ABSTRACT
A sensitive and convenient method is described for estimating superoxide dismutase activity using a photochemical augmentation procedure. This method is applicable to both liquid assays and polyacrylamide gel electropherograms. The flux of superoxide is generated by illuminating a reaction mixture containing dianisidine and riboflavin by either a laser source or light from a fluorescent lamp. The oxidation of dianisidine, as sensitized by riboflavin, is enhanced by superoxide dismutase. The increase is linearly dependent on superoxide dismutase concentration. The photochemical reaction is allowed to proceed uninterrupted for a standardized optimum time and intensity of illumination and then terminated by addition of a buffer, 'finibuf', which stabilizes the chromophoric complex formed. This permits the spectrophotometric absorbance measurements of a number of samples collectively and also eliminates the interruption of illumination with the concomitant requirement of a spectrophotometer for constant recording of the absorbance. This method is of utility to both biochemists and clinicians.
Subject(s)
Spectrophotometry/methods , Superoxide Dismutase/analysis , Buffers , Chromogenic Compounds/analysis , Dianisidine/chemistry , Dianisidine/radiation effects , Electrophoresis, Polyacrylamide Gel , Fluorescence , Lasers , Oxidation-Reduction , Photochemistry , Riboflavin/chemistry , Riboflavin/radiation effects , Sensitivity and Specificity , Superoxides/metabolismABSTRACT
Preimplantation genetic diagnosis (PGD) is an early diagnosis of genetic disorders, prior to the onset of pregnancy. PGD incorporates the latest techniques in assisted reproduction and molecular genetics. Embryos or oocytes are biopsied during culture in vitro and genetic analysis is carried out on the blastomeres or polar bodies. Embryos shown to be free of the genetic disease under investigation are transferred to the uterus. Multicolour fluorescence in situ hybridisation (FISH) is used to diagnose numerical and certain structural abnormalities of chromosomes in the embryo. The common probes used are for chromosomes 13, 18, 21, X and Y. FISH can also be used for PGD of translocations, when one of the parents is a carrier. PGD was carried out recently in 4 cases using multicolour FISH. In one of the embryos, trisomy 18 was detected. Tetraploidy was seen in another embryo. Only chromosomally normal embryos were transferred back to the uterus. Care has to be taken while interpreting FISH signals as the signal may be split, diffused, superimposed or in a different focus.
Subject(s)
Genetic Testing/methods , In Situ Hybridization, Fluorescence , Preimplantation Diagnosis/methods , Blastomeres , Chromosome Aberrations , Embryo Transfer , Female , Fertilization in Vitro/methods , Humans , Pregnancy , Prospective Studies , Sensitivity and SpecificityABSTRACT
Ultrasonography was performed during the second trimester (17 weeks) in a pregnancy at risk for osteogenesis imperfecta congenita (OI). The scan showed that the femur was short, bent and dense. Radiologic examination of the fetus after interruption of pregnancy showed typical X-ray changes of OI.
