Simple reaction time as a measure of global attention in Alzheimer's disease

Alzheimer's disease (AD) is characterized by progressive decline in memory, language and other cognitive functions. Deficits in attentional processes have also been suggested. A simple reaction time (RT) task was used to assess global attention in AD. The length and consistency of a warning signal given prior to the response stimulus were manipulated to determine if patients with AD and age-matched controls benefit from predictability in RT tasks. Overall reaction time was slower in the AD group than in the and control group. Both groups demonstrated significant improvement in RT with long warning signals compared to short warning signals, but only the control group benefited from the consistency of the warning.

Event-related potential and behavioral correlates of semantic processing in Alzheimer's patients and normal controls

In normal young adults, N400 amplitude varies inversely with the extent to which a word has been primed by its preceding semantic context. Based on a series of behavioral studies, it appears that in Probable Alzheimer's patients (PAD) the organization of semantic memory is disrupted such that specific items within a category lose their distinction, although superordinate information remains relatively intact. The present study examined whether the N400 gradient which has been found with normal young adults would also reflect this loss of discriminability among semantically related items in PAD patients. Ten normal young adults, 10 normal elderly, and 6 "mild" PAD patients made speeded (but accurate) sense/nonsense decisions to the terminal words of a series of highly constrained sentence contexts. The terminal words belonged to one of four stimulus types which varied as a function of relatedness to a highly expected word. Counter to our predictions, N400 amplitude was identically responsive to semantic relatedness in the young normal and PAD groups, but was characterized differently in the normal elderly. Given the significantly greater number of errors committed by PAD patients, we concluded that their disruption in semantic processing occurs at some point between the elicitation of N400 and the generation of the reaction time response. The anomalous N400 pattern in the normal elderly appeared to be strategy related and superimposed upon an otherwise normal semantic network.

Rapid activation of the interferon-gamma signal transduction pathway by inhibitors of tyrosine phosphatases

Induction of gene expression by interferon-gamma involves the activation of a latent cytoplasmic transcription factor, p91, by phosphorylation on a single tyrosyl residue. This phosphorylation triggers dimerization, nuclear translocation, and the binding of p91 to interferon-gamma response elements present in the promoters of induced genes. Phosphorylation of p91 requires the activation of two tyrosine kinases, JAK1 and JAK2, that themselves become phosphorylated on tyrosyl residues shortly after interferon-gamma binds to its receptor. The importance of tyrosine phosphorylation in this pathway prompted us to investigate the role of protein tyrosine phosphatases in the regulation of the pathway. We find that in the absence of interferon-gamma, treatment of cells with an inhibitor of tyrosine phosphatases causes a rapid and potent activation of the components of the interferon-gamma signal transduction pathway and induces an interferon-gamma-responsive gene. This suggests that tyrosine phosphatases act both to repress the interferon-gamma signal transduction pathway in the absence of interferon-gamma and to downregulate the pathway after interferon-gamma induction.

Early detection of neuroleptic-induced parkinsonism in elderly patients with dementia

The recently promulgated Health Care Finance Administration guidelines regarding the use of neuroleptic medications for nursing home residents do not offer criteria for the frequency or nature of the required assessments of neuroleptic-induced parkinsonism (NIP). NIP has been poorly characterized in the elderly and empirical evidence on which to base guidelines for monitoring NIP is sparse. We examined the onset of NIP in 12 closely monitored, elderly psychiatric inpatients diagnosed with dementia being treated with perphenazine. Significant increases in the Simpson Extrapyramidal Side Effect Scale total score were detected by day 4 of treatment with perphenazine at a mean dose of 8.0 mg. This increase was highly correlated with the final NIP severity. This is the first report to demonstrate that routine screening of elderly patients can detect NIP within days of the initiation of neuroleptic treatment. Early detection of NIP may allow for effective intervention to reduce the ultimate severity and associated morbidity of NIP.

