Traumatic brain injury modifies synaptic plasticity in newly-generated granule cells of the adult hippocampus.

The hippocampus is vulnerable to traumatic brain injury (TBI), and hippocampal damage is associated with cognitive deficits that are often the hallmark of TBI. Recent studies have found that TBI induces enhanced neurogenesis in the dentate gyrus (DG) of the hippocampus, and this cellular response is related to innate cognitive recovery. However, cellular mechanisms of the role of DG neurogenesis in post-TBI recovery remain unclear. This study investigated changes in long-term potentiation (LTP) within the DG in relation to TBI-induced neurogenesis. Adult male rats received a moderate TBI or sham injury and were sacrificed for brain slice recordings at 30 or 60 days post-injury. Recordings were taken from the medial perforant path input to DG granule cells in the presence or absence of the GABAergic antagonist picrotoxin, reflecting activity of either all DG granule cells or predominately newborn granule cells, respectively. Measurements of LTP observed in the total granule cell population (with picrotoxin) showed a prolonged impairment which worsened between 30 and 60 days post-TBI. Under conditions which predominantly reflected the LTP elicited in newly born granule cells (no picrotoxin), a strikingly different pattern of post-TBI changes was observed, with a time-dependent cycle of functional impairment and recovery. At 30 days after injury this cell population showed little or no LTP, but by 60 days the capacity for LTP of the newly born granule cells was no different from that of sham controls. The time-frame of LTP improvements in the newborn cell population, comparable to that of behavioral recovery reported previously, suggests the unique functional properties of newborn granule cells enable them to contribute to restorative change following brain injury.

Absolute phase measurement in fringe projection using multiple perspectives.

A technique for absolute phase measurement in fringe projection for shape measurement is presented. A standard fringe projection system is used, comprising a camera and a projector fixed relative to each other. The test object is moved to different orientations relative to the fringe projection system. Using the system calibration parameters, the technique identifies homologous surface areas imaged from different perspectives and resolves the 2 π phase ambiguity between them simultaneously. The technique is also used to identify regions of the phase maps corresponding to discrete surfaces on the object. The methods described are suitable for automatic shape measurement with a lightweight fringe projection probe mounted to a coordinate measuring machine.

Phase-stepped fringe projection by rotation about the camera's perspective center.

A technique to produce phase steps in a fringe projection system for shape measurement is presented. Phase steps are produced by introducing relative rotation between the object and the fringe projection probe (comprising a projector and camera) about the camera's perspective center. Relative motion of the object in the camera image can be compensated, because it is independent of the distance of the object from the camera, whilst the phase of the projected fringes is stepped due to the motion of the projector with respect to the object. The technique was validated with a static fringe projection system by moving an object on a coordinate measuring machine (CMM). The alternative approach, of rotating a lightweight and robust CMM-mounted fringe projection probe, is discussed. An experimental accuracy of approximately 1.5% of the projected fringe pitch was achieved, limited by the standard phase-stepping algorithms used rather than by the accuracy of the phase steps produced by the new technique.

Cytocompatibility and hemocompatibility of a novel chitosan-alginate gel system.

Two chitosan-alginate gel systems in the form of membranes were produced and evaluated. The first membrane was produced by a novel gel system formed after blending N-(methylsulfonic acid) chitosan with ammonium alginate (CAG1) and the second was an N-(methylsulfonic acid) chitosan-sodium alginate blend cross-linked with glutaraldehyde and calcium chloride (CAG2). The cytocompatibility and hemocompatibility of the gels were examined by assessing the cell viability of 3T3 Swiss mouse fibroblasts, whole blood hemolysis, and platelet activation. Cell viability was not significantly different by exposure to these gels compared to the controls. Both gel types had minimal effect on hemolysis of whole heparinized rabbit blood after 1-h exposure. Further platelet activation by the surfaces was also minimal. These results indicate that these novel gels merit further investigation for blood contact applications.

A general practice-based prevalence study of epilepsy among adults with intellectual disabilities and of its association with psychiatric disorder, behaviour disturbance and carer stress.

