Evaluation of modelling study shows limits of COVID-19 importing risk simulations in sub-Saharan Africa.

Mathematical modelling studies predicting the spread of the coronavirus disease 2019 (COVID-19) have been used worldwide, but precisions are limited. Thus, continuous evaluation of the modelling studies is crucial. We investigated situations of virus importation in sub-Saharan Africa (SSA) to assess effectiveness of a modelling study by Haider N et al. titled 'Passengers' destinations from China: low risk of novel coronavirus (2019-nCoV) transmission into Africa and South America'. We obtained epidemiological data of 2417 COVID-19 cases reported by 40 countries in SSA within 30 days of the first case confirmed in Nigeria on 27 February. Out of 442 cases which had travel history available, only one (0.2%) had a travel history to China. These findings underline the result of the model. However, the fact that there were numbers of imported cases from other regions shows the limits of the model. The limits could be attributed to the characteristics of the COVID-19 which is infectious even when the patients do not express any symptoms. Therefore, there is a profound need for all modelling researchers to take asymptomatic cases into account when they establish modelling studies.

New physician specialty training system impact on distribution of trainees in Japan.

OBJECTIVES: The problem of uneven distribution of medical services and inequitable distribution of physicians is drawing much attention worldwide. Revealing how changes in the specialty training system in Japan have affected the distribution of doctors could help us understand this problem. In 2018, a new and standardized specialty training system was implemented by the Japanese Medical Specialty Board, which is recognized by the Ministry of Health, Labor and Welfare. The purpose of this study was to investigate how this new system has affected the geographical distribution of doctors commencing specialty training (trainees) and choice of specialty in Japan. STUDY DESIGN: Retrospective observational study. METHODS: The change in the number of trainees between the control period (2012-2014) and 2018 was investigated, taking into account the prefecture and specialty selected. Population, the proportion of residents aged 65 years or older (aging rate), and the total number of overall doctors in each prefecture were considered as the background characteristics of each prefecture. We created a Lorenz curve and calculated the Gini coefficient for the distribution of trainees. RESULTS: In 2018, the number of trainees per 100,000 population increased to 6.6 nationwide compared with 5.5 during the control period. The number of trainees per 100,000 population in 2018 increased in prefectures with a large population of ≧ 2,000,000, a low aging rate (<27%), and a high doctor density (≧ 250 doctors per 100,000 population). The Gini coefficient showed an increase to 0.226 in 2018 compared with only 0.160 during the control period. CONCLUSIONS: After the implementation of the new training system, there was an increase in the number of doctors enrolling in specialty programs, and the specialties other than internal medicine and surgery have attracted more trainees. Inequality in the distribution of doctors between urban and rural prefectures worsened. This indicates the need to explore new ways of balancing distribution while maintaining optimal opportunities for specialist training.

Trend in unequal geographical distribution of dentists by age and gender in Japan from 1996-2014.

OBJECTIVES: To evaluate the relationship between dentists' demographic changes and their uneven geographical distribution. METHODS: Secondary analysis of nationwide government surveys, to assess trends in the geographical distribution of dentists by gender and age from 1996 to 2014 in Japan. RESULTS: The Gini-coefficient for the number of dentists per population from 47 prefectures decreased from 0.084 in 1996 to 0.069 in 2014. The coefficients for female (0.124-0.144) were higher than for male dentists (0.058-0.081). Coefficients for dentists aged 60 and older were lower than those for dentists younger than 40 in 2014 (male: 0.060 vs. 0.112; female: 0.107 vs. 0.169). CONCLUSION: The geographical maldistribution of dentists in Japan has improved. Demographic changes among dentists, including the increasing number of female dentists, could moderate this improvement.

Trend in unequal geographical distribution of doctors by age and sex in Japan from 2004 to 2014.

OBJECTIVES: In Japan, the proportion of female doctors and elderly doctors is increasing as in other countries. We investigated the relationship between doctors' demographic changes and their geographical distribution. STUDY DESIGN: A national database study. METHODS: We assessed trends in unequal geographical distribution of the number of doctors by sex and age from 2004 to 2014 in Japan. RESULTS: The Gini coefficient values for the number of female doctors (0.18) were larger than those for male doctors across all generations (0.13-0.14). The Gini coefficient values for the number of elderly doctors aged 60 years and older (male: 0.12, female: 0.18-0.23) were larger than those for majority age groups aged 40-59 years (male: 0.10, female: 0.16-0.17). CONCLUSION: The persisting geographical maldistribution of doctors may be associated with demographic changes, such as increase in the number of female doctors.

