High specificity PCR screening for 22q11.2 microdeletion in three different ethnic groups

Congenital heart defects are the most common of all human birth defects. Numerous studies have shown that a deletion within chromosome 22q11 is associated with DiGeorge syndrome and certain forms of sporadic congenital cardiovascular disease. We have determined the value of a PCR assay using markers D22S941, D22S944 and D22S264 designed for the screening of 22q11.2 deletion through consecutive homozygosity in an ethnically admixed urban population. The study population comprised 149 unrelated men and women from three different ethnic groups (white, mulatto and black). Test specificity for the overall population was estimated at 98.3%. We found no significant difference when comparing heterozygosity indices and ethnicity (P value = 0.43 (D22S944), 0.22 (D22S264), and 0.58 (D22S941)). There was no significant difference regarding assay specificity between the three different ethnic groups studied. This assay could constitute a cost-effective way to screen a large number of patients at increased risk, since PCR techniques are easily available, are fast, can be automatized, and are significantly less expensive than fluorescence in situ hybridization

Effect of the potassium permanganate during papaya fruit ripening: Ethylene production

The effect of potassium permanganate (KMnO$_4$) on the ripening process of papaya fruits by monitoring the ethylene emission rates is reported. The ethylene emission was monitored by a photoacoustic spectrometer. Two experimental conditions were applied, being one of them just putting the fruit alone inside the sampling chamber and the second, modifying the atmosphere by the presence of KMnO$_4$. The use of the ethylene absorber reduces the autocatalytic process of ethylene during papaya fruit ripening. For 20 g of KMnO$_4$ the maximal intensity of the ethylene emission decreases by a factor two. Using the same amount of KMnO$_4$, a reduction of about 2.2% in the concentration of ethylene for a mixture of 1ppmv of ethylene in synthetic air was observed

Photoacoustic technique applied to ethylene emission in passion fruit seedlings: An experimental approach

It is well known that plants respond to mechanical perturbation, such as swaying in the wind, touching or brushing, by a reduction in stem length and an increase in stem diameter. Brushing provides a tactile or thigmic stimulation of the plant growing points and undergo physiological and developmental changes that increase stress tolerance. One of the main hormones released by brushing plants is thought to be ethylene, a plant hormone difficult to trace and monitor because it is a gas. The emission rate of ethylene was monitored using a photoacoustic spectrometer based on the infrared absorption of the line 10P12 and 10P14 of CO$_2$ LASER. In response to the brushing treatment, seedlings of passion fruit (Passiflora edulis L.) showed a increase in the ethylene emission. The aim of this work was to investigate the effect of brushing on the ethylene emission rate of passion fruit seedlings

Photoacoustic study of ethylene emission and respiration rate of carbon dioxide from insulin germinated beans (Phaseolus vulgaris L.)

Photoacoustic (PA) technique was used to study ethylene and CO$_2$ respiration emission rates from germinating bean (Phaseolus vulgaris L) seeds. The concentration of ethylene was measured at 10P(12) and 10P(14) lines of the CO$_2$ laser with the PA cell in the intracavity configuration. On the other hand, the respiration rate of CO$_2$ was deduced (precision 1 ppm) from the concentration data measured by the commercial PA analyser operating in the infrared range. The objective of this study was to obtain better understanding of insulin signalling in the germinating seeds. The experiments were performed with seeds imbibed either in water or in aqueous solution of insulin (0,9 $\mu$g.mL$^{-1}$ H$_2$O)

Correlation between ethylene emission and skin colour changes during papaya (Carica papaya L.) fruit ripening

The skin colour changes and ethylene emission rates were monitored during papaya (C. papaya L.) fruit ripening. Two groups of papaya (‘Formosa’ and ‘Solo’) were applied in this study. The total colour difference was used as measured parameter and the corresponding half time of its saturation was used as correlation parameter. A high correlation factor between the saturation half time and corresponding climacteric peak time was found. It was concluded that high ethylene emission rate in ‘Solo’ fruit promotes a quick change of the total colour difference