Accelerated long-term forgetting in patients with acquired brain injury

OBJECTIVE

Recent research suggests that patients with neurological disorders without overt seizures may also experience accelerated long-term forgetting (ALF). This term describes unimpaired learning and memory performance after standard retention intervals, but an excessive rate of forgetting over delays of days or weeks. The objective of this retrospective study was to investigate ALF in patients with an acquired brain injury (ABI) and to associate memory performance with executive functions.

METHODS

Verbal memory performance (short-term recall, 30-min recall, 1-week recall) was assessed in 34 adult patients with ABI and compared to a healthy control group (n = 54) using an auditory word learning and memory test.

RESULTS

Repeated measure analysis showed significant effects of time and group as well as interaction effects between time and group regarding recall and recognition performance. Patients with ABI had a significantly impaired 1-week recall and recognition performance compared to the healthy control group. Correlations between recall performance and executive functions were nonsignificant.

DISCUSSION

Our results demonstrate that non-epileptic patients with ABI, especially patients with frontal and fronto-temporal lesions, are prone to ALF. Additionally, our data support the assumption that ALF results from a consolidation impairment since verbal recall and recognition were impaired in patients with ABI.

Experimental computer tomograph

The computed tomography is one of the most important medical instruments, allowing the non-invasive visualization of cross sections which are free from superpositions. Since 2000 an experimental computer tomo-graph of the third generation for the purpose of education and research was set up and further developed. Besides the mechanical construction design reconstruction algorithms, including certain corrections of the measured data were developed and implemented. In 2013 iterative reconstruction methods were investigated and implemented for advanced reconstructions and dose reduction using various ray tracing algorithms. The new reconstruction technique leads to improvements in image quality and low dose reconstructions.

Investigation of balancing effects in long term renewable energy feed-in with respect to the transmission grid

Abstract. A European power system mainly based on renewable sources will have dominant contributions from wind and solar power. However, wind and solar generation facilities have, due to the weather dependent nature of their resources, highly fluctuating feed-in profiles. To overcome the mismatch between power consumption and generation it is important to study and understand the generation patterns and balancing potentials. High temporally and spatially resolved long term weather data was used to simulate the feed-in from wind and photovoltaics for European countries for the years 2003 to 2012. We investigate storage energy and capacity needs in Europe in dependency of the generation mix from wind onshore, wind offshore and photovoltaics and the share of renewables. Furthermore we compute the storage energy and capacity needs for different transmission scenarios. We show that for unlimited transmission storage needs are reduced mostly by high wind offshore shares. We also show that higher shares above 100% of renewables can decrease the required storage capacity to a higher extent than the required storage energy.

Delivery of proteins to mammalian cells via gold nanoparticle mediated laser transfection

Nanoparticle laser interactions are in widespread use in cell manipulation. In particular, molecular medicine needs techniques for the directed delivery of molecules into mammalian cells. Proteins are the final mediator of most cellular cascades. However, despite several methodical approaches, the efficient delivery of proteins to cells remains challenging. This paper presents a new protein transfection technique via laser scanning of cells previously incubated with gold nanoparticles. The laser-induced plasmonic effects on the gold nanoparticles cause a transient permeabilization of the cellular membrane, allowing proteins to enter the cell. Applying this technique, it was possible to deliver green fluorescent protein into mammalian cells with an efficiency of 43%, maintaining a high level of cell viability. Furthermore, a functional delivery of Caspase 3, an apoptosis mediating protein, was demonstrated and evaluated in several cellular assays. Compared to conventional protein transfection techniques such as microinjection, the methodical approach presented here enables high-throughput transfection of about 10 000 cells per second. Moreover, a well-defined point in time of delivery is guaranteed by gold nanoparticle mediated laser transfection, allowing the detailed temporal analysis of cellular pathways and protein trafficking.

A global map of human impact on marine ecosystems

The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research.

