Wheat photosystem II heat tolerance: evidence for genotype-by-environment interactions

High temperature stress inhibits photosynthesis and threatens wheat production. One measure of photosynthetic heat tolerance is T_crit - the critical temperature at which incipient damage to photosystem II (PSII) occurs. This trait could be improved in wheat by exploiting genetic variation and genotype-by-environment interactions (GEI). Flag leaf T_crit of 54 wheat genotypes was evaluated in 12 thermal environments over 3 years in Australia, and analysed using linear mixed models to assess GEI effects. Nine of the 12 environments had significant genetic effects and highly variable broad-sense heritability (H² ranged from 0.15 to 0.75). T_crit GEI was variable, with 55.6% of the genetic variance across environments accounted for by the factor analytic model. Mean daily growth temperature in the month preceding anthesis was the most influential environmental driver of T_crit GEI, suggesting biochemical, physiological and structural adjustments to temperature requiring different durations to manifest. These changes help protect or repair PSII upon exposure to heat stress, and may improve carbon assimilation under high temperature. To support breeding efforts to improve wheat performance under high temperature, we identified genotypes superior to commercial cultivars commonly grown by farmers, and demonstrated potential for developing genotypes with greater photosynthetic heat tolerance.

The medico-legal investigation of abandoned fetuses and newborns--a review of cases admitted to the Pretoria Medico-Legal Laboratory, South Africa

There is a dearth of literature on the extent of fetal or newborn abandonment or "dumping" and the medico-legal investigation procedures these cases require. This is despite the fact that these occurrences are a worldwide phenomenon and by definition involve criminal law concerns such as illegal abortion, concealment of birth, murder, or neonaticide, depending on the country concerned. This article contributes to current literature in both respects and provides a retrospective case audit for the period 2004-2008 pertaining to all abandoned newborns and fetuses admitted to the Pretoria Medico-Legal Laboratory (PMLL) in South Africa. Demographic details, scope, and nature of the medico-legal investigation as well as formulation of cause of death were recorded. A total of 289 cases were identified for inclusion in this study, 57% of which were considered to have been non-viable fetuses, while 45 of the viable fetuses were deemed to have been stillborn. These instances involve the crimes of concealment of birth and at times illegal abortion, yet prosecution of these cases are relatively unheard of. Signs of live birth were identified in 38 of the cases in the study. Of these infants, 9 were deemed to have died from injuries they have sustained, and in a further 9 cases, no anatomical cause of death could be identified. Homicidal cases should be brought in cases where death ensued as a result of abandonment; however, it is not known how many cases were prosecuted. A comparatively large number of cases were found to have been admitted to the Pretoria Medico-Legal Laboratory. This is alarming because South African abortion laws are liberal and services are free at point of access in the public health care sector. A substantial percentage of cases of abandoned infants were found to have shown signs of life after birth implying a homicidal manner of death or death by abandonment, but it seems these cases are merely shelved.

Management of women who test positive for high-risk types of human papillomavirus: the HART study

BACKGROUND

Certain types of human papillomavirus (HPV) are the primary cause of almost all cervical cancers. HPV testing of cervical smears is more sensitive but less specific than cytology for detecting high-grade cervical intraepithelial neoplasia (CIN2+). HPV testing as a primary screening approach requires efficient management of HPV-positive women with negative or borderline cytology. We aimed to compare the detection rate and positive predictive values of HPV assay with cytology and to determine the best management strategy for HPV-positive women.

METHODS

We did a multicentre screening study of 11085 women aged 30-60 years. Women with borderline cytology and women positive for high-risk HPV with negative cytology were randomised to immediate colposcopy or to surveillance by repeat HPV testing, cytology, and colposcopy at 12 months.

FINDINGS

HPV testing was more sensitive than borderline or worse cytology (97.1% vs 76.6%, p=0.002) but less specific (93.3% vs 95.8%, p<0.0001) for detecting CIN2+. Of 825 randomised women, surveillance at 12 months was as effective as immediate colposcopy. In women positive for HPV at baseline, who had surveillance, 73 (45%) of 164 women with negative cytology and eight (35%) of 23 women with borderline cytology were HPV negative at 6-12 months. No CIN2+ was found in these women, nor in women with an initial negative HPV test with borderline (n=211) or mild (32) cytology.

INTERPRETATION

HPV testing could be used for primary screening in women older than 30 years, with cytology used to triage HPV-positive women. HPV-positive women with normal or borderline cytology (about 6% of screened women) could be managed by repeat testing after 12 months. This approach could potentially improve detection rates of CIN2+ without increasing the colposcopy referral rate.

The misdiagnosis of epilepsy: findings of a population study

This paper reports the results of a population study designed to assess the standards of epilepsy care within a geographical population in relation to diagnosis, seizure management and quality of life. One of the findings was the unexpectedly high frequency of the misdiagnosis of epilepsy. Forty-nine of 214 patients with a primary diagnosis of epilepsy were subsequently found to have been misdiagnosed following a specialist review and investigations. All except two have been withdrawn from antiepileptic medication. The diagnosis of epilepsy was disputed in a further 26 patients. Of the 49 patients, 20 were found to have cardiovascular or cerebrovascular pathology. Seven had only ever experienced a single seizure and a further 10 were found to have underlying psychopathology. Such observations support the view that epilepsy is frequently misdiagnosed and this paper discusses some of the implications of misdiagnosis.

The effects of posture on abnormalities of forearm venous tone in women with pregnancy-induced hypertension

1. Forearm venous tone was measured in the left lateral supine position and in response to passive leg elevation in a group of women with pregnancy-induced hypertension and compared with a group of normotensive pregnant women and a group of non-pregnant women. 2. The women with pregnancy-induced hypertension were venoconstricted in the supine position compared with the normal pregnant women (P less than 0.002). There was no difference in forearm venous tone between the women with pregnancy-induced hypertension and the non-pregnant women. 3. In response to passive leg elevation the women with pregnancy-induced hypertension venodilated (P less than 0.002) whereas there was no change in forearm venous tone in the normotensive pregnant women and the non-pregnant women. There was no change in blood pressure in any of the women after 35 min of leg elevation. 4. These results demonstrate that the abnormal venous vasoconstriction that occurs in women with pregnancy-induced hypertension in the supine position is corrected by passive leg elevation, a manoeuvre which leads to an increase in central blood volume.

Abnormalities of peripheral venous tone in women with pregnancy-induced hypertension

Forearm venous tone was measured in two groups of pregnant women: one group with pregnancy-induced hypertension and the other group with normal blood pressure. The women with pregnancy-induced hypertension were venoconstricted in the forearm (P less than 0.01) compared with the pregnant women with normal blood pressure. However, there was no difference in venous tone between the women with pregnancy-induced hypertension and non-pregnant women. There was an inverse correlation between mean arterial blood pressure and forearm venous tone (r = -0.581, P less than 0.001) for all the pregnant women studied. Further evaluation of peripheral venous tone may provide valuable information about the pathophysiology and treatment of women with pregnancy-induced hypertension.