Ultrasound simulation of blood with different red blood cell aggregations and concentrations

BACKGROUND: Considerable progress of ultrasound simulation on blood has enhanced the characterizing of red blood cell (RBC) aggregation. OBJECTIVE: A novel simulation method aims at modeling the blood with different RBC aggregations and concentrations is proposed. METHODS: The modeling process is as follows: (i) A three-dimensional scatterer model is first built by a mapping with a Hilbert space-filling curve from the one-dimensional scatterer distribution. (ii) To illustrate the relationship between the model parameters and the RBC aggregation level, a variety of blood samples are prepared and scanned to acquire their radiofrequency signals in-vitro. (iii) The model parameters are determined by matching the Nakagami-distribution characteristics of envelope signals simulated from the model with those measured from the blood samples. RESULTS: Nakagami metrics m estimated from 15 kinds of blood samples (hematocrits of 20%, 40%, 60% and plasma concentrations of 15%, 30%, 45%, 60%, 75%) are compared with metrics estimated by their corresponding models (each with different eligible parameters). Results show that for the three hematocrit levels, the mean and standard deviation of the root-mean-squared deviations of m are 0.27 ± 0.0026, 0.16 ± 0.0021, 0.12 ± 0.0018 respectively. CONCLUSION: The proposed simulation model provides a viable data source to evaluate the performance of the ultrasound-based methods for quantifying RBC aggregation.

Huffmanela sp. (Nematoda: Trichosomoididae: Huffmanelinae) encountered in the whitecheek shark (Carcharhinus dussumieri) in the Arabian Gulf

Summary Veterinary inspection of fish caught at the western side of the Arabian Gulf off the shore of Saudi Arabia in 2017 revealed abnormal irregular zigzag black lines in the skins of 135 out of 1500 (prevalence = 9 %) whitecheek sharks (Carcharhinus dussumieri). These lesions have been noticed in the dorsal and ventral part of the head near the snout and around the eyes, as well as in the skin of the pectoral fins. The parasitological, pathological and ultramorphological aspects of the sampled fish were studied using a light microscope, as well as scanning and transmission electron microscopes. Trichosomoidid-type eggs identified as Huffmanela sp. were found in the superficial layer of the skin. The mature eggs containing larvae (n = 75) were ellipsoidal or spindle-shaped, smooth-shelled, amber-brown to dark brown or even black in colour. The width of the eggs ranged from 34 to 49μm with lengths ranging from 95 to 107μm. The polar plugs of the immature eggs were slightly protruding, whereas mature eggs had clearly protruding polar plugs. The width of the polar plugs ranged from 4.5 – 9.5μm. The shells of the eggs were smooth and there was a thin layer seen near the polar areas. The infected skin exhibited desquamated epithelium, with inflammatory cell aggregations and melanophores in the debris. The underlying musculatures of the skin were free from any eggs, but showed mild pathological changes, including congestion of blood vessels, haemorrhages and oedema. The prevalence of infection showed seasonality, peaking significantly in the spring (18.18 %), with comparable prevalence rates in winter and summer (9.43 % and 8.57 %, respectively). However, infections dropped significantly during the autumn months (3.75 %). It is believed that this is the first study reporting the presence of Huffmanela sp. in whitecheek sharks at El-Jubail Province, Saudi Arabia, Arabian Gulf.

Non-Newtonian Patient-specific Simulations of Left Atrial Hemodynamics

Atrial fibrillation (AF) is the most common arrhythmia, affecting ~35M people worldwide. The irregular beating of the left atrial (LA) caused by AF impacts the LA hemodynamics increasing the risk of thrombosis and ischemic stroke. Most LA thrombi appear in its appendage (LAA), a narrow sac of varied morphology where blood is prone to stagnate. In the LAA, the combination of slow blood flow and low shear rates (<100 [1/s]) promotes the formation of red blood cell aggregations called rouleaux. Blood experiences a non-Newtonian behavior when rouleaux formed that has not been considered in previous CFD analysis of the LA. We model the anatomy and motion of the LA from 4D-CT images and solve the blood flow inside the LA geometry with our CFD in-house code, which models Non-Newtonian rheology with the shear-hematocrit-dependent Carreau-Yasuda equation. We cover a wide range of non-Newtonian effects considering a small and a large hematocrit, including an additional constitutive relation to account for themrouleaux formation time, and we compare our results with Newtonian simulations. Blood rheology influence in LAA hemostasis is studied in 6 patient-specific anatomies. Two subjects had an LAA thrombus (digitally removed before running the simulations), another had a history of TIAs, and the remaining three had normal atrial function. In our simulations, the shear rate remains below 50 [1/s] in the LAA for all non-Newtonian models considered. This triggers an increase of viscosity that alters the flow behavior in that site, which exhibits different flow patterns than Newtonian simulations. These hemodynamic changes translate into differences in the LAA hemostasis, calculated with the residence time.