Epileptic activity influences the speech organization in medial temporal lobe epilepsy

Factors influencing atypical speech lateralization have theoretical importance in understanding the organization and reorganization of higher cognitive functions, as well as having practical implications, especially in brain surgery and neurorehabilitation. Atypical (right-sided or bilateral) language representation is more frequent in focal epilepsy than in healthy people. This difference is thought to be related to early childhood brain injuries localized in the neighbourhood of speech centres. The effect of epileptic activity on speech lateralization has not been investigated, although much data suggest that epileptic activity may interfere with higher brain functions. It can only be evaluated in a homogeneous human population with epilepsy having the same lesion type in the same localization. For these reasons, we investigated 184 patients with medial temporal lobe epilepsy (MTLE) due to unilateral hippocampal sclerosis (HS), but without other epileptogenic lesions. All patients underwent comprehensive presurgical evaluation. In MTLE, the influence of age at the time of brain damage, i.e. the initial precipitating injury (IPI), could be evaluated separately from the other timing factors. Of 100 patients in whom a Wada test was performed, left-sided speech occurred in 76% of the left-sided and in 100% of the right-sided MTLE patients (P < 0.05). For further evaluation, we included only the 83 left-sided MTLE patients. The mean age at seizure onset was 10.1 +/- 7.8 years (range 1-37 years); the mean age at evaluation was 35.7 +/- 9.8 years. Based on the Wada test, left-sided speech was present in 63 patients, while in 20 (24%) patients the Wada test revealed atypical speech dominance. We found that atypical speech representation in left MTLE was associated with higher spiking frequency (P < 0.05) and with sensory auras representing an ictal involvement of the lateral temporal structures (P < 0.01). Psychic auras suggesting limbic seizure spread showed a significant association with left-sided speech dominance in left MTLE (P < 0.05). Neither age at epilepsy onset, nor age at IPI was associated with atypical speech in left MTLE. Conclusively, we found that in patients with focal epilepsy, not only the known factors, i.e. the age at which the brain injury occurred and its localization, but also the epileptic activity itself, i.e. interictal discharges and seizure spread, may influence speech reorganization. Our findings also suggest that not only structural elements but also functional factors have an effect on the language organization of the brain.

Hemispheric asymmetry in visuospatial attention assessed with transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) was used to study visuospatial attention processing in ten healthy volunteers. In a forced choice recognition task the subjects were confronted with two symbols simultaneously presented during 120 ms at random positions, one in the left and the other in the right visual field. The subject had to identify the presented pattern out of four possible combinations and to press the corresponding response key within 2 s. Double-pulse TMS (dTMS) with a 100-ms interstimulus interval (ISI) and an intensity of 80% of the stimulator output (corresponding to 110-120% of the motor threshold) was applied by a non-focal coil over the right or left posterior parietal cortex (PPC, corresponding to P3/P4 of the international 10-20 system) at different time intervals after onset of the visual stimulus (starting at 120 ms, 270 ms and 520 ms). Double-pulse TMS over the right PPC starting at 270 ms led to a significant increase in percentage of errors in the contralateral, left visual field (median: 23% with TMS vs 13% without TMS, P=0.0025). TMS applied earlier or later showed no effect. Furthermore, no significant increase in contra- or ipsilateral percentage of errors was found when the left parietal cortex was stimulated with the same timing. These data indicate that: (1) parietal influence on visuospatial attention is mainly controlled by the right lobe since the same stimulation over the left parietal cortex had no significant effect, and (2) there is a vulnerable time window to disturb this cortical process, since dTMS had a significant effect on the percentage of errors in the contralateral visual hemifield only when applied 270 ms after visual stimulus presentation.

Collaboration in research: testing the PIPC model on clinical and nonclinical outcomes

This outcomes research used a collaborative framework between a college of nursing and a medical center to test the effects of the Partners in Patient Care delivery model (PIPC) on clinical and nonclinical outcomes. An experimental pretest-postest design was used to compare selected nonclinical outcomes and clinical outcomes of care in two patient units. Results showed that there were significant differences between units in the nonclinical outcomes of nurse satisfaction, salary costs, supply costs, and productivity as measured by documentation time. In addition, there were significant differences in the clinical outcomes of care in terms of patient satisfaction. No significant differences were found in number of falls, medication errors, and intravenous infections; however, when ratios of these indicators were examined in relation to patient days, significant differences in the medication error ratio and the fall ratio were revealed. The results indicate that the PIPC delivery model did have positive effects on patient satisfaction and nurse satisfaction but that there were increased costs and increased time spent in documentation on the pilot unit.

