scholarly journals Quantitation of Friend spleen focus-forming virus by a nine-day 59Fe assay

1976 ◽  
Vol 4 (6) ◽  
pp. 486-491
Author(s):  
J H Menna ◽  
W D Hankins ◽  
S B Krantz
Keyword(s):  
Coefficient Of Variation ◽  
Intraperitoneal Injection ◽  
Dose Range ◽  
Intravenous Injections ◽  
Counting Procedure ◽  
Virus Dose ◽  
Ad Libitum

A previously described 3-day 59Fe assay for quantitation of Friend spleen focus-forming virus has been modified to produce a 200-fold more sensitive 9-day 59Fe assay. A characterization of this assay is reported here. Male BALB/c mice received intravenous injections of appropriately diluted Friend polycythemia virus (FVP); control mice received virus diluent. All mice were allowed food and water ad libitum for 6 days, and on day 6 after virus injection were fasted by removal of food but not water. On day 3 of the fast (the 9th day after virus injection) each mouse received an intraperitoneal injection of 1 muCi of 59Fe. Six hours later the mice were sacrificed and the splenic radioactivity was determined. The percent splenic incorporation of 59Fe was directly related to the logarithm of spleen focus-forming units (SFFU) of FVP injected in a range of approximately 25 to 1,000 SFFU. Using a standard FVP preparation in a dose range of 25 to 1,000 SFFU, it was possible to determine the SFFU titers of unknown samples by extrapolation of the percent splenic 59Fe incorporation to the logarithm of SFFU. SFFU titers obtained by the 9-day 59Fe assay were similar to those obtained by the enumerative-response assay. Advantages of the 9-day 59Fe assay over the enumerative-response assay include a 50-fold greater virus dose range, an easier and a more objective counting procedure, and a reduced coefficient of variation.

Responses to supplements by weaned lambs when grazing mature pasture or eating hay cut from the same pasture

1988 ◽  
Vol 110 (3) ◽  
pp. 661-667 ◽  
Author(s):  
M. Freer ◽  
H. Dove ◽  
A. Axelsen ◽  
J. R. Donnelly
Keyword(s):  
Weight Gain ◽  
Coefficient Of Variation ◽  
Substitution Rate ◽  
Eating Behaviour ◽  
Sunflower Meal ◽  
Total Intake ◽  
Grazed Pasture ◽  
Ad Libitum ◽  
Four Levels ◽  
Supplement Intake

SummaryWeaned cross-bred lambs either grazed mature pasture or were confined to yards where they were offered material cut from ungrazed areas of the same pasture. A 1:2 mixture (on an air-dry basis) of sunflower meal and oat grain was offered for 81 days at 0, 200, 400 or 600 g/head or ad libitum. Individual estimates of intake of pasture and supplement by grazing sheep at four levels of supplementation were made on four adjacent plots.Weight gain increased from –30 to 178 g/day in the grazing animals as supplement intake increased up to 1030 g D.M./day and from –25 to 142 g/day in the yarded animals as supplement intake increased to 1076 g D.M./day. Growth of greasy wool increased from 4·5 to 11·7 g/day for grazing animals and from 4·5 to 10·2 g/day for those kept in yards.At levels of supplement intake below 400 g D.M./day, the intake of grazed pasture increased by up to 58% compared with unsupplemented animals. However, when the intake of supplement was increased to about 650 g D.M./day, pasture intake fell, with an estimated substitution rate of 1·1 g D.M. pasture per g D.M. supplement. At all levels of supplementation, the intake of hay by the yarded lambs was less than half the intake of herbage in the field. However, at levels of supplement intake between 300 and 500 g D.M./day, the substitution rate was similar to that measured in the grazing animals, suggesting that this is an attribute of roughage quality, rather than differential eating behaviour between grazing and yarded animals.The wastage, w (g D.M./day), of supplement was linearly related to the amount offered, s (g D.M./day), by the equationw = 0·263s − 38·8; R2 = 0·89Variability in supplement intake between individual grazing lambs was not affected by the level of supplementation but the coefficient of variation of supplement intake was considerably greater than that of the intake of unsupplemented pasture. Variability in the intake of pasture increased with the level of supplementation but variability in the total intake of food was similar at each level of supplement, indicating some degree of individual compensation in the intake of the two components.