Rapid activation of the STAT3 transcription factor by granulocyte colony-stimulating factor

Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein that stimulates proliferation and differentiation of progenitor cells of neutrophils by signaling through its receptor (G-CSFR). Although the G-CSFR belongs to the cytokine receptor superfamily, which lacks an intracellular kinase domain, G-CSF-induced tyrosine phosphorylation of cellular proteins is critical for its biologic activities. We report here that JAK1 and JAK2 tyrosine kinases are tyrosine phosphorylated in response to G-CSF induction. We also demonstrate that the DNA-binding protein STAT3 (also called the acute-phase response factor [APRF], activated by interleukin-6) is an early target of G-CSF-induced tyrosine phosphorylation. G-CSF induces two DNA-binding complexes; the major complex contains tyrosine phosphorylated STAT3 protein and the minor complex appears to be a heterodimer of the STAT1 (previously p91, a component of DNA-binding complexes activated by interferons) and STAT3 proteins. Antiphosphotyrosine antibody interferes with the DNA binding activity of activated STAT3, indicating that tyrosine phosphorylation of STAT3 is important for the DNA binding activity. These results identify a signal transduction pathway activated in response to G-CSF and provide a mechanism for the rapid modulation of gene expression by G-CSF.

Generation of continuous complex-valued functions for a joint transform correlator

The principle of representing continuous complex-valued functions by their decomposition into three positive-valued ones is proposed for the generation of complex reference functions for a joint transform correlator. Three basic approaches involving coherent and incoherent superposition of the component functions are analyzed. The potentials and limitations of the techniques are discussed.

Reliability of NINDS-AIREN clinical criteria for the diagnosis of vascular dementia

We evaluated the reliability of clinical diagnoses using the recently standardized criteria for the diagnosis of vascular dementia (VaD) developed by the National Institute of Neurological Disorders and Stroke (NINDS) and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN). Two neurologists and two psychiatrists independently reviewed clinical data abstracted from those of 42 demented subjects participating in a longitudinal study of dementia at the University of Pittsburgh. For each patient we abstracted the clinical data on a standardized form. Each physician diagnosed each case according to the NINDS-AIREN criteria, using both clinical information and MRIs. We calculated the interrater agreement for all two-way combinations of clinicians with kappa statistics, which ranged from 0.46 (moderate agreement) to 0.72 (substantial agreement). The moderate reliability observed in this study may be attributable to patient-, clinician-, or criteria-centered sources of variance.

Synthesis of an arbitrary axial field profile by computer-generated holograms

Computer-generated holograms are employed to design any desired intensity distribution along the propagation axis for a finite specified distance.

Rapid activation of proteins that interact with the interferon gamma activation site in response to multiple cytokines

Many cytokines and growth factors trigger rapid changes in gene expression upon binding to their receptors. In many cases, the mechanism by which these changes are affected is unknown. In this report, we show that interleukin-2 (IL-2), IL-3, IL-4, IL-6, leukemia inhibitory factor (LIF), erythropoietin (Epo), and granulocyte-macrophage colony-stimulating factor (GM-CSF) treatment of cells causes rapid activation of DNA-binding activities that recognize a DNA sequence element previously implicated in regulation of gene expression by interferon gamma (IFN gamma). The IL-4-, IL-6-, and GM-CSF-induced complexes can be distinguished from the recently characterized IFN gamma-activated protein p91 on the basis of mobility in polyacrylamide gels, sequence preferences, and lack of reactivity with an anti-p91 antiserum. The IL-4- and GM-CSF-induced complexes react with antiphosphotyrosine antibodies, demonstrating the presence of phosphotyrosine-containing proteins in these DNA-binding complexes. Transcriptional activation of a reporter gene linked to a synthetic IFN gamma-responsive promoter is observed in response to IFN gamma, IL-6, and LIF. These data suggest a pathway by which cytokines induce rapid changes in gene expression.

