SARS-CoV-2-specific antibodies and neutralization capacity in breast milk following infection vs vaccination.

Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies have been found in breast milk following both natural SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19) vaccination. This was a prospective study to evaluate the temporal changes in amount and neutralization capacity of anti-SARS-CoV-2 antibodies in breast milk stimulated by natural infection and by vaccination. Serial breast milk samples were collected from postnatal women who were recruited through convenience sampling. We found a rapid increase in neutralizing SARS-CoV-2-specific antibodies in breast milk from both study groups. Amongst the infection group, the median immunoglobulin A (IgA) level was 16.99 (range, 0-86.56) ng/mL and median binding capacity was 33.65% (range, 0-67.65%), while in the vaccination group these were 30.80 (range, 0-77.40) ng/mL and 23.80% (range, 0-42.80%), respectively. In both groups, both binding capacity and IgA levels decreased progressively over time after peaking. Neutralizing activity had become undetectable by about 150 days after the first dose of the vaccine, but a vaccine booster dose restored secretion of neutralizing IgA, albeit with different levels of response in different individuals. This highlights the importance of the vaccine booster dose in sustaining neutralizing antibody levels in breast milk, which may potentially provide protection for very young children, who cannot receive the COVID-19 vaccine. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Relationship between viral load, infection-to-delivery interval and mother-to-child transfer of anti-SARS-CoV-2 antibodies.

OBJECTIVE: To investigate the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and infection-to-delivery interval with maternal and cord serum concentrations of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies and transplacental transfer ratio in pregnant women with active or recovered SARS-CoV-2 infection. METHODS: This was a prospective case series of consecutive pregnant women with laboratory-confirmed SARS-CoV-2 infection between 27 March 2020 and 24 January 2021. We collected information regarding deep throat saliva or nasopharyngeal swab (NPS) reverse transcription polymerase chain reaction (RT-PCR) test results, serial cycle threshold (Ct) values at and after diagnosis, demographic, clinical and outcome data, and neonatal NPS RT-PCR results. Qualitative and quantitative analysis of IgG and immunoglobulin M (IgM) antibodies against SARS-CoV-2 was performed in maternal and cord blood serum samples obtained at delivery. Correlation of maternal Ct values, infection-to-delivery interval, infection duration and viral load area under the curve (AUC) with gestational age (GA) at diagnosis, maternal and cord serum IgG concentrations and transplacental transfer ratio of IgG were evaluated using Pearson's correlation. RESULTS: Twenty pregnant women who consented to participate and who had delivered their babies by 31 January 2021 were included in the study, comprising 14 who had recovered from coronavirus disease 2019 (COVID-19) and six with active infection at delivery. The median GA at clinical manifestation was 32.7 (range, 11.9-39.4) weeks. The median infection-to-delivery interval and infection duration were 41.5 (range, 2-187) days and 10.0 (range, 1-48) days, respectively. The median GA at delivery was 39.1 (range, 32.4-40.7) weeks and the median seroconversion interval was 14 (range, 1-19) days. Of 13 neonates born to seropositive mothers with recovered infection at delivery, 12 tested positive for anti-SARS-CoV-2 IgG. All neonatal NPS samples were negative for SARS-CoV-2 and all cord sera tested negative for IgM. The median transplacental transfer ratio of IgG was 1.3 (interquartile range, 0.9-1.6). There was a negative correlation between infection-to-delivery interval and anti-SARS-CoV-2 IgG concentrations in maternal (r = -0.6693, P = 0.0087) and cord (r = -0.6554, P = 0.0068) serum and a positive correlation between IgG concentration in maternal serum and viral load AUC (r = 0.5109, P = 0.0310). A negative correlation was observed between transfer ratio and viral load AUC (r = -0.4757, P = 0.0409). CONCLUSIONS: In pregnant women who have recovered from COVID-19, anti-SARS-CoV-2 IgG concentrations at delivery increased with increasing viral load during infection and decreased with increasing infection-to-delivery interval. The median transplacental transfer ratio of IgG was 1.3 and it decreased with increasing viral load during infection. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Survey for the presence of BK, JC, KI, WU and Merkel cell polyomaviruses in human brain tissues.