scholarly journals Preliminary magnetic resonance relaxometric analysis of Fricke gel dosimeters produced with polyvinyl alcohol and glutaraldehyde

2017 ◽  
Vol 32 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Salvatore Gallo ◽  
Giorgio Collura ◽  
Giuseppina Iacoviello ◽  
Anna Longo ◽  
Luigi Tranchina ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Polyvinyl Alcohol ◽  
Dose Range ◽  
Relaxation Times ◽  
Ion Concentration ◽  
Nuclear Magnetic Resonance Relaxometry ◽  
New Formulation ◽  
Nuclear Magnetic

This work describes the preliminary analysis of Fricke gels dosimeters characterized by a new formulation making use of a matrix of polyvinyl alcohol cross-linked by adding glutaraldehyde and analyzed by means of nuclear magnetic resonance relaxometry. In previous optical studies, these gels have shown promising dosimetric features in terms of photon sensitivity and low diffusion of ferric ions produced after irradiation. In this work, we used a portable nuclear magnetic resonance relaxometer to measure the relaxation times (which are important for dosimetric applications) of these gel materials. For this purpose, we performed a study for optimizing the acquisition parameters with a nuclear magnetic resonance relaxometer. Gel samples were exposed to clinical 6 MV photons in the dose range between 0 and 20 Gy. Nuclear magnetic resonance relaxometry measurements were per- formed and the sensitivity to photon beams was measured for various values of the Fe2+ ion concentration. The analyses pointed out that the MR signal increases as the Fe2+ content in- creases and the increase is about 75 % when the concentration of Fe2+ ions is increased from 0.5 mM to 2.5 mM. Furthermore, the sensitivity improvement achieved with increasing the Fe2+ concentration is about 60 %. This paper shows that the portable nuclear magnetic resonance relaxometer used for analysis of porous materials can be used for characterization of these dosimetric gels and this study can be considered as the first step for the characterization of these dosimeters which in future could be used for 3-D dose mapping in clinical applications.

scholarly journals Safety and Pharmacokinetic Characterization of Nacubactam, a Novel β-Lactamase Inhibitor, Alone and in Combination with Meropenem, in Healthy Volunteers

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Navita L. Mallalieu ◽  
Erica Winter ◽  
Scott Fettner ◽  
Katie Patel ◽  
Elke Zwanziger ◽  
...  
Keyword(s):  
Dose Range ◽  
Drug Dose ◽  
Test Results ◽  
Safety Test ◽  
Class D ◽  
Apparent Relationship ◽  
Dose Study ◽  
Relevant Dose ◽  
Lactamase Inhibitor

ABSTRACT Nacubactam is a novel β-lactamase inhibitor with dual mechanisms of action as an inhibitor of serine β-lactamases (classes A and C and some class D) and an inhibitor of penicillin binding protein 2 in Enterobacteriaceae. The safety, tolerability, and pharmacokinetics of intravenous nacubactam were evaluated in single- and multiple-ascending-dose, placebo-controlled studies. Healthy participants received single ascending doses of nacubactam of 50 to 8,000 mg, multiple ascending doses of nacubactam of 1,000 to 4,000 mg every 8 h (q8h) for up to 7 days, or nacubactam of 2,000 mg plus meropenem of 2,000 mg q8h for 6 days after a 3-day lead-in period. Nacubactam was generally well tolerated, with the most frequently reported adverse events (AEs) being mild to moderate complications associated with intravenous access and headache. There was no apparent relationship between drug dose and the pattern, incidence, or severity of AEs. No clinically relevant dose-related trends were observed in laboratory safety test results. No serious AEs, dose-limiting AEs, or deaths were reported. After single or multiple doses, nacubactam pharmacokinetics appeared linear, and exposure increased in an approximately dose-proportional manner across the dose range investigated. Nacubactam was excreted largely unchanged into urine. Coadministration of nacubactam with meropenem did not significantly alter the pharmacokinetics of either drug. These findings support the continued clinical development of nacubactam and demonstrate the suitability of meropenem as a potential β-lactam partner for nacubactam. (The studies described in this paper have been registered at ClinicalTrials.gov under NCT02134834 [single ascending dose study] and NCT02972255 [multiple ascending dose study].)

