Optical fiber-based dispersion for spectral discrimination in fluorescence lifetime imaging systems.

The excited state lifetime of a fluorophore together with its fluorescence emission spectrum provide information that can yield valuable insights into the nature of a fluorophore and its microenvironment. However, it is difficult to obtain both channels of information in a conventional scheme as detectors are typically configured either for spectral or lifetime detection. We present a fiber-based method to obtain spectral information from a multiphoton fluorescence lifetime imaging (FLIM) system. This is made possible using the time delay introduced in the fluorescence emission path by a dispersive optical fiber coupled to a detector operating in time-correlated single-photon counting mode. This add-on spectral implementation requires only a few simple modifications to any existing FLIM system and is considerably more cost-efficient compared to currently available spectral detectors.

The Prevalence of Dementia and Cognitive Impairment in Hospitals.

BACKGROUND: The care of elderly patients with comorbid dementia poses an increasing challenge in the acute inpatient setting, yet there remains a lack of representative studies on the prevalence and distribution of dementia in general hospitals. METHODS: We conducted a cross-sectional study of patients aged 65 and older in randomly selected general hospitals in southern Germany. Patients were excluded if they were in an intensive care unit or isolation unit or if they were on specialized wards for psychiatry, neurology, or geriatric medicine. The findings are derived from patient interviews, neuropsychological testing, standardized rating scales, questioning of nursing staff, and the patients' medical records. RESULTS: 1469 patients on 172 inpatient wards of 33 hospitals were studied. 40.0% of them (95% confidence interval, [36.2; 43.7]) had at least mild cognitive impairment. The point-prevalence of dementing illnesses was 18.4% [16.3; 20.7]. Delirium, most often on the basis of dementia, was present in 5.1% [3.9; 6.7]. 60.0% had no cognitive impairment. Dementia was more common among patients of very advanced age, those who were dependent on nursing care, those who lived in old-age or nursing homes, and those with a low level of education. Among patients with dementia, only 36.7% had a documented diagnosis of dementia in the medical record. Patients with dementia were treated more often for dehydration, electrolyte disturbances, urinary tract infections, contusions, and bone fractures, as well as for symptoms and findings of an unknown nature, and much less often for cancer or musculoskeletal diseases. CONCLUSION: Two out of five elderly patients in general hospitals suffer from a cognitive disturbance. Patients with severe impairments such as dementia or delirium often need special care. Guidelines and model projects offer approaches by which the inpatient care of patients with comorbid dementia can be improved.

[Dementia friendly care services in general hospitals : Representative results of the general hospital study (GHoSt)]. / Demenzsensible Versorgungsangebote im Allgemeinkrankenhaus : Repräsentative Ergebnisse aus der General Hospital Study (GHoSt).

BACKGROUND: Mostly model projects report on special care services and procedures for general hospital patients with cognitive impairment. The objective of this study was to determine the frequency of special care services and procedures in general hospitals on the basis of a representative cross-sectional study. METHODS: From a list of all general hospitals in southern Germany we randomly selected a specified number of hospitals und somatic wards. The hospitals were visited and all older patients on the selected wards on that day were included in the study. Information about care services and their utilization was collected with standardized instruments. RESULTS: A total of 33 general hospitals and 172 wards participated in the study. The patient sample included 1469 persons over 65 (mean age 78.6 years) and 40% of the patients showed cognitive impairments. The staff reported that the most frequent measures for patients with cognitive impairments concerned patients with wandering behavior (63.1%), efforts to involve the patients' relatives to help with their daily care (60.1%), conducting nonintrusive interviews to identify cognitive impairments (59.9%), allocation to other rooms (58%) and visual aids for place orientation of patients (50.6%). In accordance with earlier studies our results show that other dementia friendly services implemented in pilot projects were rare. The existing special services for patients with cognitive impairment were rarely used by the patients or their relatives. DISCUSSION: The results demonstrate the urgent need to improve special care services and routines for identification of elderly patients with cognitive impairment and risk of delirium in general hospitals.

The 6-Item Cognitive Impairment Test as a bedside screening for dementia in general hospital patients: results of the General Hospital Study (GHoSt).