BACKGROUND: Although the elevated occurrence of epilepsy in people with intellectual disabilities (ID) is well recognized, the nature of seizures and their association with psychopathology and carer strain are less clearly understood. The aims were to determine the prevalence and features of epilepsy in a community-based population of adults with ID, and to explore whether the presence of epilepsy was associated with greater psychopathology or carer strain. METHODS: Data were collected on the age, gender, place of residence, adaptive and challenging behaviour, social abilities and psychiatric status of 318 adults from 40 general practices, together with the degree of malaise and strain of family carers. For participants with epilepsy, a nurse collected information on seizures, investigations, treatment and carer concerns by interview. Association between epilepsy and psychiatric morbidity, challenging behaviour and caregiver malaise or strain, was explored by comparing those with epilepsy with a comparison group matched on adaptive behaviour. RESULTS: Fifty-eight participants (18%) had epilepsy: 26% were seizure free, but 34% had extremely poorly controlled seizures. Earlier onset and seizure frequency were associated with adaptive behaviour. Carer concerns were related to seizure frequency and a history of injury. There were no significant differences in psychopathology, carer malaise or caregiver strain between the matched epilepsy and non-epilepsy groups. CONCLUSIONS: This study supports the high occurrence and chronicity of epilepsy among people with ID. While psychopathology and carer strain is common within this population, underlying disability-related factors appear to be more important than the presence of epilepsy per se.

Liposome formulation of poorly water soluble drugs: optimisation of drug loading and ESEM analysis of stability.

Liposomes due to their biphasic characteristic and diversity in design, composition and construction, offer a dynamic and adaptable technology for enhancing drug solubility. Starting with equimolar egg-phosphatidylcholine (PC)/cholesterol liposomes, the influence of the liposomal composition and surface charge on the incorporation and retention of a model poorly water soluble drug, ibuprofen was investigated. Both the incorporation and the release of ibuprofen were influenced by the lipid composition of the multi-lamellar vesicles (MLV) with inclusion of the long alkyl chain lipid (dilignoceroyl phosphatidylcholine (C24PC)) resulting in enhanced ibuprofen incorporation efficiency and retention. The cholesterol content of the liposome bilayer was also shown to influence ibuprofen incorporation with maximum ibuprofen incorporation efficiency achieved when 4 micromol of cholesterol was present in the MLV formulation. Addition of anionic lipid dicetylphosphate (DCP) reduced ibuprofen drug loading presumably due to electrostatic repulsive forces between the carboxyl group of ibuprofen and the anionic head-group of DCP. In contrast, the addition of 2 micromol of the cationic lipid stearylamine (SA) to the liposome formulation (PC:Chol - 16 micromol:4 micromol) increased ibuprofen incorporation efficiency by approximately 8%. However further increases of the SA content to 4 micromol and above reduced incorporation by almost 50% compared to liposome formulations excluding the cationic lipid. Environmental scanning electron microscopy (ESEM) was used to dynamically follow the changes in liposome morphology during dehydration to provide an alternative assay of liposome stability. ESEM analysis clearly demonstrated that ibuprofen incorporation improved the stability of PC:Chol liposomes as evidenced by an increased resistance to coalescence during dehydration. These finding suggest a positive interaction between amphiphilic ibuprofen molecules and the bilayer structure of the liposome.

The potential contribution of the Queensland wet tropics region natural resource plan to river improvement and water quality.

This paper reports on work in progress on the new Wet Tropics Regional Natural Resource Management Plan and its potential to deliver river management and water quality outcomes. The plan is being prepared in accordance with the guidelines of the Nation Action Plan for Salinity and Water Quality/Natural Heritage Trust (NAP/NHT2). In particular the paper discusses the technical basis for priorities, target setting and implementation and the most effective instruments for achieving river improvement and water quality outcomes in the region.

Fertility in schizophrenia: results from a contemporary US cohort.

To investigate procreation in schizophrenia, as well as gender-related differences, female patients with schizophrenia (n = 79, DSM-III-R criteria) were compared with screened female controls (n = 124) and subsequently with male patients (n = 86). Two outcomes were investigated: (i) the proportion of subjects with one or more children (an index of fertility) and (ii) the number of children per subject among those with one or more children (an index of fecundity). Multivariate analysis was used to control for confounding variables. No significant differences in fertility between female patients and controls were detected, but reduced fecundity was noted among female patients past the reproductive period. Male patients showed a significant reduction in both fertility and fecundity compared to female patients. These results suggest that there is a relatively small impairment of fecundity among female patients compared with controls, but that there are more significant gender-related differences in both fertility and fecundity. The latter have important implications for the genetics of schizophrenia.

Ultrasensitive spectral trace detection of individual molecular components in an atmospheric binary mixture.

We present what is, to our knowledge, the first demonstration of the application of the laser homodyne interferometric technique to the quantitative identification of individual trace molecular constituents of a binary mixture in an ambient atmospheric background. Operation of the laser interferometric detection system to within a factor of 26 of the theoretical quantum noise limit, without extensive vibrationisolation, is observed. We realize the spectral identification of SF(6) and CF(2)Cl(2) mixed in various trace concentrations, without significant cross interference, using molecular spectral features overlapping the 10P CO(2) laser transitions.

Cyclic deposition of calcium salts during growth of cholesterol gallstones.

