Zinc and manganese homeostasis closely interact in mammalian cells.

Understanding the homeostatic interactions among essential trace metals is important for explaining their roles in cellular systems. Recent studies in vertebrates suggest that cellular Mn metabolism is related to Zn metabolism in multifarious cellular processes. However, the underlying mechanism remains unclear. In this study, we examined the changes in the expression of proteins involved in cellular Zn and/or Mn homeostatic control and measured the Mn as well as Zn contents and Zn enzyme activities to elucidate the effects of Mn and Zn homeostasis on each other. Mn treatment decreased the expression of the Zn homeostatic proteins metallothionein (MT) and ZNT1 and reduced Zn enzyme activities, which were attributed to the decreased Zn content. Moreover, loss of Mn efflux transport protein decreased MT and ZNT1 expression and Zn enzyme activity without changing extracellular Mn content. This reduction was not observed when supplementing with the same Cu concentrations and in cells lacking Cu efflux proteins. Furthermore, cellular Zn homeostasis was oppositely regulated in cells expressing Zn and Mn importer ZIP8, depending on whether Zn or Mn concentration was elevated in the extracellular milieu. Our results provide novel insights into the intricate interactions between Mn and Zn homeostasis in mammalian cells and facilitate our understanding of the physiopathology of Mn, which may lead to the development of treatment strategies for Mn-related diseases in the future.

Usefulness of an interprofessional work manual for perioperative glucose control of an artificial pancreas.

BACKGROUND: A closed-loop bedside-type artificial pancreas for perioperative glucose control has previously been introduced. However, artificial pancreas therapy was often interrupted due to continuous blood sampling failure. We developed an interprofessional work manual to reduce the interruption time of artificial pancreatic therapy for perioperative blood glucose control due to continuous blood sampling failure. This study aimed to investigate the usefulness of this manual. METHODS: The manual consisted of the following sections: (1) the roles of the professionals in the preparation and management of the artificial pancreas, (2) how to address continuous blood sampling failure, and (3) checkpoints for interprofessional transfer of the artificial pancreas. We compared the results before the introduction of the manual and 2 years after the introduction of the manual. RESULTS: There were 35 and 37 patients in the Before and After groups, respectively. There were no significant differences in patient backgrounds between the two groups, although there was significantly less blood loss in the After group (1164 vs. 366 mL; p < 0.001). The mean artificial pancreas therapy and artificial pancreas therapy interruption times were 847 min and 20 min, respectively. Artificial pancreas therapy interruption time (34 vs. 8 min; p = 0.078) and time per interruption (24 vs. 4 min; p < 0.001) were significantly shorter in the After group than in the Before group. CONCLUSIONS: The interprofessional working manual was useful in reducing the artificial pancreatic therapy interruption time for perioperative glucose control.

Blood flow evaluation of reconstructed gastric tube in esophageal surgery using near-infrared imaging and retrospective time-intensity curve analysis.

PURPOSE: Near-infrared fluorescence imaging using indocyanine green (ICG-NIFI) can visualize a blood flow in reconstructed gastric tube; however, it depends on surgeon's visual assessment. The aim of this study was to re-analyze the ICG-NIFI data by an evaluator independent from the surgeon and feasibility of creating the time-intensity curve (TIC). METHODS: We retrospectively reviewed 97 patients who underwent esophageal surgery with gastric tube reconstruction between January 2017 and November 2022. From the stored ICG videos, fluorescence intensity was examined in the four regions of interest (ROIs), which was set around the planned anastomosis site on the elevated gastric tube. After creation the TICs using the OpenCV library, we measured the intensity starting point and time constant and assessed the correlation between the anastomotic leakage. RESULTS: Postoperative leakage occurred for 12 patients. The leakage group had significantly lack of blood flow continuity between the right and left gastroepiploic arteries (75.0% vs. 22.4%; P < 0.001) and tended to have slower ICG visualization time assessed by the surgeon's eyes (40 vs. 32 s; P = 0.066). TIC could create in 65 cases. Intensity starting point at all ROIs was faster than the surgeon's assessment. The leakage group tended to have slower intensity starting point at ROI 3 compared to those in the non-leakage group (22.5 vs. 19.0 s; P = 0.087). CONCLUSION: A TIC analysis of ICG-NIFI by an independent evaluator was able to quantify the fluorescence intensity changes that the surgeon had visually determined.

Arbekacin-Loaded Inhalable Nanocomposite Particles Specific to Pseudomonas aeruginosa Prepared Using a Two-Solution Mixing-Type Spray Nozzle.

