Temporal dynamics in viral shedding and transmissibility of COVID-19

We report temporal patterns of viral shedding in 94 patients with laboratory-confirmed COVID-19 and modeled COVID-19 infectiousness profiles from a separate sample of 77 infector-infectee transmission pairs. We observed the highest viral load in throat swabs at the time of symptom onset, and inferred that infectiousness peaked on or before symptom onset. We estimated that 44% (95% confidence interval, 25-69%) of secondary cases were infected during the index cases' presymptomatic stage, in settings with substantial household clustering, active case finding and quarantine outside the home. Disease control measures should be adjusted to account for probable substantial presymptomatic transmission.

Molecular cloning and tissue distribution of a Schistosoma japonicum gene encoding AMY-1

It is well known that the mammalian associate of Myc-1 (AMY-1) plays a significant role in spermatogenesis or cellular differentiation. A full-length complementary DNA (cDNA) encoding AMY-1 of Schistosoma japonicum (SjAMY-1) was identified and isolated from a cDNA library. The gene contained an open reading frame of 315 nucleotides, encoding 105 amino acids. Sequence analysis showed that SjAMY-1 shares 65.7% homology with Homo sapiens AMY-1 amino acids and contains a conserved domain from the AMY-1 family. In this study, we cloned and expressed a recombinant SjAMY-1 (rSjAMY-1) with a molecular size of 14 kDa. The native SjAMY-1 in soluble worm antigen was identified by anti-rSjAMY-1 sera in the Western blot analysis, which demonstrated the presence of this protein in the parasite. Immunofluorescence studies indicated a localization of SjAMY-1 in various tissues and organs including the tegument and subtegumental muscles in adult worms, the ventral sucker in cercariae and the internal structures of eggs. Given the key roles of mammalian AMY-1 in cell proliferation and differentiation, the characterization of SjAMY-1 may allow for a better understanding of the development of S. japonicum.

Fine structure of the human retina defined by confocal microscopic immunohistochemistry

INTRODUCTION

Research in to the pathophysiology of the complex layers of retinal and sub-retinal cells is hampered by inadequate recognition of particular cells and tissues. A comprehensive panel of antibodies recognising retinal tissues is lacking. Our purpose was to determine the value of a panel of antibodies labelling various cells in the human retina.

METHOD

Five groups of antibodies labelled frozen sections of retinas: (1) protein kinase C-α, Glutamine Synthetase (GS) and ionized calcium-binding adapter molecule 1 (Iba1); (2) Parvalbumin, Calretinin and glial fibrillary acidic protein (GFAP); (3) Thy1, GS and Iba1; (4) Rhodopsin, GS and Iba1; and (5) Brn3a, Rhodopsin and protein kinase C-α. The distribution of these antigens were determined by confocal microscopy and calculated grey value of each antibody in each layer of the retina by Image J.

RESULTS

Different antibodies determined certain retinal layers. Thy 1 is a good determinant of the ganglion cell layer, whilst GS is present in all layers except the photoreceptor layer. Brn3a is specific for the ganglion cell layer whilst parvalbumin marks the ganglion cell layer and the outer plexiform layer. Rhodopsin strongly marks the photoreceptor layer, but this is also marked weakly by GFAP.

CONCLUSION

The multiple labelling of human retinal cells brings further understanding of the biological characteristics and functions of these cells, and provides a theoretical basis for their possible role in diseases. In the growing field of human retina research, our data may provide a point of reference for future studies of the human retina.

