Senior manager leadership competencies for quality residential aged care: an Australian industry perspective.

BACKGROUND: Documented poor quality and standards of care in Australia's residential aged care (RAC) sector have highlighted a need to better understand the role of and skills required by, RAC senior management personnel to address these concerns. This study examined which senior management leadership skills and personal qualities are necessary to deliver and strengthen the quality of RAC, with the aim of improving understanding of the professional development needs of leaders in the sector. METHODS: We conducted 12 in-depth interviews with Australian aged care industry experts, including academics, and representatives from the primary health network, consumer, and provider advocate groups. Abductive, thematic analysis incorporated coding derived from existing leadership skills frameworks as well as inductively identified themes. RESULTS: Identified leadership skills were grouped into five domains including i) workforce development and retention, ii) governance and business acumen; iii) health systems knowledge; iv) stewardship and v) responding to regulatory and political contexts. Skills particularly emphasised by participants were those required to recruit and retain a skilled workforce, manage relationships, and promote a positive organisational culture and employee wellbeing. CONCLUSIONS: RAC senior managers require a complex mix of business, human resource management, and clinical skills to deliver quality care in Australia's complex RAC setting. The lack of any professional development framework to guide the acquisition or updating of those skills is a concern.

Experiences of maternity care in New South Wales among women with mental health conditions.

BACKGROUND: High quality maternity care is increasingly understood to represent a continuum of care. As well as ensuring a positive experience for mothers and families, integrated maternity care is responsive to mental health needs of mothers. The aim of this paper is to summarize differences in women's experiences of maternity care between women with and without a self-reported mental health condition. METHODS: Secondary analyses of a randomized, stratified sample patient experience survey of 4787 women who gave birth in a New South Wales public hospital in 2017. We focused on 64 measures of experiences of antenatal care, hospital care during and following birth and follow up at home. Experiences covered eight dimensions: overall impressions, emotional support, respect for preferences, information, involvement, physical comfort and continuity. Multivariable logistic regression was used to compare experiences of women with and without a self-reported longstanding mental health condition. RESULTS: Compared to women without a condition, women with a longstanding mental health condition (n = 353) reported significantly less positive experiences by eight percentage points on average, with significant differences on 41 out of 64 measures after adjusting for age, education, language, parity, type of birth and region. Disparities were pronounced for key measures of emotional support (discussion of worries and fears, trust in providers), physical comfort (assistance, pain management) and overall impressions of care. Most women with mental health conditions (75% or more) reported positive experiences for measures related to guidelines for maternity care for women with mental illness (discussion of emotional health, healthy behaviours, weight gain). Their experiences were not significantly different from those of women with no reported conditions. CONCLUSIONS: Women with a mental health condition had significantly less positive experiences of maternity care across all stages of care compared to women with no condition. However, for some measures, including those related to guidelines for maternity care for women with mental illness, there were highly positive ratings and no significant differences between groups. This suggests disparities in experiences of care for women with mental health conditions are not inevitable. More can be done to improve experiences of maternity care for women with mental health conditions.

Poor continuity of care for TB diagnosis and treatment in Zambian Prisons: a situation analysis.

OBJECTIVES: Prisons act as infectious disease reservoirs. We aimed to explore the challenges of TB control and continuity of care in prisons in Zambia. METHODS: We evaluated treatment outcomes for a cohort of inmates diagnosed with TB during a TB REACH funded screening programme initiated by the Zambia Prisons Service and the Centre for Infectious Disease Research in Zambia. RESULTS: Between October 2010 and September 2011, 6282 inmates from six prisons were screened for TB, of whom 374 (6.0%) were diagnosed. TB treatment was initiated in 345 of 374 (92%) inmates. Of those, 66% were cured or completed treatment, 5% died and 29% were lost to follow-up. Among those lost to follow-up, 11% were released into the community and 13% were transferred to other prisons. CONCLUSIONS: Weak health systems within the Zambian prison service currently undermines continuity of care, despite intensive TB screening and case-finding interventions. To prevent TB transmission and the development of drug resistance, we need sufficient numbers of competent staff for health care, reliable health information systems including electronic record keeping for prison facilities, and standard operating procedures to guide surveillance, case-finding and timely treatment initiation and completion.

