-
Journal of the Mechanical Behavior of... Feb 2024Tissue fixation is a prevalent method for bone conservation. Bone biopsies are typically fixed in formalin, dehydrated in ethanol, and infiltrated with polymethyl...
Tissue fixation is a prevalent method for bone conservation. Bone biopsies are typically fixed in formalin, dehydrated in ethanol, and infiltrated with polymethyl methacrylate (PMMA) Since some experiments can only be performed on fixed bone samples, it is essential to understand how fixation affects the measured material properties. The aim of this study was to quantify the influence of tissue fixation on the mechanical properties of cortical ovine bone at the extracellular matrix (ECM) level with state-of-the-art micromechanical techniques. A small section from the middle of the diaphysis of two ovine tibias (3.5 and 5.5 years old) was cut in the middle and polished on each side, resulting in a pair of mirrored surfaces. For each pair, one specimen underwent a fixation protocol involving immersion in formalin, dehydration with ethanol, and infiltration with PMMA. The other specimen (mirrored) was air-dried. Six osteons were selected in both pairs, which could be identified in both specimens. The influence of fixation on the mechanical properties was first analyzed using micropillar compression tests and nanoindentation in dry condition. Additionally, changes in the degree of mineralization were evaluated with Raman spectroscopy in both fixed and native bone ECM. Finally, micro tensile experiments were conducted in the 3.5-year fixed ovine bone ECM and compared to reported properties of unfixed dry ovine bone ECM. Interestingly, we found that tissue fixation does not alter the mechanical properties of ovine cortical bone ECM compared to experiments in dry state. However, animal age increases the degree of mineralization (p = 0.0159) and compressive yield stress (p = 0.041). Tissue fixation appears therefore as a valid conservation technique for investigating the mechanical properties of dehydrated bone ECM.
Topics: Sheep; Animals; Tissue Fixation; Polymethyl Methacrylate; Formaldehyde; Ethanol; Extracellular Matrix
PubMed: 38128472
DOI: 10.1016/j.jmbbm.2023.106294 -
Neurosurgical Review Dec 2023The mastoid foramen (MF) is located on the mastoid process of the temporal bone, adjacent to the occipitomastoid suture or the parietomastoid suture, and contains the...
The mastoid foramen (MF) is located on the mastoid process of the temporal bone, adjacent to the occipitomastoid suture or the parietomastoid suture, and contains the mastoid emissary vein (MEV). In retrosigmoid craniotomy, the MEV has been used to localize the position of the sigmoid sinus and, thus, the placement of the initial burr hole. Therefore, this study aimed to examine the exact location and variants of the MF and MEV to determine if their use in localizing the sigmoid sinus is reasonable. The sample in this study comprised 22 adult dried skulls (44 sides). MF were identified and classified into five types based on location, prevalence, whether they communicated with the sigmoid sinus and exact entrance into the groove of the sigmoid sinus. The diameters and relative locations of the MF in the skull were measured and recorded. Finally, the skulls were drilled to investigate the course of the MEV. Additionally, ten latex-injected sides from human cadavers were also dissected to follow the MEV, especially in cases with more than one vein. We found that type I MFs (single foramen) were the most prevalent (50%). These MFs were mainly located on the occipitomastoid suture; only one case on the right side was adjacent to the parietomastoid suture. Type II (paired foramina) was the second most prevalent (22.73%), followed by type III (13.64%), type 0 (9.09%), and type IV (4.55%). The diameter of the external opening in a connecting MF (2.43 ± 0.79) was twice that of a non-connecting MF (1.14 ± 0.56). Interestingly, on one side, two MFs on the external surface shared a single internal opening; the MEV bifurcated. MFs followed three different courses: ascending, almost horizontal, and descending. Regardless of how many external openings there were for the MF, these all ended at a single opening in the groove for the sigmoid sinus. For cadaveric specimens with multiple MEVs, all terminated in the sigmoid sinus as a single vein, with the more medial veins terminating more medially into the sinus. Based on our study, the MF/MEV can guide the surgeon and help localize the deeper-lying sigmoid sinus. Knowledge of this anatomical relationship could be an adjunct to neuronavigational technologies.
