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Biomedical subjects

J Beer

Publications and source records attributed to J Beer.

At least 19 recordsLinked to original sources
PubMed2005

Prospective reliability of the STRokE DOC wireless/site independent telemedicine system.

The authors evaluated a site-independent telemedicine system. Telemedicine may be limited by the need for fixed connectivity. Wireless and site-independent technologies eliminate this limitation. Twenty-five stroke patients underwent evaluations by remote and bedside examiners. Ten of 15 (67%) NIH Stroke Scale and 9 of 11 (82%) Modified NIH Stroke Scale items showed excellent interrater reliability. Spearman correlations were > or =0.93. This Internet system is reliable and valid. Further studies should assess its use in acute stroke.

Adolescent↗
PubMed2004

Unusual activity of the Sun during recent decades compared to the previous 11,000 years.

Direct observations of sunspot numbers are available for the past four centuries, but longer time series are required, for example, for the identification of a possible solar influence on climate and for testing models of the solar dynamo. Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. We combine physics-based models for each of the processes connecting the radiocarbon concentration with sunspot number. According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode. Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades.

Atmosphere↗
PubMed2001

Persistent solar influence on North Atlantic climate during the Holocene.

Surface winds and surface ocean hydrography in the subpolar North Atlantic appear to have been influenced by variations in solar output through the entire Holocene. The evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon-14 and beryllium-10 and centennial to millennial time scale changes in proxies of drift ice measured in deep-sea sediment cores. A solar forcing mechanism therefore may underlie at least the Holocene segment of the North Atlantic's "1500-year" cycle. The surface hydrographic changes may have affected production of North Atlantic Deep Water, potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally.

Journal Article↗
PubMed2001

The relationship between interview characteristics and accuracy of recall in young children: do individual differences matter?

The relationship between interview characteristics and accuracy of recall in young children, as mediated by child characteristics, was examined. The interview characteristics included preinterview instructions and level of questioning. Fifty-six children ranging from ages 3 to 6 years participated in a Circus Day event and were interviewed 10 days later. Following either instructions or filler questions, children were questioned about the event. Results indicated that based on several individual difference factors, young children varied significantly in the accuracy of their interviews and their ability to resist misleading questions. However, individual differences did not mediate children's ability to benefit from different question types or preinterview instructions. As a whole, children provided limited information to the most open-ended questions and more correct information to highly structured questions. In contrast to the research with older children, younger children did not benefit from preinterview instructions. Suggestions for future research and implications for investigative interviews in the field of child abuse are discussed.

Black or African American↗
PubMed2000

Changes in deep-water formation during the Younger Dryas event inferred from 10Be and 14C records.

Variations in atmospheric radiocarbon (14C) concentrations can be attributed either to changes in the carbon cycle--through the rate of radiocarbon removal from the atmosphere--or to variations in the production rate of 14C due to changes in solar activity or the Earth's magnetic field. The production rates of 10Be and 14C vary in the same way, but whereas atmospheric radiocarbon concentrations are additionally affected by the carbon cycle, 10Be concentrations reflect production rates more directly. A record of the 10Be production-rate variations can therefore be used to separate the two influences--production rates and the carbon cycle--on radiocarbon concentrations. Here we present such an analysis of the large fluctuations in atmospheric 14C concentrations, of unclear origin, that occurred during the Younger Dryas cold period. We use the 10Be record from the GISP2 ice core to model past production rates of radionuclides, and find that the largest part of the fluctuations in atmospheric radiocarbon concentrations can be attributed to variations in production rate. The residual difference between measured 14C concentrations and those modelled using the 10Be record can be explained with an additional change in the carbon cycle, most probably in the amount of deep-water formation.

Journal Article↗
PubMed2000

Functional imaging of brain areas involved in the processing of coherent and incoherent wide field-of-view visual motion.

