and unmethylated CpG-oligodeoxynucleotides (CpG) adjuvants, more cross-protective immunity against SARS-CoV-2 prototype and variants were elicited by bivalent vaccine than monovalent wtRBD or Delta RBD. Furthermore, a heterologous boosting strategy consisting of two doses of bivalent vaccines followed by one dose adenovirus vectored vaccine exhibited cross-neutralization capacity and specific T cell responses against Delta and Omicron (BA.1 and BA.4/5) variants in mice, superior to a homologous vaccination strategy. This study suggested that heterologous prime-boost vaccination with yeast-derived bivalent protein vaccine could be a potential approach to address the challenge of emerging variants.

An mRNA-based rabies vaccine induces strong protective immune responses in mice and dogs.

Rabies is a lethal zoonotic disease that is mainly caused by the rabies virus (RABV). Although effective vaccines have long existed, current vaccines take both time and cost to produce. Messenger RNA (mRNA) technology is an emergent vaccine platform that supports rapid vaccine development on a large scale. Here, an optimized mRNA vaccine construct (LVRNA001) expressing rabies virus glycoprotein (RABV-G) was developed in vitro and then evaluated in vivo for its immunogenicity and protective capacity in mice and dogs. LVRNA001 induced neutralizing antibody production and a strong Th1 cellular immune response in mice. In both mice and dogs, LVRNA001 provided protection against challenge with 50-fold lethal dose 50 (LD50) of RABV. With regards to protective efficiency, an extended dosing interval (14 days) induced greater antibody production than 3- or 7-day intervals in mice. Finally, post-exposure immunization against RABV was performed to evaluate the survival rates of dogs receiving two 25 µg doses of LVRNA001 vs. five doses of inactivated vaccine over the course of three months. Survival rate in the LVRNA001 group was 100%, whereas survival rate in the inactivated vaccine control group was only 33.33%. In conclusion, these results demonstrated that LVRNA001 induced strong protective immune responses in mice and dogs, which provides a new and promising prophylactic strategy for rabies.

Neuronal intranuclear inclusion disease presented with recurrent vestibular migraine-like attack: a case presentation.

BACKGROUND: Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder characterized by dementia, tremor, episodic encephalopathy and autonomic nervous dysfunction. To date, vestibular migraine (VM)-like attack has never been reported in cases with NIID. Here, we describe an 86-year-old patient with NIID who presented with recurrent vertigo associated with headache for more than 30 years. CASE PRESENTATION: An 86-year-old Chinese woman with vertigo, headache, weakness of limbs, fever, and disturbance of consciousness was admitted to our hospital. She had suffered from recurrent vertigo associated with headache since her 50 s,followed by essential tremor and dementia. On this admission, brain magnetic resonance imaging revealed high intensity signals along the corticomedullary junction on diffusion weighted imaging (DWI). Peripheral neuropathy of the extremities was detected through electrophysiological studies. We diagnosed NIID after detecting eosinophilic intranuclear inclusions in the ductal epithelial cells of sweat glands and identifying an abnormal expansion of 81 GGC repeats in the 5'UTR of NOTCH2NLC gene. CONCLUSIONS: VM-like attack may be associated with NIID.

Evaluation of environment safety of a Japanese encephalitis live attenuated vaccine.

JE vaccination is the most effective and economical method of preventing JE. A live attenuated JE vaccine has been widely used in many countries since 1989, playing an important role in controlling JE outbreaks. However, whether the large-scale use of the live attenuated JE vaccine will lead to the dissemination of the vaccine virus in the environment and whether reversion of the neuroattenuation of the virus will occur during the transmission process remain major concerns for some researchers. To evaluate the transmission of a live attenuated JEV vaccine in mosquitoes and hosts, JE SA14-14-2 attenuated vaccine virus was intrathoracically (i.t.) inoculated into Culex tritaeniorhynchus, a native vector. Subsequently, virus harvested from inoculated mosquitoes was inoculated into pigs, a mammalian reservoir. The virus was isolated from the pigs and passaged once again in Culex tritaeniorhynchus. The genome sequences and virulence of the passaged viruses were then investigated. While a few nucleotide substitutions occurred during passaging, there was no change in the encoded amino acids. After intracerebral (i.c.) inoculation of mice with the vaccine, no pathological effects were observed. In addition, virus virulence remained low after inoculation of suckling mouse brains. These results indicate that vaccination of individuals with the live vaccine will not result in transmission of the live SA14-14-2 vaccine virus through mosquito biting and virus amplified in pigs.