Hospital-acquired pneumonia is an important infectious disease that requires special management and therapy for patients with compromised immunity, as opportunistic infections with microorganisms such as Pseudomonas aeruginosa can be fatal. Nanoparticle-based drug delivery to lung tissue provides several advantages in the treatment of respiratory diseases. In the current study, inhalable nanocomposite particles consisting of microparticles containing solid-state arbekacin (ABK) nanoparticles coated with hydrophobic surfactant (ABK-SD nanoparticles) were prepared using a spray dryer equipped with a two-solution mixing-type spray nozzle we previously developed. ABK-SD/mannitol (MAN) nanocomposite particles were obtained from ABK-SD nanoparticles by varying the amounts of hydrophobic surfactant and ABK. The aerosol performance of ABK-SD/MAN nanocomposite particles was superior to that of ABK-MAN microparticles in terms of the fine particle fraction (28.4 ± 5.4%, ABK-SD/MAN nanocomposite particles; 11.4 ± 7.6%, ABK-MAN microparticles). These results suggest that ABK-SD/MAN nanocomposite particles are suitable for use in inhalation drug formulations and useful for the treatment of lung infections involving Pseudomonas aeruginosa.

Development of Spray Formulations Applied to the Oral Mucosa Using Non-lamellar Liquid Crystal-Forming Lipids.

We examined the physicochemical and biochemical properties of mono-O-(5,9,13-trimethyl-4-tetradecenyl)glycerol ester (MGE), including ease of handling, high bioadhesiveness, quick and stable in vivo self-organization (forming a non-lamellar lyotropic liquid crystal [NLLC]), and high biomembrane permeation enhancement. We prepared MGE oral mucosa-applied spray preparations containing triamcinolone acetonide (TA), which is widely used in the treatment of stomatitis, and we examined the usefulness of the MGE preparations compared with commercially available oral mucosal application preparations containing 2,3-dihydroxypropyl oleate (1-mono(cis-9-octadecenoyl)glycerol (GMO) (previously studied as an NLLC-forming lipid) preparation. As a result, the MGE preparation applied to the oral mucosa can rapidly formed an NLLC with reverse hexagonal or cubic structures, or a mixture, on contact with water. In addition, by adding hydroxypropyl cellulose to the MGE preparation, similar retention properties on the oral mucous membrane were obtained to that using marketed drug preparations. Furthermore, the MGE spray formulation on the oral mucosa showed an equivalent or higher TA release as well as oral mucous membrane permeability compared with commercial formulations. Because MGE forms a stable NLLC and is easy to handle compared with GMO, MGE was considered to be a useful pharmaceutical additive for a spray preparation applied to the oral mucosa in combination.

Modelling the impact of correlations between condom use and sexual contact pattern on the dynamics of sexually transmitted infections.

BACKGROUND: It is believed that sexually active people, i.e. people having multiple or concurrent sexual partners, are at a high risk of sexually transmitted infections (STI), but they are likely to be more aware of the risk and may exhibit greater fraction of the use of condom. The purpose of the present study is to examine the correlation between condom use and sexual contact pattern and clarify its impact on the transmission dynamics of STIs using a mathematical model. METHODS: The definition of sexual contact pattern can be broad, but we focus on two specific aspects: (i) type of partnership (i.e. steady or casual partnership) and (ii) existence of concurrency (i.e. with single or multiple partners). Systematic review and meta-analysis of published studies are performed, analysing literature that epidemiologically examined the relationship between condom use and sexual contact pattern. Subsequently, we employ an epidemiological model and compute the reproduction number that accounts for with and without concurrency so that the corresponding coverage of condom use and its correlation with existence of concurrency can be explicitly investigated using the mathematical model. Combining the model with parameters estimated from the meta-analysis along with other assumed parameters, the impact of varying the proportion of population with multiple partners on the reproduction number is examined. RESULTS: Based on systematic review, we show that a greater number of people used condoms during sexual contact with casual partners than with steady partners. Furthermore, people with multiple partners use condoms more frequently than people with a single partner alone. Our mathematical model revealed a positive relationship between the effective reproduction number and the proportion of people with multiple partners. Nevertheless, the association was reversed to be negative by employing a slightly greater value of the relative risk of condom use for people with multiple partners than that empirically estimated. CONCLUSIONS: Depending on the correlation between condom use and the existence of concurrency, association between the proportion of people with multiple partners and the reproduction number can be reversed, suggesting the sexually active population is not necessary a primary target population to encourage condom use (i.e., sexually less active individuals could equivalently be a target in some cases).

