Unlocking the potential of forage fish to reduce the global burden of disease.

Red meat consumption is associated with an elevated risk of mortality from non-communicable diseases (NCDs). In contrast, forage fish, as highly nutritious, environmentally friendly, affordable, and the most abundant fish species in the ocean, are receiving increasing interest from a global food system perspective. However, little research has examined the impact of replacing red meat with forage fish in the global diet on diet-related NCDs. METHODS: We based our study on datasets of red meat projections in 2050 for 137 countries and forage fish catches. We replaced the red meat consumption in each country with forage fish (from marine habitats), without exceeding the potential supply of forage fish. We used a comparative risk assessment framework to investigate how such substitutions could reduce the global burden of diet-related NCDs in adults. RESULTS: The results of our study show that forage fish may replace only a fraction (approximately 8%) of the world's red meat due to its limited supply, but it may increase global daily per capita fish consumption close to the recommended level. Such a substitution could avoid 0.5-0.75 million deaths and 8-15 million disability-adjusted life years, concentrated in low- and middle-income countries. Forage fish as an alternative to red meat could double (or more) the number of deaths that could be avoided by simply reducing red meat consumption. CONCLUSIONS: Our analysis suggests that forage fish is a promising alternative to red meat. Policies targeting the allocation of forage fish to regions where they are needed, such as the Global South, could be more effective in maximising the potential of forage fish to reduce the global burden of disease.

Contribution of Agriculture to Health Promotion.

Agriculture has been an important source of the human diet throughout human history, but its relationship with human societies has transformed over the long course of more than 10,000 y. Urbanization and agricultural commercialization are significant among such changes and wield considerable impact on human diets, nutrition, and health. This paper presents four studies examining the influence of agriculture on diet and general health: 1) the impact of urban allotment gardening on human health and wellbeing in Japan, 2) the preference of people in Japan for collaborations between citizens' farms and food-support organizations 3) the linkages between dietary diversity and agriculture in Indonesia, and 4) food sources and child nutrition in the deforested frontiers of Cambodia.

Climate-driven divergent long-term trends of forest beetles in Japan.

Concerning declines in insect populations have been reported from Europe and the United States, yet there are gaps in our knowledge of the drivers of insect trends and their distribution across the world. We report on our analysis of a spatially extensive, 14-year study of ground-dwelling beetles in four natural forest biomes spanning Japan's entire latitudinal range (3000 km). Beetle species richness, abundance and biomass declined in evergreen coniferous forests but increased in broadleaf-coniferous mixed forests. Further, beetles in evergreen coniferous forests responded negatively to increased temperature and precipitation anomalies, which have both risen over the study's timespan. These significant changes parallel reports of climate-driven changes in forest tree species, providing further evidence that climate change is altering forest ecosystems fundamentally. Given the enormous biodiversity and ecosystem services that forests support globally, the implications for biodiversity change resulting from climate change could be profound.

Drug-interaction between paclitaxel and goshajinkigan extract and its constituents.

Paclitaxel, a standard chemotherapeutic agent for several types of cancer, including ovarian, breast, and non-small-cell lung cancer, causes peripheral neuropathy as an adverse effect in 60-70% of the patients. The utility of combination therapy with paclitaxel and goshajinkigan, a traditional Japanese Kampo medicine, in managing paclitaxel-induced neuropathy during chemotherapy has been explored. Paclitaxel is predominantly metabolized in the liver by cytochrome P450 (CYP) 2C8 to produce 6α-hydroxypaclitaxel and by CYP3A4 to produce 3'-p-hydroxypaclitaxel. In this study, we evaluated the inhibitory or inducing effects of goshajinkigan extract (GJG) and its representative and bioavailable constituents, geniposidic acid, plantagoguanidinic acid, paeoniflorin, catalpol, loganin, and neoline, on the metabolism of paclitaxel via CYP2C8 and CYP3A4 using pooled human liver microsomes and cultured human cryopreserved hepatocytes to provide the drug information about the pharmacokinetic interaction of this combination therapy. GJG significantly inhibited the production of 3'-p-hydroxypaclitaxel and 6α-hydroxypaclitaxel in vitro in a concentration-dependent manner. The half maximal inhibitory concentration (IC50) values of GJG were 4.5 and 7.8 mg/ml, respectively, for 3'-p-hydroxypaclitaxel and 6α-hydroxypaclitaxel productions. Neoline inhibited the production of 3'-p-hydroxypaclitaxel at 50 µM, but not at lower concentrations. Apart from neoline, other GJG constituents (at concentrations up to 50 or 10 µM of all test substances) did not exhibit inhibitory or inducing effects. Since GJG showed the inhibitory effect on the metabolism of paclitaxel at much higher concentrations than those used clinically, it can be concluded that GJG product does not exhibit any pharmacokinetic interaction with paclitaxel in clinical practice.