Impact of glucose fluctuation and monocyte subsets on coronary plaque rupture.

BACKGROUND AND AIMS: It remains unclear whether glycemic fluctuation can affect plaque rupture in acute myocardial infarction (AMI). Here we investigate the impact of glucose fluctuation on plaque rupture, as observed by optical coherence tomography (OCT), and monocyte subsets in patients with AMI. METHODS AND RESULTS: We studied 37 consecutive patients with AMI. All patients underwent OCT examination, which revealed 24 patients with plaque rupture and 13 patients without plaque rupture at the culprit site. Peripheral blood sampling was performed on admission. Three monocyte subsets (CD14(+)CD16(-), CD14(bright)CD16(+), and CD14(dim)CD16(+)) were assessed by flow cytometry. Glycemic variability, expressed as the mean amplitude of glycemic excursion (MAGE), was determined by a continuous glucose monitoring system 7 days after the onset of AMI. MAGE was significantly higher in the rupture patients than in the non-rupture patients (P=0.036). Levels of CD14(bright)CD16(+) monocytes from the rupture patients were significantly higher than those from the non-rupture patients (P=0.042). Of interest, levels of CD14(bright)CD16(+) monocytes correlated positively and significantly with MAGE (r=0.39, P=0.02). CONCLUSION: Dynamic glucose fluctuation may be associated with coronary plaque rupture, possibly through the preferential increase in CD14(bright)CD16(+) monocyte levels.

Observation of postsoliton expansion following laser propagation through an underdense plasma.

The expansion of electromagnetic postsolitons emerging from the interaction of a 30 ps, 3×10¹8 W cm⁻² laser pulse with an underdense deuterium plasma has been observed up to 100 ps after the pulse propagation, when large numbers of postsolitons were seen to remain in the plasma. The temporal evolution of the postsolitons has been accurately characterized with a high spatial and temporal resolution. The observed expansion is compared to analytical models and three-dimensional particle-in-cell results, revealing a polarization dependence of the postsoliton dynamics.

Characteristics of doctors' fatality due to COVID-19 in Western Europe and Asia-Pacific countries.

Under the coronavirus disease 2019 (COVID-19) pandemic, the deaths of healthcare professionals have been increasingly reported worldwide. We performed a cross-sectional, observational study using news reports on the websites among selected countries as of April 2020. We found 120 dead medical doctors due to COVID-19 in Western Europe and Asia-Pacific countries; 67 in Italy (47 in the Northern part), 34 in China (22 in Hubei), 6 in France, 4 in the UK, the USA and Spain and 1 in South Korea, respectively. Among them, 90% were men, and specialties were reported as general practitioners for 30% and as physicians for 11.6%. The overall proportions of dead medical doctors amounted to 1.9 per 10 000 confirmed cases and 30.2 per 10 000 dead cases, respectively. Proactive measures are warranted to protect doctors especially who often encounters with COVID-19 patients.

Underestimation of COVID-19 cases in Japan: an analysis of RT-PCR testing for COVID-19 among 47 prefectures in Japan.

BACKGROUND: Under the unique Japanese policy to restrict reverse transcriptase-polymerase chain reaction (RT-PCR) testing against severe acute respiratory syndrome coronavirus 2, a nationwide number of its confirmed cases and mortality remains to be low. Yet the information is lacking on geographical differences of these measures and their associated factors. AIM: Evaluation of prefecture-based geographical differences and associated predictors for the incidence and number of RT-PCR tests for coronavirus disease 2019 (COVID-19). DESIGN: Cross-sectional study using regression and correlation analysis. METHODS: We retrieved domestic laboratory-confirmed cases, deaths and the number of RT-PCR testing for COVID-19 from 15 January to 6 April 2020 in 47 prefectures in Japan, using publicly available data by the Ministry of Health, Labour and Welfare. We did descriptive analyses of these three measures and identified significant predictors for the incidence and RT-PCR testing through multiple regression analyses and correlates with the number of deaths through correlation analysis. RESULTS: The median prefectural-level incidence and number of RT-PCR testing per 100 000 population were 1.14 and 38.6, respectively. Multiple regression analyses revealed that significant predictors for the incidence were prefectural-level population (P < 0.001) and the number of RT-PCR testing (P = 0.03); and those for RT-PCR testing were the incidence (P = 0.025), available beds (P = 0.045) and cluster infections (P = 0.034). CONCLUSION: Considering bidirectional association between the incidence and RT-PCR testing, there may have been an underdiagnosed population for the infection. The restraint policy for RT-PCR testing should be revisited to meet the increasing demand under the COVID-19 epidemic.