Discovery of Cell Aggregate-Inducing Peptides

Most cells within the human body interact with neighboring cells and extracellular matrix (ECM) components to establish a unique 3D organization. These cell–cell and cell–ECM interactions form a complex communication network of biochemical and mechanical signals critical for normal cell physiology. The behavior of cells in a 3D environment is fundamentally different from that of cells in monolayer culture. Aggregation can affect cell–cell interactions, being more representative of the normal tissue microenvironment. Therefore, 3D cell culture technologies have been developed. The general method for cell aggregate is a physical method; it is difficult to control the size and number of cell aggregates. In any case, no chemical method has been discovered yet, so a new method to solve these problems is needed. In this paper, we describe the induction of a cell aggregate of the newly discovered (Lys-Pro)12(KP24) peptide. Since it was revealed that KP24 had cell aggregate-inducing activity, its derivatives were molecularly designed to clarify the importance of the KP24 sequence. We report that cell aggregations were induced by KP24 to form aggregates of fibroblast cells. We evaluated KP24 derivative periodic peptides such as (Lys-Pro-Pro)8(KPP24) and (Lys-Lys-Pro)8(KKP24). The relationship between the structure of the peptide chain and the activity induced by the cell aggregations was investigated from the viewpoint of basic research and the biomedical engineering field.

A potent antibiofilm agent inhibits and eradicates mono- and multi-species biofilms

Biofilms are surface-attached multicellular communities that create many problems in human health and various industries. Given the prominence of biofilms in biofouling and infectious diseases, antibiofilm control approaches are highly sought after. In the present study, we identified elasnin as a potent antibiofilm agent through a bioassay-guided approach. Elasnin specifically inhibited the biofilm formation of bacterial mono-species and eradicated the mature biofilm of Gram-positive bacteria at concentrations below 2.5 μg/mL with a low toxic effect on cells and a low resistance risk. Confocal observations illustrated that elasnin decreased cell aggregations and destroyed the biofilm matrix. Furthermore, elasnin-based antibiofilm coatings were prepared and inhibited the formation of multi-species biofilms and the attachment of large biofouling organisms in the field test. These findings suggest that elasnin is a promising antibiofilm agent for future applications in biofilm control.ImportanceDue to the increased diversity of biofilm-associated infections and the failure of conventional antimicrobial treatment, new and effective biofilm-specific pharmacologic strategies are urgently needed. Elasnin is a new antibiofilm natural product produced by Streptomyces with high efficiency and low toxicity. Elasnin effectively destroyed the biofilm matrix of Gram-positive bacteria, thus making them more susceptible to antibiotics. Unlike currently deployed antibiotic vancomycin, which exclusively targets essential life processes and kills the pathogen, elasnin did not exhibit bactericidal effect and thus held great potential in delaying resistance. With high yield, elasnin-based coatings were easily prepared with low expenditures and exhibited favorable performance in field test. Collectively, the antibiofilm properties of elasnin, combined with the low cost of supply and the low risk of resistance, could provide the basis for the development of a novel antibiofilm agent that could help fight to antibiotics resistance.

Courtship behaviour in the genus Nomada – antennal grabbing and possible transfer of male secretions

Due to low population densities, copulation in the cuckoo bee genus Nomada has not previously been observed, although a seminal paper by Tengö and Bergström (1977) on the chemomimesis between these parasitic bees and their Andrena or Melitta hosts postulated that secretions from male glands might be sprayed onto females during copulation. Our observations on the initiation and insertion phase of copulation in three species of Nomada now indicate antennal grabbing as a mechanism by which chemicals are transferred between the sexes. Histological studies of the antennae of N.fucata and N.lathburiana reveal antennal modifications associated with cell aggregations that represent glandular cells, and SEM studies revealed numerous excretory canals.