Topics: Adult; Humans; Mastoid; Skull; Cranial Sinuses; Craniotomy; Jugular Veins
PubMed: 38110768
DOI: 10.1007/s10143-023-02229-4 -
Toxicon : Official Journal of the... Feb 2024Scorpion venom is a cocktail of molecules whose composition is remarkably plastic, controlled by several factors. The Moroccan scorpion fauna is characterized by its...
Scorpion venom is a cocktail of molecules whose composition is remarkably plastic, controlled by several factors. The Moroccan scorpion fauna is characterized by its richness and high rate of endemism and the venom molecular variability of many species is not yet well characterized. The aim of the present study was to highlight the molecular variability of the venom composition of Androctonus amoreuxi and Buthacus stockmanni (endemic species), both belonging to the Buthidae family, collected from two Moroccan regions, Zagora and Tan-tan. Characterization of the molecular mass fingerprints (MFPs) of each specimen was performed by Matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) using a sandwich (Sand) and a dried-droplet (DD) sample preparation and dilutions. Considering these two methods, a total of 828 ion signals were detected, and Sand method produced more adducts (56%) than DD (44%). We observed interspecific variations in the venom composition between these two species showing they share 235 ion signals, while 226 and 367 are specific for these two species, respectively. Moreover, B. stockmanni specimens showed a clear difference in their MFPs between the two geographical areas studied, suggesting intraspecific variations. Moreover, specimens from each population also show an intraspecific variability. In addition, for the same individual, a variation in the venom composition was also recorded depending on the milking frequency. Our results confirmed the presence of characteristic components in each extracted venom sample. In conclusion, MFPs assessed by MALDI-MS represent a fast, non-supervised, sensitive, reliable and cost-efficient approach for taxonomic identification and molecular variability characterization. This study undoubtedly represents a step forward for understanding the scorpion venom plasticity, intra/inter variations, and their temporal and geographical variability.
Topics: Animals; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Scorpions; Scorpion Venoms; Morocco; Sand; Animals, Poisonous
PubMed: 38103799
DOI: 10.1016/j.toxicon.2023.107562 -
Malaria Journal Dec 2023In many studies to evaluate the quality of malaria diagnosis, microscopy or rapid diagnostic tests (RDT) are compared to PCR. Depending on the method for sample...
In many studies to evaluate the quality of malaria diagnosis, microscopy or rapid diagnostic tests (RDT) are compared to PCR. Depending on the method for sample collection and storage (whole blood or dried blood spot), volume of blood used for extraction, volume of DNA used as PCR template, and choice of PCR target (single vs. multi-copy gene), the limit of detection (LOD) of PCR might not exceed the LOD of expert microscopy or RDT. One should not assume that PCR always detects the highest number of infections.
Topics: Humans; Malaria; Polymerase Chain Reaction; Limit of Detection; Specimen Handling; Microscopy; Diagnostic Tests, Routine; Malaria, Falciparum; Plasmodium falciparum; Sensitivity and Specificity
PubMed: 38102649
DOI: 10.1186/s12936-023-04822-w -
The Science of the Total Environment Feb 2024The practical advantages of capillary whole blood collection over venipuncture plasma collection for human exposome research are well known. However, before...
The practical advantages of capillary whole blood collection over venipuncture plasma collection for human exposome research are well known. However, before epidemiologists, clinicians, and public health researchers employ these microvolume sample collections, a rigorous evaluation of pre-analytical storage conditions is needed to develop protocols that maximize sample stability and reliability over time. Therefore, we performed a controlled experiment of dried whole blood collected on 10 μL Mitra microsamplers (DBM), 5-mm punches of whole blood from a dried blood spot (DBS), and 10 μL of plasma, and evaluated the effects of storage conditions at 4 °C, -20 °C, or -80 °C for up to 6 months on the resulting metabolite profiles measured with untargeted liquid chromatography-high resolution mass spectrometry (LC-HRMS). At -80 °C storage conditions, metabolite profiles from DBS, DBM, and plasma showed similar stability. While DBS and DBM metabolite profiles remained similarly stable at -20 °C storage, plasma profiles showed decreased stability at -20 °C compared to -80 °C storage. At refrigerated temperatures (4 °C), metabolite profiles collected on DBM were more stable than plasma or DBS, particularly for lipid classes. These results inform robust capillary blood sample storage protocols for DBM and DBS at potentially warmer temperatures than -80 °C, which may facilitate blood collections for populations outside of a clinical setting.
