The endocrine control of reproductive suppression in an aseasonally breeding social subterranean rodent, the Mahali mole-rat (Cryptomys hottentotus mahali).

Cooperative behaviour, sociality and reproductive suppression in African mole-rats have been extensively studied. Nevertheless, endocrine correlates of some species of social mole-rats have been neglected, and these species may hold the key to understanding the behavioural and physiological complexity that allows the maintenance of social groups in African mole-rats. In this study, we investigated endocrine correlates implicated in the suppression of reproduction and cooperative behaviours, namely glucocorticoids (a stress-related indicator) through faecal glucocorticoid metabolites (fGCMs), plasma testosterone (an indicator of aggression) and plasma prolactin in the Mahali mole-rat (Cryptomys hottentotus mahali) across reproductive classes (breeding females and males, non-breeding females and males) and season (wet and dry). Breeders possessed higher levels of testosterone than non-breeders. In reproductively suppressed non-breeding females, fGCMs were significantly higher than in breeders. Furthermore, an adrenocorticotropic hormone stimulation test (ACTH challenge test) on both male and female non-breeders revealed that female non-breeders show a more significant response to the ACTH challenge than males. At the same time, plasma prolactin levels were equally elevated to similar levels in breeding and non-breeding females. Chronically high levels of prolactin and fGCM are reported to cause reproductive suppression and promote cooperative behaviours in non-breeding animals. Furthermore, there was a negative relationship between plasma prolactin and progesterone in non-breeding females. However, during the wet season, a relaxation of suppression occurs through reduced prolactin which corresponds with elevated levels of plasma progesterone in non-breeding females. Therefore, prolactin is hypothesised to be the primary hormone controlling reproductive suppression and cooperative behaviours in non-breeding females. This study provides new endocrine findings for the maintenance of social suppression in the genus Cryptomys.

Resistance Status of Busseola fusca (Lepidoptera: Noctuidae) Populations to Single- and Stacked-Gene Bt Maize in South Africa.

Transgenic Bt maize expressing Cry insecticidal δ-endotoxins of Bacillus thuringiensis has been cultivated in South Africa for the control of Busseola fusca since 1998. Busseola fusca is resistant to Cry1Ab Bt maize at many localities throughout the maize production region. Pre-release evaluation (1994-1996) of the inherent susceptibility and post-release assessments (1998-2011) of resistance status of B. fusca focused on a limited number of pest populations. This study reports the current levels of susceptibility of 10 B. fusca populations evaluated between 2013 and 2017 and compared this data with previously reported data on the survival of this pest on Bt maize, including data of pre-release evaluations done during 1994 and 1995. Larval feeding bioassays in which plant tissue of maize events expressing either Cry1Ab or Cry1A.105+Cry2Ab2 (stacked event) proteins were conducted and survival and different life history parameters recorded. Results show a shift in levels of susceptibility of B. fusca to Bt maize. Pre-release evaluation of the single-gene event showed very low larval survival on Bt maize leaf tissue while studies 10 yr later and the current study reported survival of up to 40% and 100% on Cry1Ab maize, respectively. While no larvae completed their life cycle on the stacked event, higher LT50 values in this study indicate a shift in susceptibility of B. fusca to the stacked-gene event and highlight the importance of baseline information and monitoring of pest populations for their susceptibility to Bt maize.

Effects of Bt maize on Agrotis segetum (Lepidoptera: Noctuidae): a pest of maize seedlings.

The lepidopteran stemborers Busseola fusca (Fuller) (Lepidoptera: Noctuidae), Sesamia calamistis (Hampson) (Lepidoptera: Noctuidae), and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) are effectively controlled by Bt maize that expresses the Cry1Ab insecticidal protein. Another noctuid species, the cutworm Agrotis segetum (Denis and Schiffermüller) (Lepidoptera: Noctuidae), which is the most common and injurious pest of maize seedlings in South Africa, is exposed to Bt toxin for a part of its life cycle. The effect of this exposure to Bt maize has not been studied yet. The aims of this study were to determine the effects of Bt maize (events MON810 and Bt11) on larval mass, development time, survival, and fecundity of A. segetum. Laboratory studies were conducted with first- and fourth-instar larvae and moths. Results showed that the effect of Cry1Ab toxin on the biology of A. segetum larvae and moths were largely insignificant. The effects of the two Bt maize events on the different parameters measured in this study was not similar between the Bt events and their respective iso-hybrids. Compared with larvae that fed on conventional (non-Bt) maize, Bt maize did not affect survival of first-instar larvae. However, mean mass of larvae that fed on Bt maize (Bt11) was significantly lower. Feeding on Bt maize did not have a significant effect on development and survival of fourth-instar larvae or moth longevity. It did, however, delay the development period to pupa formation. Fewer eggs were laid by moths fed as larvae on maize event Bt11 compared with MON810. This study indicates that Bt maize will most likely not have any significant effect on the control of A. segetum under field conditions.

Pre-operative embolisation of metastatic paraganglioma of the thoracic spine.

We report a 46-year-old male with metastatic functioning paraganglioma of the thoracic spine. Thoracic spine functioning paragangliomas are rare and we describe the benefits of embolisation of the lesion prior to surgical decompression.

Newcastle disease and avian influenza A virus in wild waterfowl in South Africa.

In an intensive ostrich farming area in South Africa with a history of ostrich influenza outbreaks, we conducted a survey of avian influenza virus (AIV) and Newcastle disease virus (NDV) in wild aquatic birds. During late autumn and winter 1998, the time of year when outbreaks in ostriches typically start to occur, 262 aquatic birds comprising 14 species were sampled and tested for both virus infections. From eight samples, AIV, serotype H10N9, could be isolated. All isolates were apathogenic as determined by the intravenous pathogenicity index (0.00). Conversely, none of 33 sera of these wild birds showed antibodies against H10. However, one bird was found serologically positive for H6 AIV. This AIV serotype was later isolated from ostriches during an avian influenza outbreak in this area. No NDV was isolated although 34 of 46 serum samples contained NDV-specific antibodies. This is the first H10N9 isolate to be reported from Africa. In addition, our data support the notion that wild aquatic birds may function as a reservoir for AIV and NDV in South Africa.

Prognostic factors for supratentorial low grade astrocytomas in adults.

The principal prognostic factors and effect on survival were retrospectively evaluated in 56 adult patients with supratentorial low grade astrocytomas treated between 1967 and 1993. Fifteen factors were evaluated with uni- and multivariate analysis to investigate their importance in predicting the length of survival. The median patient age at presentation was 42 years and the median survival was 5.0 years. The following characteristics were associated with improved patient survival by univariate analysis (p < 0.01): Age group, preoperative Karnofsky scale, and extent of surgery. Age group and Karnofsky scale were significant by multivariate analysis, but not the extent of surgery. Thus the usefulness of cytoreductive surgery in the management remains unclear, but the extent of surgery is determined by the characteristics of the tumor and the potential of the patient. Since 93% of our patients received postoperative radiotherapy, the effect of adjuvant irradiation could not be determined.

CG-clip expansive open-door laminoplasty: a technical note.

The CG clip is a device designed for use in expansive open-door laminoplasty with both a spacer and means of attachment in a single unit. It provides an effective technique for open-door laminoplasty, which obviates the need for bone grafting or complex internal fixation by providing dynamic stabilization of the open laminae. A number of techniques for expansive open-door laminoplasty have been devised for the decompression of the spinal cord and nerve roots in cervical spondylotic myeloradiculopathy. Each of these techniques requires some degree of internal fixation and/or bone grafting. The CG clip is a single device which is composed of both a spacer and a spring clip for attachment. The spacer ensures a 4-5-mm sagittal expansion of the cervical spinal canal. The spacer is held in place along the lateral cut margin of the laminae by a spring-wound titanium clip, which folds over the central spinous process of the unilaterally elevated laminar block. In all respects except for grafting and internal fixation, the surgery is performed as for a standard expansive open-door laminoplasty. Sixteen of the first 24 patients to undergo this procedure improved at least one point on the Neurosurgical Cervical Spine Scale. Of the remaining eight patients, four remained the same and four deteriorated. The authors have found the CG-clip laminoplasty technique quick and easy to perform, with early results in the treatment of cervical spondylotic myeloradiculopathy consistent with those of other decompressive procedures.

Unusual presentations of cerebral hydatid disease in children.

Three children with hydatid disease of the central nervous system (CNS) were seen. In two patients the lateral ventricles were involved, whilst one case involved the cerebellar hemisphere. In addition, one child presented with a deposit in the maxillary antrum, and deposits were also found in the liver. Operative removal of the deposits was performed, followed by post-operative treatment with praziquantel and albendazole. Investigation of other sites outside the CNS was undertaken for occult lesions. All hydatid cysts were clearly demonstrated on CT, but two cases posed the pre-operative problem of differential diagnosis from arachnoid cysts.