CT-1501R selectively inhibits induced inflammatory monokines in human whole blood ex vivo

The effect of (R)-1-(5-hydroxyhexyl)-3,7-dimethylxanthine (CT-1501R; the nonproprietary name for CT-1501R approved by the United States Name Council is lisofylline), an inhibitor of second messenger signaling through phosphatidic acid, on release of endogenous mediators important in the systemic inflammatory response syndrome (SIRS) was studied using the human whole blood ex vivo assay system. Human blood was stimulated with various endotoxin preparations, zymosan, or protein A, and the levels of secreted monokines were measured by enzyme-linked immunosorbent assay. CT-1501R inhibited tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), and IL-6 release in a dose-dependent manner and was active with all stimuli tested including Salmonella and Escherichia coli-derived endotoxin, endotoxin from both rough and smooth E. coli strains, as well as zymosan and protein A. CT-1501R inhibited monokine release by approximately 50% at 200 microM and 30% at 50 microM and was independent of the relative potency of stimulus. CT-1501R also inhibited IL-1 alpha or IL-1 beta induction of either TNF-alpha or IL-1 beta and inhibited the synergistic effects of stimulation with both human IL-1 beta and murine TNF-alpha on release of human TNF-alpha. Inhibition of monokine release following stimulation with monokine(s) was, in general, greater than that achieved with lipopolysaccharide (LPS) stimulation. Northern blot analysis showed decreased mRNA accumulation of TNF-alpha and IL-1 beta in CT-1501R-treated samples following LPS stimulation suggesting that CT-1501R acts at least in part, at the pretranslational level. In contrast, CT-1501R does not inhibit LPS-stimulated IL-8 or IL-1 receptor antagonist (IL-1ra) release in human whole blood or IL-1 alpha-induced release of PGE2 in human foreskin fibroblast cells. These data suggest that CT-1501R may be of use for clinical intervention in SIRS.

Synthesis of nondiffracting beams in free space

A novel method of designing the longitudinal intensity profile of a diffracted beam in free space is proposed. By use of this method illumination of an arbitrarily synthesized aperture can yield a desired intensity distribution, including a constant (nondiffracting) curve, along a chosen limited range.

YY1 represses beta-casein gene expression by preventing the formation of a lactation-associated complex

Site-specific mutagenesis of the highly conserved milk box (-140 to -110) region suggested that beta-casein expression is regulated by a hormone-mediated relief of repression (M. Schmitt-Ney, W. Doppler, R. K. Ball, and B. Groner, Mol. Cell. Biol. 11:3745-3755, 1991). However, when this sequence was placed upstream of a heterologous thymidine kinase promoter, it activated reporter gene expression. This apparent paradox was resolved when the trans-acting factor YY1, capable of acting as both a positive and negative regulator, was shown to interact with the milk box region, using bacterially expressed YY1 and specific oligonucleotide and antibody competition experiments. Second, it was demonstrated that extracts prepared from several cell types contained a protein(s) interacting with the mammary gland-specific factor (MGF) binding site, previously shown to be required for beta-casein promoter activity (Schmitt-Ney et al., Mol. Cell. Biol. 11:3745-3755, 1991). Sequence analysis of this site revealed similarity to the gamma interferon-activated sequence, suggesting that MGF may be related to the stat91 signaling protein. Finally, using an oligonucleotide encompassing both the YY1 and MGF sites, we detected a slow-mobility complex only in extracts from mammary glands at late pregnancy and lactation (lactation-associated complex [LAC]). Site-specific mutation of the YY1 binding site led to an enhancement in LAC DNA binding activity, while mutation of the MGF site decreased detectable LAC. These results support a model in which lactogenic stimuli lead to a decrease in YY1 binding, and subsequent increased formation of LAC at a nearby binding site, to stimulate beta-casein transcription.