OBJECTIVE: The objective of this study was to examine the psychometric quality of the 6-Item Cognitive Impairment Test (6CIT) as a bedside screening for the detection of dementia in general hospital patients. METHOD: Participants (N = 1,440) were inpatients aged ≥65 of 33 randomly selected general hospitals in Southern Germany. The 6CIT was conducted at bedside, and dementia was diagnosed according to DSM-IV. Nursing staff was asked to rate the patients' cognitive status, and previous diagnoses of dementia were extracted from medical records. Completion rates and validity statistics were calculated. RESULTS: Two-hundred seventy patients had dementia. Cases with delirium but no dementia were excluded. Feasibility was 97.9% and 83.3% for patients without and with dementia, respectively, and decreased from moderate (93.8%) to severe dementia (53%). The area under the curve of the 6CIT was 0.98. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated for the cutoffs 7/8 (0.96, 0.82, 0.85, 0.52, 0.99) and 10/11 (0.88, 0.95, 0.94, 0.76, 0.98). The nurse ratings and medical records information had lower validity statistics. Logistic regression analyses revealed that the 6CIT statistically significantly provided information above nurse ratings and medical records. Twenty-five and 37 additional patients were correctly classified by the 7/8 and 10/11 cutoffs, respectively. CONCLUSION: The 6CIT is a feasible and valid screening tool for the detection of dementia in older general hospital patients. The 6CIT outperformed the nurse ratings of cognitive status and dementia diagnoses from medical records, suggesting that standardized screening may have benefits with regard to case finding. Copyright © 2016 John Wiley & Sons, Ltd.

TRANSDUCER FIELD IMAGING USING ACOUSTOGRAPHY.

A common current practice for transducer field mapping is to scan, point-by-point, a hydrophone element in a 2D raster at various distances from the transducer radiating surface. This approach is tedious, requiring hours of scanning time to generate full cross-sectional and/or axial field distributions. Moreover, the lateral resolution of the field distribution image is dependent on the indexing steps between data points. Acoustography is an imaging process in which an acousto-optical (AO) area sensor is employed to record the intensity of an ultrasound wavefield on a two-dimensional plane. This paper reports on the application of acoustography as a simple but practical method for assessing transducer field characteristics. A case study performed on a commercial transducer is reported, where the radiated fields are imaged using acoustography and compared to the corresponding quantities that are predicted numerically.

Feasibility study of complex wavefield retrieval in off-axis acoustic holography employing an acousto-optic sensor.

We propose and experimentally demonstrate a new method for complex-valued wavefield retrieval in off-axis acoustic holography. The method involves use of an intensity-sensitive acousto-optic (AO) sensor, optimized for use at 3.3 MHz, to record the acoustic hologram and a computational method for reconstruction of the object wavefield. The proposed method may circumvent limitations of conventional implementations of acoustic holography and may facilitate the development of acoustic-holography-based biomedical imaging methods.

Activation drives PD-1 expression during vaccine-specific proliferation and following lentiviral infection in macaques.

Recent data supports that increased expression of PD-1, a negative regulator of immune function, is associated with T cell exhaustion during chronic viral infection. However, PD-1 expression during acute infection and vaccination has not been studied in great detail in primates. Here, we examine PD-1 expression on CD3(+) T cells following DNA vaccination or lentiviral infection of macaques. Ex vivo peptide stimulation of PBMC from DNA-vaccinated uninfected macaques revealed a temporal increase in PD-1 expression in proliferating antigen-specific CD8(+) T cells. Following the initial increase, PD-1 expression steadily declined as proliferation continued, with a concomitant increase in IFN-gamma secretion. Subsequent examination of PD-1 expression on T cells from uninfected and lentivirus-infected non-vaccinated macaques revealed a significant increase in PD-1 expression with lentiviral infection, consistent with previous reports. PD-1 expression was highest on cells with activated memory and effector phenotypes. Despite their decreased telomere length, PD-1(hi) T cell populations do not appear to have statistically significant uncapped telomeres, typically indicative of proliferative exhaustion, suggesting a different mechanistic regulation of proliferation by PD-1. Our data indicate that PD-1 expression is increased as a result of T cell activation during a primary immune response as well as during persistent immune activation in macaques.