The brain areas involved in processing wide field-of-view (FOV) coherent and incoherent visual stimuli were studied using positron emission tomography (PET). The brains of nine subjects were scanned as they viewed texture patterns moving in the roll plane. Five visual conditions were used: (1) coherent clockwise (CW) wide-FOV (>100 degrees) roll motion; (2) coherent counter-clockwise (CCW) wide-FOV roll motion; (3) wide-FOV incoherent motion; (4) CCW motion confined to the central visual field (approximately 55 degrees); and (5) a stationary control texture. The region most activated by the coherent-motion stimulus relative to the static one was the medial-occipital cortex, whereas both the medial- and lateral-occipital cortices were activated by incoherent motion relative to a static texture. Portions of the retroinsular parietal-temporal cortex, superior insula, putamen, and vestibulocerebellum responded specifically to the coherence of the stimulus, whereas a widespread lateralized activation was observed upon subtracting the CW scans from the CCW scans. The results indicate separate neural regions for processing wide-FOV motion versus stimulus coherence.

Adult↗
PubMed2000

Child characteristics which impact accuracy of recall and suggestibility in preschoolers: is age the best predictor?

OBJECTIVE: The purpose of the present study was to determine whether individual difference factors of metamemory, intelligence, and temperament can improve the ability to predict accuracy of recall and suggestibility in preschoolers. METHOD: Fifty-six children ranging in age from 43 months to 83 months (M = 61, SD = 9) were recruited from 13 child care centers in a rural southeastern town. Children participated in a "Circus Day" event conducted by two female undergraduate psychology students dressed as clowns. Approximately 10 days (M = 10; SD = 2) after the event, children were interviewed regarding their experiences. RESULTS AND CONCLUSIONS: Bivariate correlations and multiple regression analyses were performed in order to determine which factors were related and unique contributors to accuracy of recall and suggestibility. Of principal importance is the finding that child characteristics such as metamemory ability, intellectual functioning, and temperament may indeed be helpful in determining a child's capacity to accurately recall information in an interview, although for the most part age is the best predictor. Findings also underscore the importance of considering a child's SES and race when planning and conducting interviews with young children. Possible explanations for these findings as well as implications for future research and clinical application are discussed.

Child↗
PubMed2000

Comparison of Mycobacterium tuberculosis susceptibility testing performed with BACTEC 460TB (Becton Dickinson) and MB/BacT (Organon Teknika) systems.

The recently introduced automated culture systems MB/BacT (Organon Teknika, Belgium) was compared with radiometric BACTEC 460TB (Becton Dickinson, USA) to test antimicrobial susceptibility of Mycobacterium tuberculosis to first line drugs. On 113 strains 97.5% agreement was obtained, with the difference being not significant. Concordance was practically complete for the most important drugs, isoniazid and rifampin. The two methods however significantly differed for the time needed to complete the test; in fact MB/BacT required on the average five days more than BACTEC 460TB. Despite the delay in the completion of the test, the excellent reliability along with the elimination of radioactivity and full automation make MB/BacT an attractive alternative for susceptibility testing of M. tuberculosis.

Antibiotics, Antitubercular↗
PubMed2000

Is "ambient vision" distributed in the brain? Effects of wide-field-view visual yaw motion on PET activation.

Ambient vision comprises the visual functions that are associated with the maintenance of spatial orientation and that depend on peripheral, preconscious visual inputs. Although a limited number of brain areas appear to be activated by coherent wide-field-of-view (WFOV) motion in more than one axis, a diffuse pattern of lateralized brain activity occurs in response to clockwise or counterclockwise ambient visual roll motion. In the present study involving positron emission tomography (PET), a similar finding was shown for rightward versus leftward yaw stimulation. A total of 18 PET scans were obtained from six subjects in response to either leftward or rightward WFOV motion in a collimated display subtending > 100 degrees horizontally. Rightward stimulation elicited mainly activation throughout the right hemisphere, whereas leftward stimulation elicited mainly activation throughout the left hemisphere. These findings provide further evidence that the ambient vision signal is either processed or transmitted throughout the entire brain, as befits a visual function that is fundamental to all other perceptual systems.

Adult↗
PubMed1998

Expression of c-jun, junB, c-fos, fra-1 and fra-2 mRNA in the rat brain following seizure activity and axotomy.

