Comparison of risk factors for SARS-CoV-2 infection among healthcare workers during Omicron and Delta dominance periods in Japan.

BACKGROUND: The risk factors for coronavirus disease (COVID-19) among healthcare workers (HCWs) might have changed since the emergence of the highly immune evasive Omicron variant. AIM: To compare the risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among HCWs during the Delta- and Omicron-predominant periods. METHODS: Using data from repeated serosurveys among the staff of a medical research centre in Tokyo, two cohorts were established: Delta period cohort (N = 858) and Omicron period cohort (N = 652). The potential risk factors were assessed using a questionnaire. Acute/current or past SARS-CoV-2 infection was identified by polymerase chain reaction or anti-nucleocapsid antibody tests, respectively. Poisson regression was used to calculate the risk ratio (RR) of infection risk. FINDINGS: The risk of SARS-CoV-2 infection during the early Omicron-predominant period was 3.4-fold higher than during the Delta-predominant period. Neither working in a COVID-19-related department nor having a higher degree of occupational exposure to SARS-CoV-2 was associated with an increased infection risk during both periods. During the Omicron-predominant period, infection risk was higher among those who spent ≥30 min in closed spaces, crowded spaces, and close-contact settings without wearing mask (≥3 times versus never: RR: 6.62; 95% confidence interval: 3.01-14.58), whereas no such association was found during the Delta period. CONCLUSION: Occupational exposure to COVID-19-related work was not associated with the risk of SARS-CoV-2 infection in the Delta or Omicron period, whereas high-risk behaviours were associated with an increased infection risk during the Omicron period.

Silk fibroin nanofibers: a promising ink additive for extrusion three-dimensional bioprinting.

Here, we investigated the usefulness of silk fibroin nanofibers obtained via mechanical grinding of degummed silkworm silk fibers as an additive in bioinks for extrusion three-dimensional (3D) bioprinting of cell-laden constructs. The nanofibers could be sterilized by autoclaving, and addition of the nanofibers improved the shear thinning of polymeric aqueous solutions, independent of electric charge and the content of cross-linkable moieties in the polymers. The addition of nanofibers to bioinks resulted in the fabrication of hydrogel constructs with higher fidelity to blueprints. Mammalian cells in the constructs showed >85% viability independent of the presence of nanofibers. The nanofibers did not affect the morphologies of enclosed cells. These results demonstrate the great potential of silk fibroin nanofibers obtained via mechanical grinding of degummed silkworm silk fibers as an additive in bioinks for extrusion 3D bioprinting.

Correction to: Incidental diagnosis of tuberous sclerosis complex by exome sequencing in three families with subclinical findings.

The published online version contain mistake in the author list. Instead of "A.M.Ilyas" it should have been "M.Ilyas ".

Incidental diagnosis of tuberous sclerosis complex by exome sequencing in three families with subclinical findings.

Tuberous sclerosis complex (TSC) is an autosomal-dominant neurocutaneous disorder characterized by lesions and benign tumors in multiple organ systems including the brain, skin, heart, eyes, kidneys, and lungs. The phenotype is highly variable, although penetrance is reportedly complete. We report the molecular diagnosis of TSC in individuals exhibiting extreme intra-familial variability, including the incidental diagnosis of asymptomatic family members. Exome sequencing was performed in three families, with probands referred for epilepsy, autism, and absent speech (Family 1); epileptic spasms (Family 2); and connective tissue disorders (Family 3.) Pathogenic variants in TSC1 or TSC2 were identified in nine individuals, including relatives with limited or no medical concerns at the time of testing. Of the nine individuals reported here, six had post-diagnosis examinations and three met clinical diagnostic criteria for TSC. One did not meet clinical criteria for a possible or definite diagnosis of TSC, and two had only a possible clinical diagnosis following post-diagnosis workup. These individuals as well as their mothers demonstrated limited features that would not raise concern for TSC in the absence of molecular results. In addition, three individuals exhibited epilepsy with normal brain MRIs, and two without seizures or intellectual disability had MRI findings fulfilling major criteria for TSC highlighting the difficulty providers face when relying on clinical criteria to guide genetic testing. Given the importance of a timely TSC diagnosis for clinical management, such cases demonstrate a potential benefit for clinical criteria to include seizures and an unbiased molecular approach to genetic testing.

