Differential antioxidative response of tolerant and sensitive maize (Zea mays L.) genotypes to drought stress at reproductive stage.

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes - Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools - glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.

Malignant risk and surgical outcomes of presacral tailgut cysts.

BACKGROUND: Presacral tailgut cysts are uncommon and few data exist on the outcomes following surgery. METHODS: Patients undergoing tailgut cyst resection at the Mayo Clinic between 1985 and 2008 were analysed retrospectively. Demographic data, clinicopathological features, operative details, postoperative complications and recurrence were reviewed. RESULTS: Thirty-one patients were identified (28 women), with a median age of 52 years. Seventeen patients were symptomatic and 28 had a palpable mass on digital rectal examination. Median cyst diameter was 4.4 cm. Four patients had a fistula to the rectum. Complete cyst excision was achieved in all patients; eight underwent distal sacral resection or coccygectomy. Postoperative complications occurred in eight patients but without 30-day mortality. Malignant transformation was present in four patients: adenocarcinoma in three and carcinoid in one. The cyst recurred in one patient after surgery for a benign lesion. CONCLUSION: Presacral tailgut cysts should be removed due to the risk of malignant transformation.

Cardiovascular effects of nasotracheal intubation.

Intubation time, arterial pressure, heart rate and arterial oxygen saturation during nasotracheal intubation effected with the Macintosh laryngoscope blade were compared with those during orotracheal intubation. The 60 patients studied received a standardised general anaesthetic and were randomly allocated to one of two groups immediately before tracheal intubation. The mean nasal intubation time (33.2 seconds) was significantly greater than mean oral intubation time (14.8 seconds). The mean arterial pressure changes in the nasal group were significantly greater and more prolonged than in the oral group. The mean heart rate in the nasal group was significantly lower than in the oral group during the first minute after intubation, after which heart rates were similar. There were no significant differences between the two groups with regard to arterial oxygen saturation levels at any stage.

Dermatoglyphic profile in congenital cataracts.

Forty-five children with congenital cataract cases were studied for patterns and compared with age sex matched controls. The patients showed marked differences in different dermatoglyphic traits. The intra uterine aetiological groups i.e. rubella, hereditary and undetected aetiology, showed variations in mainline terminations. Rubella group showed increased angle atd.

Sister chromatid exchanges in congenital cataracts.

A total of 25 patients with bilateral congenital cataracts, from three aetiological groups i.e. rubella (6 patients) hereditary (6 patients) and undetected aetiology (13 patients) were studied for sister chromatid exchanges (SCE). SCEs were markedly raised in the rubella groups as compared with age sex matched controls. The other two groups also showed raised SCE, more so in hereditary group.

Genetic appraisal of congenital cataract.

A total of 45 congenital cataract cases were studied for chromosomal aberrations and dermatoglyphic patterns. Whereas parents showed no marked differences, patients showed marked differences in different dermatoglyphic traits as compared to age-sex matched controls. Out of all the patients Rubella, hereditary and undetected actiology groups showed variations differently, SCE were seen in all cataracts irrespective of their aetiology as compared to controls.

Further examples of trisomy-20 mosaicism in amniotic cell cultures.

Amniotic fluid cultures from two patients showed trisomy-20 mosaicism. No trisomy-20 cells were found in a normal full term infant and in multiple tissue biopsies and fetal blood from a fetus after a termination of pregnancy. No definitive advice is yet possible for parents where trisomy-20 amniotic cell mosaicism is detected. Fetoscopy and fetal blood sampling are of no value and termination of pregnancy is not indicated by empirical evidence. Preferential trophoblastic non-disjunction (Kalousek and Dill, 1983) is discussed as a possible partial explanation for the variable occurrence and distribution of this type of mosaicism.

DNA loss in the developing cerebellum of nervous mouse: a flow cytometric study.

Flow-cytometry of cerebellar EGL cells of nervous (nr) mouse revealed a reduction in DNA quantity per cell accompanied by an increase in the DNA dispersion during 6-8 days of postnatal life. This loss of DNA is due to a partial degeneration of the cells of EGL during the first week of postnatal life. The surviving cells later on achieve a DNA content equivalent to their bone marrow cells. The flow-cytometric technique also facilitates an early detection of the homozygous nervous mutant, almost 2 weeks before the clinical manifestation of the disease, which to date was not possible.