Modeling the elevated risk of yellow fever among travelers visiting Brazil, 2018.

BACKGROUND: Unlike the epidemic of yellow fever from 2016 to 17 in Brazil mostly restricted to the States of Minas Gerais and Espirito Santo, the epidemic from 2017 to 18 mainly involved São Paulo and Rio de Janeiro and resulted in multiple international disseminations. To understand mechanisms behind this observation, the present study analyzed the distribution of imported cases from Brazil, 2018. METHODS: A statistical model was employed to capture the risk of importing yellow fever by returning international travelers from Brazil. We estimated the relative risk of importation among travelers by the extent of wealth measured by GDP per capita and the relative risk obtained by random assignment of travelers' destination within Brazil by the relative population size. RESULTS: Upper-half wealthier countries had 2.1 to 3.4 times greater risk of importation than remainders. Even among countries with lower half of GDP per capita, the risk of importation was 2.5 to 2.8 times greater than assuming that the risk of travelers' infection within Brazil is determined by the regional population size. CONCLUSIONS: Travelers from wealthier countries were at elevated risk of yellow fever, allowing us to speculate that travelers' local destination and behavior at high risk of infection are likely to act as a key determinant of the heterogeneous risk of importation. It is advised to inform travelers over the ongoing geographic foci of transmission, and if it appears unavoidable to visit tourist destination that has the history of producing imported cases, travelers must be strongly advised to receive vaccination in advance.

[Diagnosis and Treatment of MSI-H Cancer in Gynecological Cancer].

Among gynecological cancers, microsatellite instability(MSI)is most commonly found in endometrial carcinoma. When an allelic variation is observed in multiple microsatellite regions, it is called MSI-high(MSI-H). Hereditary MSI-H endometrial cancer develops through a germline mutation ofthe mismatch repair(MMR)gene, resulting in Lynch syndrome, and increased risk ofsporadic MSI-H endometrial cancer is caused by somatic lineage mutations or methylation abnormalities. Clinical characteristics ofendometrial cancer involved in Lynch syndrome include symptoms such as onset at a younger age, a lower corpus segment at the site, earlier stage cancer, and varied histology, when compared with those ofthe sporadic cancer. Alternatively, somatic mutations ofthe MMR gene are highly heterogeneous; however, a meta-analysis showed no difference in prognosis between with and without MSI-H. MSI-H is considered to be a biomarker, showing the therapeutic effects of an immune checkpoint inhibitor. A recent randomized controlled trial(RCT)demonstrated that an immune checkpoint inhibitor was effective against colorectal cancer with MSI-H. An additional RCT proved its effectiveness for MSI-H solid cancers, regardless oforgan type, including endometrial cancer. As the number ofcases ofendometrial cancer is increasing in Japan, MSI-H may hold utility as a biomarker for new molecular-target drugs, including immune checkpoint inhibitors. Ongoing surveillance ofcarcinomas in patients and family members is important because endometrial carcinoma associated with Lynch syndrome is a hereditary tumor. However, there is currently no established surveillance method for endometrial cancer. To improve the overall prognosis ofpatients with Lynch syndrome, genetic counseling and cross-division management are necessary, and also establishing the system is urgently required.

Beta-Catenin and SMAD3 Are Associated with Skeletal Muscle Aging in the Taurine Transpoeter Knockout Mouse.

Tissue taurine depletion mediated by knocking out the taurine transporter causes several skeletal muscle abnormalities, including acceleration of cellular aging. In the present study, we investigated the signaling pathway involved in the acceleration of skeletal muscle aging by tissue taurine depletion using the bioinformatic approach of transcriptome data. We previously performed transcriptome analysis on skeletal muscle of taurine transporter knockout (TauTKO) mice using DNA microarray. Bioinformatic analysis of transcriptome data predicted the activation of SMAD3 and ß-catenin as upstream signaling molecules of cyclin-dependent kinase inhibitor 2A (CDKN2A, also called p16INK4A), which is a biomarker gene of cellular senescence. The activation of SMAD3 and ß-catenin in old TauTKO muscle was verified by western blot analysis. These data indicate that SMAD3- and ß-catenin-dependent induction occurs in the TauTKO mouse.

Establishment of a multi-species biofilm model and metatranscriptomic analysis of biofilm and planktonic cell communities.