Serotonin-induced contractile responses of esophageal smooth muscle in the house musk shrew (Suncus murinus).

BACKGROUND: Serotonin (5-hydroxytryptamine, 5-HT) is a regulatory factor in motility of the gastrointestinal tract including the esophagus. Although we proposed that vagal cholinergic and mast cell-derived non-cholinergic components including serotonin coordinately shorten the esophagus, the precise mechanism of serotonin-induced contractions in the suncus esophagus is still unclear. Therefore, the aims of this study were to determine characteristics of contractile responses induced by serotonin and to identify 5-HT receptor subtypes responsible for regulating motility in the suncus esophagus. METHODS: An isolated segment of the suncus esophagus was placed in an organ bath, and longitudinal or circular mechanical responses were recorded using a force transducer. KEY RESULTS: Serotonin evoked contractile responses of the suncus esophagus in the longitudinal direction but not in the circular direction. Tetrodotoxin did not affect the serotonin-induced contractions. Pretreatment with a non-selective 5-HT receptor antagonist or double application of 5-HT1 and 5-HT2 receptor antagonists blocked the serotonin-induced contractions. 5-HT1 and 5-HT2 receptor agonists, but not a 5-HT3 receptor agonist, evoked contractile responses in the suncus esophagus. CONCLUSION & INFERENCES: The findings suggest that serotonin induces contractile responses of the longitudinal smooth muscle in the muscularis mucosae of the suncus esophagus that are mediated via 5-HT1 and 5-HT2 receptors on muscle cells. The serotonin-induced contractions might contribute to esophageal peristalsis and emetic response.

Phototherapy induced cutaneous eruption in a neonate with transient porphyrinemia.

UNLABELLED: Phototherapy for hyperbilirubinemia has rare complications. We report a case of phototherapy induced eruption in a neonate with transient porphyrinemia. Our patient received phototherapy due to hyperbilirubinemia secondary to erythroblastosis fetalis (hemolytic disease of the newborn). He developed a cutaneous rash in the light-exposed areas of his skin. Erythrocyte and plasma porphyrins were elevated at the time. Phototherapy induced eruption with a transient porphyrinemia is rare. Upon review of the literature, we found only 5 other cases of patients with phototherapy induced rash and elevated porphyrins reported. We compared the five other reported cases to our case, looking at drug exposure, age, and receipt of exchange transfusion. CONCLUSION: While this is an uncommon occurrence, transient porphyrinemia should be considered in neonates with phototherapy induced cutaneous eruption and erythroblastosis fetalis.

Novel ultrasonic bone densitometry based on two longitudinal waves: significant correlation with pQCT measurement values and age-related changes in trabecular bone density, cortical thickness, and elastic modulus of trabecular bone in a normal Japanese population.

UNLABELLED: A reference database for trabecular bone density, cortical thickness, and elastic modulus of trabecular bone for a novel ultrasonic bone densitometry system (LD-100) based on two longitudinal waves (fast and slow) was determined over a wide age range in a normal Japanese population. INTRODUCTION: A novel ultrasonic bone densitometry system (LD-100 system) was applied to create a reference database for trabecular bone density (TBD), cortical thickness (CoTh), and elastic modulus of trabecular bone (EMTb) for this device over a wide age range in a normal Japanese population. METHODS: In a comparative study between LD-100 and peripheral quantitative computed tomography (pQCT) systems, 52 individuals were examined by both systems at the same radius simultaneously. To create a reference database, a total of 2,380 healthy subjects (1,179 men, 1,201 women), ages 18-99 years, were examined using the LD-100 system. RESULTS: Highly significant correlations between the LD-100 and pQCT systems were found in TBD (r = 0.877, p < 0.001) and CoTh (r = 0.723, p < 0.001). For the reference database, peak values of TBD, CoTh, and EMTb were observed at 30-34 years (255.09 mg/cm(3)), 20-24 years (5.23 mm), and 20-24 years (4.09 GPa) in men, and at 25-29 years (209.24 mg/cm(3)), 25-29 years (3.98 mm), and 20-24 years (3.33 GPa) in women, respectively. The TBD fell significantly (p < 0.05) beginning at 55-59 years in both sexes, with a relatively rapid decrease in women. The CoTh showed a significant decrease beginning at 40-44 years in men and 50-54 years in women. The EMTb showed a significant decrease beginning at 40-44 years in men and 55-59 years in women. CONCLUSIONS: The LD-100 system is a useful bone densitometry device and the database of age-related changes in TBD, CoTh, and EMTb established in this study will provide fundamental data for future studies related to bone status.