Some cholesterol gallstones contain darkly pigmented centers or peripheral concentric pigmented bands. We examined the cross-sectional surface of three cholesterol gallstones which contained both central and peripheral pigmented areas with electron-probe microanalysis (EPM) and energy dispersive x-ray microanalysis (EDXA) to determine the elemental composition of the pigmented regions. Linear EPM across the cross-sectional surface of the stones demonstrated that most of the pigmented regions of all three stones had high Ca and P signals; the non-pigmented intervening areas had markedly lower or no detectable Ca and P signals. In two of the three stones, high O signals coincided with the high Ca and P signals suggesting that both calcium bilirubinate and calcium phosphate were present in these pigmented areas. EDXA of the central and peripheral pigmented areas of each stone confirmed the presence of a high Ca signal. Our results demonstrate that in some cholesterol gallstones there is cyclic deposition of calcium bilirubinate and other calcium salts.

Black and brown pigment gallstones differ in microstructure and microcomposition.

The two subtypes of pigment gallstones, black and brown stones, differ in chemical composition and pathogenesis. We examined a black bilirubinate stone and a black phosphate stone (which represented opposite ends of the compositional spectrum of black noncarbonate stones), a black carbonate stone, and a brown pigment stone using scanning electron microscopy and microchemical techniques to determine if stone microstructure and microcomposition reflected different patterns of formation. The cross-sectional surfaces of the black bilirubinate and black phosphate stones were smooth and homogenous. Electron probe microanalysis demonstrated high concentrations of sulfur and copper in the center of the black bilirubinate stone; sulfur was in a low valence state consistent with disulfide linkages in proteins. The brown stone was rough-surfaced with lamellated bands on cross-section. The lighter-colored bands in this stone contained virtually all of the detected calcium palmitate, while the darker sections contained much more calcium bilirubinate. Plasma oxygen etching demonstrated a network of protein interdigitating with calcium bilirubinate salts in the black bilirubinate and black phosphate stones but not in the black carbonate or brown stones. Argon ion etching demonstrated that calcium bilirubinate was in a closely packed rod-shaped arrangement in all three black stones but not in the brown stone. We conclude that the marked differences in structure and composition between the black noncarbonate and brown pigment gallstones support the hypothesis that the two major pigment gallstone types form by different mechanisms. In addition, the layered structures of the black carbonate and brown stones suggest that stone growth is affected by cyclic changes in biliary composition.

A spectrometric study of the fluorescence detection of fecal urobilinoids.

Fluorescence spectra of extracts of fecal material, in the presence of zinc ion, display the well-known green fluorescence used in the Schlesinger test for the urobilinoids, together with several other fluorescences. All of these can be demonstrated in a single spectrum by the synchronous fluorescence technique, which, with new extraction conditions, enables the urobilinoid fluorescence to be detected in quantities of human fecal material down to about 50 ng in mass. This represents a reduction on the order of a thousandfold in the detection limit of the original visual technique; selectivity too is greatly increased. The effects caused by a variety of reagents on the fluorescences have been examined. It is shown that in Edelman's version of the test the presence of mercuric ion largely quenches the fluorescence. The synchronous spectra vary considerably between different samples of human feces and between different mammals according to their diet. The specificity of the recommended technique is discussed with reference to the spectra given by other body materials.

Water content of gallstones: location and contribution to a hypothesis concerning stone structure.

The water content of black pigment and cholesterol gallstones was evaluated with the use of moisture evolution analysis, electron spectroscopy for surface analysis, and X-ray diffraction. X-ray diffraction identified complex hydrated hydroxyapatite compounds in two stones. Moisture evolution analysis demonstrated that 18 pigment gallstones contained between 0.83 and 6.87% water; six cholesterol stones contained 0 to 0.27% (p less than 0.001). When black stones were subdivided into subgroups containing large proportions of pigment, phosphate, or carbonate, the proportion of water evolved at each temperature was the same. Water content was inversely related to carbonate content (r = -0.81) and did not correlate well with other stone components. Electron spectroscopy for surface analysis independently suggested that water of hydration was present since the ratio of oxygen to other elements exceeded ratios in any known compound in stone. A peripheral-central gradient for water was absent in one stone which was analyzed in peripheral mid-, and central portions. Progressive removal of the surface of previously ground stone particles using an argon beam followed by repeated electron spectroscopy for surface analysis indicated that much of the water was present in the outer 20 to 50 A of the particles. The data are consistent with the hypothesis that pigment stones form by deposition of calcium salts on an organic matrix and that hydrated water is associated with thin layers of calcium salts. These layers may be distributed throughout the stone; powdering appears to fractionate stones through these areas of hydrated calcium salts since oxygen was in highest concentration on the surface of powder particles.