Persistent chronic immune activation in HIV/HBV-coinfected patients after antiretroviral therapy

We studied the characteristics of immune activation and investigated the underlying mechanisms in patients with human immunodeficiency virus-1/hepatitis B virus (HIV/HBV) coinfection after receiving HBV-active antiretroviral therapy. Forty patients with HIV/HBV coinfection, 38 patients with HIV monoinfection and 20 healthy controls were enrolled. CD4⁺ count, HIV load, HBV load, markers of immune activation and regulatory T-cell (Treg cell) frequency were assessed and compared between HIV-monoinfected and HIV/HBV-coinfected patients at week 0 (baseline), 12, 24, 36 and 48 after the onset of HBV-active antiretroviral therapy. Before antiretroviral therapy, frequencies of CD4⁺ HLADR⁺ CD38⁺ , CD8⁺ HLADR⁺ CD38⁺ , and Treg cells, and sCD163 and sCD14 levels were significantly higher in both HIV/HBV-coinfected patients and HIV-monoinfected patients, compared with healthy controls. Frequencies of CD4⁺ HLADR⁺ CD38⁺ and CD8⁺ HLADR⁺ CD38⁺ cells decreased following antiretroviral therapy in both groups. sCD163 levels did not change significantly in both groups and no significant difference was observed between the two groups at each time point during the 48-week antiretroviral therapy. In week 24, levels of sCD14 and frequencies of Treg cells appeared significantly higher in HIV/HBV-coinfected patients than in HIV-monoinfected patients, in which sCD14 levels and Treg cell frequencies declined to those in healthy controls. The Treg cell frequency was consistent with that of sCD14 levels in HIV/HBV-coinfected patients. Coinfection with HBV significantly increases sCD14 levels in HIV-infected patients during HBV-active antiretroviral therapy, which may potentially contribute to liver inflammation.

Prenatal betamethasone does not affect glutamatergic or GABAergic neurogenesis in preterm newborns

Prenatal glucocorticoids (GCs) are routinely used for pregnant women in preterm labor to prevent respiratory distress syndrome and intraventricular hemorrhage in premature infants. However, the effect of antenatal GCs on neurogenesis in preterm neonates remains elusive. Herein, we hypothesized that prenatal GCs might suppress both glutamatergic and GABAergic neurogenesis in preterm rabbits and that this treatment would induce distinct changes in the expression of transcription factors regulating these developmental events. To test our hypotheses, we treated pregnant rabbits with betamethasone at E27 and E28, delivered the pups at E29 (term=32d), and assessed neurogenesis at birth and postnatal day 3. We quantified radial glia (Sox2(+)) and intermediate progenitor cells (Tbr2(+)) in the dorsal cortical subventricular zone to assess glutamatergic neuronal progenitors, and counted Nkx2.1(+) and Dlx2(+) cells in the ganglionic eminence to evaluate GABAergic neurogenesis. In addition, we assayed transcription factors regulating neurogenesis. We found that prenatal GCs did not affect the densities of radial glia and intermediate progenitors of glutamatergic or GABAergic neurons. The number of GABA(+) interneurons in the ganglionic eminence was similar between the prenatal GC-treated pups compared to untreated controls. Moreover, the mRNA expression of transcription factors, including Pax6, Ngn1/2, Emx1/2, Insm1, Dlx1, Nkx2.1, and Gsh2, were comparable between the two groups. However, there was a transient elevation in Mash1 protein in betamethasone-treated pups relative to controls at birth. These data suggest that prenatal GC treatment does not significantly impact the balance of glutamatergic and GABAergic neurogenesis in premature infants.

Association between Sedentary Time and 6-Year All-Cause Mortality in Adults: The Rural Chinese Cohort Study

OBJECTIVES

This study aims to prospectively explore the association between sedentary time and the risk of all-cause mortality in adults based on a cohort from rural areas of China.

METHODS

The study population included 20,194 adults at baseline (2007-2008) who participated in the Rural Chinese Cohort Study. Cox's proportional hazard regression model was used to analyze the hazard ratios (HRs) and 95% confidence intervals (CIs) of sedentary time and all-cause mortality, and a restricted cubic spline was used to model the dose-response relation. We also carried out a series of sensitivity analyses to verify the robustness of our main results.

