Immune Protection against Virus Challenge in Aging Mice Is Not Affected by Latent Herpesviral Infections

Latent herpesvirus infections alter immune homeostasis. To understand if this results in aging-related loss of immune protection against emerging infections, we challenged old mice carrying latent mouse cytomegalovirus (CMV), herpes simplex virus 1 (HSV-1), and/or murine gammaherpesvirus 68 (MHV-68) with influenza virus, West Nile virus (WNV), or vesicular stomatitis virus (VSV). We observed no increase in mortality or weight loss compared to results seen with herpesvirus-negative counterparts and a relative but not absolute reduction in CD8 responses to acute infections. Therefore, the presence of herpesviruses does not appear to increase susceptibility to emerging infections in aging patients.     

A model predicting delivery of saquinavir in nanoparticles to human monocyte/macrophage (Mo/Mac) cells

Modeling the influence of a technology such as nanoparticle systems on drug delivery is beneficial in rational formulation design. While there are many studies showing drug delivery enhancement by nanoparticles, the literature provides little guidance regarding when nanoparticles are useful for delivery of a given drug. A model was developed predicting intracellular drug concentration in cultured cells dosed with nanoparticles. The model considered drug release from nanoparticles as well as drug and nanoparticle uptake by the cells as the key system processes. Mathematical expressions for these key processes were determined using experiments in which each process occurred in isolation. In these experiments, intracellular delivery of saquinavir, a low solubility drug dosed as a formulation of poly(ethylene oxide)-modified poly(epsilon- caprolactone) (PEO-PCL) nanoparticles, was studied in THP-1 human monocyte/macrophage (Mo/Mac) cells. The model accurately predicted the enhancement in intracellular concentration when drug was administered in nanoparticles compared to aqueous solution. This simple model highlights the importance of relative kinetics of nanoparticle uptake and drug release in determining overall enhancement of intracellular drug concentration when dosing with nanoparticles.     

Effect of rat salivary glands extracts on the proliferation of cultured skin cells - a wound healing model

Objective: Salivary gland secretions play an important role in promotion of wound healing. The healing of intra- or extra-oral wounds is delayed in desalivated rats. However, the specific role of each salivary gland in promoting wound healing is unknown. This study was aimed to investigate the effect of crude extracts of rat salivary glands on a simplified in vitro wound healing model. Design/methods: Cultured human keratinocytes (HaCat) and murine fibroblasts (3T3) were subjected to 48 h serum starvation, and were later activated by extracts of rat salivary glands, 1–10 μg protein/ml of each gland. The resultant cellular metabolic activity of the activated cells was determined 24 h later, measuring reduction of XTT by mitochondrial enzymes, and calculated relatively to positive controls [optimal supplementation of 10% fetal calf serum (FCS)], and negative controls (starved non-supplemented cells). Results: The relative stimulatory effect of parotid (P) extract on the cells was significantly lower than either submandibular (SM) or sublingual (SL) extracts. Under the assumption that physiologically, the cells are exposed to the combined effect of saliva secreted from all the glands, different combinations of the extracts were presented to the cells. The relative stimulation was maximal following treatment with the three glands extracts (P + SM + SL) and exceeded the effect of 10% FCS. Conclusion: The results suggest that each salivary gland has a specific effect on wound healing and the combination of the three extracts has an additive effect but no the sum of all individual glands. This model might be useful to study the wound healing effect of salivary glands. In partial fulfillment of the requirement for MD thesis, The Joyce and Irving Goldman School of Medicine, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel.     

Proficiency testing in cytology laboratories in Ontario, Canada: a decade of experience. II. Results of initial surveys

The results of the initial surveys in the cytology proficiency testing of the medical laboratories in the Province of Ontario, Canada, showed a high correlation between the opinions of the testing committee and the participants in the categories of "no abnormal cells," "metaplasia" and forms of "benign atypia." The proportion of times that slides were tested in the categories of dysplasia and malignancy in the surveys increased from 38% by the end of survey 3 to 46% by the end of survey 5. A progressive improvement in the diagnostic accuracy was demonstrated in the categories of malignancy and severe dysplasia while results were more variable in the categories of moderate and mild dysplasia. Several educational activities were initiated following survey 3, including development and circulation of demonstration sets of marked glass slides for repeated circulation to participants as well as copies of a slide/tape presentation describing the program and specific case material.     