A prospective study of PHACE syndrome in infantile hemangiomas: demographic features, clinical findings, and complications.

PHACE (OMIM no. 606519) is a neurocutaneous syndrome that refers to the association of large, plaque-like, "segmental" hemangiomas of the face, with one or more of the following anomalies: posterior fossa brain malformations, arterial cerebrovascular anomalies, cardiovascular anomalies, eye anomalies, and ventral developmental defects, specifically sternal defects and/or supraumbilical raphe. The etiology and pathogenesis of PHACE is unknown, and potential risk factors for the syndrome have not been systematically studied. The purpose of this study was thus to determine (1) the incidence of PHACE and associated anomalies among a large cohort of hemangioma patients, (2) whether certain demographic, prenatal or perinatal risk factors predispose infants to this syndrome, and (3) whether the cutaneous distribution of the hemangioma can be correlated to the types of anomalies present. We undertook a prospective, cohort study of 1,096 children with hemangiomas, 25 of whom met criteria for PHACE. These 25 patients represented 20% of infants with segmental facial hemangiomas. Compared to previous reports, our PHACE patients had a higher incidence of cerebrovascular and cardiovascular anomalies. Two developed acute arterial ischemic stroke during infancy, while two with cardiovascular anomalies showed documented evidence of normalization, suggesting that both progressive and regressive vascular phenomena may occur in this syndrome. Correlation to the anatomic location of the hemangioma appears to be helpful in determining which structural abnormalities might be present. A comparison of demographic and perinatal data between our PHACE cases and the hemangioma cohort overall showed no major differences, except a trend for PHACE infants to be of slighter higher gestational age and born to slightly older mothers. Eighty-eight percent were female, a finding which has been noted in multiple other reports. Further research is needed to determine possible etiologies, optimal evaluation, and outcomes.

Spatiotemporal patterns of movement-related fields in stroke patients.

In this study, brain functions in stroke patients and normal subjects were analyzed by observing neuromagnetic fields during button pressing tasks. The measurements included force measurement, visual stimuli presentation and magnetoencephalography (MEG). A 122-channel whole-head MEG system (Neuromag 122) was used. A total of 18 subjects (11 post-stroke and 7 control subjects) participated in the study; adequate MEG data were obtained from 3 of the patients. Equivalent current dipoles for MRFs were estimated with the following parameters: goodness of fit (> 75%), confidence volume (< 6000 mm3), and the duration of dipole (> 10 msec). In addition to the single dipole analysis, Minimum Current Estimates were applied for source estimation since neural activities for stroke patients were observed at the motor cortex of the contralateral side as well as other areas of the brain. Contralateral motor cortex was activated for the normal subjects at 50 ms prior to the force onset, whereas ipsilateral motor cortex was activated for some stroke patients and patients' dipole moments differed not only in their locations but also in their latencies, ranging from -150 to 50 ms to the force onset. The results were in agreement with the findings by PET and fMRI studies; therefore, it was implied that the compensating motor functions were shifted to neighboring areas of the brain due to the recovering motor function after stroke.

Contribution of Thr29 to the thermodynamic stability of goat alpha-lactalbumin as determined by experimental and theoretical approaches.

The Thr29 residue in the hydrophobic core of goat alpha-lactalbumin (alpha-LA) was substituted with Val (Thr29Val) and Ile (Thr29Ile) to investigate the contribution of Thr29 to the thermodynamic stability of the protein. We carried out protein stability measurements, X-ray crystallographic analyses, and free energy calculations based on molecular dynamics simulation. The equilibrium unfolding transitions induced by guanidine hydrochloride demonstrated that the Thr29Val and Thr29Ile mutants were, respectively, 1.9 and 3.2 kcal/mol more stable than the wild-type protein (WT). The overall structures of the mutants were almost identical to that of WT, in spite of the disruption of the hydrogen bonding between the side-chain O-H group of Thr29 and the main-chain C=O group of Glu25. To analyze the stabilization mechanism of the mutants, we performed free energy calculations. The calculated free energy differences were in good agreement with the experimental values. The stabilization of the mutants was mainly caused by solvation loss in the denatured state. Furthermore, the O-H group of Thr29 favorably interacts with the C=O group of Glu25 to form hydrogen bonds and, simultaneously, unfavorably interacts electrostatically with the main-chain C=O group of Thr29. The difference in the free energy profile of the unfolding path between WT and the Thr29Ile mutant is discussed in light of our experimental and theoretical results.