RESULTS

The median follow-up duration was 6 years, with a total of 17,265 participants (response rate 85.5%) followed up, and 1,106 deaths observed. Data for 17,048 participants were analyzed, with the mean age of participants being 52.00. Compared with sedentary time <4 h/day group, the risk of all-cause mortality was significantly increased in the 8-11 h/day (HR=1.27, 95%CI:1.03-1.56) and ≥11 h/day groups (HR=1.48, 95%CI:1.20-1.84). With increases in sedentary time, the risk of all-cause mortality increased gradually (Ptrend <0.001). For each 1 h/day increase in sedentary time, the risk of all-cause mortality increased by 3% (HR=1.03, 95%CI: 1.01-1.05). Sensitivity analyses showed our main results were consistent.

CONCLUSIONS

Prolonged sedentary time increases the risk of all-cause mortality in the adult rural Chinese population. Reducing sedentary time may have important implications for reducing mortality risk.

Stage and tissue specific differences in SjBMI1, a Polycomb protein in Schistosoma japonicum

Polycomb group protein BMI1, plays a central role in the stem cell pluripotency and development in metazoans. A gene encoding BMI1 homologue in the Schistosoma japonicum (SjBMI1) was cloned and identified. The deduced amino acid sequence shows high identity to the homologues from Schistosoma mansoni and Homo sapiens. Quantitative real time polymerase chain reaction (RT-PCR) and Western blot analysis revealed that the SjBMI1 is highly expressed in adult worms and eggs, not in cercariae. By immunofluorescent studies, SjBMI1 was localized to testes, ovaries of mixed sex infected adult worms, but not of single sex infected adult worms. The study reveals the SjBMI1 expression profile in developmental stages and localization characteristic and provides a clue that it may be associated with reproductive development of S. japonicum.

Impact of shift work on dementia: a systematic review and dose-response meta-analysis

OBJECTIVES

Although shift work has been reported as having a link to dementia, evidence remains inconsistent, and a comprehensive dose-response meta-analysis of the association is still lacking. We therefore conducted this meta-analysis to explore the association between shift work and the risk of dementia.

STUDY DESIGN

Systematic review and dose-response meta-analysis.

METHODS

PubMed, Embase, and Web of Science databases were systematically searched. Fixed or random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (95% CIs). Generalized least squares regression was used to estimate dose-response associations, and restricted cubic splines were used to examine possible linear or non-linear associations.

RESULTS

Five articles (10 studies) with 72,999 participants and 23,067 cases were eventually included in the meta-analysis. The summary RRs and 95% CIs of dementia risk with shift work and night shift work versus daytime work were 1.13 (95% CI: 1.05-1.21, I2 = 46.70%) and 1.13 (95% CI: 1.03-1.24, I2 = 9.20%), respectively. The risk of dementia increased by 1% (RR = 1.01, 95% CI: 1.01-1.02, I2 = 41.3%) with each 1-year increase in the duration of shift work. We found a non-linear dose-response association between the duration of shift work and the risk of dementia (Pnon-linearity = 0.006). Though the shape of the curve was steeper with the duration of shift work <7 years, the increase was more gradual after 7 years.

CONCLUSION

Our findings suggest that shift work may be a risk factor for future dementia and that controlling the length of shift work is a feasible measure that may contribute to prevent dementia.

Abstract 034: A Healthy Lifestyle Score Including Sleep Duration And Risk Of Cardiovascular Disease

Objectives: The aim of this study was to evaluate the relationship between a lifestyle score including sleep duration and CVD risk, and to estimate whether adding sleep duration into a traditional lifestyle score improved CVD risk prediction.

Methods: A prospective analysis was conducted among 67250 women in the Nurses’ Health Study and 29279 men in the Health Professionals Follow-up Study who were followed from 1986 to 2016. The traditional lifestyle score was defined as not smoking, normal BMI(18.5-24.9 kg/m 2 ), ≥30 min/d of moderate physical activity, higher diet quality (top 40% of AHEI), moderate alcohol intake (women:5-15g/day; men:5-30g/day). Low-risk sleep duration, defined as sleeping ≥6 to <8 hours/day, was included as an additional component. Cox proportion hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD, CHD, and stroke. We used the likelihood ratio test and C-statistics to compare the predictive value of the two scores.

