Placenta localization using Indium-113

No Abstract

A simple automated system for the routine production of 99mTc by methyl-ethyl-ketone extraction

A relatively simple, automated system for the rapid, efficient and safe routine production of 99mTcM from 99Mo03 by the methyl-ethyl-ketone (MEK) extraction technique is described. The 4 phases of the extraction process - bubbling of air, phase separation, drawing off of 99mTc in MEK, and evaporation to dryness, are controlled by an automatic timer, suction-pressure pump and solenoid switches. The eluate was found to contain neither bacterial organisms or pyrogens nor significant levels of alumina and radio-isotopic impurities. With this system it is possible to make use of locally produced 99Mo, even of low specific activity for the routine production of 99mlc in any concentration required.S. Afr. Med. J., 48, 998 (1974)

Indium·113m vir hart-, lewer- en plasentaflikkergrafie

No Abstrac

Growth media effects on shoot physiology, nodule numbers and symbiotic nitrogen fixation in soybean

AbstractSeveral research groups (both in South Africa and other countries) are currently involved in research aimed at improving symbiotic nitrogen fixation (SNF) and root nodule sustainability in soybean [Glycine max (L.) Merr.]. In many of these experiments potted plants are used, and in this paper the importance of careful selection of growth media is demonstrated. Bradyrhizobium japonicum-inoculated soybean seedlings were cultivated in pots containing N-free growth media (sand, fine vermiculite or coarse vermiculite) or a growth medium containing low concentrations of water-soluble nitrogen predominantly in the form of ammonium (mixture of potting soil, sand and vermiculite). The effects of growth media on shoot physiology were assessed by measurement of plastochron index, chlorophyll content and CO2 assimilation rates. Nodule numbers, nitrogenase activity and nodule ureide content were also determined. Although similar source–sink relationships were maintained in plants cultured in the various growth media, large effects on nodule numbers and SNF were observed. Shoot phenotype and physiology did not provide any insight into these belowground effects. The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity. Vermiculite, irrespective of particle size, resulted in plants with root systems housing nodules with high SNF activity. It is concluded that choice of growth media for cultivating soybean plants under controlled growth conditions is an important consideration, especially in multi-institution collaborations where comparability between experiments is a pre-requisite

Inhibition of photosystem II activities in soybean (Glycine max) genotypes differing in chilling sensitivity

AbstractDue to chilling sensitivity, minimum night temperatures represent the main constraint in soybean production in South Africa. In vivo quantification of photosystem II (PSII) function by direct chlorophyll fluorescence revealed that dark chilling (8°) inhibited PSII function in the extreme chill sensitive genotype, Java 29 (JAs) mainly by deactivating reaction centers and inhibiting the conversion of excitation energy to electron transport and electron transfer from reduced plastoquinone to the PSI end electron acceptors. Further analysis of the normalized fast fluorescence transients, revealed that in JAs, upon dark chilling, disengagement of the oxygen evolution complex (ΔVK band) occurred which coincided with a concomitant decrease in O2 evolution measured in vitro. The chilling resistant Maple Arrow (MAr), though one night cold stress lead to a decrease in fluorescence emission at 2ms (−ΔVJ band) indicating a decrease in the QA− concentration due to cold-induced slow-down of electron donation from P680, however showed clear signs of recovery after the second and third cold nights. The moderate chill sensitive genotype, Fiskeby V (FBm) responded in a fashion intermediate to above-mentioned extremes. A second experiment showed that in JAs the inhibitory effect increased with increasing time of exposure to light following dark chilling. Our data demonstrated that significant differences exist in the cold tolerance of different soybean genotypes: (a) In respect to activity criteria, expressed by the quantum yields for primary photochemistry φPo=TRo/ABS, for electron transport from photosystem II to photosystem I as φEo=ETo/ABS and the efficiency, φRo=REo/ABS, to reduce the end electron acceptors of photosystem I up to NADP; (b) In respect to stability criteria, dependent on structure and conformation, such as the capability of energetic cooperativity (grouping) among photosynthetic units quantified by the grouping probability for exciton movements within the energetically connected group of entire photosynthetic units. Therefore analyzing the O-J-I-P fluorescence transient according to the JIP-test offers a practical and sensitive in vivo screening test for dark chilling tolerance in soybean

