Neuroepithelial progenitor cells explanted from human fetal brain proliferate and differentiate in vitro

Analyses tested the following contrasting hypotheses: a) The occurrence of a new symptom in the presence of ongoing life stress increases the attribution of symptoms to illness and increases the use of health care; b) new symptoms occurring in the presence of ongoing life stress are attributed to stressors if they are ambiguous indicators of illness, and they are unlikely to motivate care-seeking if the stressor, i.e., the perceived cause, is of recent onset. The 43-to-92-year old subjects in this longitudinal study were less likely to seek care for the ambiguous symptoms they experienced during the previous week if there was a concurrent life stressor that began during the previous 3 weeks; these symptoms were attributed to stress rather than to illness, and subjects tolerated the emotional distress caused by the combination of a stressor and an ambiguous symptom. Subjects were less willing to tolerate the combined distress of an ambiguous symptom and a concurrent life stressor if the stressor onset was not recent; under such conditions, subjects were more likely to seek health care. Current life stressors did not affect care-seeking for symptoms that were clear signs of disease; these symptoms were readily identified as health threats in need of medical attention. The findings contribute to a better theoretical understanding of how individuals perceive their physical states and how they cope with stress. Practical implications of these findings for increasing efficient use of health care services are also discussed.     

Developmental outcome of infants born with biological and psychosocial risks

The significance of prenatal and perinatal complications (biological risk) and of family adversity (psychosocial risk) on early child development was examined in a prospective study. Developmental outcome of 350 infants was assessed by measures of motor, cognitive, and social-emotional functioning at 3, 24, and 54 months. Results indicated a differential impact of risk factors on specific outcomes. Whereas psychosocial risks became more prominent with growing age and were related to poorer child outcome in all areas of functioning, biological risks decreased in influence and predominantly resulted in poorer motor development. The contributions of biological and psychosocial risks on outcomes were additive. A number of individual risk factors emerged as significant predictors of later maladaptation.     

Spectroscopy and structure of bacteriochlorophyll dimers. I. Structural consequences of nonconservative circular dichroism spectra

The origin of the nonconservative nature of the circular dichroism (CD) spectrum of bacteriochlorophyll dimers is investigated. It is shown that coupling between the Qy and Qx transitions can, under rather restricting circumstances, lead to an asymmetrical CD spectrum: only for a limited set of relative orientations of the monomers within the dimer is the spectrum found to be asymmetrical. The relation between intensity and asymmetry of the CD spectrum is elucidated. The results are applied to the B820 subunit of the LH1 antenna system and subsequently to the antenna system LH1 itself. Differences in the geometry of the BChls in LH1 versus the LH2 structure are discussed.     

A proposal for minimum detectable compartment in MIRD dosimetry modelling

The accuracy of radiation dose estimates from radiopharmaceutical administrations has recently become more important for three main reasons: (i) clinical providers are demanding more information on diagnostic procedures; (ii) regulatory groups are scrutinizing dosimetry for research subjects; and (iii) accurate organ doses are crucial in therapeutic administrations. These dose estimates are a sensitive function of the residence times. Because most clinical data acquisition protocols are limited to the first 24 h after dose administration, the area under the remainder of the time-activity curve (TAC) must be estimated. Estimation methods range from assuming physical decay only (overly conservative) to extrapolating end point physiological kinetics (overly liberal). This study demonstrates how much the results from these two methods vary and develops an alternative method which more accurately estimates this remainder term. A method, called the minimum detectable compartment (MDC), is constructed so that an accurate dose estimate can be made with a realistic measure of the remainder term. The method for determining MDC uses standard hypothesis testing. Using an analogue of the traditional minimal detectable activity calculation, a model with and without constant compartments is fitted to the TAC. The size of the constant compartment is varied until the relative likelihood of the two models meets the desired measure of power and sensitivity. Computer simulations of a simple mono-exponential are used to demonstrate the MDC as a function of the model, the number of data points, the range of the data and the noise in the data. The MDC is a very sensitive function of the data range. It falls by more than 50% when the data range is increased from two to three half-lives. In addition, the MDC is moderately sensitive to the noise in the data and relatively insensitive to the number of data points. These findings suggest that the MDC method can also be uses a priori to indicate what type of data collection regimen is necessary to achieve a certain accuracy.     