Plate tectonics and hotspots: the third dimension.

High-resolution seismic tomographic models of the upper mantle provide powerful new constraints on theories of plate tectonics and hotspots. Midocean ridges have extremely low seismic velocities to a depth of 100 kilometers. These low velocities imply partial melting. At greater depths, low-velocity and high-velocity anomalies record, respectively, previous positions of migrating ridges and trenches. Extensional, rifting, and hotspot regions have deep (> 200 kilometers) low-velocity anomalies. The upper mantle is characterized by vast domains of high temperature rather than small regions surrounding hotspots; the asthenosphere is not homogeneous or isothermal. Extensive magmatism requires a combination of hot upper mantle and suitable lithospheric conditions. High-velocity regions of the upper 200 kilometers of the mantle correlate with Archean cratons.

Activation of interferon-gamma inducing factor mediated by interleukin-1beta converting enzyme.

The interleukin-1beta (IL-1beta) converting enzyme (ICE) processes the inactive IL-1beta precursor to the proinflammatory cytokine. ICE was also shown to cleave the precursor of interferon-gamma inducing factor (IGIF) at the authentic processing site with high efficiency, thereby activating IGIF and facilitating its export. Lipopolysaccharide-activated ICE-deficient (ICE-/-) Kupffer cells synthesized the IGIF precursor but failed to process it into the active form. Interferon-gamma and IGIF were diminished in the sera of ICE-/- mice exposed to Propionibacterium acnes and lipopolysaccharide. The lack of multiple proinflammatory cytokines in ICE-/- mice may account for their protection from septic shock.

Enhanced excitability of rat trigeminal root ganglion neurons via decrease in A-type potassium currents following temporomandibular joint inflammation.

The aim of the present study was to investigate the effect of temporomandibular joint inflammation on the excitability of trigeminal root ganglion neurons innervating the temporomandibular joint using a perforated patch-clamp technique. Inflammation was induced by injection of complete Freund's adjuvant into the rat temporomandibular joint. The threshold for escape from mechanical stimulation in the temporomandibular joint-inflamed rats was significantly lower than that in control rats. Fluorogold labeling was used to identify the trigeminal root ganglion neurons innervating the site of inflammation. When voltage-clamp (V(h)=-60 mV) conditions were applied to these Fluorogold-labeled small diameter trigeminal root ganglion neurons (<30 mum), voltage-dependent transient K(+) current densities were significantly reduced in the inflamed rats compared with controls. In addition, the voltage-dependence of inactivation of the voltage-dependent transient K(+) current was negatively shifted in the labeled temporomandibular joint-inflamed trigeminal root ganglion neurons. Furthermore, temporomandibular joint inflammation significantly reduced the threshold current and significantly increased action potential firings evoked at two-fold threshold in the Fluorogold-labeled small trigeminal root ganglion neurons. Application of 4-aminopyridine (0.5mM) to control trigeminal root ganglion neurons mimicked the changes in the firing properties observed after complete Freund's adjuvant treatment. Together, these results suggest that temporomandibular joint inflammation increases the excitability of trigeminal root ganglion neurons innervating temporomandibular joint by suppressing voltage-dependent transient K(+) current via a leftward shift in the inactivation curve. These changes may contribute to trigeminal inflammatory allodynia in temporomandibular joint disorder.

Interleukin 18 induces the sequential activation of natural killer cells and cytotoxic T lymphocytes to protect syngeneic mice from transplantation with Meth A sarcoma.