Episodic ataxia type 2 characterised by recurrent dizziness/vertigo: a report of four cases.

PURPOSE: To report the clinical features and gene mutations in four episodic ataxia type 2 (EA2) patients whose main presentation was recurrent dizziness/vertigo. METHODS: Clinical data of four EA2 patients (three familial EA2 cases and one sporadic case) with recurrent dizziness/vertigo were collected to assess nystagmus and eye movement. Gene mutations were identified by whole exome sequencing. RESULTS: The three patients in family 1 experienced disease onset before 8 years of age, presented with a chief complaint of episodic dizziness, muscle weakness of the lower limbs and the inability to walk. These symptoms lasted a few hours and then subsided. The proband also had gaze-evoked nystagmus during attacks. Videonystagmography demonstrated that the saccade velocity was low, smooth pursuit was type III, and gain was abnormal at 0.1, 0.2 and 0.4 Hz. An optokinetic nystagmus test showed that the left eye optokinetic nystagmus disappeared, and the right eye optokinetic nystagmus weakened. A head-shaking test produced a left horizontal nystagmus. Gene analysis identified a novel c.1558 + 2T > G splice site mutation in the CACNA1A gene in the proband and his mother. The fourth patient was sporadic, with an onset age of 3 years. He mainly suffered from episodic vertigo, accompanied by severe anxiety and depression. He carried a CACNA1A mutation, c.4636C > T, which is a previously reported pathogenic mutation. CONCLUSIONS: The onset of symptoms in these EA2 patients was early. The patients mainly presented recurrent dizziness/vertigo, with the absence of characteristic episodic ataxia. Detection of CACNA1A mutations facilitates the diagnosis of EA2.

Highly sensitive determination of Cu(II) iron in ng/mL level in natural waters using Sulfochlorophenol S.

The highly sensitive complexation of Cu(II) with Sulfochlorophenol S (SCPS) at pH 4.03 was characterized by the spectral correction technique. This reaction was used to determine the Cu(II) content in various sources by the light-absorption ratio variation approach (LARVA). The limit of detection of Cu(II) was only 1.35 ng/mL, thus facilitating the direct monitoring of natural water. The Cu(II) contents in the Huangpu River, Yangtze River, and Taihu Lake of China were determined with satisfactory results, and the recovery rates of Cu(II) using SCPS were between 94.5 and 102.6 %.

Heterogeneity of axonal pathology in Chinese patients with giant axonal neuropathy.

INTRODUCTION: Giant axonal neuropathy (GAN) is a rare autosomal recessive neurodegenerative disorder caused by mutations in the GAN gene. Herein we report ultrastructural changes in Chinese patients with GAN. METHODS: General clinical assessment, sural nerve biopsy, and genetic analysis were performed. RESULTS: Sural biopsy revealed giant axons in 3 patients, 2 with a mild phenotype and 1 with a classical phenotype. Ultrastructurally, all patients had giant axons filled with closely packed neurofilaments. In addition, the classical patient had some axons containing irregular tubular-like structures. GAN mutation analysis revealed novel compound heterozygous c.98A>C and c.158C>T mutations in the BTB domain in 1 mild patient, a novel homozygous c.371T>G mutation in the BACK domain in another mild patient, and a novel c.1342G>T homozygous mutation in the Kelch domain in the classical patient. CONCLUSION: Closely packed neurofilaments in giant axons are common pathological changes in Chinese patients with GAN, whereas irregular tubular-like structures appear in the classical type of this neuropathy.