Results: A total of 11826 incident CVD cases were documented. In multivariable-adjusted models, each low-risk factor was independently and significantly associated with lower risk of CVD, CHD, and stroke. The multivariable-adjusted HRs (95% CIs) comparing six with zero low-risk factors in the healthy lifestyle score were 0.17(0.12, 0.23) for CVD, 0.15(0.10, 0.22) for CHD, and 0.19(0.12, 0.33) for stroke. Approximately 67% of CVD and CHD cases, and 62% stroke cases were attributable to poor adherence to a healthy lifestyle. P- value for likelihood ratio test comparing nested models including the traditional lifestyle score vs traditional lifestyle score plus sleep duration was <0.001. Adding sleep duration to the traditional score prediction model increased the C-statistics from 0.63 (95% CI: 0.62, 0.63) to 0.64 (95% CI: 0.63, 0.65)( P <0.001).

Conclusions: Incorporating sleep duration into traditional lifestyle scores improves prediction of CVD risk and warrants consideration for inclusion in lifestyle recommendations.

Theophylline effects on normal uveal melanocytes in culture: an ultrastructural study

Theophylline enhances maturation and differentiation of uveal melanocytes. By electron microscopy, we showed that theophylline changes small, dendritic melanocytes into large, platelike cells; it also enhances DOPA reaction as evidenced by increased deposition of DOPA reaction products in dilated cisternae and vesicles around the Golgi region. The effect is partially reversible in choroidal melanocytes but irreversible in iridial cells. It appears that theophylline, in addition to inducing tyrosine activity, accelerates the maturation and/or aging that normally occurs in cultured melanocytes when incubation is prolonged.

Reduction of anti-HIV antibody responses in subjects receiving antiretroviral therapy during chronic HIV-1 infection

OBJECTIVE

Antiretroviral therapy (ART) can lead to a decline or absence of anti-HIV antibodies in HIV-infected children or acutely HIV-infected (AHI) subjects. However, the characteristics of anti-HIV antibody response in the subjects who are treated during chronic HIV-1 infection (CHI) have not yet been fully investigated.

METHODS

Different anti-HIV antibodies were longitudinally quantified and analyzed in 81 CHI adults under ART. The factors associated with antibody decline were evaluated by binary logistic regression analysis.

RESULTS

ART led to 36.0% (27/75) and 52.1% (38/73) of the patients whose anti-HIV levels reduced by more than 75% of the baseline levels at 12 and 24 months post-ART, respectively. The reduction of anti-HIV antibodies correlated with the decline of HIV-1 viral load with correlation coefficients in the range 0.556-0.848 or R2 value of 0.576-0.873 (P < 0.001). However, no negative detection of anti-HIV antibody was observed at 24 months post-ART. The time from HIV-1 diagnosis to ART initiation and the baseline anti-HIV levels were the key factors associated with quick decline of anti-HIV antibodies during ART.

CONCLUSIONS

ART-induced kinetics of anti-HIV antibody response was different among the subjects with AHI and CHI. Misdiagnosis of HIV-1 infection may not be a serious issue in HIV-1 chronically infected subjects under ART, and could ideally be avoided by using multiple HIV-1 antigens for screening purposes.

Microspectrofluorometric analysis of surface antigens of murine melanoma and hamster peritoneal cell hybrids: comparisons of species antigenicity, chromosome number, and tumorigenicity

Somatic cell hybrids from viral fusions of murine melanoma (PAZG) X Chinese hamster peritoneal cells (CH) were compared with respect to surface antigenicity, karyotype and tumorigenicity. One line, F57-(9), which arose from the hybridization of two CH cells and one PAZG cell, had slight (6%) CH chromosome loss but 80%PAZG chromosome loss after 10 months in culture. These cells expressed CH antigens strongly and PAZG antigens weakly. In comparison, another hybrid, F57-(7), formed from one CH and one PAZG cell, lost 20% of its chromosomes after 10 months in vitro. These cells had a stronger expression of PAZG antigens and weaker expression of CH antigens than F57-(9). These findings indicate a direct relationship between chromosome number and antigenicity; tumorigenicity, however, does not appear to depend on the chromosome numbers of the parental cells.