The use of focus groups to assist in the design and implementation of a new nursing practice model

Focus groups facilitate change in healthcare institutions by providing comparative perceptions of all levels of healthcare staff in the environment, obtaining impressions of new options for healthcare delivery for which no information is available, and stimulating new ideas to improve cost-effective quality care. The authors discuss their experience using this data gathering and evaluation approach during the planning and implementation of a new nursing practice model. Factors to consider when using focus groups are offered, and lessons learned from the experience are presented.

Improving nursing practice with staff education: the challenges of dysphagia

The 15 million Americans who experience some degree of dysphagia risk choking, airway obstruction, aspiration-related pulmonary disease, and/or death. These complications increase mortality, morbidity, length of hospitalization, and healthcare costs, but may be preventable through nursing intervention. Fifty-four nursing care workers (NCWs) from medical/surgical units in two acute care hospitals were assigned by convenience to two experimental groups and a control group. Experimental groups A and B participated in an educational program on dysphagia designed to increase their knowledge of dysphagia, knowledge attention, and the number of dysphagic patients identified and referred. Group B received deliberate reinforcement of program content over a 1-month period. The educational intervention had a significant effect on knowledge level and knowledge retention, immediately and at 1-month posttest in both experimental groups. NCWs applied what they learned to clinical practice as evidenced by an increase in the number of patients identified as being at risk for or experiencing dysphagia. Reinforcement of program content did not affect the outcomes. The study has implications for staff educators and nursing personnel who care for persons at risk for dysphagia.

Partners in patient care: measuring the effects on patient satisfaction and other quality indicators

An experimental pretest/posttest design compared pilot and control nursing units in a medical center in Southwest Florida to assess the effects of a Partners in Patient Care (PIPC) nursing care delivery model on selected quality of care outcomes-patient satisfaction, patient medication errors, falls, and IV infections. There were no significant differences between units in the number of falls, medication errors, and IV infections. When the ratios of these events to patient days were examined, there was a significant difference between the pilot and control units in the medication error ratio and the fall ratio. The results indicate that the PIPC nursing model had a positive effect on patient satisfaction.

Effects of the PIPC model on outcome measures of productivity and costs

The purpose of this experimental research was to determine the effects of the Partners in Care Practice Model (PIPC) on the outcomes of productivity and costs. Over an 18-month study period, no significant differences were found in costs per patient day between the pilot and control units; however, significant differences were found in actual salaries, amount of time spent in documentation, and supply costs. Differences in costs and productivity reflected increased training costs and costs for additional supplies on the pilot unit.

Effects of the partners in care practice model on nursing outcomes

The purpose of this study was to identify the effects of an empirically-designed nursing practice model on the outcome variables of job satisfaction, autonomy, and retention/turnover of nursing staff. After 6 months significant differences were found on the experimental unit in overall job satisfaction, and on the subscales of job satisfaction in task requirements and perception of pay. Significant differences were found between the control and experimental unit on the Job Satisfaction Index subscales of interaction, task requirements, and autonomy. No significant differences were found in retention/turnover of staff between the experimental and control unit.

Redesigning nursing practice. The partners in patient care model

Several nursing practice models use nurse extenders/partners to extend nurses' time. The authors discuss the development, implementation, and evaluation of the "partner in patient care" (PIPC) model. Unique aspects of the model are emphasized, including use of a collaborative process to generate the design and guide the implementation; staff participation throughout the design and implementation of the project; and use of evaluation at each phase of the implementation process to improve on the outcomes.

Erythrocyte stearic to oleic acid ratio in patients with ocular melanoma

The main characteristics of malignant cells include increased metabolism and capacity for division which are associated with high membrane fluidity. Membrane fluidity is in turn controlled by multiple factors which include the ratio of saturated to unsaturated fatty acids in the cell wall i.e. the Saturation Index (SI). The SI is known to be reduced in neoplastic cells as well as in the circulating erythrocytes of patients with some malignant tumours but not others. It has been suggested that the SI may be useful as a marker of malignancy.