Interior automobile seats: A syntactical and perceptual study.

This study investigated the seat layout of automobile interiors and its impact on the fluidity and privacy of interior space using spatial perception and space syntax research methods. The interior of an automobile is a typical "miniature" passenger space. First, to explore the perception characteristics of interior space fluidity and privacy across different seat configurations, we conducted a perception experiment on the interior space of seven automobile models with various seat layouts. The depth, connection, global integration degree, and standardized integration degree values were obtained using spatial syntax to perform topological calculations on the experimental automobile models. We conducted a correlation analysis in conjunction with the results of the perception experiment and the spatial syntax analysis. The calculation results of spatial syntax analysis are consistent with the experimental results of perception of automobile interior space layout on the fluidity and privacy. The different layout of automobile seats can affect people's perception on the fluidity and privacy of automobile interior space. At the same time, spatial syntax can provide an effective design analysis tool for the fluidity and privacy of automobile interior space.

Correlation of slow-wave sleep with motor and nonmotor progression in Parkinson's disease.

OBJECTIVE: This study aimed to explore the association between slow-wave sleep and the progression of motor and nonmotor symptoms in patients with PD. METHODS: Data were collected from the Parkinson's Progression Markers Initiative study. Slow-wave sleep, also known as deep non-rapid eye movement (DNREM) sleep, was objectively assessed using the Verily Study Watch. Motor function was assessed using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III score, Hoehn and Yahr stage, freezing of gait, motor fluctuations, and dyskinesia severity. Comprehensive assessments were conducted on nonmotor symptoms, including depression, anxiety, global cognitive function, and autonomic dysfunction. Statistical analyses involved repeated-measures analysis of variance and linear regression. RESULTS: A total of 102 patients with PD were included in the study, with a median follow-up duration of 3.4 years. In the long DNREM sleep duration group (n = 55), better motor function (DNREM × time interaction: F(1,100) = 4.866, p = 0.030), less severe sexual dysfunction (p = 0.026), and improved activities of daily living (p = 0.033) were observed at the last follow-up visit compared with the short DNREM sleep duration group (n = 47). Reduced DNREM sleep duration is a risk factor for motor progression (ß = -0.251, p = 0.021; 95% confidence interval = -0.465 to -0.038). INTERPRETATION: The findings suggest an association between longer DNREM sleep duration and slower motor and nonmotor progression in patients with PD.

Predictors for early-onset psychotic symptoms in patients newly diagnosed with Parkinson's disease without psychosis at baseline: A 5-year cohort study.

AIMS: To investigate the risk factors for early-onset psychosis in Parkinson's disease (PD) in a cohort of patients from the Parkinson's Progression Markers Initiative. METHODS: Longitudinal data on motor and non-motor features, dopamine transporter (DAT) imaging, and cerebrospinal fluid (CSF) measurements were collected. The survival probability of psychotic symptoms, potential risk factors for psychosis development over a 5-year follow-up period, and the performance of the prediction model were evaluated. RESULTS: Among the 338 newly diagnosed patients with PD, 83 developed psychotic symptoms. Gastrointestinal autonomic dysfunction, presence of probable rapid-eye-movement sleep behavior disorder, and the ratio Aß42: total-tau could independently predict onset of psychosis in PD (hazard ratio (HR) = 1.157, 95% confidence interval (CI) 1.022-1.309, p = 0.021, HR = 2.596, 95% CI 1.287-5.237, p = 0.008, and HR = 0.842, 95% CI 0.723-0.980, p = 0.027, respectively). The combined model integrating baseline clinical predictors, DAT imaging, and CSF measurements achieved better sensitivity than the clinical predictors alone (area under the curve = 0.770 [95% CI 0.672-0.868] vs. 0.714 [95% CI 0.625-0.802], p = 0.098). CONCLUSION: We identified clinical and CSF predictors of early-onset psychosis in patients with PD. Our study provides evidence and implications for prognostic stratification and therapeutic approaches for PD psychosis.

