Analyzing the Functions of Mast Cells In Vivo Using 'Mast Cell Knock-in' Mice

Mast cells (MCs) are hematopoietic cells which reside in various tissues, and are especially abundant at sites exposed to the external environment, such as skin, airways and gastrointestinal tract. Best known for their detrimental role in IgE-dependent allergic reactions, MCs have also emerged as important players in host defense against venom and invading bacteria and parasites. MC phenotype and function can be influenced by microenvironmental factors that may differ according to anatomic location and/or based on the type or stage of development of immune responses. For this reason, we and others have favored in vivo approaches over in vitro methods to gain insight into MC functions. Here, we describe methods for the generation of mouse bone marrow-derived cultured MCs (BMCMCs), their adoptive transfer into genetically MC-deficient mice, and the analysis of the numbers and distribution of adoptively transferred MCs at different anatomical sites. This method, named the ‘mast cell knock-in’ approach, has been extensively used over the past 30 years to assess the functions of MCs and MC-derived products in vivo. We discuss the advantages and limitations of this method, in light of alternative approaches that have been developed in recent years.     

Radiotherapy and technetium-99m-labeled red blood cell scintigraphy for hemoptysis from chronic MRSA infection

Aim

To discuss the application of external beam radiotherapy (EBRT) and technetium-99m-labeled red blood cell scintigraphy (LRBCS) in life-threatening hemoptysis from a non-malignant condition.

Materials and methods

This case report presents a patient with persistent hemoptysis secondary to chronic Methicillin-resistant Staphylococcus aureus (MRSA) infection in whom conventional management failed to localize the site of pulmonary bleeding or to provide effective therapy.

Results

EBRT was successfully given for life-threatening hemoptysis with improvement in quality of life for nearly 1 year. LRBCS was used to localize the source of further bleeding and facilitate targeted therapy.

Conclusion

EBRT can be an effective and well-tolerated modality in treating life-threatening hemoptysis refractory to conventional methods. LRBCS is a non-invasive diagnostic tool that can be used to detect the source of pulmonary bleeding.     

Lipase-catalyzed synthesis of aliphatic polyesters and properties characterization

A novel lipase-catalyzed synthesis of aliphatic polyesters has been achieved successfully by using Candida sp.99-125 with diethyl sebacate and 1,4-butanediol as starting substrates in absence of organic solvents. The lipase from Candida sp.99-125 was employed for the first time to catalyze synthesis of poly(butylene sebacate) and showed high catalytic activity for bulkpolymerization under mild reaction conditions. The eco-friendly processes, without any environmental pollution, avoided both phase separation of the reactants and the use of toxic solvents effectively. The polycondensation reactions were performed in two stages: first stage reaction under atmospheric pressure to convert the monomers to oligomers followed by second stage reaction under vacuum process, with a highest molecular weight of 15,800 obtained in molar ratio of 1:1 at 70 °C. The corresponding polyesters determined by thermogravimetric analysis (TGA) were much thermally stable up to 300 °C. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXS) analysis demonstrated the polymers had a strong ability to crystallize with the degree of crystallinity up to 66%.     

Lung perfusion is affected by chronic cold exposure

Background/Aim

The Respiratory system can be affected by exposure to cold. It is well known that acute cold exposure induces asthmatic attacks. However, the influence of chronic cold environment exposure on lung perfusion and the pulmonary circulation was not studied in any previous study. Therefore this study was designed to investigates the effects of chronic cold exposure on lung perfusion using radionuclide study.

Methods

New Zealand White rabbits were used in these experiments. The rabbits were kept in the cold room (4 °C) for 7 weeks. Lung perfusion scintigraphy was performed at the end of this period. Each rabbit was injected with 74 MBq (2 mCi) technetium-99m macroaggregated of albumin (^99mTc MAA). Perfusion studies were done using Gamma camera equipped with a low energy, high resolution, parallel hole collimator interfaced with a computer. Static images were obtained 5 min after administration of the radiotracer. Static images were acquired include anterior/posterior (Ant/Post), right anterior oblique/left posterior oblique (RAO/LPO), right lateral/left lateral (RLat/LLat), right posterior oblique/left anterior oblique (RPO/LAO).

Results

Rabbits chronically exposed to cold had lesser lung perfusion than controls using radionuclide perfusion study. The lung counts of chronic cold exposure (4 °C) for 7 weeks on rabbit lung perfusion for 5 min was 64±4%. (n=6, ^???P<0.001).

Conclusions

Our results indicate that chronic cold exposure decreased pulmonary circulation and lung perfusion in normal subjects. Therefore chronic cold exposure might worsen some diseases that are affected by cold such as asthma.     

Effect of Lipid Dose on the Redistribution and Blood Pool Clearance Kinetics of Peg-Modified Technetium-Labeled Lipid Vesicles

Abstract

The current literature reports that the circulation half-life of PEG-modified vesicles is independent of lipid dose over the range of β4-400 μmol/ kg. The results presented in this paper indicate that PEG-modified vesicles exhibit a dose-dependent circulation half-life at even lower lipid doses. At lipid doses of 2.13, 1.30, 0.50 and 0.16 μmol/kg, the half-life for the blood pool clearance of activity of technetium-99m encapsulated in PEG-coated vesicles was approximately 20, 16, 4, and 2 hr respectively. There was no statistically significant difference in clearance half-life for lipid doses of 2.13 and 1.30 μmol/kg (Kruskal-Wallis Anova, p>0.05). These results suggest that the dose-independent range may be extended down to approximately 1 (μmol/kg but that at lower doses, the circulation half-life is dependent on the lipid dose. These results are discussed in terms of the mechanism of clearance of activity from the circulation and the potential utility of PEG-modified technetium-99m labeled vesicles as blood pool imaging agents for nuclear medicine.     