Structural evidence for entropic contribution of salt bridge formation to a protein antigen-antibody interaction: the case of hen lysozyme-HyHEL-10 Fv complex.

A structural and thermodynamic study of the entropic contribution of salt bridge formation to the interaction between hen egg white lysozyme (HEL) and the variable domain fragment (Fv) of anti-HEL antibody, HyHEL-10, was carried out. Three Fv mutants (HD32A, HD96A, and HD32AD96A) were prepared, and the interactions between the mutant Fvs and HEL were investigated. Crystallography revealed that the overall structures of these mutant complexes were almost identical to that of wild-type Fv. Little structural changes were observed in the HD32AD96A mutant-HEL complex, and two water molecules were introduced into the mutation site, indicating that the two water molecules structurally compensated for the complete removal of the salt bridges. This result suggests that the entropic contribution of the salt bridge originates from dehydration. In the singly mutated complexes, one water molecule was also introduced into the mutated site, bridging the antigen-antibody interface. However, a local structural difference was observed in the HD32A Fv-HEL complex, and conformational changes occurred due to changes in the relative orientation of the heavy chain to the light chain upon complexation in HD96A Fv-HEL complexes. The reduced affinity of these single mutants for the antigen originates from the increase in entropy loss, indicating that these structural changes also introduced an increase in entropy loss. These results suggest that salt bridge formation makes an entropic contribution to the protein antigen-antibody interaction through reduction of entropy loss due to dehydration and structural changes.

Folding-unfolding of goat alpha-lactalbumin studied by stopped-flow circular dichroism and molecular dynamics simulations.

Folding reaction of goat alpha-lactalbumin has been studied by stopped-flow circular dichroism and molecular dynamics simulations. The effects of four single mutations and a double mutation on the stability of the protein under a native condition were studied. The mutations were introduced into residues located at a hydrophobic core in the alpha-domain of the molecule. Here we show that an amino acid substitution (T29I) increases the native-state stability of goat alpha-lactalbumin against the guanidine hydrochloride-induced unfolding by 3.5 kcal/mol. Kinetic refolding and unfolding of wild-type and mutant goat alpha-lactalbumin measured by stopped-flow circular dichroism showed that the local structure around the Thr29 side chain was not constructed in the transition state of the folding reaction. To characterize the local structural change around the Thr29 side chain to an atomic level of resolution, we performed high-temperature (at 400 K and 600 K) molecular dynamics simulations and studied the structural change at an initial stage of unfolding observed in the simulation trajectories. The Thr29 portion of the molecule experienced structural disruption accompanied with the loss of inter-residue contacts and with the water molecule penetration in the 400-K simulation as well as in four of the six 600-K simulations. Disruption of the N-terminal portion was also observed and was consistent with the results of kinetic refolding/unfolding experiments shown in our previous report.

Transcriptional regulation of the gene for epidermal growth factor-like peptides in sea urchin embryos.

Exogastrula-inducing peptides (EGIPs), which are epidermal growth factor-related peptides of the sea urchin Anthocidaris crassispina, are substances that elicit abnormal gastrulation (exogastrulation) during embryogenesis of the sea urchin. In the present study we have examined the regulation of the expression of the EGIP precursor gene (EGIP) in sea urchin embryos. Whole mount in situ hybridization showed that EGIP is zygotically expressed afterthe onset of gastrulation in subdomains of the embryonic and larval ectoderm. The expression is confined in early gastrulae to small ectodermal regions adjoining the vegetal plate, which progressively expand to almost the entire ectoderm except the oral hood and postoral tips of the arms in later stages. In adults the expression is restricted to the ovary. Zygotic EGIP expression is sensitive to dissociation of embryonic cells, as well as to disruption of the extracellular matrix (ECM) with 5-cis-hydroxyproline, suggesting requirements for interaction with neighboring cells and/or with the ECM. The expression of reporter genes (chloramphenicol acetyl transferase and green fluorescent protein) under the regulation of the 4.6 kb upstream region of EGIP is temporally and spatially similar to that of the endogenous gene, showing that EGIP expression is regulated at the transcription level during embryogenesis by the cis-elements within the 4.6 kb upstream region.