Predicting Inchinkoto efficacy, in patients with obstructive jaundice associated with malignant tumors, through pharmacomicrobiomics.

Inchinkoto (ICKT) is a popular choleretic and hepatoprotective herbal medicine that is widely used in Japan. Geniposide, a major ingredient of ICKT, is metabolized to genipin by gut microbiota, which exerts a choleretic effect. This study investigates the relationship between stool genipin-producing activity and diversity of the clinical effect of ICKT in patients with malignant obstructive jaundice. Fifty-two patients with malignant obstructive jaundice who underwent external biliary drainage were included. ICKT was administered as three packets per day (7.5 g/day) for three days and 2.5 g on the morning of the fourth day. Stool samples were collected before ICKT administration and bile flow was monitored on a daily basis. The microbiome, genipin-producing activity, and organic acids in stools were analyzed. The Shannon-Wiener (SW) index was calculated to evaluate gut microbiome diversity. The stool genipin-producing activity showed a significant positive correlation with the SW index. Stool genipin-producing activity positively correlated with the order Clostridia (obligate anaerobes), but negatively correlated with the order Lactobacillales (facultative anaerobes). Moreover, stool genipin-producing activity was positively correlated to the concentration valeric acid, but negatively correlated to the concentration of lactic acid and succinic acid. The change of bile flow at 2 and 3 days after ICKT administration showed significant positive correlation with genipin-producing activity (correlation coefficient, 0.40 and 0.29, respectively, P < 0.05). An analysis of stool profile, including stool genipin-producing activity, may predict the efficacy of ICKT. Modification of the microbiome may be a target to enhance the therapeutic effect of ICKT.

Comprehensive metabolome analysis for the pharmacological action of inchinkoto, a hepatoprotective herbal medicine.

INTRODUCTION: The precise pharmacological action of inchinkoto (ICKT, Yin-Chen-Hao-Tang in Chinese), a hepatoprotective herbal medicine, on total metabolic pathways has not been well investigated. OBJECTIVES: The aim of this study was to explore the serum metabolites reflecting the pharmacological activity of ICKT, and mechanism of action of ICKT using serum metabolome analysis. METHODS: 54 patients with obstructive jaundice due to malignancies were included in this study. ICKT was administered for 3 days. Serum and bile samples were collected before and 1 h after ICKT administration on days 1 and 4. Serum metabolome analysis including ICKT components were performed. RESULTS: The levels of total/direct bilirubin, C-reactive protein, γ-glutamyl transpeptidase, and albumin in the serum were significantly improved after ICKT administration. In the serum metabolome analysis, inosine was the only elevated metabolite on days 1 and 4. Most of the metabolites which were significantly changed after ICKT administration were lipid mediators, and all decreased on day 1. Notably, the levels of many lipid mediators were increased on day 4. The difference in serum aspartic acid 1 h after ICKT administration was significantly correlated with a decrease in the levels of total bilirubin in the serum on day 4. CONCLUSIONS: Using metabolome analysis, we demonstrated several metabolic changes that may be associated with the pharmacological mechanisms of ICKT. The biological implications of these metabolites should be further investigated in basic research studies.

A room with a green view: the importance of nearby nature for mental health during the COVID-19 pandemic.

The COVID-19 pandemic and its global response have resulted in unprecedented and rapid changes to most people's day-to-day lives. To slow the spread of the virus, governments have implemented the practice of physical distancing ("social distancing"), which includes isolation within the home with limited time spent outdoors. During this extraordinary time, nature around the home may play a key role in mitigating against adverse mental health outcomes due to the pandemic and the measures taken to address it. To assess whether this is the case, we conducted an online questionnaire survey (n = 3,000) in Tokyo, Japan, to quantify the association between five mental health outcomes (depression, life satisfaction, subjective happiness, self-esteem, and loneliness) and two measures of nature experiences (frequency of greenspace use and green view through windows from home). Accounting for sociodemographic and lifestyle variables, we found that the frequency of greenspace use and the existence of green window views from within the home was associated with increased levels of self-esteem, life satisfaction, and subjective happiness and decreased levels of depression, anxiety, and loneliness. Our findings suggest that a regular dose of nature can contribute to the improvement of a wide range of mental health outcomes. With the recent escalation in the prevalence of mental health disorders, and the possible negative impacts of the COVID-19 pandemic on public mental health, our findings have major implications for policy, suggesting that urban nature has great potential to be used as a "nature-based solution" for improved public health.