scholarly journals Soybean lecithin stabilizes disulfiram nanosuspensions with a high drug-loading content: remarkably improved antitumor efficacy

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Haowen Li ◽  
Biao Liu ◽  
Hui Ao ◽  
Jingxin Fu ◽  
Yian Wang ◽  
...  
Keyword(s):  
Soybean Lecithin ◽  
Drug Loading ◽  
Antitumor Efficacy ◽  
Oral Drug ◽  
High Drug ◽  
Breast Cancer Chemotherapy ◽  
Intravenous Injections

AbstractDisulfiram (DSF) has been considered as “Repurposing drug” in cancer therapy in recent years based on its good antitumor efficacy. DSF is traditionally used as an oral drug in the treatment of alcoholism. To overcome its rapid degradation and instability, DSF nanosuspensions (DSF/SPC-NSps) were prepared using soybean lecithin (SPC) as a stabilizer of high drug-loaded content (44.36 ± 1.09%). Comprehensive characterization of the nanosuspensions was performed, and cell cytotoxicity, in vivo antitumor efficacy and biodistribution were studied. DSF/SPC-NSps, having a spherical appearance with particle size of 155 nm, could remain very stable in different physiological media, and sustained release. The in vitro MTT assay indicated that the cytotoxicity of DSF/SPC-NSps was enhanced remarkably compared to free DSF against the 4T1 cell line. The IC50 value decreased by 11-fold (1.23 vs. 13.93 μg/mL, p < 0.01). DSF/SPC-NSps groups administered via intravenous injections exhibited better antitumor efficacy compared to the commercial paclitaxel injection (PTX injection) and had a dose-dependent effect in vivo. Notably, DSF/SPC-NSps exhibited similar antitumor activity following oral administration as PTX administration via injection into a vein. These results suggest that the prepared nanosuspensions can be used as a stable delivery vehicle for disulfiram, which has potential application in breast cancer chemotherapy.

Synthesis and Characterization of Novel ZnO Nanophosphors

2014 ◽  
Vol 938 ◽  
pp. 145-148
Author(s):  
Manmohan Singh Kurrey ◽  
Bhoopendra Dhar Diwan
Keyword(s):  
Zinc Oxide ◽  
Dose Range ◽  
Synthesis And Characterization ◽  
The Novel ◽  
Maximum Value ◽  
Solgel Method ◽  
Thermo Luminescence

In this paper, the novel ZnO nanophosphors is synthesized by solgel method. The study exposed ZnO nanophosphors samples in Gamma (y) radiation to investigate their thermo-luminescence (TL) intensity as a function of temperature. The thermo-luminescence response has been studied in the dose range 0.291.16 kGy and it is observed that the thermo-luminescence response increases with increase in the dose. Moreover, the TL intensity increases with temperature and attains its maximum value near 200 Cand decreases after this temperature. Keywords: Dosimetry; Thermo-luminescence; Zinc oxide; Nanophosphors.