Topics: Humans; Temperature; Reproducibility of Results; Plasma; Specimen Handling
PubMed: 38101622
DOI: 10.1016/j.scitotenv.2023.169383 -
Applied Biosafety : Journal of the... Dec 2023Crimean Congo Hemorrhagic Fever (CCHF) virus and Lassa virus (LASV) are zoonotic agents regarded as high-consequence pathogens due to their high case fatality rates.... (Review)
Review
INTRODUCTION
Crimean Congo Hemorrhagic Fever (CCHF) virus and Lassa virus (LASV) are zoonotic agents regarded as high-consequence pathogens due to their high case fatality rates. CCHF virus is a vector-borne disease and is transmitted by tick bites. Lassa virus is spread via aerosolization of dried rat urine, ingesting infected rats, and direct contact with or consuming food and water contaminated with rat excreta.
METHODS
The scientific literature for biosafety practices has been reviewed for both these two agents to assess the evidence base and biosafety-related knowledge gaps. The review focused on five main areas, including the route of inoculation/modes of transmission, infectious dose, laboratory-acquired infections, containment releases, and disinfection and decontamination strategies.
RESULTS
There is a lack of data on the safe collection and handling procedures for tick specimens and the infectious dose from an infective tick bite for CCHF investigations. In addition, there are gaps in knowledge about gastrointestinal and contact infectious doses for Lassa virus, sample handling and transport procedures outside of infectious disease areas, and the contribution of asymptomatic carriers in viral circulation.
CONCLUSION
Due to the additional laboratory hazards posed by these two agents, the authors recommend developing protocols that work effectively and safely in highly specialized laboratories in non-endemic regions and a laboratory with limited resources in endemic areas.
PubMed: 38090357
DOI: 10.1089/apb.2022.0044 -
RSC Advances Dec 2023Bioactive glass is a potential biomaterial for bone reconstruction owing to its superior bioactivity and non-toxicity. Yet, the absence of a circulatory system to carry...
Bioactive glass is a potential biomaterial for bone reconstruction owing to its superior bioactivity and non-toxicity. Yet, the absence of a circulatory system to carry waste and nutrients is a key issue with biomaterials implanted in the body. Thus the development of functional and vascularized new tissue requires the development of angiogenesis, which involves the formation of new blood vessels. Based on this perspective, we aimed to fabricate boron-doped 58S bioactive glass microspheres using the spray drying method, which could offer great flowability, controllable morphology, and narrow size distribution. Characterization of particle morphology and elemental composition were examined using scanning electron microscopy along with energy dispersive spectroscopy, respectively. To evaluate the effect of the boron dopant on bioactivity, X-ray diffraction and Fourier transform infrared spectroscopy were employed, while MC3T3-E1 osteoblast cells and BAOEC endothelial cells were used to assess the osteoblast and angiogenic activities, respectively. Finally, the results showed that two distinct morphologies, smooth and concave spheres, were found, with discussion of the corresponding formation mechanism. In addition, positive effects of the boron dopant were demonstrated on the bioactivity, and osteoblast and angiogenic activity when compared to the un-doped BG specimen.
PubMed: 38090089
DOI: 10.1039/d3ra07472b -
Journal of Biosciences 2023Having recently published a book on herbaria, collections of preserved plants, I look back on my career teaching biology and the experiences that led me to the world of...