Role of O-C2 angle in the development of dysphagia in patients with halo-vest fixation.

BACKGROUND: Dysphagia is one of the most serious complications in patients treated with a halo-vest brace. However, the cause of dysphagia development by halo-vest fixation is not yet clear. We therefore investigated the incidence of dysphagia and cervical alignment as well as clinical data from medical charts in patients treated with a halo-vest brace. METHODS: We retrospectively reviewed clinical data from the medical charts of 49 patients who had undergone halo-vest fixation. Occipito (O)-C2 angle, C2-C6 angle, and pharyngeal inlet angle were assessed by lateral plain X-rays of the cervical spine. The impacts of these parameters on incidence and severity of dysphagia were analyzed. RESULTS: Thirteen patients (32%) suffered from dysphagia during halo-vest fixation, and age and length of intensive care unit (ICU) stay were greater in the dysphagia group (p = 0.044 and 0.013, respectively) than in those who did not develop dysphagia. O-C2 angle was smaller in the dysphagia group (p = 0.016). After multivariate logistic analysis, body mass index, ICU stay, and O-C2 angle remained as independent risk factors related to incidence of dysphagia. Spearman rank correlation showed a negative correlation between ICU stay and Food Intake Level Scale (FILS) (p = 0.026), and a positive correlation between O-C2 angle and FILS (p = 0.008). CONCLUSION: This study suggested that O-C2 angle is related to both incidence and severity of dysphagia due to halo-vest fixation.

Effect of biological agents on synovial tissues from patients with rheumatoid arthritis.

Objectives: To compare the inflammation of synovium before and after biological agents in the patients with rheumatoid arthritis (RA) and to investigate the association between synovial histopathology and disease activity.Methods: Synovial tissues were obtained during operations from 34 patients before and after treatment with biological agents. The synovial tissue was evaluated using hematoxylin and eosin staining. Synovial histopathology was evaluated by Rooney score.Results: The Rooney score was also significantly decreased after treatment with biological agents in all items (p < .001). After the treatment with biological agents, Moderate disease activity group had significantly higher scores of focal aggregates of lymphocytes (p = .02), diffuse infiltrates of lymphocytes (p = .019), and the Rooney total scores (p = .002) than remission and low disease activity groups.Conclusion: Our results demonstrated that biological agents significantly decreased the RA synovial inflammation and synovial histopathology in sublining layer reflected disease activity.

Vegetation dynamics of abandoned paddy fields and surrounding wetlands in the lower Tumen River Basin, Northeast China.

On the temperate lowland plain of the lower Tumen River, agricultural development has converted most marshland into paddy fields. However, the locations of old paddy fields in the lowland temperate zone, where the vegetation structure is dominated by herbs adapted to seasonally wet or waterlogged conditions, are poorly known, and the impact of land use history on marshland diversity and shifts in plant functional groups has been scantly researched. In this study, we used a chronosequence approach to investigate herbaceous wetland communities in different recovery phases (<5 years, 5-15 years, and >15 years), as well as natural wetland as a reference. We assessed their ecological characteristics, species composition and diversity to determine how they change during natural succession. Plant species composition and dominance in the abandoned fields changed markedly during natural secondary succession. Initially, the annual weeds Echinochloa crus-galli and Bidens tripartita were dominant. Later, communities gradually became dominated first by Polygonum thunbergii and then by tussock-forming Carex rostrata. Species diversity was higher in abandoned fields than in natural wetlands and decreased with time. The partition of ß-diversity components revealed that replacement was the prominent process structuring plant communities in paddy field at different times since abandonment. Our results suggest that the vegetation of abandoned paddy fields could be restored effectively through natural succession, although there were some differences in plant functional group traits. Abandoned paddy fields may be good sites for restoration of wetland species and conservation of wetland habitat.

A Case of Spontaneous Spinal Subdural Hematoma Complicated by Cranial Subarachnoid Hemorrhage and Spinal Adhesive Arachnoiditis.

