High Dilutions of a Drug of Covid-19 Origin Show Difference in Ranks

High dilutions (HDs) of drugs, used in Homeopathy, are prepared in aqueous EtOH (ethanol) through serial dilution accompanying mechanical agitation or succussion, and are called potencies. The potencies from the rank 12 onwards are too dilute to contain any original drug molecules. Do the potency ranks show any difference from each other? Do serial dilution and succussion contribute to the difference in potency ranks? This study aims to address these two questions. The throat swab of a Covid-19 patient was preserved and diluted with aqueous EtOH 90% to prepare the mother tincture (MT) and five different potencies of Covid named Covidinum. These potencies and their solvent media were analysed by electronic and vibrational spectroscopy. Charge transfer (CT) and proton transfer interactions occur during preparation of the potencies. The FT-IR spectra of all the test samples after normalization show difference from each other with respect to O-H stretching and bending (v2) bands. Serial dilution and succussion contribute to the observed difference in ranks and CT interactions.

Development of a Serial Dilution Technique for Obtaining Monoclonal Cell Populations

Single cell-based techniques have drawn the attention of researchers, because they provide invaluable information of various domains ranging from genomics to epigenetics, transcriptomics, and proteomics. Single cell-derived clones provide a reliable and sustainable source of genetic information due to the homogeneity of the cell population. Aiming to obtain single-cell clones, several approaches were engineered, among which, the Limiting dilution approach stands out as a cost-effective and unsophisticated, and easy-to-apply method. Here, we demonstrate how to acquire single cell-derived clones through a simple 1:10 diluting from genetically modified heterogeneous cell populations.

A method to reduce ELISA serial dilution assay workload applied to SARS-CoV-2 and seasonal HCoVs

Objectives Assays using ELISA measurements on serially diluted serum samples have been heavily used to measure serum reactivity to SARS-CoV-2 antigens and are widely used in virology and elsewhere in biology. We test a method to reduce the workload of these assays, and measure reactivity of SARS-CoV-2 and HCoV antigens to human serum samples collected before and during the COVID-19 pandemic. Methods We apply Bayesian hierarchical modelling to ELISA measurements of human serum samples against SARS-CoV-2 and HCoV antigens. Results Inflection titers for SARS-CoV-2 full-length spike protein (S1S2), spike protein receptor-binding domain (RBD), and nucleoprotein (N) inferred from three spread-out dilutions correlated with those inferred from eight consecutive dilutions with an R2 value of 0.97 or higher. We confirm existing findings showing a small proportion of pre-pandemic human serum samples contain cross-reactive antibodies to SARS-CoV-2 S1S2 and N, and that SARS-CoV-2 infection increases serum reactivity to the beta-HCoVs OC43 and HKU1 S1S2. Conclusions In serial dilution assays, large savings in resources and/or increases in throughput can be achieved by reducing the number of dilutions measured and using Bayesian hierarchical modelling to infer inflection or endpoint titers. We have released software for conducting these types of analysis.

Optimization of dye solutions for detecting damaged pancreatic tissues during islet isolation procedures

We previously reported that dye was effective to prevent the leakage of enzyme solutions from pancreatic glands during an islet isolation procedure. However, the dye used for islet isolation has not yet been optimized. In this study, we focused on pyoktanin blue (PB), diagnogreen (DG), and indigo carmine (IC) as potential candidates among clinically established dyes. A serial dilution assay was performed to determine minimal effective concentrations of each dye for detecting damaged pancreatic tissues. According to the outcome of serial dilution assays, double minimum effective concentrations of each dye were used for in vitro toxicity assays on islets and used in the isolation procedure to investigate whether they adversely affect islet isolation efficiency. The evaluations included islet yield, ADP/ATP, ATP/DNA, glucose stimulation test, and insulin/DNA assays. Islet viability cultured with PB contained medium was significantly lower than the other dyes. DG and IC appeared to be non-toxic to the islets. In isolation experiments, the islet yield in the DG group was considerably lower than that in the Control group, suggesting that DG might inhibit enzyme activity. The present study demonstrates that IC could be a promising candidate for an effective dye to detect damaged pancreatic tissues without affecting the enzyme activity and islet quality.

Genetic Study of Phenylthiocarbamide (PTC) Taste Sensitivity In Population of The Osing in Kemiren Village-Banyuwangi

The ability to taste phenylthiocarbamide (PTC), is autosomal trait inherited in a simple Mendelian recessive pattern. The frequency of Taster and non-Taster allele is varies in different populations. The purpose of the research is to investigate the prevalence, gene frequency and genotype frequency of taster (T) and non taster (ts of Osing population in Kemiren-Banyuwangi. PTC serial dilution method was used to assess the PTC Taster and non-Taster phenotypes. The Hardy–Weinberg method was used to determine allele frequencies. The total of samples were 227 people, male were 117 and female were 110 with age range of 15–30 years were randomly selected. The result showed that the Osing population as Taster were 210 (92,52%) and non Taster were 17samples (7,48%) . The allele frecuency of Taster (T) was 0,73 and non Taster (t) was 0,27 respectively. The genotype frequency of dominant Taster (TT) was 0,54, heterozygosity Taster (Tt) was 0,39, and genotype of non Taster (tt) was 0,07.

An Integrated Centrifugal Degassed PDMS-Based Microfluidic Device for Serial Dilution

We propose an integrated serial dilution generator utilizing centrifugal force with a degassed polydimethylsiloxane (PDMS) microfluidic device. Using gas-soluble PDMS as a centrifugal microfluidic device material, the sample can be dragged in any arbitrary direction using vacuum-driven force, as opposed to in a single direction, without adding further actuation components. The vacuum-driven force allows the device to avoid the formation of air bubbles and exhibit high tolerance in the surface condition. The device was then used for sample metering and sample transferring. In addition, centrifugal force was used for sample loading and sample mixing. In this study, a series of ten-fold serial dilutions ranging from 100 to 10−4 with about 8 μL in each chamber was achieved, while the serial dilution ratio and chamber volume could easily be altered by changing the geometrical designs of the device. As a proof of concept of our hybrid approach with the centrifugal and vacuum-driven forces, ten-fold serial dilutions of a cDNA (complementary DNA) sample were prepared using the device. Then, the diluted samples were collected by fine needles and subject to a quantitative polymerase chain reaction (qPCR), and the results were found to be in good agreement with those for samples prepared by manual pipetting.