[Confusion about P. Schröder, W. Villinger and H. Heinze : The three chairmen of the German Society for Child Psychiatry and Therapeutic Education between 1940 and 1945]. / Wirren um Paul Schröder, Werner Villinger und Hans Heinze : Die drei Vorsitzenden der Deutschen Gesellschaft für Kinderpsychiatrie und Heilpädagogik zwischen 1940 und 1945.

On 5 September 1940, the German Society for Child Psychiatry and Therapeutic Education (DGKH) was founded. In order to secure sustainable impact, the young professional association aimed to: (1) Increase its scientific reputation through the organization of regular conventions and publications, (2) Attain continuity in its leadership (board) and membership growth, and (3) Establish itself in national socialistic politics and society for health care policy matters. Due to the unexpected death of the first chairman, Paul Schröder, only nine months after DGKH's foundation, these objectives were seriously put into question. The search for a new chairman led to a struggle for power and direction involving rival medical and non-medical associations as well as governmental institutions. Rather contrary to current knowledge, newly discovered documents indicate that the DGKH definitely acted out and initially influenced healthcare policy both before and directly after Schroeder's death. To interpret the complexity of the succession decision process - which led to the more radical Hans Heinze being chosen over Werner Villinger - this study employs a qualitative historical network analysis approach. For the broader interpretation of results within the national socialistic healthcare context we refer to Lutz Raphael's concept of radical order theory.

[New aspects in thyroid cancer treatment: Highlights of the ASCO Annual Meeting 2015]. / Neue Aspekte in der Therapie von Schilddrüsenkarzinomen: Highlights des ASCO-Kongresses 2015.

At the beginning of June 2015, the Annual Meeting of the American Society of Clinical Oncology (ASCO) took place in Chicago. A total of 24 studies in the field of thyroid oncology were presented, being discussed in the present review article according to the degree of cancer cell differentiation. The leading curative treatment modality is still surgery. Kinase inhibitors are used primarily in the context of palliative treatment concepts. The most recent treatment options in thyroid oncology, both surgical and medical, are summarized in the following article.

In situ liver transection with portal vein ligation for rapid growth of the future liver remnant in two-stage liver resection.

BACKGROUND: Portal vein embolization (PVE) has become a standard procedure to increase the future liver remnant (FLR) and enable curative resection of initially unresectable liver tumours. This study investigated the safety and feasibility of a new two-stage liver resection technique that uses in situ liver transection (ISLT) and portal vein ligation before completion hepatectomy. METHODS: A consecutive series of patients undergoing ISLT and extended right hepatectomy between 2009 and 2011 were compared with consecutive patients undergoing extended right hepatectomy after PVE. All patients had initially unresectable primary or secondary liver tumours, owing to an insufficient FLR (liver segments II/III). RESULTS: Fifteen patients who had PVE and seven who underwent ISLT before extended right hepatectomy were evaluated. ISLT induced rapid growth of the FLR within 3 days, particularly after insufficient PVE, from a mean(s.d.) of 293(58) ml to 477(85) ml, corresponding to a volume increase of 63(29) per cent. All patients who had ISLT underwent completion extended right hepatectomy within 8 days (range 4-8 days). CONCLUSION: ISLT is an effective and reliable technique to induce rapid growth of the FLR, even in patients with insufficient volume increase after PVE.

Splenic artery switch for revascularization of the liver: a salvage procedure for inflammatory arterial hemorrhage.

BACKGROUND: Hemorrhage caused by inflammatory vessel erosion represents a life-threatening complication after upper abdominal surgery such as pancreatic head resection. The gold standard therapeutic choice is an endovascular minimally invasive technique such as embolization or stent placement. Hepatic arterial hemorrhage in presence of pancreatitis and peritonitis is a particular challenge is if a standard therapeutic option is not possible. METHODS: The management of five patients with massive bleeding from the common hepatic artery is described. All patients underwent a splenic artery switch. The splenic artery was dissected close to the splenic hilum and transposed end-to-end to the common hepatic artery after resection of the eroded part. Patients' medical records, radiology reports, and images were reviewed retrospectively. Technical success was defined as immediate cessation of hemorrhage and preserved liver vascularization. Clinical success was defined as hemodynamic stability and adequate long-term liver function. RESULTS: Total pancreatectomy and splenectomy were performed in four of the five cases. Hemodynamic stability and good liver perfusion was achieved in these patients. CONCLUSIONS: Splenic artery switch is an effective, safe procedure for revascularization of the liver in case of hepatic arterial hemorrhage following pancreatic surgery, pancreatitis, and/or peritonitis. The technique is a promising option if a standard procedure-e.g., stent implantation, embolization and surgical repair with alloplastic prosthesis or autologous venous interposition graft-is not possible.