Having recently published a book on herbaria, collections of preserved plants, I look back on my career teaching biology and the experiences that led me to the world of dried plants. My first job was teaching non-science majors, to which I devoted 45 years. Over that time, I worked to make biological inquiry as fascinating to my students as it was to me. I found that the private side of science, how science is actually done, was a good entry point with stories about the wrong turns, difficulties, and joys of research. This led me to biographies and essays by biologists, works on the philosophy and history of science, and interest in the relationship between science and art. Eventually these avenues brought me to the aesthetics of biology and then to botanical art and finally to where these streams seemed to come together in herbaria. I literally fell in love with them. Specimens contain a rich history of people and places, of exploration, colonization, exploitation, and the development of modern botany. Herbaria today are key to documenting and conserving the earth's biodiversity and tracing how climate change is shaping it. Through digitization, herbaria are an essential component of bioinformatics.
Topics: Humans; Botany; Plants; Esthetics; Biodiversity
PubMed: 38088380
DOI: No ID Found -
Odontology Dec 2023To evaluate and compare the effect of calcium hydroxide [Ca(OH)] and 2-hydroxyisocaproic acid (HICA) on the microhardness of root dentine. Fifty-one matured maxillary...
To evaluate and compare the effect of calcium hydroxide [Ca(OH)] and 2-hydroxyisocaproic acid (HICA) on the microhardness of root dentine. Fifty-one matured maxillary central incisors with straight root and type I canal configuration were decoronated to a standardized length of 16 mm. The root canals were cleaned and shaped using rotary instruments up to size F5. The tooth samples were then randomly assigned into three groups (n = 17) based on the intracanal medicament placed. Group A: control group with no intracanal medicament, Group B: root canals placed with Ca(OH), and Group C: root canals placed with HICA. After 1 week, the intracanal medicaments placed within the root canals were removed and the canals were dried. Subsequently, the specimens were split longitudinally into two halves and subjected to the Vickers microhardness test with indentations made at the coronal, middle, and apical-third root regions. The data were analyzed using one-way ANOVA and Tukey's post hoc tests. The control group showed significantly highest microhardness value (P < 0.001), followed by HICA and finally, Ca(OH) at the coronal, middle, and apical-third root regions, respectively. Nonetheless, there were no statistically significant differences in microhardness values across different root regions within each group. HICA was found to have a significantly lesser reduction in root dentine microhardness which could be a potential alternative to Ca(OH). Nevertheless, future studies are warranted to verify the present outcomes in the clinical setting.
PubMed: 38087010
DOI: 10.1007/s10266-023-00874-1 -
American Journal of Human Biology : the... May 2024A growing number of international population surveys have included measurement of biomarkers, but differ in the type of specimens collected, sample processing...
INTRODUCTION
A growing number of international population surveys have included measurement of biomarkers, but differ in the type of specimens collected, sample processing procedures, shipment protocols, and laboratory assay platforms. The purpose of this study is to harmonize biomarker data from nine nationally representative studies of people 50 years of age and over by adjusting for assay platforms and type of specimens for total cholesterol (total-C), high-density lipoprotein cholesterol (HDL-C), glycosylated hemoglobin (HbA1c), and C-reactive protein (CRP).
METHODS
Sets of 24 identical serum, plasma, whole blood, and dried blood spot harmonization samples with known analyte levels were generated at a reference laboratory, shipped at -80°C to the respective study laboratories, and subsequently assayed following the study laboratory's protocol. Both original and harmonized study data were used to calculate mean values and at-risk prevalence.
RESULTS
The correlation coefficients between the biomarker values of the harmonization samples obtained by the study laboratories and the reference laboratory were 0.99 or above for all analytes and laboratories, indicating the high quality of assays at all laboratories. However, using the harmonized data from each study, there were significant differences in the mean values and country ranking of the prevalence of at-risk levels of these four biomarkers.
CONCLUSIONS
While the biomarker data from the different study laboratories were highly correlated, indicating very high correlation of rank order of specimens, absolute values did vary significantly. This can have a major impact on assessment of international differences in estimates of risks for chronic morbidity and mortality.
Topics: Humans; Biomarkers; Middle Aged; Glycated Hemoglobin; Aged; C-Reactive Protein; Cholesterol, HDL; Male; Female; Aged, 80 and over; Cholesterol
PubMed: 38069621
DOI: 10.1002/ajhb.24030