Erythrocytosis caused by an erythropoietin-producing hepatocellular carcinoma.

A case of erythrocytosis caused by a hepatocellular carcinoma (HCC) that produced erythropoietin (Epo) is described. A 64-year-old man, with a huge HCC tumor in the right lobe of the liver, showed a high concentration of hemoglobin and increased levels of serum Epo, alpha-fetoprotein (AFP), and protein induced by vitamin K absence II (PIVKA-II). Right lobectomy of the liver was performed. Histological findings of the specimen showed a moderately differentiated HCC. The existence of Epo was confirmed immunohistochemically only in the tumor tissue and not in the normal liver tissue. Erythrocytosis disappeared and the serum levels of Epo, AFP, and PIVKA-II returned to the normal range after the operation. Within 2 months after the operation, recurrent tumors appeared in the remnant liver, and the patient died 13 months after the operation.

Successful treatment of a hepatic abscess that formed secondary to fish bone penetration by percutaneous transhepatic removal of the foreign body: report of a case.

We describe herein the case of a hepatic abscess that developed secondary to fish bone penetration which was successfully treated without laparotomy. A 61-year-old man was admitted to our hospital with a high fever that had persisted for 2 weeks in spite of medication. Abdominal ultrasonography (AUS) and computed tomography (CT) of the abdomen revealed a hepatic abscess with a linear calcified foreign body and gas. Percutaneous abscess drainage was performed under ultrasonographic guidance. After drainage, the patient became afebrile, and AUS and CT findings demonstrated that the abscess cavity had decreased in size, but still contained the foreign body. Under ultrasonographic guidance and fluoroscopy, we inserted endoscopic forceps into the sinus tract and succeeded in removing the foreign body from the liver. It was found to be a fish bone that was 2.8 cm long and 0.3 cm wide.

Serum endothelin-1 and hepatocyte growth factor levels in patients with obstructive jaundice.

BACKGROUND/AIMS: Endothelin-1, a potent vasoconstrictive peptide, is known to modulate changes in local circulation. Additionally, hepatocyte growth factor, a potent mitogen for hepatocytes, is increased in various liver diseases. The present study examined changes in serum endothelin-1 and hepatocyte growth factor levels in patients with obstructive jaundice before and after percutaneous transhepatic cholangio drainage. METHODOLOGY: Endothelin-1 and hepatocyte growth factor levels were measured by enzyme-linked immunosorbent assay using sera from 16 patients with obstructive jaundice before and after percutaneous transhepatic cholangio drainage. RESULTS: Serum endothelin-1 levels decreased rapidly in the good bilirubin decrease group after biliary drainage. Endothelin-1 levels decreased 1 week after drainage but then increased gradually in the worse bilirubin decrease group. Serum hepatocyte growth factor levels decreased gradually after biliary drainage, and were higher in the worse bilirubin decrease group than in the good bilirubin decrease group throughout the study. CONCLUSIONS: These results suggest that endothelin-1 may be associated with the microcirculatory disturbance in obstructive jaundice and prolonged cholestasis. Measurement of hepatocyte growth factor levels in patients with obstructive jaundice before percutaneous transhepatic cholangio drainage may be an early clinical predictor of the subsequent rate of decrease of the serum bilirubin concentration.

Portal serum human hepatocyte growth factor levels after partial hepatectomy.