The POSNA pediatric musculoskeletal functional health questionnaire: report on reliability, validity, and sensitivity to change. Pediatric Outcomes Instrument Development Group. Pediatric Orthopaedic Society of North America

The goal of orthopaedic interventions is to improve the functional health of patients, particularly physical function. The American Academy of Orthopaedic Surgeons and the Pediatric Orthopaedic Society of North America (POSNA) commissioned a work group to construct functional health outcomes scales for children and adolescents, focusing on musculoskeletal health. The work group developed scales assessing upper extremity function, transfers and mobility, physical function and sports, comfort (pain free), happiness and satisfaction, and expectations for treatment. Parent and adolescent self-report forms were developed and tested on 470 subjects aged 2-18 years. The POSNA scales demonstrated good reliability, construct validity, sensitivity to change over a 9-month period, and ability to outperform a standard instrument, the Child Health Questionnaire physical functioning scale. They were useful for a wide variety of ages and diagnoses. They appear to be ideally suited for orthopaedic surgeons to assess the functional health and efficacy of treatment of their patients at baseline and follow-up.     

Higher glycation of beta L- and beta S-crystallins in the anterior lens cortex and maximum glycation of gamma-crystallins in the bovine lens nucleus, demonstrated by frozen sectioning, isoelectric focusing and lectin staining

The aim of the current study was to demonstrate glycation of beta L-, beta S- and gamma-crystallins in the young bovine lens. To establish which of the crystallins are glycated and where they are located in the lens, we carried out microsectioning of the lens, followed by isoelectric focusing (IEF). Four bovine lenses of 1.183 +/- 0.070 years were frozen-sectioned into equator and 11 layers. Water-soluble crystallins were separated by IEF and stained: (1) with Coomassie brilliant blue for proteins; (2) with the lectin concanavalin A, followed by horseradish peroxidase and diaminobenzidine, for glycated proteins. Experiments were performed with crystallins and proteins in native form, in the absence of denaturants. The crystallins were separated by IEF into alpha-crystallins of high molecular weight (HM), alpha L-, beta H-, beta L-, beta S- and gamma-crystallins. In the lectin staining experiments, only HM, beta L-, beta S- and gamma-crystallins were positive, whereas the alpha L- and beta H-crystallins were negative. Contrary to the glycated gamma-crystallins in the lens nucleus, the beta S- and beta L-crystallins were predominantly glycated in the anterior cortex and to a somewhat lower extent also in the posterior cortical regions. The degree of glycation (total densitometric readings of lectin-stained bands/Coomassie-blue-stained bands) is as follows: total gamma-crystallins 2.44, beta S-crystallins 0.77 and beta L-crystallins 0.28. Though glycation in the bovine lens is very low, lectin staining is sufficiently sensitive to detect the various glycated crystallins. The degree of glycation of gamma-crystallins was 3 times higher than that of beta S-crystallins and 9 times higher than that of beta L-crystallins.     

Kappa Delta Award. Low back pain and whole body vibration

The investigators describe their multifaceted approach to the study of the relationship between whole body vibration and low back pain. The epidemiologic study was a two center study of drivers and sedentary workers in the United States and Sweden. The vibration exposure was measured in the vehicles. It was found that the career vibration exposure was related to low back, neck, and shoulder pain. However, disability was related to job satisfaction. In vivo experiments, using percutaneous pin mounted accelerometers have shown that the natural frequency is at 4.5 Hz. The frequency response is affected by posture, seating, and seat back inclination. The response appears to be determined largely by the rocking of the pelvis. Electromyographic studies have shown that muscle fatigue occurs under whole body vibration. After whole body vibration exposure the muscle response to a sudden load has greater latency. Vehicle driving may be a reason for low back pain or herniated nucleus pulposus. Prolonged seating exposure, coupled with the whole body vibration, should be reduced for those recovering from these problems. Vibration attenuating seats and correct ergonomic layout of the cabs may reduce the risks of recurrence.     

The roles of the N-linked glycans and extension regions of soybean beta-conglycinin in folding, assembly and structural features

Beta-conglycinin, one of the dominant storage proteins of soybean, is a trimer composed of three subunits, alpha, alpha' and beta. All subunits are N-glycosylated and alpha and alpha' contain extension regions in addition to the core regions common to all subunits. Non-glycosylated individual subunits and deletion mutants (alpha(c) and alpha'(c)) lacking the extension regions of alpha and alpha' were expressed in Escherichia coli. All recombinant proteins were purified to near homogeneity and appeared to have the correct conformation, as judged by CD, density-gradient centrifugation and gel-filtration profiles, indicating that the N-linked glycans and extension regions are not essential for the folding and the assembly into trimers of beta-conglycinin. Density-gradient centrifugation, gel-filtration and differential scanning calorimetry profiles of the recombinant proteins and the native beta-conglycinin indicated that the N-linked glycans and extension regions contribute to the dimension of beta-conglycinin but not to the density and the thermal stability. Comparing the solubilities of the individual subunits with those of deletion mutants, only the alpha and alpha' subunits were soluble at lower ionic strength (mu < 0.25) at around the pH value of the endoplasmic reticulum. This suggests that the extension regions play an important role in the prevention of aggregation in the endoplasmic reticulum in analogy with the N-linked glycans.