Redox changes during cold acclimation affect freezing tolerance but not the vegetative/reproductive transition of the shoot apex in wheat.

Cold acclimation is necessary for winter wheat (Triticum aestivum L.) to achieve its genetically determined maximum freezing tolerance, and cold also fulfils the vernalisation requirement. Chromosome 5A is a major regulator of these traits. The aim of the present study was to discover whether changes in the half-cell redox potential of the glutathione/glutathione disulphide (GSH/GSSG) and ascorbate/dehydroascorbate (AA/DHA) couples induced by cold acclimation are related to freezing tolerance and vernalisation requirement in a specific genetic system including chromosome 5A substitution lines. The amounts of H2O2 and AA, and the AA/DHA ratio showed a rapid and transient increase in the crown of all genotypes during the first week of acclimation, followed by a gradual increase during the subsequent 2 weeks. The amount of GSH and its ratio compared to GSSG quickly decreased during the first day, while later these parameters showed a continuous slow increase. The H2O2, AA and GSH concentrations, AA/DHA and GSH/GSSG ratios and the half-cell reduction potential of the GSH/GSSG couple were correlated with the level of freezing tolerance after 22 days at 2 °C; hence these parameters may have an important role in the acclimation process. In contrast to H2O2 and the non-enzymatic antioxidants, the lipid peroxide concentration and activity of the four antioxidant enzymes exhibited a transient increase during the first week, with no significant difference between genotypes. None of the parameters studied showed any relationship with the vegetative/generative transition state monitored as apex morphology and vernalisation gene expression.

Stress hormones and abiotic stresses have different effects on antioxidants in maize lines with different sensitivity.

The effect of stress hormones and abiotic stress treatments on reactive oxygen species and on antioxidants was compared in two maize (Zea mays L.) lines (Penjalinan and Z7) having different stress tolerance. Following treatment with abscisic acid, salicylic acid or hydrogen peroxide, the amount of hydrogen peroxide and lipid peroxides increased, while after osmotic stress or cultivation in continuous darkness, the levels were unchanged or decreased. The higher amount of lipid peroxides in Penjalinan indicated its greater sensitivity compared to Z7. The level of the examined antioxidants was increased by nearly all treatments. Glutathione and cysteine contents were higher after salicylic acid, hydrogen peroxide and polyethylene glycol treatments and lower after application of abscisic acid, NaCl and growth in darkness in Z7 than in Penjalinan. The activity of glutathione reductase, ascorbate peroxidase, catalase and glutathione S-transferase was higher after almost all treatments in Z7. The expression of the glutathione synthetase (EC 6.3.2.3) gene was not affected by the treatments, while the level of gamma-glutamylcysteine synthetase (EC 6.3.2.2) and glutathione reductase (EC 1.6.4.2) transcripts increased after most treatments. The two stress hormones and the stress treatments resulted in different changes in antioxidant levels in the two maize lines, which indicates the specific, stress tolerance-dependent response of plants to the various growth regulators and adverse environmental effects that were examined.

Rate of Rh immunization after induced abortion.

The occurrence of Rh immunization was investigated in 386 secundigravidae whose first pregnancy was terminated by induced abortion and who were not given anti-D immunoglobulin after the induced abortion. Of these, 6 (1.57%) already proved to be seropositive at the beginning of their second pregnancy, another 6 (1.57%) became positive by the end of the second pregnancy, i.e. 3.14% altogether as demonstrated with papain-treated RBC. If instead the indirect antiglobulin (Coombs) test was used, 3 women (0.77%) proved to be positive at the beginning and 9 (2.31%) at the end of the second pregnancy. Supposing that 0.5% of the secundigravidae became immunized during the second pregnancy, the rate of immunization after induced abortion in non-protected cases may be calculated to be 2.64% using the papain technique and 1.81% when the antiglobulin test is applied.

[Ulcer on the presternal tube after esophagoplasty of the greater curvature of the stomach]. / Ulcer pe tubul presternal dupa esofagoplastie din marea curbura gastrica.

Two cases are discussed, of ulcerations that have developed on the pre-sternal tube following oesophagoplasty according to the D. Gavriliu procedure. In the first case the ulceration determined stenozing of the pre-sternal tube necessitating a by-pass at the lower end of the tube with iso-peristaltic transverse colon. In the second case an external fistula developed at the level of the ulceration. After excision and restoration of the tube continuity by suture two more ulcerative episodes were noted, that benefited from drug treatment and excision of the ulceration.