[Stem cell-induced liver regeneration]. / Stammzell-induzierte Leberregeneration.

BACKGROUND: The liver has an excellent regenerative capacity after resection. However, below a critical level of future liver remnant volume (FLRV), partial hepatectomy is accompanied by a significant increase of postoperative liver failure. There is accumulating evidence for the contribution of bone marrow stem cells (BMSC) to participate in liver regeneration. Here we report our experience with portal vein embolisation (PVE) and CD133+ BMSC administration to the liver, compared with PVE alone, to augment hepatic regeneration in patients with critically low FLRV or impaired liver function. PATIENTS AND METHODS: Eleven patients underwent PVE of liver segments I and IV-VIII to stimulate hepatic regeneration prior to extended right hepatectomy. In these 11 patients with a FLRV below 25% and/or limited quality of hepatic parenchyma, PVE alone did not promise adequate proliferation. These patients underwent additional BMSC administration to segments II and III. Two radiologists blinded to patients' identity and each other's results measured liver and tumour volumes with helical computed tomography. Absolute, relative and daily FLRV gains were compared with a group of patients that underwent PVE alone. RESULTS: The increase of the mean absolute FLRV after PVE with BMSC application from 239.3 mL±103.5 (standard deviation) to 417.1 mL±150.4 was significantly higher than that from 286.3 mL±77.1 to 395.9 mL±94.1 after PVE alone (p<0.05). Also the relative gain of FLRV in this group (77.3%±38.2%) was significantly higher than that after PVE alone (39.1%±20.4%) (P=0.039). In addition, the daily hepatic growth rate after PVE and BMSC application (9.5±4.3 mL/d) was significantly superior to that after PVE alone (4.1±1.9 mL/d) (p=0.03). Time to surgery was 27 days±11 in this group and 45 days±21 after PVE alone (p=0.02). Short- and long-term survival were not negatively influenced by the shorter waiting period. CONCLUSION: In patients with malignant liver lesions, the combination of PVE with CD133+ BMSC administration substantially increased hepatic regeneration compared with PVE alone. This procedure bears the potential to allow the safe resection of patients with a curative intention that would otherwise carry the risk post-operative liver failure.

Feline leukemia virus integrase and capsid packaging functions do not change the insertion profile of standard Moloney retroviral vectors.

Adverse events linked to perturbations of cellular genes by vector insertion reported in gene therapy trials and animal models have prompted attempts to better understand the mechanisms directing viral vector integration. The integration profiles of vectors based on MLV, ASLV, SIV and HIV have all been shown to be non-random, and novel vectors with a safer integration pattern have been sought. Recently, we developed a producer cell line called CatPac that packages standard MoMLV vectors with feline leukemia virus (FeLV) gag, pol and env gene products. We now report the integration profile of this vector, asking if the FeLV integrase and capsid proteins could modify the MoMLV integration profile, potentially resulting in a less genotoxic pattern. We transduced rhesus macaque CD34+ hematopoietic progenitor cells with CatPac or standard MoMLV vectors, and determined their integration profile by LAM-PCR. We obtained 184 and 175 unique integration sites (ISs) respectively for CatPac and standard MoMLV vectors, and these were compared with 10 000 in silico-generated random IS. The integration profile for CatPac vector was similar to MoMLV and equally non-random, with a propensity for integration near transcription start sites and in highly dense gene regions. We found an IS for CatPac vector localized 715 nucleotides upstream of LMO-2, the gene involved in the acute lymphoblastic leukemia developed by X-SCID patients treated by gene therapy using MoMLV vectors. In conclusion, we found that replacement of MoMLV env, gag and pol gene products with FeLV did not alter the basic integration profile. Thus, there appears to be no safety advantage for this packaging system. However, considering the stability and efficacy of CatPac vectors, further development is warranted, using potentially safer vector backbones, for instance those with a SIN configuration.

Disparities in access to health care in Australia for people with mental health conditions.