99mTc-MIBI stress-rest myocardial perfusion scintigraphy in patients with complete left bundle branch block

Background. Patients with complete left bundle branch block (LBBB) often show a false-positive ischaemic pattern in the interventricular septum on thallium-201 (201Tl) stress-rest myocardial perfusion scintigraphy. Equivocal results have been reported with technetium-99m labelled hexakis-methoxyisobutyl isonitrile (99mTc-MIBI) in such patients. The aim of this retrospective study was to determine the effect of LBBB on the septal uptake of 99mTc-MIBI during stress-rest single photon emission computed tomography (SPECT) scintigraphy. Methods. We studied 75 consecutive patients with LBBB, referred for 99mTc-MIBI stress-rest SPECT. Studies were evaluated by visual analysis using a semi-quantitative grading technique. In all patients with abnormal septal segments, the presence or absence of ischaemic heart disease was confirmed either clinically or by means of angiographical examination. Results. Forty-three patients (57.3%) had completely normal studies. Only 15 (20%) had septal abnormalities (11 with reversible and 4 with fixed defects), while 17 patients (22.7%) had abnormal segments in areas other than the interventricular septum. Except for 1 patient lost to follow-up, ischaemic heart disease was confirmed in all the patients with septal changes. Conclusion. We conclude that 99mTc-MIBI is more specific than 201Tl for identifying ischaemic heart disease in the presence of LBBB.Articl

Evaluation of proline accumulation as an indicator of drought tolerance in spring wheat cultivars

The aim of this study was to evaluate proline accumulation as an indicator of drought stress and drought tolerance in spring wheat cultivars (Triticum aestivum L.) grown in the Western Cape. Drought stress was induced in whole plants and leaf discs in two cultivars with known drought tolerance, namely, Gamtoos (drought tolerant) and SST 66 (slightly drought sensitive), as well as in two cultivars with unknown drought tolerance, namely, Nantes and SST 44. To assess the effect of growth stage on the reaction of the cultivars to drought stress, stress was induced during pre-anthesis and also during anthesis. Proline accumulation in whole plants showed clear genotypical differences during pre-anthesis and, to a lesser extent, during anthesis. A positive correlation between the degree (onset and extent) of proline accumulation and drought tolerance was found for Gamtoos and SST 66. Proline accumulation patterns in leaf discs did not correlate with results obtained with whole plants.Revie

Evaluation of the relative water content and the reduction of 2,3,5-triphenyltetrazoliumchloride as indicators of drought tolerance in spring wheat cultivars

The aim of this study was to evaluate the relative water content and the reduction of 2,3,5-triphenyltetrazoliumchloride, as indicators of drought stress and drought tolerance in spring wheat cultivars (Triticum aestivum L.) grown in the Western Cape. Drought stress was induced in two cultivars with known drought tolerance, namely, Gamtoos (drought tolerant) and SST 66 (slightly drought sensitive), as well as in two cultivars with unknown drought tolerance, namely, Nantes and SST 44. To assess the effect of growth stage on the reaction of the cultivars to drought stress, stress was induced during pre-anthesis and also during anthesis. Relative water content patterns for the different cultivars showed clear genotypical differences during pre-anthesis and, to a lesser extent, during anthesis. A positive correlation between the ability to maintain relative water content levels and drought tolerance was found for Gamtoos and SST 66. The results obtained with the reduction of 2,3,5-triphenyltetrazoliumchloride during drought stress showed only minor genotypical differences, and no correlation could be shown between the degree of reduction and drought tolerance.Revie