Sox17 is essential for proper formation of the marginal zone of extraembryonic endoderm adjacent to a developing mouse placental disk.

In mouse conceptus, two yolk-sac membranes, the parietal endoderm (PE) and visceral endoderm (VE), are involved in protecting and nourishing early-somite-stage embryos prior to the establishment of placental circulation. Both PE and VE membranes are tightly anchored to the marginal edge of the developing placental disk, in which the extraembryonic endoderm (marginal zone endoderm: ME) shows the typical flat epithelial morphology intermediate between those of PE and VE in vivo. However, the molecular characteristics and functions of the ME in mouse placentation remain unclear. Here, we show that SOX17, not SOX7, is continuously expressed in the ME cells, whereas both SOX17 and SOX7 are coexpressed in PE cells, by at least 10.5 days postconception. The Sox17-null conceptus, but not the Sox7-null one, showed the ectopic appearance of squamous VE-like epithelial cells in the presumptive ME region, together with reduced cell density and aberrant morphology of PE cells. Such aberrant ME formation in the Sox17-null extraembryonic endoderm was not rescued by the chimeric embryo replaced with the wild-type gut endoderm by the injection of wild-type ES cells into the Sox17-null blastocyst, suggesting the cell autonomous defects in the extraembryonic endoderm of Sox17-null concepti. These findings provide direct evidence of the crucial roles of SOX17 in proper formation and maintenance of the ME region, highlighting a novel entry point to understand the in vivo VE-to-PE transition in the marginal edge of developing placenta.

Study on AAV-mediated gene therapy for diabetes in humanized liver mouse to predict efficacy in humans.

Most in vivo studies on the conversion to insulin-producing cells with AAV carrying PDX1 gene are performed in rodents. However, there is little information regarding Adeno-associated virus (AAV) carrying PDX1 gene transduced to human liver in vivo because accidental death caused by unpredicted factors cannot be denied, such as the hypoglycemic agent troglitazone with hepatic failure. Here we aim to confirm insulin secretion from human liver transduced with AAV carrying PDX1 gene in vivo and any secondary effect using a humanized liver mouse. As the results, AAV2-PG succeeded to improve the hyperglycemia of STZ-induced diabetic humanized liver mice. Then, the analysis of humanized liver mice revealed that the AAV2-PG was more transducible to humanized liver area than to mouse liver area. In conclusion, the humanized liver mouse model could be used to examine AAV transduction of human hepatocytes in vivo and better predict clinical transduction efficiency than nonhumanized mice.

Characteristics of COVID-19 infection clusters occurring among workers in several Asia-Pacific countries.

The types of workplaces and occupations with coronavirus 2019 (COVID-19) clusters vary between countries and periods. We aimed to characterize major occupational groups with mass outbreaks of COVID-19 infections in several Asia-Pacific countries. Data on the major occupations or workplaces reporting COVID-19 cases in workplaces from January 2020 to July 2021 was collected from industrial hygiene professionals in nine countries. The proportion of workers accounted for 39.1 to 56.6% of the population in each country. The number of workers covered in the national statistics varies among nations based on their definition of a worker. None of the countries examined here have systematically collected occupational data on COVID-19 illnesses and deaths classified by type of industry, occupation, or job. Most countries experienced COVID-19 clusters among health and social care workers (HSCW) in hospitals or long-term care facilities. The types of occupations or workplaces with virus clusters in some participating countries included prisons, call centers, workplaces employing immigrants, garment facilities, grocery stores, and the military, which differed among countries, except for a few common occupations such as HSCW and those populated by immigrants. Further study is necessary in order to seek ways to control infection risks, including revisions to industrial-health-related laws.

Overview of Legal Measures for Managing Workplace COVID-19 Infection Risk in Several Asia-Pacific Countries.