Objective One aim of Australia's Equally Well National Consensus Statement is to improve monitoring of the physical health of people with mental health conditions, which includes measures of accessibility and people's experiences of physical health care services. The present analysis contributes to this aim by using population survey data to evaluate whether, and in what domains, Australians with a mental health condition experience barriers in accessing care when compared with Australians without a mental health condition. Methods The 2016 Commonwealth Fund International Health Policy Survey includes a sample of 5248 Australian adults. Access to care was measured using 39 survey questions from before to after reaching services. Multivariable logistic regression models were used to identify disparities in barriers to access, comparing experiences of people with and without a self-reported mental health condition, adjusting for age, sex, immigrant status, income and self-rated health. Results Australians with mental health conditions were more likely to experience barriers for 29 of 39 access measures (odds ratio (OR) >1.55; P<0.05). On average, the prevalence of barriers was 10 percentage points higher for those with a condition. When measured as ratios, the largest barriers for people with mental health conditions were for affordability. When measured as percentage point differences, the largest disparities were observed for experiences of not being treated with respect in hospital. Disparities remained after adjusting for income, rurality, education, immigrant status and self-rated health for 25 of 39 measures. Conclusion Compared with the rest of the community, Australians with mental health conditions have additional challenges negotiating the health system, and are more likely to experience barriers to access to care across a wide range of measures. Understanding the extent to which people with mental health conditions experience barriers throughout the pathway to accessing care is crucial to inform care planning and delivery for this vulnerable group. Results may inform improvements in regular performance monitoring of disparities in access for people with mental health conditions. What is known about this topic? A stated national aim of the Equally Well National Consensus Statement is to improve monitoring of the physical health and well-being of people with mental health conditions through measures of service accessibility and people's experiences of physical healthcare services. What does this paper add? This paper highlights areas in which health services are not providing equal access to overall care for people with mental health conditions. The analysis offers quantitative evidence of 'red flag areas' where people with mental health conditions are significantly more likely to experience barriers to access to care. What are the implications for practitioners? Systematic attention across the health system to making care more approachable and accessible for people with mental health conditions is needed. Practitioners may be engaged to discuss possible interventions to improve access disparities for people with mental health conditions.

Diagnosis of colo-rectal cancer revealed by haemorrhagic complication of intraarterial thrombolysis.

Haemorrhage is a recognized complication of catheter-directed thrombolysis. We report one case of an afore unknown colo-rectal carcinoma, which was detected due to rectal bleeding following intraarterial thrombolysis. As reported with warfarin induced gastrointestinal bleeding complications, patients with unknown tumor developing rectal bleeding after thrombolysis procedure, should receive full diagnostic work-up of the gastrointestinal tract in order to exclude serious but potentially curable disease.

N-Acetylaspartate distribution in rat brain striatum during acute brain ischemia.

Brain N-acetylaspartate (NAA) can be quantified by in vivo proton magnetic resonance spectroscopy (1H-MRS) and is used in clinical settings as a marker of neuronal density. It is, however, uncertain whether the change in brain NAA content in acute stroke is reliably measured by 1H-MRS and how NAA is distributed within the ischemic area. Rats were exposed to middle cerebral artery occlusion. Preischemic values of [NAA] in striatum were 11 mmol/L by 1H-MRS and 8 mmol/kg by HPLC. The methods showed a comparable reduction during the 8 hours of ischemia. The interstitial level of [NAA] ([NAA]e) was determined by microdialysis using [3H]NAA to assess in vivo recovery. After induction of ischemia, [NAA]e increased linearly from 70 micromol/L to a peak level of 2 mmol/L after 2 to 3 hours before declining to 0.7 mmol/L at 7 hours. For comparison, [NAA]e was measured in striatum during global ischemia, revealing that [NAA]e increased linearly to 4 mmol/L after 3 hours and this level was maintained for the next 4 h. From the change in in vivo recovery of the interstitial space volume marker [14C]mannitol, the relative amount of NAA distributed in the interstitial space was calculated to be 0.2% of the total brain NAA during normal conditions and only 2 to 6% during ischemia. It was concluded that the majority of brain NAA is intracellularly located during ischemia despite large increases of interstitial [NAA]. Thus, MR quantification of NAA during acute ischemia reflects primarily changes in intracellular levels of NAA.

Quantification of brain metabolites in amyotrophic lateral sclerosis by localized proton magnetic resonance spectroscopy.