Protist predation can favour cooperation within bacterial species

Here, we studied how protist predation affects cooperation in the opportunistic pathogen bacterium Pseudomonas aeruginosa , which uses quorum sensing (QS) cell-to-cell signalling to regulate the production of public goods. By competing wild-type bacteria with QS mutants (cheats), we show that a functioning QS system confers an elevated resistance to predation. Surprisingly, cheats were unable to exploit this resistance in the presence of cooperators, which suggests that resistance does not appear to result from activation of QS-regulated public goods. Instead, elevated resistance of wild-type bacteria was related to the ability to form more predation-resistant biofilms. This could be explained by the expression of QS-regulated resistance traits in densely populated biofilms and floating cell aggregations, or alternatively, by a pleiotropic cost of cheating where less resistant cheats are selectively removed from biofilms. These results show that trophic interactions among species can maintain cooperation within species, and have further implications for P. aeruginosa virulence in environmental reservoirs by potentially enriching the cooperative and highly infective strains with functional QS system.

PSEUDOTUMOR TUBERKULOSIS HATI DIAGNOSIS MELALUI BIOPSI ASPIRASI JARUM HALUS

Nowadays, the role of Fine Needle Aspiration Biopsy (FNAB) in the evaluation of focal lesions in the liver, especially nodular hepatocellular carcinoma, is well developed. As one of the diagnostic tools, FNAB is very important in making a preoperative diagnosis to prevent unneeded hepatectomy. Although a CT scan or USG can detect a tubercular lesion in the abdo-minal cavity, this imaging is not always specific, and still needs microbiologic and histo-pathologic examinations for further confirmation. We reported a case of a 45-year-old female with a tumor in the right upper abdominal cavity. She had undergone a USG twice with two different results: the first one was a hepatoma, and the second one was a benign nodule of the liver. The AFP test was within normal limits (2.6 mg/ul). FNAB showed a tubercular granuloma consisting of epitheloid cell aggregations and Langhans datia cells, with a background of necrotic tissues, connective tissue fibrils, and normal hepatocytes. Localized tuberculosis as a clinical entity producing large nodules is exceedingly rare, even in endemic areas. These pseudotumors often resemble metastatic cancer, clinically and radiographically. By using FNAB we can detect liver tuberculosis that clinically manifests as a tumor. Key words: FNAB, liver tuberculosis, pseudotumor. Abstrak: Saat ini peranan biopsi aspirasi jarum halus dalam hal menilai kelainan-kelainan fo-kal pada hati sudah berkembang, terutama pada nodul karsinoma hepatoseluler. Biopsi aspirasi jarum halus pada hati sebagai salah satu sarana diagnostik sangat berguna untuk menegakkan diagnosis preoperatif sehingga dapat menghindari tindakan hepatektomi yang tidak perlu. Meskipun pemeriksaan computerized tomography scan (CT-scan) dan ultrasonography (USG) pada hati dapat mendeteksi lesi tuberkulosis dalam rongga perut, namun pencitraannya tidak selalu spesifik sehingga membutuhkan konfirmasi pemeriksaan mikrobiologi dan histopatologi. Dilaporkan kasus seorang wanita berusia 45 tahun dengan tumor pada perut kanan atas. Telah dilakukan dua kali pemeriksaan USG: yang pertama hasilnya suatu hepatoma dan yang kedua suatu nodul jinak pada hati. Pemeriksaan alpha-feto protein (AFP) dalam batas normal (2,6 mg/ul). Kemudian dilakukan pemeriksaan biopsi aspirasi jarum halus dengan hasil menunjukkan granuloma tuberkulosis dari agregat sel-sel epiteloid yang tersusun dalam granuloma dan sel-sel datia Langhans dengan latar belakang fokus-fokus nekrosis, fibril jaringan ikat serta sel-sel hati normal. Tuberkulosis terlokalisir pada hati yang secara klinik menimbulkan nodul besar, sangat jarang terjadi, sekalipun pada daerah endemik. Pseudotumor seperti ini sering menyerupai metastatik kanker secara klinik dan radiologik. Melalui pemeriksaan biopsi aspirasi jarum halus dapat dikonfirmasi suatu tuberkulosis hati yang klinisnya memberi manifestasi seperti tumor. Kata kunci: biopsi aspirasi jarum halus, tuberkulosis hati, pseudotumor.