We have recently reported that interleukin 18 (IL-18) pretreatment induces immunologically mediated antitumor effects in BALB/c mice injected i.p. with syngeneic Meth A sarcoma. In this study, mice were pretreated with IL-18 before Meth A transplantation, and immunocompetency in pretreated or untreated tumor-bearing mice (TBM) 3, 9, and 15 days after transplantation was compared with that of normal mice. On day 3, pretreated TBM mitogen-stimulated spleen cells produced significantly decreased levels of IL-2 and IFN-gamma during 24-h culture. In contrast, IL-10 and granulocyte macrophage colony-stimulating factor productions were significantly enhanced in pretreated TBM cultures, and natural killer (NK) cell activity was also significantly augmented. Splenomegaly was also observed in the pretreated TBM on day 3, and the proliferating cells were identified as asialo GM1+ cells by flow cytometry. Cytotoxic activity of pretreated TBM spleen cells after a 5-day mixed lymphocyte-tumor cell culture did not differ from that of untreated TBM and normal mice on day 3 but was significantly enhanced on days 9 and 15 compared with that observed in normal mice and untreated TBM. Concurrently, the production of IL-2 and of IL-10 recovered and decreased, respectively, and NK activity dropped to normal levels. The effects of IL-18 on cytokine production and NK activity observed on day 3 treated TBM were also reproduced in normal mice. In conclusion, IL-18 seems to enhance the generation of NK activity early after tumor transplantation and simultaneously induces an increase and a decrease in the production of IL-10 and IL-2, respectively. As NK activity subsides to normal levels and IL-10 synthesis decreases, IL-2 synthesis is restored, and cytolytic cell activity is significantly enhanced. These results provide new insight into the immunologically mediated antitumor effects of IL-18.

Formation of a phorbol ester-binding fragment from protein kinase C by proteolytic digestion.

When washed human platelets were disrupted by sonication in the presence of ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, both the catalytic and [3H]phorbol-12,13-dibutyrate (PDBu)-binding activities of protein kinase C were recovered in the soluble fraction and were not separable from each other upon several column chromatographies. Platelet protein kinase C required diacylglycerol, Ca2+, and phospholipid for its activation and showed a molecular weight of about 87,000 as estimated by gel filtration analysis. However, when platelets were first incubated with 2 microM Ca2+-ionophore A23187 for 5 min at 37 degrees C in the medium containing 3 mM CaCl2 and then disrupted under the same conditions, the catalytic and [3H]phorbol-12,13-dibutyrate-binding activities were separately recovered in the soluble and particulate fractions, respectively; moreover, the catalytic activity recovered in the soluble fraction became independent of diacylglycerol, Ca2+, and phospholipid, and showed a molecular weight of about 50,000 as estimated by gel filtration analysis. The kinetic properties of this Mr 50,000 enzyme were similar to those of the catalytic fragment of rat brain protein kinase C described previously. In a cell-free system, digestion with trypsin of protein kinase C highly purified from rat brain caused the generation of a fragment which had no catalytic activity but showed full [3H]phorbol-12,13-dibutyrate-binding activity. The molecular weight of this fragment was estimated to be about 35,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results indicate that protein kinase C consists of at least two functionally different domains, a hydrophobic phorbol ester- or diacylglycerol-binding and hydrophilic catalytic domains.

Localization, isolation and properties of three NADPH-dependent aldehyde reducing enzymes from dog kidney.

Three kinds of NADPH-dependent aldehyde reducing enzymes were present in the dog kidney. Aldose reductase was located in the inner medulla region and aldehyde reductase in all regions of the renal cortex, outer medulla and inner medulla. In addition, a new reductase designated tentatively as high-Km aldose reductase, which was converted into an aldose reductase-like enzyme, was present in the inner medulla region of the kidney. Aldose reductase, aldehyde reductase and high-Km aldose reductase were purified to homogeneity from each region of the dog kidney. The molecular weight of aldose reductase was estimated to be 38,500 by SDS-polyacrylamide gel electrophoresis and the isoelectric point was found to be 5.7 by chromatofocusing. Aldose reductase had activity for aldo-sugars such as D-xylose, D-glucose and D-galactose as substrates and utilized both NADPH and NADH as coenzymes. Sulfate ions resulted in over 2-fold activation of aldose reductase. All aldehyde reductases from the three regions had the same properties. The molecular weights and isoelectric points of aldehyde reductases were 40,000 and 6.1, respectively. The aldehyde reductases were inactive for D-hexose, utilized only NADPH as coenzyme and were not affected by sulfate ions. High-Km aldose reductase had a molecular weight of 38,500 and an isoelectric point of 5.4. It had activity for aldo-sugars, but showed much higher Km and lower kcat/Km values than aldose reductase. Sulfate ions inhibited high-Km aldose reductase. It was converted into an aldose reductase-like enzyme by incubation in phosphate buffer at pH 7.0. The three kinds of enzymes were strongly inhibited by the known aldose reductase inhibitors. However, aldehyde reductase and high-Km aldose reductase were, in general, less susceptible than aldose reductase.

Characterization of aldose reductase and aldehyde reductase from rat testis.