We performed proton magnetic resonance spectroscopy (1H-MRS) in patients with motor neuron disease (MND) to determine the absolute in vivo concentrations in the brain of the metabolites N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr/PCr). We examined the spectra acquired from a 20 x 20 x 20-mm3 voxel placed in the motor cortex and in the cerebellum from seven patients with clinically probable or definite amyotrophic lateral sclerosis (ALS) according to the El Escorial criteria, from three patients with suspected ALS (progressive muscular atrophy), and from eight normal control subjects. We estimated the concentrations of the metabolites using the water signal as an internal standard. The concentrations of Cho and Cr/PCr in both brain regions, as well as the concentration of NAA in the cerebellum, were unaltered in the MND patients compared with the controls. Only MND patients with both upper and lower motor neuron signs had a significantly decreased concentration of NAA (9.13 +/- 0.28 mM, mean +/- SEM) in the primary motor cortex when compared with healthy controls (10.03 +/- 0.22 mM). In conclusion, the slightly decreased concentration of NAA in the primary motor cortex from ALS patients may represent a loss of neurons in this region.

Are grammatical representations useful for learning from biological sequence data?--a case study.

This paper investigates whether Chomsky-like grammar representations are useful for learning cost-effective, comprehensible predictors of members of biological sequence families. The Inductive Logic Programming (ILP) Bayesian approach to learning from positive examples is used to generate a grammar for recognising a class of proteins known as human neuropeptide precursors (NPPs). Collectively, five of the co-authors of this paper, have extensive expertise on NPPs and general bioinformatics methods. Their motivation for generating a NPP grammar was that none of the existing bioinformatics methods could provide sufficient cost-savings during the search for new NPPs. Prior to this project experienced specialists at SmithKline Beecham had tried for many months to hand-code such a grammar but without success. Our best predictor makes the search for novel NPPs more than 100 times more efficient than randomly selecting proteins for synthesis and testing them for biological activity. As far as these authors are aware, this is both the first biological grammar learnt using ILP and the first real-world scientific application of the ILP Bayesian approach to learning from positive examples. A group of features is derived from this grammar. Other groups of features of NPPs are derived using other learning strategies. Amalgams of these groups are formed. A recognition model is generated for each amalgam using C4.5 and C4.5rules and its performance is measured using both predictive accuracy and a new cost function, Relative Advantage (RA). The highest RA was achieved by a model which includes grammar-derived features. This RA is significantly higher than the best RA achieved without the use of the grammar-derived features. Predictive accuracy is not a good measure of performance for this domain because it does not discriminate well between NPP recognition models: despite covering varying numbers of (the rare) positives, all the models are awarded a similar (high) score by predictive accuracy because they all exclude most of the abundant negatives.

Characterisation of gene expression changes following permanent MCAO in the rat using subtractive hybridisation.

Failure of several putative neuroprotectants in large multicentred clinical trials has re-focussed attention on the predictability of pre-clinical animal models of stroke. Model characterisation and relationship to heterogeneous patient sub-groups remains of paramount importance. Information gained from magnetic resonance imaging (MRI) signatures indicates that the Zea Longa model of rat middle cerebral artery occlusion may be more representative of slowly evolving infarcts. Understanding the molecular changes over several hours following cerebral ischaemia will allow detailed characterisation of the adaptive response to brain injury. Using a fully characterised model of Zea Longa middle cerebral artery occlusion we have used the representational difference analysis (RDA) subtractive hybridisation method to identify transcripts that accumulate in the ischaemic cortex. Along with a number of established ischaemia-induced gene products (including MCP-1, TIMP-1, hsp 70) we were also able to identify nine genes which have not previously been shown to accumulate following focal ischaemia (including SOCS-3, GADD45gamma, Xin).

Evaluation of CA1 damage using single-voxel 1H-MRS and un-biased stereology: Can non-invasive measures of N-acetyl-asparate following global ischemia be used as a reliable measure of neuronal damage?

Global brain ischemia provoked by transient occlusion of the carotid arteries (2VO) in gerbils results in a severe loss of neurons in the hippocampal CA1 region. We measured the concentration of the neuron specific N-acetyl-aspartate, [NAA], in the gerbil dorsal hippocampus by proton MR spectroscopy (1H-MRS) in situ, and HPLC, 4 days after global ischemia. The [NAA] was correlated with graded hippocampus damage scoring and stereologically determined neuronal density. A basal hippocampal [NAA] of 8.37+/-0.10 and 9.81+/-0.44 mmol/l were found from HPLC and 1H-MRS, respectively. HPLC measurements of [NAA] obtained from hippocampus 4 days after 2VO showed a 20% reduction in the [NAA] following 4 min of ischemia (P<0.001). 1H-MRS measurements on gerbils subjected to 4 or 8 min of ischemia showed a similar 24% decline in the [NAA] (P<0.05). Thus, there was correlation between the HPLC and 1H-MRS determined NAA decline. There was also a significant correlation between 1H-MRS [NAA] and the corresponding reduction in CA1 neuronal density (P<0.004). In summary our findings show that single voxel 1H-MRS can be used as a supplement to histological evaluation of neuronal injury in studies after global brain ischemia. Accordingly, volume selective spectroscopy has a potential for assessment of neuroprotective therapeutic compounds/strategies with respect to neuronal rescue for delayed ischemic brain damage.

