Most hepatitis A virus replication in cell cutter has been reported to be nonlytic and relatively slow. A rapidly replicating isolate of strain HM-175 from persistently infected, serially passed cell cultures (pHM-175) was found to induce a cytopathic effect. This observation allowed the development of a classic plaque assay for pHM-175 in FRhK-4 cells (fetal rhesus kidney) which were used for the preparation of some lytic virus stocks and for all plaque assays. All cells were cultured at 37oC in DMEM + 10% FCS + 5mcg/ml gentamicin sulfate (GIBCO, Grand, NY). The pHM-175 stock was made by decanting supernatant medium and freezing infected cells in DMEM at -70oC.
Hepatitis A virus ; Titrimetry

AIMTo indicate the titration end-point of precipitation reaction by measuring the relative intensity of the scattered light in the titrate for use in pharmaceutical analysis.

METHODSA visible light-emitting diode (LED) was used as a light source and a photodiode was used as the optical detector. Light on the detector creates an electric current through the diode. With the addition of the titrant, the titrate became turbid and the intensity of the scattered light in the solution increased gradually. If the precipitation reaction proceeded the completion and the solubility of the precipitate was small enough, the intensity of the scattered light will reach maximum at the stoichiometric point; thus, the titration end-point can be indicated. The accuracy of nephelometric titrimetry was discussed theoretically and the titration of NaCl with AgNO3 was used as a model. To demonstrate the applicability of the new titrimetry in pharmaceutical analysis, phenytoin sodium and procaine hydrochloride were titrated with AgNO3 and NaOH solutions, respectively.

RESULTSWith our new titrator and nephelometric sensor, the accuracy and precision of our new titrimetry can be better than 0.2% under suitable conditions.

CONCLUSIONThis new titrimetry can be used for pharmaceutical analysis.

Phenytoin ; analysis ; Procaine ; analysis ; Titrimetry ; instrumentation ; methods

This essay is to present an improvement on the concentration assay for hemihydrate gypsum in plaster of Paris bandage-Viscose form.
Calcium Sulfate ; analysis ; Casts, Surgical ; Titrimetry ; methods

AIMTo determine phenytoin sodium by a highly accurate nephelometric titration.

METHODSThe titration operating conditions were optimized and the solubility product constant of phenytoin silver precipitation was determined.

RESULTSThe result of the titration is comparable to those of control experiments.

CONCLUSIONThe proposed method has been found to be accurate, precise, specific, reproducible, and linear.

Nephelometry and Turbidimetry ; methods ; Phenytoin ; analysis ; Reproducibility of Results ; Solutions ; Titrimetry ; methods

Determined the easily oxidized substance of the injector based on GB15810-2001, and analyzed the source of uncertainty of the process of titration symmetrically, and valued the uncertainty of the result of data analysis.
Oxidation-Reduction ; Oxygen Compounds ; analysis ; Syringes ; Titrimetry ; Uncertainty

The main physiological role of iodine in the body is to synthesize thyroid hormone. Both iodine deficiency and iodine excess can lead to severe thyroid diseases. While its role in thyroid diseases has increasingly been recognized, few relevant platforms and techniques for iodine detection have been available in China. This paper summarizes the advantages and disadvantages of currently iodine detection methods including direct titration, arsenic cerium catalytic spectrophotometry, chromatography with pulsed amperometry, colorimetry based on automatic biochemistry, inductively coupled plasma mass spectrometry, so as to optimize the iodine nutrition for patients with thyroid diseases.
Humans ; Iodides ; analysis ; Iodine ; analysis ; metabolism ; Mass Spectrometry ; Spectrophotometry ; Thyroid Diseases ; diagnosis ; Titrimetry

OBJECTIVETo explore the HSVtk gene expression mediated by the retroviral vector and to obtain high titer recombinant retroviral virus.

METHODSThe recombinant vector pRevTRE/HSVtk was constructed by inserting HSVtk gene into pRevTRE. The recombinant retrovirus, which was produced from cloned PA317 cells screened by hygromycin B after "micro-pingpong" technique transferring with pRevTRE/HSVtk plasmids DNA by using modified calcium phosphate precipitation method. HSVtk gene expression was performed on target cells and virus titers were detected in different cultured temper, time and sodium butyrate concentration.

RESULTSThe recombinant retroviral vector pRevTRE/HSVtk was constructed and HSVtk gene expression was detected on target cells after they were infected with the recombinant retrovirus.

CONCLUSIONHigh titer of retroviruses could be obtained in the culture medium of PA317 cell line through "micro-pingpong" technique at 30 hours and 10 mmol/L sodium butyrate concentration followed by frozen ultrafiltration.

Animals ; Breast Neoplasms ; enzymology ; pathology ; virology ; Cell Line ; Cell Line, Tumor ; Female ; Gene Expression Regulation, Enzymologic ; Genetic Vectors ; Humans ; Mice ; NIH 3T3 Cells ; Recombination, Genetic ; Retroviridae ; genetics ; Simplexvirus ; enzymology ; genetics ; Thymidine Kinase ; biosynthesis ; genetics ; Titrimetry ; Transfection