Acid and alkaline phosphatase activity in the fat body and midgut of the beet armyworm,Spodoptera exigua (Lepidoptera: Noctuidae), infected with nuclear polyhedrosis virus

Changes in the activity of acid and alkaline phosphatase in Spodoptera exigua larvae infected with nuclear polyhedrosis virus have been investigated. Three days after per os infection, the activity of acid phosphatase in the fat body and midgut of infected larvae was significantly higher than that in normal larvae. Alkaline phosphatase activity did not show such significant changes. There were differences in the phosphatase patterns depending on whether their activities were expressed as enzyme units per milligram of fresh organ weight or per milligram of homogenate protein. The literature relevant to the subject allows us to conclude that the increase in phosphatase activities in S. exigua larvae is not specifically associated with virus infection itself, but, rather, is a reaction of the insect organism to the diminishing supply of energy sources.     

Serotonin transporter in rat platelets. Level of protein expression underlies inherited differences in uptake kinetics.

By breeding selection for the extreme values of platelet serotonin level (PSL), two sublines of Wistar-derived rats, with constitutionally high or low PSL and platelet serotonin uptake (PSU), have been developed. Searching for the basis of these differences, we performed quantitative western blot analysis of serotonin transporter (5HTt) in platelet membranes isolated from both rat sublines. A polyclonal anti-5HTt antibody labeled a single, 5HTt-related 94 kDa protein band in platelet membranes, with significantly stronger intensity in membranes from rats that exhibited a high PSL. We conclude that the inherited differences in PSL and PSU in rats, following breeding selection, are determined by the level of 5HTt expression in platelet membranes.     

Development of an in vitro model for study of the efficacy of ischemic preconditioning in human skeletal muscle against ischemia-reperfusion injury.

Ischemia-reperfusion (I/R) injury causes skeletal muscle infarction and ischemic preconditioning (IPC) augments ischemic tolerance in animal models. To date, this has not been demonstrated in human skeletal muscle. This study aimed to develop an in vitro model to investigate the efficacy of simulated IPC in human skeletal muscle. Human skeletal muscle strips were equilibrated in oxygenated Krebs-Henseleit-HEPES buffer (37 degrees C). Aerobic and reperfusion phases were simulated by normoxic incubation and reoxygenation, respectively. Ischemia was simulated by hypoxic incubation. Energy store, cell viability, and cellular injury were assessed using ATP, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), and lactate dehydrogenase (LDH) assays, respectively. Morphological integrity was assessed using electron microscopy. Studies were designed to test stability of the preparation (n = 5-11) under normoxic incubation over 24 h; the effect of 1, 2, 3, 4, or 6 h hypoxia followed by 2 h of reoxygenation; and the protective effect of hypoxic preconditioning (HPC; 5 min of hypoxia/5 min of reoxygenation) before 3 h of hypoxia/2 h of reoxygenation. Over 24 h of normoxic incubation, muscle strips remained physiologically intact as assessed by MTT, ATP, and LDH assays. After 3 h of hypoxia/2 h of reoxygenation, MTT reduction levels declined to 50.1 +/- 5.5% (P < 0.05). MTT reduction levels in HPC (82.3 +/- 10.8%) and normoxic control (81.3 +/- 10.2%) groups were similar and higher (P < 0.05) than the 3 h of hypoxia/2 h of reoxygenation group (45.2 +/- 5.8%). Ultrastructural morphology was preserved in normoxic and HPC groups but not in the hypoxia/reoxygenation group. This is the first study to characterize a stable in vitro model of human skeletal muscle and to demonstrate a protective effect of HPC in human skeletal muscle against hypoxia/reoxygenation-induced injury.