Study on immune persistence of the CTN-1V strain rabies vaccine in humans.

This study is a single-arm, single-center phase IV clinical trial on a rabies vaccine that has been marketed in China. The Vero cells and CTN-1V strain are used in the rabies vaccine product. The purpose of this study was to investigate the safety, immunogenicity and immune persistence of this product. One hundred and forty-nine participants were enrolled to the study, all of whom were included in the safety analysis set (SS), among which 116 participants were included in the protocol analysis set (PPS), One hundred and fifteen participants were included in the 6-month immune persistence analysis set (IPS6) and 111 in the 12-month immune persistence analysis set IPS12. Results showed that: 1) In the SS analysis set, adverse reactions were mainly pyrexia and pain at the vaccination site, the severity of which were mostly grade 1, and concentrated in 0-3 days after vaccination. No grade 3 or above adverse events and serious adverse events (SAE) related to the experimental vaccine were observed. 2) In the PPS analysis set, the antibody positive conversion rate reached 100% at 14 days after full immunization of the pre-immunized negative population; The antibody geometric mean titer (GMT) (95% CI) was 14.82 (13.00, 16.90). 3) The positive rate of serum neutralizing antibody was 93.91 % and the GMT at 1.58 IU/ml at 6 months after full immunization. The positive rate of neutralizing antibody was 85.59 % and GMT at 1.30 IU/ml at 12 months after immunization. Our results show that the human rabies vaccine with the CTN-1V strain and Vero cells as matrix had good safety, immunogenicity and immune persistence in our study.

Microbial biomarker discovery in Parkinson's disease through a network-based approach.

Associations between the gut microbiota and Parkinson's disease (PD) have been widely investigated. However, the replicable biomarkers for PD diagnosis across multiple populations remain elusive. Herein, we performed a meta-analysis to investigate the pivotal role of the gut microbiome in PD and its potential diagnostic implications. Six 16S rRNA gene amplicon sequence datasets from five independent studies were integrated, encompassing 550 PD and 456 healthy control samples. The analysis revealed significant alterations in microbial composition and alpha and beta diversity, emphasizing altered gut microbiota in PD. Specific microbial taxa, including Faecalibacterium, Roseburia, and Coprococcus_2, known as butyrate producers, were notably diminished in PD, potentially contributing to intestinal inflammation. Conversely, genera such as Akkermansia and Bilophila exhibited increased relative abundances. A network-based algorithm called NetMoss was utilized to identify potential biomarkers of PD. Afterwards, a classification model incorporating 11 optimized genera demonstrated high performance. Further functional analyses indicated enrichment in pathways related to neurodegeneration and metabolic pathways. These findings illuminate the intricate relationship between the gut microbiota and PD, offering insights into potential therapeutic interventions and personalized diagnostic strategies.

Structure-Based Design and Optimization of Methionine Adenosyltransferase 2A (MAT2A) Inhibitors with High Selectivity, Brain Penetration, and In Vivo Efficacy.

Synthetic lethality has recently emerged as a new approach for the treatment of mutated genes that were previously considered undruggable. Targeting methionine adenosyltransferase 2A (MAT2A) in cancers with deletion of the methylthioadenosine phosphorylase (MTAP) gene leads to synthetic lethality and thus has attracted significant interest in the field of precise anticancer drug development. Herein, we report the discovery of a series of novel MAT2A inhibitors featuring a pyrazolo[3,4-c]quinolin-4-one skeleton based on structure-based drug design. Further optimization led to compound 39, which has a high potency for inhibiting MAT2A and a remarkable selectivity for MTAP-deleted cancer cell lines. Compound 39 has a favorable pharmacokinetic profile with high plasma exposure and oral bioavailability, and it exhibits significant efficacy in xenograft MTAP-depleted models. Moreover, 39 demonstrates excellent brain exposure with a Kpuu of 0.64 in rats.