Systemic effects and side effects of interstitial techniques used in liver tissue.

BACKGROUND: Percutaneous ethanol injection (PEI) and cryosurgery are increasingly used for the treatment of liver malignancies. To create a safety margin and to destroy completely diffusely growing tumors, the precise destruction of healthy liver tissue is necessary. Little is known about the effects of operating on this type of tissue. This study evaluated the effects and side effects of PEI and cryosurgery when applied to normal parenchyma of the liver. STUDY DESIGN: Two groups of six minipigs each were treated with either PEI or cryosurgery to create necrosis in the liver. During and after the procedures, vital signs were monitored and necrotic areas were observed by ultrasonography. Standard and immunohistochemistry stains were made from samples of the necrosis, the liver, and the lung. RESULTS: In the PEI group, thromboembolic complications occurred in all animals (fatality rate 50%). Hematogenous spread of hepatocytes was demonstrated by immunohistochemistry and was a cause of pulmonary embolism. In the cryosurgery group, neither specific complications nor signs of cell spillage occurred. Because of an isolating effect of blood perfusion, hepatocytes close to the portal triads were less damaged, vital cells were present in the periphery, and the necroses were smaller than the induced lesions. CONCLUSIONS: The effect of PEI in healthy liver tissue is unpredictable. This makes the creation of a safety margin or the treatment of a diffusely infiltrating tumor impossible. PEI always introduces the risk of hematogenous cell spread. Effects of cryosurgery are less dependent on tissue qualities. In both techniques, the real extent of complete tissue destruction cannot be visualized by ultrasonography.

Effect on the content of n-acetylaspartate, total creatine, choline containing compounds, and lactate in the hippocampus of rats exposed to aromatic white spirit for three weeks measured by NMR spectroscopy.

Several epidemiological studies of workers occupationally exposed to white spirit show that neuropsychiatric disorders are a frequent cause of early disability pension in this population compared with non-exposed controls. In the rat, we have demonstrated that exposure to different kinds of white spirit induces changes in neurotransmitter concentrations, indices of oxidative stress, and electrophysiological parameters. Others have confirmed that acute behavioural effects can be induced by short-term high-level exposure. With NMR spectroscopy technique it is possible to study neurochemical parameters in vivo, and to examine the same subjects repeatedly over time. NMR spectroscopy was used to study the effects of organic solvents in rats. Rats were exposed to 0, 400 ppm, or 800 ppm of aromatic white spirit 6 hr/day, 7 days/week for 3 weeks. During the first week, the rats showed signs of irritation of mucous membranes, and appeared to be sedated. Both types of effect gradually diminished during the second week. The rats were examined by single volume of interest (VOI) NMR spectroscopy. N-acetylaspartate, creatinine and phosphocreatinine, and choline containing compounds were measured in the hippocampus and surrounding regions. The concentration of N-acetylaspartate for the three groups was found to be in the range of 8.2-8.5 mM with a standard deviation of 0.6-0.9. There was no difference between the three groups. In a previous study no change in the number of astrocytes in hippocampus was found following exposure to white spirit for six months. Since N-acetylaspartate is thought to be a marker for neurons, the results of these two studies indicate that white spirit does not produce a marked neuronal loss. However, it was not possible to show effect of trimethyltin. In this study trimethyltin was used as a "positive control'. The NMR technique can be applied to the rat, and it is possible to obtain reasonable signal-to-noise ratios.

Quantitative 1D saturation profiles on chalk by NMR.

Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal that strong saturation gradients exist in chalk core samples after core floods, due to capillary effects. The method is useful in analysis of corefloods, e.g., for determination of capillary pressure functions.

Absolute metabolite quantification by in vivo NMR spectroscopy: II. A multicentre trial of protocols for in vivo localised proton studies of human brain.

We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy.