Stem cell repair of central nervous system injury

Neural stem cells (NSCs) have great potential as a therapeutic tool for the repair of a number of CNS disorders. NSCs can either be isolated from embryonic and adult brain tissue or be induced from both mouse and human ES cells. These cells proliferate in vitro through many passages without losing their multipotentiality. Following engraftment into the adult CNS, NSCs differentiate mainly into glia, except in neurogenic areas. After engraftment into the injured and diseased CNS, their differentiation is further retarded. In vitro manipulation of NSC fate prior to transplantation and/or modification of the host environment may be necessary to control the terminal lineage of the transplanted cells to obtain functionally significant numbers of neurons. NSCs and a few types of glial precursors have shown the capability to differentiate into oligodendrocytes and to remyeliate the demyelinated axons in the CNS, but the functional extent of remyelination achieved by these transplants is limited. Manipulation of endogenous neural precursors may be an alternative therapy or a complimentary therapy to stem cell transplantation for neurodegenerative disease and CNS injury. However, this at present is challenging and so far has been unsuccessful. Understanding mechanisms of NSC differentiation in the context of the injured CNS will be critical to achieving these therapeutic strategies.     

Carbohydrate ingestion,blood glucose and mood

A series of studies have reported that a high carbohydrate meal, or diets high in carbohydrate, were associated with feeling less energetic. However, after a drink containing pure sugar most studies report no effect. Meals almost exclusively carbohydrate increase the availability of tryptophan and hence serotonin synthesis in the brain, however, a small amount of protein blocks this mechanism making it an uncommon response. In many individuals, poor mood stimulates the eating of palatable high carbohydrate/high fat foods that stimulate the release of endorphins. There is a tendency for those with lower blood glucose, when performing cognitively demanding tasks, to report poorer mood. In a range of situations an association between a tendency for blood glucose levels to fall rapidly, and irritability, has been found. Differences in the ability to control blood glucose levels influence the association between carbohydrate intake and mood. There is a need in future research to contrast the impact of carbohydrate on mood in those distinguished because of their pre-existing psychological and physiological functioning.     

An unknown combination of infantile spasms, retinal lesions, facial dysmorphism and limb abnormalities

A female patient is presented with infantile spasms, punched-out retinal lesions, facial dysmorphism, short upper arms, short thumbs, left lower limb hypoplasia with foot deformity, a hemivertebra, atrial septal defect, growth retardation and severe developmental delay. There is some similarity to patients with Aicardi syndrome (AS), but the retinal lesions in our patient are different and she does not have agenesis of the corpus callosum, one of the diagnostic features of AS. She might represent an atypical form of this syndrome with additional features, usually not present in AS. As there is no diagnostic test for AS yet, this diagnosis cannot be confirmed nor rejected with certainty. However, it might be more likely that our patient has another, possibly unique, condition.     

Glucose tolerance predicts performance on tests of memory and cognition

The hypothesis that the ability to control blood glucose levels influence memory and other aspects of cognition was considered. Individual differences in the ability to control blood glucose were measured by giving a glucose tolerance test (GTT) to 46 young adult females. A factor analysis of a series of measures of glucose tolerance produced four dimensions. A week later, having eaten their normal breakfast, they took tests of memory, reaction times and vigilance. The speed with which blood glucose increased, having its lowest point in the GTT, was associated with memory measured a week later. While performing the tests those with higher levels of blood glucose on arrival in the laboratory had quicker reaction times when monitoring eight but not four, two or one lamps. The finding was interpreted as demonstrating that higher levels of blood glucose specially influence tasks placing higher demands on the brain.     

CYP11β1 (11-beta-hydroxylase) deficiency in congenital adrenal hyperplasia

Objective : To review experience of CYP11β1 deficiency (previously known as 11β-hydroxylase) at the Royal Children's Hospital, Melbourne, Victoria.
Methodology : A retrospective case review was conducted from 1974 to 1995 with five cases identified.
Results : Age of presentation ranged from 1 day to 7 years. Presentation was with ambiguous genitatia at birth (two females), simple virilization (two males) and suspected early puberty in mid childhood (one female). Associated clinical features were hypertension (three cases) and tall stature with markedly advanced bone age (four cases). Biochemical abnormalities consistent with CYP11β1-deficiency were elevated urinary tetrahydro-11-deoxycortisol ( n = 5) and elevated serum 11-deoxycortisol ( n = 3). Additional abnormalities were elevated 17-hydroxyprogesterone ( n = 3), elevated androstenedione ( n = 4) and elevated dehydroepiandrosterone sulphate ( n = 4). The clinical features and investigations suggested CYP11β1-classical deficiency in four patients and CYP11β1-non-classical deficiency in one patient.
Conclusions : The five cases of CYP11β1-deficiency demonstrate a spectrum of clinical abnormalities, with diagnostic difficulties in two cases and delayed presentation in three cases. Prompt diagnosis of CYP11β1-deficiency is facilitated greatly by the availability of a gas chromatography-mass spectrometry instrument and is essential to avoid the long-term effects of hypertension and hyperandrogenism.     

Visuospatial judgment and right hemisphere disease.

The performances of patients with stroke-produced unilateral hemispheric lesions on a test requiring the identification of lines were examined in the light of a recent report that contradicted previous observations. The study confirmed the results of earlier studies that patients with lesions of the right hemisphere show a remarkably high frequency of defective performances while those with lesions of the left hemisphere do not. Possible reasons for findings that deviate from this rule are discussed.