A rare case of association between Budd-Chiari syndrome and sea-blue histiocytosis

Budd-Chiari syndrome (BCS) is a rare disease characterized by obstruction of hepatic venous outflow tract with diversified etiologies. Sea-blue histiocytosis (SBH) is a kind of storage diseases defined by the deposition of abundant sea-blue histiocytes in various organs and can lead to hepatosplenomegaly, cirrhosis, or even liver failure. The association between BCS and SBH has never been reported before. Here, we report a patient with BCS presenting with hepatosplenomegaly, portal hypertension, and pancytopenia who was later confirmed to also have SBH.

Geographic difference in safety and efficacy of systemic chemotherapy for advanced gastric or gastroesophageal carcinoma: A meta-regression approach

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Background: The standard of chemotherapy regimens for patients with advanced or metastatic gastric cancer vary and the clinical outcome were heterogeneous in Asian vs. non-Asian countries.

Methods: Treatment group-based meta-analysis and meta-regression were performed to analyze results of randomized trials published since 2005 for advanced or metastatic gastric cancer patients who received systemic chemotherapy as first-line treatment. Data were extracted and synthesized according to the Cochrane guidelines.

Results: Among the 24 trials (totally 6,502 patients) eligible for meta-analysis, Asian trials reported lower percentage of gastroesophageal junctional carcinoma, higher percentage of diffuse-type histology, and more frequent use of second-line chemotherapy. Meta- regression analyses indicate that, after controlling other patient or treatment factors, Asian trials are associated with 22.7% (95% CI: 19.5-26.0%, p<0.0001) lower incidence of grade 3-4 neutropenia and 3.5% (95% CI: 2.1-4.9%, p<0.0001) lower incidence of grade 3-4 diarrhea, which were the most commonly reported toxicity. The use of high-dose infusional 5-fluorouracil, compared with other fuoropyrimidine regimens, reported 16.6% lower incidence of neutropenia (95% CI: 13.3-19.9%, p<0.0001). Higher percentage of patients with gastroesophageal junction carcinoma and patients with 2 or more organs involved predicted poor progression-free survival. The use of second-line chemotherapy predicts better 1-year overall survival, which will increase by 9% (95% CI: 8-10%) for every 10 percent increase in patients who received second-line chemotherapy.

Conclusions: Geographic region (Asian vs. non-Asian) plays an important role in the heterogeneity of gastric cancer clinical trials and is an independent predictor of safety in systemic therapy for gastric cancer.

No significant financial relationships to disclose.

High titers of neutralizing antibodies in the blood fail to eliminate SARS-CoV-2 viral RNA in the upper respiratory tract

Retest-positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA, as a unique phenomenon among discharged individuals, has been demonstrated to be safe in the community. Still, the underlying mechanism of viral lingering is less investigated. In this study, first, we find that the frequency of viral RNA-positive retesting differs among variants. Higher ratios of viral RNA-positive retest were more frequently observed among Delta (61.41%, 514 of 837 cases) and Omicron (39.53%, 119 of 301 cases) infections than among ancestral viral infection (7.27%, 21 of 289 cases). Second, the tissues where viral RNA reoccurred were altered. Delta RNA reoccurred mainly in the upper respiratory tract (90%), but ancestral virus RNA reoccurred mainly in the gastrointestinal tract (71%). Third, vaccination did not reduce the frequency of viral RNA-positive retests, despite high concentrations of viral-specific antibodies in the blood. Finally, 37 of 55 (67.27%) Delta-infected patients receiving neutralizing antibody therapy become viral RNA retest positive when high concentrations of neutralizing antibodies still patrol in the blood. Altogether, our findings suggest that the presentence of high titers of neutralizing antibodies in the blood is incompetent in clearing residual viral RNA in the upper respiratory tract.