Erythrocyte stearic to oleic acid ratio in prostatic carcinoma

The red cell membrane stearic acid to oleic acid ratio was analysed in 34 men with histologically proven carcinoma of the prostate and distant metastases. This ratio was expressed as the saturation index (SI). A mean SI of 0.97 was found in control patients without evidence of any malignancy whereas all patients with advanced prostatic cancer showed a reduced stearic to oleic acid ratio (mean SI 0.466). Untreated patients had a significantly lower SI (mean 0.36) than those who had responded to hormonal therapy (mean 0.547; P less than 0.0001). A drop in SI correlated well with more advanced disease as judged by radiological findings and serum PSA. It is suggested that red cell membrane SI correlates well with radiological and biochemical markers of advanced prostatic carcinoma and may be used as a marker to assess progress and response to treatment.

Effect of stilboestrol and testosterone on the incorporation of 75selenomethionine by prostatic carcinoma cells

Controversy still exists as to whether oestrogens exert a direct effect on the prostatic cell. Incorporation of 75Selenomethionine (SeM) was used as a measure of protein synthesis by prostatic carcinoma cells in vitro to investigate the action of hormones on prostatic carcinoma cells in tissue culture. Stilboestrol (DES) and stilboestrol diphosphate (Honvan) inhibited protein synthesis in a proportion of patients, while testosterone was stimulatory. A similar effect was noted in cells from patients with benign hyperplasia (BPH). This work confirms that oestrogens have a direct inhibitory effect on prostatic cells at high concentrations which can be attained in patients given intravenous stilboestrol diphosphate.

[HIV infections in the Frankfurt area: results of viral serologic laboratory diagnosis]

Basing on routine laboratory diagnosis of serum antibodies to the human immunodeficiency virus (HIV-1) in the years 1985 and 1986, the monthly detection rate of infection amounts to 50 persons on an average in the region of Frankfurt/FRG. The relation of female to male persons changed from 1:7 to 1:3 during one year. This might be influenced by a screening programme performed with female prostitutes who are found seropositive in about 2.5%. In December 1986, the first case of an HIV-2 infection was recorded. The clinical examination of HIV-infected patients admitted to the City Hospital of Offenbach/FRG revealed striking signs in about 35-40%, of AIDS in 6%. The infected persons belong to risk groups. No positive result was seen in pregnant women (n = 1100), medical staff (n = 405) and patients requiring renal transplants (n = 115) who do not belong to the risk groups.

Expression of histocompatibility antigens and characterisation of mononuclear cell infiltrates in human renal cell carcinomas

Neoplastic tissue was obtained at operation from 10 renal cell carcinomas, from the adjacent 'normal' kidney in 6 cases and from 1 other normal kidney. The biopsies were snap frozen in liquid nitrogen and sections were subsequently stained with monoclonal antibodies against major histocompatibility complex (MHC) antigens, class I and II, and several types of mononuclear cell, by the indirect immunoperoxidase method. The degree of staining or the number of cells stained was estimated as heavy 4, through moderate 3, few 2, occasional 1, or nil 0. MHC Ag were consistently expressed, grade 2-4, by the glomeruli and proximal convoluted tubules of normal kidney, but were absent in 8 of 10 carcinomas. There was a grade 3-4 mononuclear cell infiltration in the stroma of normal kidney and between the carcinoma cells which was composed principally of macrophages. However in the two carcinomas expressing MHC Ag there was also a grade 2-3 infiltration with T lymphocytes. The absence of MHC Ag on carcinoma cells mitigates against attempts to potentiate the patient's immune response to his tumour, e.g. by renal artery embolisation.