A 76-year-old woman with a spinal subdural hematoma (SDH) was presented with severe back pain without headache. Magnetic resonance imaging (MRI) performed 4 days after onset showed SDH extending from Th2 to L3. She was diagnosed with spontaneous SDH without neurological manifestation, and conservative treatment was selected. Transient disturbance of orientation appeared 7 days after onset. Small subarachnoid hemorrhage (SAH) was detected on head CT, and strict antihypertensive therapy was started. Symptoms changed for the better. Back pain disappeared 4 weeks after onset. On follow-up MRI at 6 months after onset, the SDH had been resolved spontaneously. Although adhesive arachnoiditis was observed at Th4-6, the recurrence of clinical symptoms was not observed at one year and a half after onset. Spinal subdural space is almost avascular; a hematoma in a subdural space is considered to come from a subarachnoid space when it is a lot. A hemorrhage in subarachnoid space was flushed by cerebral spinal fluid; hematoma or arachnoiditis was not formed in general. In our case, hemorrhage was a lot and expansion of SDH was large enough to cause cranial SAH and arachnoiditis. But longitudinally expanded SDH did not show neurological manifestation and resolved spontaneously in our case.

Epstein-Barr virus infection and variants of Epstein-Barr nuclear antigen-1 in synovial　tissues of rheumatoid arthritis.

OBJECTIVE: The objective of the present study was to investigate Epstein-Barr virus (EBV) infection as an environmental factor for the development of rheumatoid arthritis (RA). METHODS: Synovial tissues were collected during surgery from 128 RA and 98 osteoarthritis (OA) patients. DNA was extracted from synovial tissues. The EBV gene was assessed by nested PCR for the amplification of EBV nuclear antigen-1 (EBNA-1). The nucleotide sequence of the PCR product was elucidated. HLA-DRB1 genotyping was also performed. RESULTS: EBV DNA was more frequently detected in the synovial tissues of RA patients (32.8%) than OA patients (15.3%) (p<0.01). The frequency of EBNA-1 variants did not significantly differ between RA and OA (RA: 17%, OA: 13%). The population with the HLA-DRB1 shared epitope (SE) was significantly higher in RA patients (70.3%) than in OA patients (44.9%) (p<0.001). In RA patients, the presence of EBV DNA was similar among SE-positive and -negative patients (SE-positive: 34.4%, -negative: 28.9%). The population with the EBNA-1 variant did not significantly differ between SE-positive and -negative patients (SE-positive: 12.9%, -negative: 27.3%). DISCUSSION: The present results indicate that EBV infection contributes to the onset of RA and chronic inflammation in synovial tissues. The frequency of EBNA-1 gene variants was low and not significantly different between RA and OA, suggesting that EBNA-1 gene variants are not a risk factor for RA. HLA-DRB1 with SE is a genetic risk factor for the development of RA. However, neither the presence of EBV nor EBNA-1 gene variants differed between SE-positive and -negative RA patients. Therefore, these two risk factors, SE and EBV, may be independent. CONCLUSION: EBV infection may be an environmental risk factor for the development of RA, while nucleotide variants of EBNA-1 do not appear to contribute to its development.

Percutaneous fixation of avulsion fracture at the plantar lateral base of the first metatarsal using ZipTight Fixation System: A case report.

Isolated avulsion fracture of the peroneus longus tendon insertion at the base of the first metatarsal without injury of the tarsometatarsal joint is very rare. Similar to most avulsion fractures, this type of injury is caused by strong tension exerted by the peroneus longus tendon. The mechanism leading to this lesion and treatment options are not clearly defined. Several surgical techniques have been advocated for this fracture, including excision of an avulsion fragment and open reduction for internal fixation through the medial aspect of the foot or minimal plantar incision. We have described a method of percutaneous fixing of the avulsion fracture at the plantar lateral base of the first metatarsal using the ZipTight Fixation System (Zimmer Biomet Warsaw, Indiana, USA), which offers the advantage of allowing a rigid fixation and minimal invasive surgical technique for a small fragment.

Resistin upregulates chemokine production by fibroblast-like synoviocytes from patients with rheumatoid arthritis.