Predictors of cognitive impairment in newly diagnosed Parkinson's disease with normal cognition at baseline: A 5-year cohort study.

Background and objective: Cognitive impairment (CI) is a substantial contributor to the disability associated with Parkinson's disease (PD). We aimed to assess the clinical features and explore the underlying biomarkers as predictors of CI in patients with newly diagnosed PD (NDPD; less than 2 years). Methods: We evaluated the cognitive function status using the Montreal Cognitive Assessment (MoCA) and a battery of neuropsychological tests at baseline and subsequent annual follow-up for 5 years from the Parkinson's Progression Markers Initiative (PPMI) database. We assessed the baseline clinical features, apolipoprotein (APO) E status, ß-glucocerebrosidase (GBA) mutation status, cerebrospinal fluid findings, and dopamine transporter imaging results. Using a diagnosis of CI (combined mild cognitive impairment and dementia) developed during the 5-year follow-up as outcome measures, we assessed the predictive values of baseline clinical variables and biomarkers. We also constructed a predictive model for the diagnosis of CI using logistic regression analysis. Results: A total of 409 patients with NDPD with 5-year follow-up were enrolled, 232 with normal cognitive function at baseline, and 94 patients developed CI during the 5-year follow-up. In multivariate analyses, age, current diagnosis of hypertension, baseline MoCA scores, Movement disorder society Unified PD Rating Scale part III (MDS-UPDRS III) scores, and APOE status were associated with the development of CI. Predictive accuracy of CI using age alone improved by the addition of clinical variables and biomarkers (current diagnosis of hypertension, baseline MoCA scores, and MDS-UPDRS III scores, APOE status; AUC 0.80 [95% CI 0.74-0.86] vs. 0.71 [0.64-0.77], p = 0.008). Cognitive domains that had higher frequencies of impairment were found in verbal memory (12.6 vs. 16.8%) and attention/processing speed (12.7 vs. 16.9%), however, no significant difference in the prevalence of CI at annual follow-up was found during the 5-year follow-up in NDPD patients. Conclusion: In NDPD, the development of CI during the 5-year follow-up can be predicted with good accuracy using a model combining age, current diagnosis of hypertension, baseline MoCA scores, MDS-UPDRS III scores, and APOE status. Our study underscores the need for the earlier identification of CI in NDPD patients in our clinical practice.

A Randomized, Double-Blind, Controlled Phase III Clinical Trial to Evaluate the Immunogenicity and Safety of a Lyophilized Human Rabies Vaccine (Vero Cells) in Healthy Participants Aged 10-60 Years Following Essen and Zagreb Vaccination Procedures.

OBJECTIVE: In this paper, we aim to show that the immunogenicity of the lyophilized human rabies vaccine (Vero cells) (investigational vaccine) developed by Dalian Aleph Biomedical Co., Ltd. in healthy participants aged 10-60 years old is non-inferior to the lyophilized PVRV (positive control) manufactured by Liaoning Chengda Biotechnology Co., Ltd. (Shenyang, China), and that its safety is clinically acceptable. METHOD: A total of 2776 participants were enrolled in this study and divided into four groups: a five-dose test group, a five-dose control group, a four-dose test group, and a four-dose control group. The patients in the four-dose groups (Zagreb) were vaccinated on Days 0 (two doses), 7 (one dose), and 21 (one dose), and those in the five-dose groups (Essen) were vaccinated on Days 0, 3, 7, 14, and 28 (one dose each). The rabies-virus-neutralizing antibody assay with the RFFIT was used to assess the immunogenicity, and the adverse events (AEs) and serious adverse events (SAEs) were identified and collated. RESULTS: The positive seroconversion rate was up to 100% on Days 14 and 35/42 after vaccination following any procedures in pre-immunization antibody-negative participants, and the positive seroconversion rate and geometric mean concentration (GMC) of the test groups (Zagreb and Essen vaccination procedures) was not inferior to that of the control groups. On Day 7 after vaccination, the immunogenicity of the Zagreb procedure with two doses of the vaccine on Day 0 was superior to the Essen procedure with one dose of vaccine, that is, the former had a higher seroconversion rate and RVNA titer. The non-inferiority criterion of immunogenicity was met for the whole population, the population aged 10-18 years and ≥18 years, and the pre-immunization antibody-positive population. The incidences of all AEs, solicited AEs, and unsolicited AEs in both groups were not statistically significant, and no vaccination-related SAEs were observed. CONCLUSION: The investigated vaccine is safe, its immunogenicity is non-inferior to that of the control vaccine, and the efficacy of the Zagreb procedure is superior to that of the Essen procedure 7 days after the first dose.