Comparison of in vivo and in silico growth performance and variability in pigs when applying a feeding strategy designed by simulation to control the variability of slaughter weight

2014 ◽  
Vol 54 (12) ◽  
pp. 1939 ◽  
Author(s):  
L. Brossard ◽  
B. Vautier ◽  
J. van Milgen ◽  
Y. Salaun ◽  
N. Quiniou
Keyword(s):  
Growth Performance ◽  
Coefficient Of Variation ◽  
In Silico ◽  
Feeding Strategy ◽  
Feeding Strategies ◽  
Net Energy ◽  
Two Phase ◽  
In Silico Simulation ◽  
Ad Libitum

Variability in bodyweight (BW) among pigs complicates the management of feeding strategies and slaughter. Including variability among individuals in modelling approaches can help to design feeding strategies to control performance level, but also its variability. The InraPorc model was used to perform simulations on 10 batches of 84 crossbred pigs each to characterise the effect of feeding strategies differing in amino acid supply or feed allowance on the mean and variation in growth rate. Results suggested that a feed restriction reduces the coefficient of variation of BW at first departure for slaughter (BW1) by 34%. Growth performance obtained from an in silico simulation using ad libitum and restricted feeding plans was compared with results obtained in an in vivo experiment on a batch of 168 pigs. Pigs were offered feed ad libitum or were restricted (increase in feed allowance by 27 g/day up to a maximum of 2.4 and 2.7 kg/day for gilts and barrows, respectively). A two-phase feeding strategy was applied, with 0.9 and 0.7 g of digestible lysine per MJ of net energy (NE) in diets provided before or after 65 kg BW, respectively. Actual growth was similar to that obtained by simulation. Coefficient of variation of BW1 was similar in vivo and in silico for the ad libitum feeding strategy but was underestimated by 1 percentage point in silico for the restriction strategy. This study confirms the relevance of using simulations performed to predict the level and variability in performance of group housed pigs.

Characterizations of the Exponential Distribution via the Blocking Time in a Queueing System with an Unreliable Server

1998 ◽  
Vol 35 (1) ◽  
pp. 236-239 ◽  
Author(s):  
Jian-Lun Xu
Keyword(s):  
Exponential Distribution ◽  
Service Time ◽  
Coefficient Of Variation ◽  
Queueing System ◽  
Random Variables ◽  
Unreliable Server ◽  
Failure Times ◽  
Server Failure

The characterization of the exponential distribution via the coefficient of the variation of the blocking time in a queueing system with an unreliable server, as given by Lin (1993), is improved by substantially weakening the conditions. Based on the coefficient of variation of certain random variables, including the blocking time, the normal service time and the minimum of the normal service and the server failure times, two new characterizations of the exponential distribution are obtained.

Characterization of macrophages elicited by intraperitoneal injection of hyaluronate

1986 ◽  
Vol 18 (5-6) ◽  
pp. 544-549 ◽  
Author(s):  
D. Ponzin ◽  
P. Vecchia ◽  
G. Toffano ◽  
C. Giordano ◽  
A. Bruni
Keyword(s):  
Intraperitoneal Injection

Electronic Platelet Counting after Isopycnic Differential Centrifugation A Simple Rapid and Accurate Method

1974 ◽  
Vol 32 (01) ◽  
pp. 232-238 ◽  
Author(s):  
M De Bruyere ◽  
CL Bellenot ◽  
G Sokal
Keyword(s):  
Blood Sample ◽  
Coefficient Of Variation ◽  
Accurate Method ◽  
Routine Laboratory ◽  
Differential Centrifugation ◽  
Nacl Solution ◽  
Counting Procedure ◽  
Platelet Number ◽  
Electronic Method ◽  
Electronic Platelet Counting

SummaryA semi-automatized platelet counting procedure with the use of a Coulter Counter is described. Its originality consists in providing an electronic method of counting of the platelets after a differential centrifugation of the blood sample previously diluted with a hypertonic NaCl solution (density 1.053) which is isopycnic to platelet density. This procedure allows elimination of red and white cells without loss of platelets in the supernatant. The final platelet number can be calculated without further corrections.The method is quick and does not require specially skilled technicians. A single technician can perform 40 counts in one hour. The reproductibility of the method is excellent and the coefficient of variation 2,4 %.The accuracy and feasibility of the method is also sustained by two years’ experience in an haematological routine laboratory.

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