BACKGROUND: Despite the lack of official COVID-19 statistics, various workplaces and occupations have been at the center of COVID-19 outbreaks. We aimed to compare legal measures and governance established for managing COVID-19 infection risks at workplaces in nine Asia and Pacific countries and to recommend key administrative measures. METHODS: We collected information on legal measures and governance from both general citizens and workers regarding infection risks such as COVID-19 from industrial hygiene professionals in nine countries (Indonesia, India, Japan, Malaysia, New Zealand, Republic of the Philippines, Republic of Korea, Taiwan, and Thailand) using a structured questionnaire. RESULTS: A governmental body overseeing public health and welfare was in charge of containing the spread and occurrence of infectious diseases under an infectious disease control and prevention act or another special act, although the name of the pertinent organizations and legislation vary among countries. Unlike in the case of other traditional hazards, there have been no specific articles or clauses describing the means of mitigating virus risk in the workplace that are legally required of employers, making it difficult to define the responsibilities of the employer. Each country maintains own legal systems regarding access to the duration, administration, and financing of paid sick leave. Many workers may not have access to paid sick leave even if it is legally guaranteed. CONCLUSION: Specific legal measures to manage infectious disease risks, such as providing proper personal protective equipment, education, engineering control measures, and paid sick leave are recommended to be stipulated in Industrial safety and health-related acts.

Development of blastocyst complementation technology without contributions to gametes and the brain.

In Japan, it is possible to generate chimeric animals from specified embryos by combining animal blastocysts with human pluripotent stem (PS) cells (animal-human PS chimera). However, the production of animal-human PS chimeras has been restricted because of ethical concerns, such as the development of human-like intelligence and formation of humanized gametes in the animals, owing to the contributions of human PS cells to the brain and reproductive organs. To solve these problems, we established a novel blastocyst complementation technology that does not contribute to the gametes or the brain. First, we established GFP-expressing mouse embryonic stem cells (G-mESCs) in which the Prdm14 and Otx2 genes were knocked out and generated chimeric mice by injecting them into PDX-1-deficient blastocysts. The results showed that the G-mESCs did not contribute to the formation of gametes and the brain. Therefore, in the PDX-1-deficient mice complemented by G-mESCs without the Prdm14 and Otx2 genes, the germline was not transmitted to the next generations. This approach could address concerns regarding the development of both human gametes and a human-like brain upon mouse blastocyst complementation using human stem cells.

Correlation between body weight (epididymal fat) and permeation rate of serum leptin through the blood-brain barrier (BBB) in male rats aged 8 months.

In this study, in order to clarify the kinetics of leptin, we focused on the ratio of leptin concentrations in cerebrospinal fluid and serum in aged male rats, and examined the weight of epididymal fat, and the passage rate of leptin through the blood-brain barrier. In the lighter animals, the epididymal fat weight was low, while leptin concentrations in the serum and cerebrospinal fluid were also low. Conversely, in the heavier animals, the weight of epididymal fat and leptin concentrations in the serum and cerebrospinal fluid were higher. With regard to the ratio of leptin in the cerebrospinal fluid and serum, the passage rate of leptin through the blood-brain barrier was lower in the heavier animals than in the lighter animals.

An Efficient reproductive method for Irs2-/- mice with C57BL/6JJcl genetic background.

Efficient reproduction using natural mating and reproduction technology [in vitro fertilization (IVF) and embryo transfer (ET)] was investigated in IRS2 deficient mice with C57BL/6JJcl genetic background (Irs2(-/-) mice) as a typical type 2 diabetes model. From the results using various combinations of Irs2(-/-) and Irs2(-/+) mice, the combination of female Irs2(-/+) x male Irs2(-/-) was found to be more efficient than other combinations. In applications of reproduction technology using IVF and ET, the combination of female Irs2(-/+) x male Irs2(-/-) involves the possibility of Irs2(-/-) production by repeats using female Irs2(-/+) mice. However, reproductive continuity using this combination is difficult because of dependence on human technique and the cost of ET. Therefore, we concluded that Irs2(-/-) mice should be produced by embryo transfer using Irs2(-/-) mice from a colony consisting of female Irs2(-/+) x male Irs2(-/-).

Guidelines for personal exposure monitoring of chemicals: Part III.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Guidelines for personal exposure monitoring of chemicals: Part VI.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Guidelines for personal exposure monitoring of chemicals: Part V.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Guidelines for personal exposure monitoring of chemicals: Part IV.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Adiponectin deficiency-induced diabetes increases TNFα and FFA via downregulation of PPARα.