Aldose reductase (alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21) and aldehyde reductase (alcohol:NADP+ oxidoreductase, EC 1.1.1.2) were purified to a homogeneity from rat testis. The molecular weights of aldose reductase and aldehyde reductase were estimated to be 38,000 and 41,000 by SDS-polyacrylamide gel electrophoresis, and the pI values of these enzymes were found to be 5.3 and 6.1 by chromatofocusing, respectively. Aldose reductase had activity for aldo-sugars such as xylose, glucose and galactose, whereas aldehyde reductase was virtually inactive for these aldo-sugars. The Km values of aldose reductase for aldo-sugars were relatively high. When a correction was made for the fraction of aldo-sugar present as the aldehyde form, which is the real substrate of the enzyme, the Km values were much lower. Aldose reductase utilized both NADPH and NADH as coenzyme, whereas aldehyde reductase utilized only NADPH. Aldose reductase was activated significantly by sulfate ion, while aldehyde reductase was little affected. Both enzymes were inhibited strongly by the known aldose reductase inhibitors. However, aldehyde reductase was in general less susceptible to these inhibitors when compared to aldose reductase. Both aldose reductase and aldehyde reductase treated with pyridoxal 5-phosphate have lost the susceptibility to aldose reductase inhibitor, suggesting that in these two enzymes aldose reductase inhibitor interacts with a lysine residue.

Purification and characterization of the recombinant human aldose reductase expressed in baculovirus system.

Large quantities of recombinant human aldose reductase were produced using Spodoptera frugiperda cells and properties of the enzyme were characterized. Direct purification of the recombinant aldose reductase by affinity column chromatography using Matrex gel orange A yielded a single 36 kDa band, similar in size to the purified human muscle aldose reductase, on a sodium dodecyl sulfate-polyacrylamide gel after silver staining. The isoelectric point of the recombinant enzyme was 5.85 which is identical to the human muscle aldose reductase. Following the treatment with an acylamino-acid releasing enzyme, the blocked NH2-terminal amino acid was identified to be acetylalanine. The successive NH2-terminal sequence and that of the COOH-terminal peptide concurred with the expected translated sequence. Kinetic analyses of the recombinant enzyme activity for various substrates and the cofactor, NADPH, demonstrated a good agreement with the previously reported kinetic data on the purified human aldose reductase. A high concentration of (NH4)2SO4 elicited a significant increase in both Km and Kcat for DL-glyceraldehyde as well as D-glucose. Although IC50 values for most of the aldose reductase inhibitors with recombinant enzyme were found to fall within the comparable range of those obtained with nonhuman mammalian enzymes, the IC50 value for epalrestat was more than 10-fold higher in the recombinant enzyme. These results indicate that the recombinant human aldose reductase expressed in the baculovirus system possesses structurally and enzymatically similar properties as those reported for the native human enzyme and should serve as a superior enzyme preparation to nonhuman mammalian enzymes for the screening of the efficacy and potency of newly developed aldose reductase inhibitors.

Inhibition of lipoprotein lipase activity by sphingomyelin: role of membrane surface structure.

We have recently shown that sphingomyelin (SM) strongly inhibits lipoprotein lipase (LPL)-mediated lipolysis in monolayers and emulsion particles. To further evaluate how SM modulates LPL activity on the emulsion surface, the relationship between membrane surface structure and LPL activity was investigated. We measured fluorescence anisotropy of 1-palmitoyl-2-[3-(diphenylhexatrienyl)propionyl]-sn-3-phosphati dylcho line, probing surface acyl chain fluidity, and fluorescence lifetime of N-(5-dimethylaminonaphthalene-1-sulfonyl)dipalmitoylphosphatidylethan olamine in H(2)O and D(2)O buffer, assessing the degree of hydration in the head group region. The results revealed that incorporation of egg SM into triolein-egg phosphatidylcholine emulsions markedly increased acyl chain order and decreased head group hydration of the surface monolayers. In contrast, cholesterol was shown to increase head group hydration despite a strong increase in acyl chain order. The close correlation between the apparent K(m) values of LPL and the degree of head group hydration indicated that LPL interacts with the head group region rather than with the hydrophobic interior of the surface monolayers. However, apparent V(max) did not show a simple correlation with any surface structure, and the finding in which SM had no effect on apparent V(max) of medium-chain triglyceride emulsions suggested that the hydrophobic interaction between acyl chains of SM and triglyceride at the emulsion surface is important for determining the apparent V(max). These results showed conclusively that SM inhibits LPL activity mainly by changing the emulsion surface structure and not by a specific interaction between SM and LPL.