No abstract available.
Centrifugation ; Weightlessness

No abstract available.
Centrifugation ; Stem Cells

No abstract available.
Centrifugation ; Stem Cells

PURPOSE: The purpose of this study was to observe the effect of IFN- and PGE2 on TNF- production by human peripheral mononuclear cells(PBMC) that were stimulated with LPS. METHODS: PBMC were separated by Ficoll-Hypaque gradient centrifugation from human peripheral venous blood and were incubated for 72 hours with or without LPS, IFN- , PGE2, and indomethacin according to various conditions. TNF- activity of PBMC culture supernatants was assayed by determining the cytotoxicity against L929 cells. RESULTS: 1) The production of TNF- by PBMC in response to LPS reached the highest level between 8-24 hours and returned to control level by 72 hours. 2) When IFN- was added together with LPS, LPS-induced TNF- production was enhanced and prolonged, which was more remarkable when IFN- was added at higher concentration or earlier than LPS. 3) When PGE2 was added together with LPS, LPS-induced TNF- production was suppressed. 4) The addition of IFN-gamma reduced the suppressive effect of PGE2 on LPS-induced TNF- production. 5) Enough amount of indomethacin enhanced production of TNF- by LPS. CONCLUSIONS: IFN-gamma increased and PGE2 decreased the production of TNF- by PBMC which were stimulated with LPS. And PBMC which were pretreated with IFN-gamma were resistent to the suppressive effect of PGE2.
Centrifugation ; Dinoprostone* ; Humans* ; Indomethacin

Background: In Vietnam, the proportion infertile couples was about 7-10% of reproductive couples. Assisted reproductive technologies appeared and expanded rapidly. In 1970, sperm preparation techniques were found out, artificial insemination became widespread. Sperm preparation stage is very important in assisted reproductive techniques and increasingly improved. Objectives: To compare the efficiency of two sperm preparation techniques: swim \ufffd?up and discontinuous density gradient. Subjects and method: This was a cross-sectional described study included 30 normal semen samples were chosen based on WHO 1999 criteria. We examined sperm vitality, concentration, motility, morphology before and after applied these techniques. Results: Both procedures resulted in a significant higher percentage of vitality, motility, morphology compared with the original semen sample (p<0.01), but the concentration reduced approximately 5 times from whole semen to sediment when swim \ufffd?up was used and 3 times with density gradient, the difference was statically significant (p< 0.01). Conclusion: Normal semen should be prepared by these method. But in oligozoospermic man, to obtain a higher concentration of sperm, semen should be prepared by density gradient method.
Spermatozoa ; Centrifugation ; Density Gradient ;

No abstract available.
Centrifugation, Density Gradient* ; Humans* ; Spermatozoa*

PURPOSE: Although various sampling methods of tears from conjunctival sac have been reported, no previous study compared their effectiveness or efficiency based on protein extraction. By comparing the compliance, volume and protein concentration of each tear sampling method, we searched for the most efficient tear collection method. METHODS: Resting tear samples of 14 eyes of normal subjects were collected using Schirmer paper, capillary tube, cellolose acetate rod and 3 different ophthalmic sponges made of different materials and density (Merocel(R), KeraCel(R) and Weck-Cel(R)). After centrifugation of the collected tear samples, the tear volume and protein concentration were measured for each method. Additionally, the compliance of each tear sampling method was analyzed by numerically representing the amount of discomfort experienced during resting tear collection. RESULTS: The average volume retrieved by each tear sampling method was 9.0 +/- 1.1 microL with no significant differences between groups. The average concentration of protein retrieved by each tear sampling method was 5.3 +/- 1.2 microg/microL. Merocel(R) retrieved 7.6 +/- 0.61 microg/microL, which was significantly higher than other sampling methods (p < 0.05). The compliance of Merocel(R) and the capillary tube were the highest, while KeraCel(R) showed the lowest compliance. CONCLUSIONS: Merocel(R) retrieved the highest amount of protein and showed high compliance and may be the most effective and easily applicable tear sampling method in clinical settings.
Capillaries ; Centrifugation ; Compliance ; Methods* ; Porifera ; Tears*

Melanosomes were isolated from the human hair by graded centrifugation and identified by transmission and scanning electron microscopic examination. Melanosomes were separated from the keratinous structures by treating with strong NaOH solution for 15 hours. The keratinous structures were removed by centrifugation ai 2,500xg and 3,500xg for 10 minutes respectively at 0 ℃. The isolated melanosomes were collected by centrifugation at 7,800xg at 0 ℃. Scanning electron microscopic examination made it possible to evaluate the global structure of purified melanosomes.
Centrifugation ; Hair* ; Humans* ; Melanosomes* ; Microscopy, Electron, Scanning

A new instrument for hematocrit measurement is introduced in the paper, which can get the same accurate Hct values while its centrifuging speed is reduced. It integrates high speed centrifuge, automatic data processing and automatic analysis of hematocrit into a system, having more advantages than the traditional measuring devices, such as lower noise, less test errors and better accuracy. Therefore, it can satisfy well clinical applications.
Automatic Data Processing ; Centrifugation ; Hematocrit ; instrumentation

BACKGROUND: Reconstructed human epidermal culture skin models have been developed for cosmetic and pharmaceutical research. OBJECTIVE: This study evaluated the total and carboxyl esterase activities (i.e., K(m) and V(max), respectively) and localization in two reconstructed human epidermal culture skin models (LabCyte EPI-MODEL [Japan Tissue Engineering] and EpiDerm [MatTek/Kurabo]). The usefulness of the reconstruction cultured epidermis was also verified by comparison with human and rat epidermis. METHODS: Homogenized epidermal samples were fractioned by centrifugation. p-nitrophenyl acetate and 4-methylumbelliferyl acetate were used as substrates of total esterase and carboxyl esterase, respectively. RESULTS: Total and carboxyl esterase activities were present in the reconstructed human epidermal culture skin models and were localized in the cytosol. Moreover, the activities and localization were the same as those in human and rat epidermis. CONCLUSION: LabCyte EPI-MODEL and EpiDerm are potentially useful for esterase activity prediction in human epidermis.
Animals ; Centrifugation ; Cytosol ; Epidermis ; Humans ; Rats ; Skin*