We collected several biofilm samples from Japanese rivers and established a reproducible multi-species biofilm model that can be analyzed in laboratories. Bacterial abundance at the generic level was highly similar between the planktonic and biofilm communities, whereas comparative metatranscriptomic analysis revealed many upregulated and downregulated genes in the biofilm. Many genes involved in iron-sulfur metabolism, stress response, and cell envelope function were upregulated; biofilm formation is mediated by an iron-dependent signaling mechanism and the signal is relayed to stress-responsive and cell envelope function genes. Flagella-related gene expression was regulated depending upon the growth phase, indicating different roles of flagella during the adherence, maturation, and dispersal steps of biofilm formation. Downregulation of DNA repair genes was observed, indicating that spontaneous mutation frequency would be elevated within the biofilm and that the biofilm is a cradle for generating novel genetic traits. Although the significance remains unclear, genes for rRNA methyltransferase, chromosome partitioning, aminoacyl-tRNA synthase, and cysteine, methionine, leucine, thiamine, nucleotide, and fatty acid metabolism were found to be differentially regulated. These results indicate that planktonic and biofilm communities are in different dynamic states. Studies on biofilm and sessile cells, which have received less attention, are important for understanding microbial ecology and for designing tailor-made anti-biofilm drugs.

Body mass index trajectories and mortality risk in Japan using a population-based prospective cohort study: the Japan Public Health Center-based Prospective Study.

BACKGROUND: Recent studies have found that long-term changes in weight during adulthood are associated with a high risk of mortality. The objective of this study was to characterize body mass index (BMI) trajectories during adulthood and to examine the association between BMI trajectories and risk of death in the Japanese population. METHODS: The data were extracted from Japan Public Health Center-based Prospective Study-a population-based prospective cohort study in Japan with participants aged 40-69 years followed over 20 years. The participants were categorized into multiple BMI trajectory groups using the latent class growth model. The Cox proportional-hazards model was conducted using all-cause mortality and cause-specific mortality as outcomes and the identified BMI trajectory groups as a predictor. In total, 65 520 participants were included in the analysis. RESULTS: Six BMI trajectory groups were identified: underweight stable (Group 1), low-to-high normal (Group 2), high-to-low normal (Group 3), normal to overweight (Group 4), overweight to normal (Group 5) and normal to obese (Group 6). Our Cox models showed a higher hazard (risk) of all-cause mortality among participants in the BMI-declining groups [Group 3, adjusted hazard ratio (aHR): 1.10, 95% CI: 1.05-1.16; Group 5, aHR: 1.16, 95% CI: 1.08-1.26], underweight stable group (Group 1, aHR: 1.27, 95% CI: 1.21-1.33) and normal to obese group (Group 6, aHR: 1.22, 95% CI: 1.13-1.33) than Group 2 (low-to-high normal BMI trajectory). CONCLUSIONS: Stable underweight and weight loss were associated with a high risk of mortality, both of which were uniquely observed in a Japanese population.

Sustained remission after cord blood transplantation for breast cancer with lung metastases and myelodysplastic syndrome.

Allogenic hematopoietic stem cell transplantation (allo-HSCT) is not a standard therapy for solid cancer because of its high toxicity and insufficient evidence levels. However, the potential graft-versus-solid-tumor (GVT) effect of this therapy has been discussed. Many case reports have also described treatment effects of allo-HSCT in patients with hematologic malignancies and active solid tumors. A 38-year-old woman treated with fulvestrant and abemaciclib for recurrent breast cancer with multiple lung metastases was diagnosed with myelodysplastic syndrome (MDS) with increased blasts 2. She was classified as adverse risk by the 2017 European LeukemiaNet risk stratification and as very high risk by the Molecular International Prognostic Scoring System. Breast cancer treatment was interrupted and venetoclax and azacitidine therapy was started. Complete hematologic response was achieved after three cycles. However, multiple lung metastases from the breast cancer remained. The patient then underwent umbilical cord blood transplantation. She has maintained complete remission of MDS as of 1 year post-transplantation, without serious complications. Lung metastatic activity on FDG-PET/CT scan also completely disappeared by half a year post-transplantation, and this response has continued as of 1 year post-transplantation. This favorable treatment course suggests the existence of a GVT effect.

Bias in nutrition-health associations is not eliminated by excluding extreme reporters in empirical or simulation studies.