2,2′,4,4′,5‐Pentabromodiphenyl ether induces lipid accumulation throughout differentiation in 3T3‐L1 and human preadipocytes in vitro

Flame retardants, specifically polybrominated diphenyl ethers (PBDEs), are chemical compounds widely used for industrial purposes and household materials. NHANES data indicate that nearly all Americans have trace amounts of PBDEs in serum, with even higher levels associated with occupational exposure. PBDEs are known to bioaccumulate in the environment due to their lipophilicity and stability, and more importantly, they have been detected in human adipose tissue. The present study examined whether the PBDE congener, BDE‐99 (2,2′,4,4′,5‐pentabromodiphenyl ether; 0.2‐20 μM), enhances the adipogenesis of mouse and human preadipocyte cell models in vitro via induced lipid accumulation. 3T3‐L1 mouse preadipocytes and human visceral preadipocytes demonstrated enhanced hormone‐induced lipid accumulation upon BDE‐99 treatment. In addition, BDE‐99 (20 μM) induced preadipocyte differentiation and lipid development in nondifferentiated human preadipocytes. BDE‐99, the second most abundant congener in human adipose tissue, increased total lipids in differentiating adipocytes and therefore showed a potential role in the regulation of adipogenesis. This warrants more research to further understand the impact of lipophilic persistent pollutants on adipose tissue homeostasis.     

Targeting arterial wall sulfated glycosaminoglycans in rabbit atherosclerosis with a mouse/human chimeric antibody

The progression of atherosclerosis is favored by increasing amounts of chondroitin sulfate proteoglycans in the artery wall. We previously reported the reactivity of chP3R99 monoclonal antibody (mAb) with sulfated glycosaminoglycans and its association with the anti-atherogenic properties displayed. Now, we evaluated the accumulation of this mAb in atherosclerotic lesions and its potential use as a probe for specific in vivo detection of the disease. Atherosclerosis was induced in NZW rabbits (n = 14) by the administration of Lipofundin 20% using PBS-receiving animals as control (n = 8). Accumulation of chP3R99 mAb in atherosclerotic lesions was assessed either by immunofluorescence detection of human IgG in fresh-frozen sections of aorta, or by immunoscintigraphy followed by biodistribution of the radiotracer upon administration of ^99mTc-chP3R99 mAb. Immunofluorescence studies revealed the presence of chP3R99 mAb in atherosclerotic lesions 24 h after intravenous administration, whereas planar images showed an evident accumulation of ^99mTc-chP3R99 mAb in atherosclerotic rabbit carotids. Accordingly, ^99mTc-chP3R99 mAb uptake by lesioned aortic arch and thoracic segment was increased 5.6-fold over controls and it was 3.9-folds higher in carotids, in agreement with immunoscintigrams. Moreover, the deposition of ^99mTc-chP3R99 mAb in the artery wall was associated both with the presence and size of the lesions in the different portions of evaluated arteries and was greater than in non-targeted organs. In conclusion, chP3R99 mAb preferentially accumulates in arterial atherosclerotic lesions supporting the potential use of this anti-glycosaminoglycans antibody for diagnosis and treatment of atherosclerosis.     

Protecting South Asian Wheat Production from Stem Rust (Ug99) Epidemic

The Ug99 group of stem rust races (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) has evolved and migrated. While the original variant overcame the widely deployed gene Sr31, and Sr21 (in Chinese Spring background), but not Sr21 in Einkorn, a new strain of Ug99, virulent on Sr24, was detected in 2006 and caused a severe epidemic in 2007 in Kenya. Forms virulent on Sr36 and Sr21 were identified in 2007. Likewise, an Ug99 variant virulent to both Sr21 and Sr24 was identified in 2008 in Kenya. Simultaneously, the original strain spread to Yemen and Sudan in 2006. Fears of a spread into Asia were confirmed when this race was detected in Iran in 2007. This has raised serious concerns that Ug99 could follow the same migratory route from Africa to Asia as Yr9 and cause major epidemics across the epidemiological region of South Asia. In 2005–06, screening in Kenya and Ethiopia of wheat materials from Asian countries revealed a very low frequency of lines resistant to Ug99 and its variants. Under the umbrella of the Borlaug Global Rust Initiative (BGRI), significant efforts have been made to counter the challenges posed by Ug99 and its derivative races. Diverse sources of resistance to the pathogen have been identified and incorporated in high‐yielding wheat backgrounds. The most promising strategy has been to deploy spring wheat varieties possessing adult plant resistance (APR) in infested and bordering areas to decrease inoculum amounts and slow down the development of new virulence, for example four CIMMYT genotypes with Sr2+ have been released in Afghanistan and their seed is also distributed in region bordering Iran. For an immediate remedy, race‐specific resistance genes can be deployed in combinations using marker‐assisted selection. Several Ug99‐resistant varieties have already been released in South Asian countries (Afghanistan, India, Nepal, Bangladesh and Pakistan), and seed dissemination is underway. The Ug99 risk in the region can be reduced to minimum levels by identifying, releasing and providing seed of high‐yielding and resistant cultivars.