BACKGROUND: Adipokines are bioactive hormones secreted by adipose tissues. Resistin, an adipokine, plays important roles in the regulation of insulin resistance and inflammation. Resistin levels are known to be increased in the serum and synovial fluid of rheumatoid arthritis (RA) patients. However, the pathogenic role of resistin in RA has not yet been elucidated. METHODS: The expression of resistin and adenylate cyclase-associated protein 1 (CAP1), a receptor for resistin, was examined immunohistochemically in synovial tissue. CAP1 expression in in vitro cultured fibroblast-like synoviocytes (FLSs) was assessed with a reverse transcription-polymerase chain reaction (PCR) and western blotting. The gene expression of resistin-stimulated FLSs was evaluated by RNA sequencing (RNA-Seq) and quantitative real-time PCR. Concentrations of chemokine (C-X-C motif) ligand (CXCL) 8, chemokine (C-C motif) ligand (CCL) 2, interleukin (IL)-1ß, IL-6 and IL-32 in culture supernatants were measured by enzyme-linked immunosorbent assay. Small interfering RNA (siRNA) for CAP1 was transfected into FLSs in order to examine inhibitory effects. RESULTS: The expression of resistin and CAP1 in synovial tissue was stronger in RA than in osteoarthritis (OA). Resistin was expressed by macrophages in the RA synovium, while CAP1 was expressed by macrophages, FLSs and endothelial cells. In vitro cultured RA FLSs also expressed CAP1. RNA-Seq revealed that the expression levels of 18 molecules were more than twofold higher in resistin-stimulated FLSs than in unstimulated FLSs. Seven chemokines, CXCL1, CXCL2, CXCL3, CXCL5, CXCL6, CXCL8, and CCL2, were included among the 18 molecules. Increases induced in the expression of CXCL1, CXCL8, and CCL2 by the resistin stimulation were confirmed by real-time PCR. The stimulation with resistin increased the protein levels of CXCL8 and CCL2 produced by RA FLSs, and the upregulated expression of CXCL8 was inhibited by the abrogation of CAP1 by siRNA for CAP1. Production of IL-6 by FLSs was also increased by resistin. Expression of IL-1ß and IL-32 was not detected by ELISA. CONCLUSIONS: Resistin contributes to the pathogenesis of RA by increasing chemokine production by FLSs via CAP1 in synovial tissue.

Exploration of serum biomarkers for predicting the response to Inchinkoto (ICKT), a Japanese traditional herbal medicine.

INTRODUCTION: In patients with obstructive jaundice, biliary drainage sometimes fails to result in improvement. A pharmaceutical-grade choleretic herbal medicine, Inchinkoto (ICKT), has been proposed to exert auxiliary effects on biliary drainage; however, its effects are variable among patients. OBJECTIVES: The aim of this study is to explore serum biomarkers that are associated with pharmaceutical efficacy of ICKT. METHODS: Obstructive jaundice patients who underwent external biliary decompression were enrolled (n = 37). ICKT was given orally 3 times a day at daily dose of 7.5 g. Serum and bile samples were collected before, 3 h after, and 24 h after ICKT administration. The concentrations of total bilirubin, direct bilirubin, and total bile acid in bile specimens were measured. Metabolites in serum samples were comprehensively profiled using LC-MS/MS and GC-MS/MS. Pharmacokinetic analysis of major ICKT components was also performed. RESULTS: ICKT administration significantly decreased serum ALT and increased bile volume after 24 h. The serum concentrations of ICKT components were not well correlated with the efficacy of ICKT. However, the ratio of 2-hydroxyisobutyric acid to arachidonic acid and the ratio of glutaric acid to niacinamide, exhibited good performance as biomarkers for the efficacy of ICKT on bile flow and ALT, respectively. Additionally, comprehensive correlation analysis revealed that serum glucuronic acid was highly correlated with serum total bilirubin, suggesting that this metabolite may be deeply involved in the pathogenesis of jaundice. CONCLUSIONS: The present study indicates that ICKT is efficacious and provides candidates for predicting ICKT efficacy. Further validation studies are warranted.

[The latest treatment of the forefoot and ankle of the patients with rheumatoid arthritis].

Operative therapy for the foot and ankle disorders of rheumatoid arthritis (RA) have been changing with advances in drug therapy. The surgical techniques, joint-preserving procedure for the RA foot and total ankle arthroplasty for the RA ankle, are the surgical techniques which allow patients with RA not only to relief their pain but also obtain higher lower limb function. Recently, more and more patients with RA have been receiving joint-preserving procedure for the foot or total ankle arthroplasty for the ankle. Therefore, in this article, we would like to describe surgical therapy for the lower limb of patients with RA.

Boiogito, a Kampo medicine, improves hydrarthrosis in a rat model of knee osteoarthritis.