The present study has investigated the congruence of mRNA induction and protein expression of inducible transcription factors (ITFs). The patterns of c-jun, junB, c-fos, fra-1 and fra-2 mRNAs were studied by radioactive and non-radioactive in situ hybridization in the adult rat brain following kainate-induced seizure activity and axotomy. In the same animals, the expression of c-Jun, JunB and c-Fos proteins was compared with the respective mRNA signals. Using radioactive labeled probes all investigated mRNAs showed an onset within 1 h after systemic kainate application and the maximal levels were generally reached after 3 h. Each mRNA displayed a specific temporo-spatial expression pattern. Whereas fra-1 and fra-2 were restricted to the hippocampus, c-jun, junB and c-fos were additionally induced in the cortex, amygdala and thalamus. The areas with maximal labeling were the dentate gyrus and the hippocampal CA1 and CA3 subfields. The expression patterns between c-jun, junB and c-fos mRNA were virtually congruent with the respective protein. Labeling of the junB and fra-2 probes with digoxigenin yielded similar results. Twenty-four hours, 3 and 10 days following transection of the medial forebrain bundle and the mamillo-thalamic tract, high levels of c-jun mRNA (either digoxigenin or radioactive labeled probes) and protein were seen in the axotomized neurons of the substantia nigra pars compacta and mamillary body whereas the other mRNAs studied and the JunB or c-Fos proteins could not be detected. These findings demonstrate that mRNAs encoding for ITFs are translated into the respective proteins following excitotoxic seizures and axotomy, and that the antisera used for immunocytochemistry yield specific expression patterns of homologous proteins.

Animals↗
PubMed1998

Geomagnetic modulation of the 36Cl flux in the GRIP ice core, greenland

Geomagnetic field strength is expected to affect the production rate of cosmogenic isotopes such as beryllium-10, carbon-14, or chlorine-36. Chlorine-36 data from the Greenland Ice Core Project (GRIP) ice core agree well with a production rate calculation based on a paleomagnetic reconstruction for the past 100,000 years over both long- and short-term variations. A chlorine-36 peak at 38,000 years ago previously found in the beryllium-10 record from the Vostok ice core can be explained by a period of low geomagnetic field intensity.

Journal Article↗
PubMed1997

Brain-derived neurotrophic factor modulates GAP-43 but not T alpha1 expression in injured retinal ganglion cells of adult rats.

The administration of neurotrophins affects neuronal survival and growth, but less is known about their ability to modify the expression of growth associated genes following injury to CNS neurons. Here we characterize the effect of brain-derived neurotrophic factor (BDNF) on mRNA levels for T alpha1 alpha-tubulin, and for GAP-43, two genes whose expression levels in retinal ganglion cells (RGC) tend to correlate with growth. We first determined that most adult rat RGCs can retrogradely transport BDNF by injecting 125I-BDNF into RGC target sites in vivo. We then used quantitative in situ hybridization to characterize the effect of axotomy, or axotomy and BDNF administration on mRNA levels for GAP-43 and T alpha1. Axotomy alone resulted in a general decrease in T alpha1 alpha-tubulin mRNA levels by 2 weeks, and elicited an increase in GAP-43 mRNA levels in an average of 30% of surviving RGCs. The intravitreal administration of a single dose of BDNF (5 microg) to axotomized RGCs on the day of injury did not affect T alpha1 alpha-tubulin mRNA levels, but was followed by a moderate (approximately 80%), and short-lasting enhancement of GAP-43 mRNA levels in most RGCs during the first week after axotomy. No significant increase in GAP-43 mRNA levels was observed when BDNF was injected into the uninjured eye. We conclude that BDNF specifically enhances GAP-43 but not T alpha1 mRNA levels in injured RGCs. Because BDNF is known to stimulate branch length of injured RGCs, we suggest that changes in the expression of GAP-43, but not T alpha1 tubulin, correlate with branching of injured neurons as opposed to long distance regrowth.

Animals↗
PubMed1997

Reduced calcium dialysate in CAPD patients: efficacy and limitations.