Heterologous prime-boost immunisation with mRNA- and AdC68-based 2019-nCoV variant vaccines induces broad-spectrum immune responses in mice.

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or 2019-nCoV) variants has been associated with the transmission and pathogenicity of COVID-19. Therefore, exploring the optimal immunisation strategy to improve the broad-spectrum cross-protection ability of COVID-19 vaccines is of great significance. Herein, we assessed different heterologous prime-boost strategies with chimpanzee adenovirus vector-based COVID-19 vaccines plus Wuhan-Hu-1 (WH-1) strain (AdW) and Beta variant (AdB) and mRNA-based COVID-19 vaccines plus WH-1 strain (ARW) and Omicron (B.1.1.529) variant (ARO) in 6-week-old female BALB/c mice. AdW and AdB were administered intramuscularly or intranasally, while ARW and ARO were administered intramuscularly. Intranasal or intramuscular vaccination with AdB followed by ARO booster exhibited the highest levels of cross-reactive IgG, pseudovirus-neutralising antibody (PNAb) responses, and angiotensin-converting enzyme-2 (ACE2)-binding inhibition rates against different 2019-nCoV variants among all vaccination groups. Moreover, intranasal AdB vaccination followed by ARO induced higher levels of IgA and neutralising antibody responses against live 2019-nCoV than intramuscular AdB vaccination followed by ARO. A single dose of AdB administered intranasally or intramuscularly induced broader cross-NAb responses than AdW. Th1-biased cellular immune response was induced in all vaccination groups. Intramuscular vaccination-only groups exhibited higher levels of Th1 cytokines than intranasal vaccination-only and intranasal vaccination-containing groups. However, no obvious differences were found in the levels of Th2 cytokines between the control and all vaccination groups. Our findings provide a basis for exploring vaccination strategies against different 2019-nCoV variants to achieve high broad-spectrum immune efficacy.

An mRNA vaccine against rabies provides strong and durable protection in mice.

Introduction: Rabies is a serious public health problem worldwide for which an effective treatment method is lacking but can be prevented by vaccines. Current vaccines are produced in cell or egg cultures, which are both costly and time consuming. Methods: Here, a non-replicating mRNA vaccine (RV021) encoding the rabies virus glycoprotein was developed in vitro, and its immunogenicity and protective efficacy against live virus was evaluated in mice. Results: A two-dose vaccination with 1 µg of RV021 at 7-day intervals induced a protective level of neutralizing antibody that was maintained for at least 260 days. RV021 induced a robust cellular immune response that was significantly superior to that of an inactivated vaccine. Two doses of 1 µg RV021 provided full protection against challenge with CVS of 30~60-fold lethal dose, 50%. Vaccine potency testing (according to the National Institutes of Health) in vivo revealed that the potency of RV021 at 15 µg/dose was 7.5 IU/dose, which is substantially higher than the standard for lot release of rabies vaccines for current human use. Conclusion: The mRNA vaccine RV021 induces a strong protective immune response in mice, providing a new and promising strategy for human rabies prevention and control.

[Clinical heterogeneity associated with mitochondrial DNA A8344G point mutation].