BACKGROUND: Hydrarthrosis, which is associated with knee pain and limited range of motion, decreases the quality of life (QOL) of patients with osteoarthritis (OA). The Kampo medicine boiogito is prescribed for the treatment of knee OA with hydrarthrosis; however, its precise mechanisms of action remain unknown. The purposes of this study were to assess the pharmacological effects of boiogito and its mechanisms of action on joint effusion in rats with surgically induced OA. METHODS: A rat OA model was produced by transecting the anterior (cranial) cruciate ligament, medial collateral ligament, and medial meniscus in the right knee joints of 7-week-old female Wistar rats. The rats were given chow containing boiogito (1 or 2%) or indomethacin (0.002 %) for 4 weeks after surgical transection. Levels of interleukin-1ß (IL-1ß) and hyaluronic acid (HA) were measured by enzyme-linked immunosorbent assay. Knee joint pain was assessed using an incapacitance tester. Osmotic water permeability in cultured rabbit synovial cells was assessed using stopped-flow analysis. RESULTS: Increased synovial fluid volume and knee joint pain were observed in rats with surgically induced OA. In rats with OA, levels of IL-1ß and HA in the articular cavity were higher but concentration of HA in synovial fluid was lower than in sham-operated rats, suggesting excessive synovial fluid secretion. Administration of boiogito improved hydrarthrosis, IL-1ß, and HA concentrations and alleviated knee joint pain in rats with OA. Indomethacin reduced IL-1ß and knee joint pain but failed to improve hydrarthrosis or HA concentration in rats with OA. Osmotic water permeability in synovial cells, which is related to the function of the water channel aquaporin, was decreased by treatment with boiogito. CONCLUSION: Boiogito ameliorates the increased knee joint effusion in rats with OA by suppressing pro-inflammatory cytokine IL-1ß production in the articular cavity and regulating function of water transport in the synovium. The improvement of hydrarthrosis by boiogito results in the increased HA concentration in synovial fluid, thus reducing joint pain. Boiogito may be a clinically useful treatment of QOL in patients with OA with hydrarthrosis.

Investigation of ossification in the posterior longitudinal ligament using micro-focus X-ray CT scanning and histological examination.

BACKGROUND: Ossification in the posterior longitudinal ligament (PLL) correlates with changes of enthesis during the early stages of development, but this issue remains controversial, as little is known regarding the details of this process. The aim of the present study was to elucidate part of the ossification mechanism. Thus, in the present study, we observed and evaluated minute ossifications in the PLL that did not exhibit symptoms of ossification of the posterior longitudinal ligament (OPLL). METHODS: The subjects in the present study were derived from serial autopsy cases from January 2009 to December 2013 at Toho University Omori Medical Center, Japan. Minute ossifications in the PLL from autopsy subjects without any history of OPLL were screened as high-density areas using micro-focus X-ray CT, and the foci were histologically examined. Subsequently, we conducted both micro-focus X-ray CT image analysis and histological examination, and evaluated the correlation between these findings and putative predictive factors reported in previous studies. RESULTS: A total of 103 individuals among the 267 subjects involved in the present study were analyzed within the study period. There were no cases involving OPLL identification prior to death, and no subjects presented with neurological symptoms of myelopathy. The incidence of cases involving high-density areas greater than 0.1 mm(2) in the PLL was 46.6 %, half of which revealed mature bone structures inside this area. Thus, the high-density areas comprised three types: a continuous posterior-annular fibrosus type (23 cases), an isolated posterior-annular fibrosus type (11 cases), and a posterior-vertebral type (29 cases). However, a positive correlation was observed between the proportion of high-density areas, age (Pearson r = 0.265, p < 0.01), and HbA1c (Pearson r = 0.294, p < 0.01). Histological examination confirmed that these high-density areas involved calcification with or without mature bone formation. CONCLUSIONS: We evaluated minute foci of calcification with and without ossification in the PLL from 103 cadavers, generating the following observations: 1. Minute calcification foci greater than 0.1 mm(2) were observed in the PLL of 48 cases (46.6 %), half of which revealed mature bone structures inside this area (23.3 %). 2. The proportion of minute calcification foci observed in the present study was correlated with age and glucose tolerance, suggesting changes in the OPLL in the early stage. 3. Three different mechanisms of ossification were suggested: The two structures developed behind the disc might reflect the elongation of enthesis or rupture of annular fibrosus, while the remaining structure developed behind the vertebral body might reflect a dystrophic calcification-based bony metaplasia sequence.