Self-reported nutrition intake (NI) data are prone to reporting bias that may induce bias in estimands in nutrition studies; however, they are used anyway due to high feasibility. We examined whether applying Goldberg cutoffs to remove 'implausible' self-reported NI could reliably reduce bias compared to biomarkers for energy, sodium, potassium, and protein. Using the Interactive Diet and Activity Tracking in the American Association of Retired Persons (IDATA) data, significant bias in mean NI was removed with Goldberg cutoffs (120 among 303 participants excluded). Associations between NI and health outcomes (weight, waist circumference, heart rate, systolic/diastolic blood pressure, and VO2 max) were estimated, but sample size was insufficient to evaluate bias reductions. We therefore simulated data based on IDATA. Significant bias in simulated associations using self-reported NI was reduced but not completely eliminated by Goldberg cutoffs in 14 of 24 nutrition-outcome pairs; bias was not reduced for the remaining 10 cases. Also, 95% coverage probabilities were improved by applying Goldberg cutoffs in most cases but underperformed compared with biomarker data. Although Goldberg cutoffs may achieve bias elimination in estimating mean NI, bias in estimates of associations between NI and outcomes will not necessarily be reduced or eliminated after application of Goldberg cutoffs. Whether one uses Goldberg cutoffs should therefore be decided based on research purposes and not general rules.

Sophisticated expression responses of ZNT1 and MT in response to changes in the expression of ZIPs.

The zinc homeostatic proteins Zn transporter 1 (ZNT1) and metallothionein (MT) function in dampening increases in cytosolic zinc concentrations. Conversely, the expression of ZNT1 and MT is expected to be suppressed during decreases in cytosolic zinc concentrations. Thus, ZNT1/MT homeostatic responses are considered to be essential for maintaining cellular zinc homeostasis because cellular zinc concentrations are readily altered by changes in the expression of several Zrt-/Irt-like proteins (ZIPs) under both physiological and pathological conditions. However, this notion remains to be tested experimentally. Here, we investigated the aforementioned homeostatic process by analyzing ZNT1 and MT protein expression in response to ZIP expression. Overexpression of cell-surface-localized ZIPs, such as ZIP4 and ZIP5, increased the cellular zinc content, which caused an increase in the expression of cell-surface ZNT1 and cytosolic MT in the absence of zinc supplementation in the culture medium. By contrast, elimination of the overexpressed ZIP4 and ZIP5 resulted in decreased expression of ZNT1 but not MT, which suggests that differential regulation of ZNT1 and MT expression at the protein level underlies the homeostatic responses necessary for zinc metabolism under certain conditions. Moreover, increased expression of apically localized ZIP4 facilitated basolateral ZNT1 expression in polarized cells, which indicates that such a coordinated expression mechanism is crucial for vectorial transcellular transport. Our results provide novel insights into the physiological maintenance of cellular zinc homeostasis in response to alterations in cytosolic zinc concentrations caused by changes in the expression of ZIPs.

Evaluating the cost-effectiveness of a pre-exposure prophylaxis program for HIV prevention for men who have sex with men in Japan.

Men who have sex with men (MSM) have been disproportionally affected by the HIV epidemic in many countries, including Japan. Although pre-exposure prophylaxis (PrEP) is a strong prevention tool, it is not yet approved in Japan. A Markov model was developed to describe HIV infection and disease progression in an MSM cohort (N = 1000) in Japan receiving a PrEP program. The model was used to evaluate the cost-effectiveness of a PrEP program. HIV/AIDS treatment, screening, hospitalization due to AIDS, and PrEP were considered as costs and quality-adjusted life-years (QALYs) gained as utilities. Cost-effectiveness was assessed by comparing the incremental cost-effectiveness ratio (ICER) over a 30-year period against the willingness to pay (WTP) threshold. One-way sensitivity and probabilistic sensitivity analyses were performed. With 50% PrEP coverage, the PrEP program became dominant against the program without PrEP, using a threshold of 5.0 million JPY/QALY (45,455 USD). The probabilistic sensitivity analysis revealed that the PrEP program was dominant or at least cost-effective in most cases of 10,000 simulations. Therefore, preparing cheaper PrEP pills, which results in PrEP being dominant or ICER being lower than the WTP threshold, is important to make the program cost-effective. Introduction of PrEP to an MSM cohort in Japan would be cost-effective over a 30-year time horizon.

Scaffold size-dependent effect on the enhanced uptake of antibiotics and other compounds by Escherichia coli and Pseudomonas aeruginosa.