OBJECTIVE: To report the clinical features of mitochondrial disease caused by mitochondrial DNA (mtDNA) A8344G point mutation. METHODS: We analyzed the clinical presentations and muscular pathological changes in 10 patients with genetically confirmed mtDNA A8344G point mutation. RESULTS: Among them, 6 patients presented as juvenile-onset myoclonic epilepsy with ragged red fibers (MERRF) syndrome, 2 suffered infant-onset Leigh syndrome and the remaining 2 were diagnosed as limb-girdle mitochondrial myopathy. The mtDNA A8344G mutation load from muscle samples showed that patients with Leigh syndrome>MERRF syndrome>mitochondrial myopathy (87.2%, 88.4%>69.0%-86.8%>67.2%, 58.4%). CONCLUSIONS: Mitochondrial disease caused by A8344G point mutation shows a great heterogeneity. The mutation load of muscle mtDNA might be associated with the severity of clinical phenotype, the higher mutation load, the more severe clinical presentations.

[Audiologic features of mitochondrial DNA A3243G mutation and its correlation with mutation rate].

OBJECTIVE: To summarize the clinical audiologic features of patients with mitochondrial DNA (mtDNA) A3243G mutation and explore the lesion location of hearing loss so as to examine its correlation with the related syndrome. METHODS: A total of 44 patients with mtDNA A3243G mutation from 2009-2011 were studied. Audiological evaluations consisted of measurements of pure-tone and speech audiometry, tympanometry, distortion-product otoacoustic emissions and auditory brainstem response. We investigated a possible correlation between the degree of hearing loss and gender, age and mutation rate. RESULTS: (1) Pure tone test was performed in 41 patients and showed normal hearing or symmetrical sensorineural hearing loss. Pure tone audiogram (PTA) showed high-frequency loss and descending curve in a majority of patients. There were 75 ears with hearing loss in 82 ears (91.46%), 22 ears with abnormal speech audiometry in 26 ears, 77 ears with abnormal distortion product otoacoustic emissions (DPOAE)testing in 86 ears, including 5 ears with normal PTA, 31 ears with abnormal electrocochleography in 75 ears, 25 ears with abnormal auditory brainstem response (ABR) in 82 ears. The abnormal ABR showed elevated threshold in 10 ears, delayed interpeak latencies of wave I-V in 2 ears and disappearance of wave V before wave I in 1 ear. In addition, there were 2 ears with speech audiometry abnormal but with normal ABR. (2) The correlation between the severity of hearing and gender did not reach statistical significance, nor the severity of hearing and mutation ratio. Age could influence the hearing of A3243G-induced MELAS. CONCLUSIONS: The predominant lesions of mtDNA A3243G is at cochlea and retrocochlear sites. Significant variations in clinical manifestation of hearing are the prominent features in patient with A3243G mutation. There was no correlation between the degree of hearing loss and mutation load. However, hearing impairment is the most common symptom of A3243G mutation.

Advances in COVID-19 mRNA vaccine development.

To date, the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has determined 399,600,607 cases and 5,757,562 deaths worldwide. COVID-19 is a serious threat to human health globally. The World Health Organization (WHO) has declared COVID-19 pandemic a major public health emergency. Vaccination is the most effective and economical intervention for controlling the spread of epidemics, and consequently saving lives and protecting the health of the population. Various techniques have been employed in the development of COVID-19 vaccines. Among these, the COVID-19 messenger RNA (mRNA) vaccine has been drawing increasing attention owing to its great application prospects and advantages, which include short development cycle, easy industrialization, simple production process, flexibility to respond to new variants, and the capacity to induce better immune response. This review summarizes current knowledge on the structural characteristics, antigen design strategies, delivery systems, industrialization potential, quality control, latest clinical trials and real-world data of COVID-19 mRNA vaccines as well as mRNA technology. Current challenges and future directions in the development of preventive mRNA vaccines for major infectious diseases are also discussed.