Expression of peroxisome proliferator-activated receptor (PPAR) α was investigated in adiponectin knockout mice to elucidate the relationship between PPARα and adiponectin deficiency-induced diabetes. Adiponectin knockout (Adp-/-) mice were generated by gene targeting. Glucose tolerance test (GTT), insulin tolerance test (ITT), and organ sampling were performed in Adp-/- mice at the age of 10 weeks. PPARα, insulin, triglyceride, free fatty acid (FFA), and tumor necrosis factor α (TNFα) were analyzed from the sampled organs. Adp-/- mice showed impaired glucose tolerance and insulin resistance. Additionally, PPARα levels were decreased and plasma concentration of triglyceride, FFA and TNFα were increased. These data may indicate that insulin resistance in Adp-/- mice is likely caused by an increase in concentrations of TNFα and FFA via downregulation of PPARα.

Evaluation of the control banding method--comparison with measurement-based comprehensive risk assessment.

The control banding method, or "control banding", is a simplified risk assessment system for chemical handling tasks. This system is supposed to provide assessment results of reasonable quality without expert involvement. The objective of this study was to evaluate the appropriateness of control banding judgment on the basis of workplace safety. A common approach for assessing workplace risk, which is called "comprehensive risk assessment" in this study, is to measure workers' exposure and compare it with relevant occupational exposure limits. Risk assessment was performed with control banding (COSHH Essentials, UK) at 12 workplaces of a petroleum company in Japan, where health risks had already been assessed separately through comprehensive risk assessment by experts and control technologies implemented accordingly. The obtained control banding judgments were then examined with regard to their adequacy by comparing them with existing control technologies. There was majority of cases (seven) where judgments by control banding were identified as "over-controlled"; there was no judgments identified as "under-controlled". Control banding also requested the seeking of expert advice in the majority of cases (eight). Thus, it was demonstrated that control banding tends to provide safe-sided judgment. A possible interpretation of this is that control banding is inherently designed to secure workplace safety by compensating for its insufficient exposure information with safe-sided judgment criteria and by requiring experts' intervention in high-risk cases. Control banding could be widely and effectively utilized in Japan, especially by employers in small enterprises, provided that the above characteristics are pre-acknowledged and health experts are made available. To this aim, it is essential to develop new local health experts and establish institutional mechanisms for facilitating employers' access to expert advice. It should however be noted that the number of workplaces evaluated in this study was small.

Ontogenetic changes of ultrasonic vocalizations emitted from infant rats.

Ontogenetic changes of USVs were investigated to establish an index of stress in infant rats. The USVs were obtained by exposing infant rats to cold stress and were analyzed by real-time spectrography. USV waveforms consisted of four types, R-I, II, III and IV. These USVs were closely monitored at the age of 3-7 days in both sexes. From day 14, the frequency and incidence of USVs gradually decreased and had disappeared completely at the age of 21 days. Therefore, USVs should be useful in estimating the stress of infant rats between the ages of 3-7 days.

Phenotypes of IRS-2 deficient mice produced by reproductive technology are stable.

We studied the impact of "IVF - ET" on the glucose tolerance test (GTT), insulin tolerance test (ITT) and adiponectin to investigate differences in the phenotypes of B6J- Irs2(-/-) mice. The B6J-Irs2(-/-) mice (KO-Nat group) were prepared by natural mating. Other mice were produced by IVF-ET used ICR strain recipients and surrogate mothers (KO-IVF group). Measurement of body weight, GTT, ITT and blood sampling were performed at the ages of 6, 14 and 24 weeks after birth. Body weights, impaired glucose tolerance, insulin resistance and plasma adiponectin concentrations did not differ for each gender between the KO-IVF and KO-Nat groups. Therefore, we concluded that phenotypes of Irs2(-/-) mice produced by reproductive technology are stable.

Efficient production of recombinant adeno-associated viral vector, serotype DJ/8, carrying the GFP gene.