BACKGROUND: The increasing use of 'reduced calcium' dialysate in CAPD patients treated with calcium-based phosphate binders has raised concerns that this could lead to negative calcium balance, worsening hyperparathyroidism, and osteopenia. METHODS: The present study was conducted to examine the possibilities (a) that 1.25 mM calcium dialysate leads to negative calcium balance and worsening hyperparathyroidism, and (b) that conversely 1.25 mM calcium dialysate is still too high for some patients. We studied 22 patients who, after a 2-month run in using 1.75 mM calcium dialysate and aluminium hydroxide binders, entered a 3-month phase of 1.25 mM calcium dialysate with continuation of aluminium hydroxide as the sole phosphate binder. The patients then entered a final 9-month phase in which dialysate calcium remained at 1.25 mM and calcium carbonate was substituted for aluminium hydroxide and progressively titrated to achieve optimum phosphate control. RESULTS: During the initial 3-month period, parathyroid hormone increased from 259, range 11-1149 to 405, range 16-1318 pg/ml (P = 0.0001) and ionized calcium decreased from 1.17 +/- 0.06 to 1.11 +/- 0.08 mM (P = 0.0004). The subsequent 9-month phase was associated with return of parathyroid hormone to baseline levels. Further dialysate calcium reduction to 0.6 mM was implemented in the four patients who became hypercalcaemic. CONCLUSION: This study has clearly shown that reduction of dialysate calcium to 1.25 mM can be harmful to CAPD patients if oral calcium availability is inadequate. It has also shown that dialysate calcium at 1.25 mM is a compromise, with increased risk of hyperparathyroidism if calcium intake is too low and, conversely, risk of hypercalcaemia and unacceptable increases of the Ca x Pi product in a minority of patients. At these extremes there is a need for a high-calcium dialysate (1.75 mM) and a very low-calcium dialysate (0.6 mM or less), to optimize management.

Adult↗
PubMed1996

Low-dose thrombolysis for thrombosed prosthetic heart valve.

This report describes two cases of successful fibrinolysis of thrombosed tricuspid and mitral valve prostheses (Carbomedics; Austin, Texas) with low-dose urokinase therapy corresponding to only one third of the dose usually recommended.

Heart Valve Prosthesis↗
PubMed1995

Cells from peripheral tissues that exhibit high APP expression are characterized by their high membrane fusion activity.

The amyloid precursor protein of Alzheimer's disease (APP) is ubiquitously expressed suggesting a general function throughout the organism. We have used APP-specific antibodies to investigate the expression and localization of APP in different tissues from rat (testis, ovary, liver, kidney, spleen, pancreas, salivary gland). Immunohistochemistry demonstrated that APP is highly expressed in Sertoli cells, follicle cells, secretory cells, podocytes and macrophages. Features common to these cells include their high membrane turnover and their functional characteristics of endocytic and phagocytic retrieval and exocytosis. This suggests APP may participate in interactions of cells of the mononuclear phagocytic system, and function in relation to tissue maintenance and repair.

Amyloid beta-Protein Precursor↗
PubMed1994

General and test anxiety, shyness, and grade point average of elementary school children of divorced and nondivorced parents.

116 boys and girls in elementary Grades 4, 5, and 6 were administered the General Anxiety Scale, Test Anxiety Scale, and the Shyness Scale. Their GPAs were obtained from school records as were Normal Curve Equivalents from the Iowa Tests of Basic Skills given the previous school year. Children of divorced parents (n = 31) had lower GPAs than children of nondivorced parents (n = 85). The girls had higher GPAs and general anxiety scores than the boys. The students who scored lower on test anxiety had higher Normal Curve Equivalents. Pearson correlations were significant for scores on Test Anxiety with those on general anxiety (r = .57), GPA (r = -.25), and Normal Curve Equivalents (r = -.26). Normal Curve Equivalents correlated significantly with GPA (r = .66), but shyness did not correlate significantly with any other measure.

Achievement↗
PubMed1994

Multiple personality: self-rape.

Multiple personality disorder is the classification given a person for whom two or more distinct personalities are diagnosed. The personalities can be different and vary in character from aggressive to submissive (victimized). The victim alters can be abused and abuse or mutilate self to relieve anxiety or guilt (deserving punishment) or to exert control. Alters may provide a means of expressing anger or other feelings. Aggression towards the body may be sexually oriented, so one may ask whether aggression could make self-rape possible. If so, such expression of self-injuries may be observed in a person with multiple personality as when one alter may injure another. Clinical case material is presented on this concept for a woman who had been formally diagnosed with multiple personality disorder.

Adult↗