BACKGROUND: Recently three previously unknown polyomaviruses (KI, WU and Merkel cell polyomaviruses) have been identified from human specimens. The spectrum of clinical manifestations and their tissue tropism are currently unknown. Since a member of this virus family, JC virus, is well-known for its capacity to establish latency in human brain tissue where reactivation in immunocompromised individuals can result in fatal progressive multifocal leukoencephalopathy, we sought to examine for the presence of all the five known human polyomaviruses in a series of human brain tissues. OBJECTIVES: To investigate the possibility of neuropersistence of the newly identified human polyomaviruses. STUDY DESIGN: Autopsy brain tissues were collected from 10 different brain regions of 30 individuals who died from diseases unrelated to viral infections. Nested PCR was used to assess the presence or absence of viral DNA. RESULTS: Ten samples collected from five individuals were found to harbour JCV DNA. In contrast, none of the 300 brain tissues examined showed positive results for BK, KI, WU or Merkel cell polyomavirus. CONCLUSION: The newly identified KI, WU and Merkel cell polyomaviruses either do not, or have a much lower neuropersistent potential compared to JCV.

Effects of sphingosine-1-phosphate and lysophosphatidic acid on human osteoblastic cells.

The effects of the lysophospholipids, sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) were studied in human primary osteoblastic cells and the human osteosarcomal cell lines, G292 and MG-63. The studies focused on the role of the Gi protein in the regulation of S1P and LPA-induced proliferation, the effects of the phospholipids on alkaline phosphatase, an early marker of osteoblastic cell proliferation, and the presence of edg receptors. Proliferation was assessed by 3H-thymidine incorporation. Short-term incubation with S1P or LPA induced increases in proliferation that were attenuated in the presence of the Gi inhibitor, pertussis toxin. Alkaline phosphatase activity was measured with a spectrophotometric assay. Biphasic effects of S1P and LPA were observed with the nature of the response dependent upon the cell type, concentration of test agent and the time period of incubation. RTPCR studies revealed that edg-1,2,4,5 receptors are present in the primary normal osteoblastic cells, the MG63 and G292 cells. Only the G292 cells expressed the edg-3 receptor to any significant extent.

Relation of dental composite formulations to their degradation and the release of hydrolyzed polymeric-resin-derived products.

This article reviews the principal modes of dental composite material degradation and relates them to the specific components of the composites themselves. Particular emphasis is placed on the selection of the monomer resins, the filler content, and the degree of monomer conversion after the clinical materials are cured. Loss of mechanical function and leaching of components from the composites are briefly described, while a more detailed description is provided of studies that have considered the chemical breakdown of materials by agents that are present in the oral cavity, or model the latter. Specific attention will be given to the hydrolysis process of monomer and composite components, i.e., the scission of condensation-type bonds (esters, ethers, amides, etc.) that make up the monomer resins, following reaction of the resins with water and salivary enzymes. A synopsis of enzyme types and their sources is outlined, along with a description of the work that supports their ability to attack and degrade specific types of monomer systems. The methods for the study of biodegradation effects are compared in terms of sensitivity and the information that they provide. The impact of biodegradation on the ultimate biocompatibility of current materials is discussed from the perspective of what is known to date and what remains to be studied. The findings of the past decade clearly indicate that there are many reasons to probe the issue of biochemical stability of composite resins in the oral cavity. The challenge will now be to have both industry and government agencies take a pro-active approach to fund research in this area, with the expectation that these studies will lead to a more concise definition of biocompatibility issues related to dental composites. In addition, the acquired information from such studies will generate the development of alternate polymeric chemistries and composite formulations that will require further investigation for use as the next generation of restorative materials with enhanced biostability.