Stearic acid and carcinogenesis

Decreased membrane rigidity is one of the characteristics of malignant cells, resulting in part from the desaturation of stearic acid into oleic acid. In this study we investigated the influence of stearic acid on tumour cell inhibition in vitro and tumour development in vivo. Stearic acid inhibited the colony-forming ability of 4 out of 5 rat and two human tumour continuous cell lines in vitro. In contrast, the colony-forming ability of rat fibroblasts was not inhibited and that of human foetal lung fibroblasts was inhibited at a higher dose than that required to inhibit human tumour cell lines. Using a model of rat mammary carcinoma induced by nitroso-methyl urea (NMU) the subcutaneous injection of stearic acid at weekly intervals prevented tumour development in 5 to 10 rats. Using iodostearic acid twice weekly, 11 of 19 rats were alive and tumour free at week 22 whilst all of 14 animals injected with NMU alone had died of tumour by the 16th week. The ratio of stearic to oleic acids in erythrocyte membranes was significantly reduced in the tumour-bearing rats, but was normal in tumour-free animals treated with stearic or iodostearic acid. These preliminary data indicate that stearic acid inhibits tumour development in rats.

Expression of histocompatibility antigens and characterization of mononuclear cell infiltrates in normal and neoplastic colorectal tissues of humans

Serial frozen sections were prepared from 22 colorectal carcinomas. Additional samples were obtained from the adjacent normal bowel in 10 patients, from 6 concomitant adenomas in 5 patients, and from another 4 isolated adenomas. Mononuclear cell infiltrates were stained by the indirect immunoperoxidase technique with the use of a panel of 6 mouse monoclonal antibodies to human leukocyte antigens. The degree of infiltration was graded from 4 (heavy) to 0 (nil). The colorectal carcinomas and adjacent normal bowel showed an equal degree of leukocyte infiltration (HLe-1), graded 3-4 in 8 cases and 2-3 in the other 2 cases. In 7 carcinomas cytotoxic-suppressor T-lymphocytes (UCHT-4) graded 2-3 predominated over helper T-cells (OKT-4) graded 0-1. By contrast, in the adjacent normal bowel cytotoxic and helper cells were present in equal numbers. Among the adenomas leukocyte infiltration was grade 4 in 9 and grade 3 in 1. In 9 of the 10 adenomas cytotoxic cells graded 2 predominated over helper cells graded 0-1. The number of helper cells was equivalent among 6 concomitant adenomas and carcinomas from 5 patients. Adenomatous epithelial cells expressed class II major histocompatibility complex antigens (OKIa-1). However, carcinomatous or normal epithelium showed only faint staining with OKIa-1. The similarity in cell infiltration is consistent with an adenoma-carcinoma sequence. The predominance of cytotoxic cells in carcinomas that expressed class I major histocompatibility complex supports the association between lymphocyte infiltration and a favorable prognosis.

Differential immune reactivity of tumour-intrinsic and peripheral-blood lymphocytes against autoplastic colorectal carcinoma cells

Peripheral blood lymphocytes (PBL) were obtained from 13 patients and tumour-intrinsic lymphocytes (TIL) from 20 patients with colorectal cancer. The PBL were separated on a Ficoll-Isopaque gradient and the TIL by digestion of the tumour with collagenase-DNase. Both PBL and TIL were passed through nylon-wool columns and the eluted cells were co-cultured for 2 h with 51Cr-labelled tumour cells from the same patient. If patients in whom spontaneous 51Cr release from the tumour cells was greater than 33% were excluded, PBL showed cytotoxicity for the autoplastic tumour cells in 5/10 cases and TIL in 3/10 cases (NS). In 12 cases the cytotoxicity of the TIL was compared with that for TIL from the same tumour after the lymphocytes had been washed a further 6 times in Medium 199. Three effector: target (E/T) ratios, 5:1, 10:1 and 20:1, were used. The proportion of effector populations showing cytotoxicity was 2/12 for unwashed TIL and 9/12 for washed TIL (P less than 0.006). At the 5:1 E/T ratio the level of cytotoxicity was not significantly greater for washed TIL, but at the 10:1 ratio washed TIL showed significantly more cytotoxicity (P less than 0.025. At the 20:1 E/T ratio, a comparison was possible in 15 cases and the washed TIL again showed greater cytotoxicity (P less than 0.001).