The purpose of this study was to establish an efficient method for the preparation of an adeno-associated viral (AAV), serotype DJ/8, carrying the GFP gene (AAV-DJ/8-GFP). We compared the yields of AAV-DJ/8 vector, which were produced by three different combination methods, consisting of two plasmid DNA transfection methods (lipofectamine and calcium phosphate co-precipitation; CaPi) and two virus DNA purification methods (iodixanol and cesium chloride; CsCl). The results showed that the highest yield of AAV-DJ/8-GFP vector was accomplished with the combination method of lipofectamine transfection and iodixanol purification. The viral protein expression levels and the transduction efficacy in HEK293 and CHO cells were not different among four different combination methods for AAV-DJ/8-GFP vectors. We confirmed that the AAV-DJ/8-GFP vector could transduce to human and murine hepatocyte-derived cell lines. These results show that AAV-DJ/8-GFP, purified by the combination of lipofectamine and iodixanol, produces an efficient yield without altering the characteristics of protein expression and AAV gene transduction.

Guidelines for personal exposure monitoring of chemicals: Part I.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided later in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Guidelines for personal exposure monitoring of chemicals: Part II.

This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

Ontogenetic characteristics of enzyme activities and plasma metabolites in C57BL/6J:Jcl mice deficient in insulin receptor substrate 2.

We have established an inbred line of mice deficient in insulin receptor substrate 2 (IRS2) on a C57BL/6J Jcl genetic background (B6J-IRS2(-/-) mice) as an animal model for typical type 2 diabetes mellitus (DM). We investigated the effect of age and sex on glucose tolerance and insulin resistance and on the activities of enzymes related to lipid metabolism in the liver and skeletal muscle of B6J-IRS2( -/-) mice. Glucose tolerance tests (GTT), insulin tolerance tests (ITT), and sampling for chemical analysis were performed at ages of 6,14, and 24 wk. GTT showed that both genders of B6J-IRs2(-/-) mice had impaired glucose tolerance at the ages of 6 and 14 wk, whereas 24-wk-old female B6J-IRs2(-/-) mice showed glucose tolerance almost comparable to that of wild-type mice; 24-wk-old male B6J-IRs2(-/-) mice still showed impaired glucose tolerance. ITT revealed that both male and female B6J-IRS2(-/-) mice remained insulin-resistant at all time points. Hepatic lipogenetic enzyme activities were higher in B6J-IRS2(-/-) mice than in wild-type mice at 6, 14 and 24 wk of age. In addition, plasma glucose, triglyceride, free fatty acid, total cholesterol, and insulin concentrations in B6J-IRS2(-/-) mice were significantly higher than those in wild-type mice at most time points; plasma triglycerides in 14-wk-old B6J-IRS2(-/-) mice were lower than those of wild-type mice. These findings suggest that young B6J-IRS2(-/-) mice are useful as type 2 DM models.

Expression of pancreatic and duodenal homeobox1 (PDX1) protein in the interior and exterior regions of the intestine, revealed by development and analysis of Pdx1 knockout mice.

We developed pancreatic and duodenal homeobox1 (Pdx1) knockout mice to improve a compensatory hyperinsulinemia, which was induced by hyperplasia in the ß cells or Langerhans' islands, as the diabetic model mice. For targeting of Pdx1 gene by homologous recombination, ES cells derived from a 129(+Ter) /SvJcl×C57BL/6JJcl hybrid mouse were electroporated and subjected to positive-negative selection with hygromycin B and ganciclovir. As these results, one of the three chimeric mice succeeded to produce the next or F1 generation. Then, the mouse fetuses were extracted from the mother's uterus and analyzed immunohistologically for the existence of a pancreas. The fetuses were analyzed at embryonic day 14.5 (E14.5) because Pdx1 knockout could not alive after birth in this study. Immunohistochemical staining revealed that 10 fetuses out of 26 did not have any PDX1 positive primordium of the pancreas and that the PDX1 expresses in both the interior and exterior regions of intestine. In particular, one the exterior of the intestine PDX1 was expressed in glands that would be expected to form the pancreas. The result of PCR genotyping with extracted DNA from the paraffin sections showed existence of 10 Pdx1-knockout mice and corresponded to results of immunostaining. Thus, we succeeded to establish a Pdx1-knockout (Pdx1 (-/-)) mice.