BACKGROUND/AIMS: We investigated whether or not hepatocyte growth factor increases in portal serum via an endocrine mode after partial hepatectomy in humans. METHODOLOGY: Portal blood was sampled through a catheter inserted through the umbilical vein to the portal trunk during surgery in 17 patients. Serum human hepatocyte growth factor levels were determined by enzyme-linked immunosorbent assay. RESULTS: Human hepatocyte growth factor levels were higher in portal than in peripheral serum throughout the study. Portal and peripheral serum human hepatocyte growth factor levels without complications increased rapidly and reached a maximum level 1 day after partial hepatectomy. The maximal level of portal and peripheral serum human hepatocyte growth factor was 1.20 and 1.00 ng/ml, respectively. In the case of hepatic failure after partial hepatectomy, portal and peripheral serum human hepatocyte growth factor levels markedly increased and reached 9.31 ng/ml and 6.78 ng/ml 2 days before death, respectively. CONCLUSIONS: These results suggest that hepatocyte growth factor increases in portal serum via an endocrine mode after partial hepatectomy in humans. Furthermore, measurement of the portal and peripheral serum human hepatocyte growth factor levels may be useful for the clinical evaluation of patients with post-operative hepatic failure.

Effect of the extra n-terminal methionine residue on the stability and folding of recombinant alpha-lactalbumin expressed in Escherichia coli.

The structure, stability, and unfolding-refolding kinetics of Escherichia coli-expressed recombinant goat alpha-lactalbumin were studied by circular dichroism spectroscopy, X-ray crystallography, and stopped-flow measurements, and the results were compared with those of the authentic protein prepared from goat milk. The electric properties of the two proteins were also studied by gel electrophoresis and ion-exchange chromatography. Although the overall structures of the authentic and recombinant proteins are the same, the extra methionine residue at the N terminus of the recombinant protein remarkably affects the native-state stability and the electric properties. The native state of the recombinant protein was 3.5 kcal/mol less stable than the authentic protein, and the recombinant protein was more negatively charged than the authentic one. The recombinant protein unfolded 5.7 times faster than the authentic one, although there were no significant differences in the refolding rates of the two proteins. The destabilization of the recombinant protein can be fully interpreted in terms of the increased unfolding rate of the protein, indicating that the N-terminal region remains unorganized in the transition state of refolding, and hence is not involved in the folding initiation site of the protein. A comparison of the X-ray structures of recombinant alpha-lactalbumin determined here with that of the authentic protein shows that the structural differences between the proteins are confined to the N-terminal region. Theoretical considerations for the differences in the conformational and solvation free energies between the proteins show that the destabilization of the recombinant protein is primarily due to excess conformational entropy of the N-terminal methionine residue in the unfolded state, and also due to less exposure of hydrophobic surface on unfolding. The results suggest that when the N-terminal region of a protein has a rigid structure, expression of the protein by E. coli, which adds the extra methionine residue, destabilizes the native state through a conformational entropy effect. It also shows that differences in the electrostatic interactions of the N-terminal amino group with the side-chain atoms of Thr38, Asp37, and Asp83 bring about a difference in the pKa value of the N-terminal amino group between the proteins, resulting in a greater negative net charge of the recombinant protein at neutral pH.

Changes in erythrocyte deformability after liver resection for hepatocellular carcinoma associated with chronic liver disease.

Erythrocyte deformability is an important factor in the microcirculation. The deformability in patients with chronic liver disease is less than normal. We studied changes in erythrocyte deformability in 32 patients undergoing liver resection for hepatocellular carcinoma with underlying chronic liver disease to investigate whether the measurement of deformability gives information useful for postoperative management. We measured erythrocyte deformability as erythrocyte transit time (ETT) before and after resection, as well as the erythrocyte adenosine triphosphate level, mean corpuscular volume, mean corpuscular hemoglobin concentration, and indices of liver function. The 15-minute indocyanine green retention rate (ICGR15) was measured before resection. Correlations between the change in deformability and these values were evaluated, as was correlation with the scale of the operation and with the occurrence of postoperative complications. Mean ETT was higher in the patients before resection than in healthy volunteers. ETT was correlated with serum high density lipoprotein-cholesterol (p < 0.05). The incidence of postoperative complications was higher (p = 0.001) in the patients (group A) with ETT increased during the first 3 postoperative days by >/=1 SD of the mean of the preoperative value than in patients (group B) with less change. Of the 12 patients whose ICGR15 value was >/=20%, all 9 patients in group A had postoperative complications. The increase in ETT (decrease in erythrocyte deformability) is associated with the development of postoperative complications. The measurement of erythrocyte deformability gives information useful for postoperative management, and special monitoring for postoperative complications is necessary in patients with the increase soon after liver resection.