The outer membrane of Gram-negative bacteria functions as an impermeable barrier to foreign compounds. Thus, modulating membrane transport can contribute to improving susceptibility to antibiotics and efficiency of bioproduction reactions. In this study, the cellular uptake of hydrophobic and large-scaffold antibiotics and other compounds in Gram-negative bacteria was investigated by modulating the homolog expression of bamB encoding an outer membrane lipoprotein and tolC encoding an outer membrane efflux protein via gene deletion and gene silencing. The potential of deletion mutants for biotechnological applications, such as drug screening and bioproduction, was also demonstrated. Instead of being subjected to gene deletion, wild-type bacterial cells were treated with cell-penetrating peptide conjugates of a peptide nucleic acid (CPP-PNA) against bamB and tolC homologs as antisense agents. Results revealed that the single deletion of bamB and tolC in Escherichia coli increased the uptake of large- and small-scaffold hydrophobic compounds, respectively. A bamB-and-tolC double deletion mutant had a higher uptake efficiency for certain antibiotics and other compounds with high hydrophobicity than each single deletion mutant. The CPP-PNA treated E. coli and Pseudomonas aeruginosa cells showed high sensitivity to various antibiotics. Therefore, these gene deletion and silencing approaches can be utilized in therapeutic and biotechnological fields.

Perihepatic Abscess due to a Liver Suture with Pledgets Used to Treat a Penetrating Liver Injury.

BACKGROUND: Selective nonoperative management has become the standard for liver injuries. Accordingly, we cannot perform surgery for liver injuries as frequently as in the past. This report is aimed at sharing a valuable experience of postoperative complications after surgery for a liver injury. Case Presentation. A 40-year-old man was stabbed in his abdomen and underwent an emergency laparotomy for a severe liver injury. Five months after the operation, he developed fever, and purulent discharge was observed from an abdominal fistula. He was diagnosed with a perihepatic abscess and duodenal perforation due to the pledgets used for the operation. He underwent a second surgery to remove the pledgets and the abscess cavity for infection control and was discharged in good condition. CONCLUSION: The intra-abdominal environment should be considered contaminated due to bile leakage in surgeries following liver injury. Furthermore, nonabsorbable agents should not be used in these contaminated areas.

Quantifying compliance with COVID-19 mitigation policies in the US: A mathematical modeling study.

The outbreak of COVID-19 disrupts the life of many people in the world. In response to this global pandemic, various institutions across the globe had soon issued their prevention guidelines. Governments in the US had also implemented social distancing policies. However, those policies, which were designed to slow the spread of COVID-19, and its compliance, have varied across the states, which led to spatial and temporal heterogeneity in COVID-19 spread. This paper aims to propose a spatio-temporal model for quantifying compliance with the US COVID-19 mitigation policies at a regional level. To achieve this goal, a specific partial differential equation (PDE) is developed and validated with short-term predictions. The proposed model describes the combined effects of transboundary spread among state clusters in the US and human mobilities on the transmission of COVID-19. The model can help inform policymakers as they decide how to react to future outbreaks.

HIV Testing by Public Health Centers and Municipalities and New HIV Cases During the COVID-19 Pandemic in Japan.

BACKGROUND: During the COVID-19 outbreak, facility capacity for HIV testing has been limited. Furthermore, people may have opted against HIV testing during this period to avoid COVID-19 exposure. We investigated the influence of the COVID-19 pandemic on HIV testing and the number of reported HIV cases in Japan. METHODS: We analyzed quarterly HIV/AIDS-related data from 2015 to the second quarter of 2020 using an anomaly detection approach. The data included the number of consultations, the number of HIV tests performed by public health centers or municipalities, and the number of newly reported HIV cases with and without an AIDS diagnosis. We further performed the same analysis for 2 subgroups: men who have sex with men (MSM) and non-Japanese persons. RESULTS: The number of HIV tests (9,584 vs. 35,908 in the year-before period) and consultations (11,689 vs. 32,565) performed by public health centers significantly declined in the second quarter of 2020, whereas the proportion of new HIV cases with an AIDS diagnosis (36.2% vs. 26.4%) significantly increased after removing the trend and seasonality effects. HIV cases without an AIDS diagnosis decreased (166 vs. 217), but the reduction was not significant. We confirmed similar trends for the men who have sex with men and non-Japanese subgroups. CONCLUSIONS: During the COVID-19 pandemic, the current HIV testing system in Japan seems to have missed more cases of HIV before developing AIDS. Continuously monitoring the situation and securing sufficient test resources by use of self-testing is essential to understand the clear epidemiological picture of HIV incidence during the COVID-19 pandemic.