Canine choledochotomy closure with diode laser-activated fibrinogen solder

BACKGROUND

An alternative to mechanical stapling or hand suturing is needed to permit laparoscopic common bile duct exploration. We evaluated the strength and healing characteristics of canine choledochotomies sealed with a fibrinogen solder and a diode laser.

METHODS

After creation of a 0.5 cm longitudinal choledochotomy, the edges were coapted with forceps, and a fibrinogen solder mixed with indocyanine green dye was applied. The solder was sealed in place with an 810 nm diode laser (125 W/cm2).

RESULTS

Immediate mean leakage pressure was 264 +/- 7 mm Hg compared with 83 +/- 66 mm Hg in suture controls. This increased to 364 +/- 115 mm Hg at 2 days and was more than 510 mm Hg at 7 days. On histologic examination rapid reabsorption of the solder with no signs of inflammation or stenosis was seen. No episodes of dehiscence or peritonitis occurred.

CONCLUSIONS

Laser soldering provides a watertight choledochotomy closure with adequate immediate strength allowing a reliable, technically feasible common bile duct exploration via a laparoscopic approach.

A user-friendly instrument for rating agitation in dementia patients

There are many rating instruments designed to assess symptoms of agitation in patients with dementia. Most scales require that raters assess multiple specific behaviors over several days, limiting the use of such scales to clinical staff who have direct contact with patients but do not have the time to complete a comprehensive assessment following each period of observation. Also, scales that assess behavior over several days must rely on "secondhand" information describing behaviors not directly observed by the rater. The Pittsburgh Agitation Scale (PAS) is an easy-to-use instrument, based on direct observations of the patient, that was developed to monitor the severity of agitation associated with dementia. Interrater reliability and measures of validity have been established with clinical staff on a busy psychogeriatric inpatient unit and with research personnel in a nursing home setting.

The Delirium Rating Scale in a psychogeriatric inpatient setting

The Delirium Rating Scale (DRS) has been shown to be a valid instrument for identifying and grading the severity of delirium in patients admitted to a general hospital for medical or surgical treatment. However, its accuracy in identifying delirium among elderly patients admitted to a psychiatric hospital for evaluation and treatment of psychiatric illness has not been previously addressed. The DRS was administered to 791 elderly patients who were consecutively admitted to a psychogeriatric unit; 70 met DSM-III-R criteria for delirium. A DRS threshold score of > or = 10 correctly identified delirious patients with a sensitivity of 94% and a specificity of 82%. Both psychosis and cognitive impairment appeared to falsely elevate the DRS score in this population.

Reduction in the reconstruction error of computer-generated holograms by photorefractive volume holography

We suggest a method for coding high-resolution computer-generated volume holograms. It involves splitting the computer-generated hologram into multiple holograms, their individual recording as volume holograms by use of the maximal resolution available from the spatial light modulator, and subsequent simultaneous reconstruction. We demonstrate the recording and the reconstruction of a computer-generated volume hologram with a space-bandwidth product much higher than the limitation imposed by the interfacing spatial light modulator. Finally, we analyze the scheduling procedure of the multiple holographic recording process in photorefractive medium in this specific application.

Effects of a history of heavy alcohol consumption on Alzheimer's disease

Neuropsychological and psychiatric evaluations were made of 39 subjects with possible Alzheimer's disease and a history of excessive alcohol consumption (AD + ETOH), who had been abstinent or had drunk minimally for at least three months before evaluation, and 225 patients with probable Alzheimer's disease (PAD) of comparable age, years of education, and baseline global impairment. At baseline, there were no significant differences between the groups in terms of age of onset of dementia, neuropsychological test scores, or current behavioural or psychiatric symptoms. One year later, no differences in rates of decline between 20 abstinent AD + ETOH patients and 88 PAD subjects could be shown. Thus, past heavy alcohol consumption does not appear to modify the presentation of dementia of the Alzheimer's type, nor does it modify progression over a one-year interval.

Peripheral nerve regeneration across 14-mm gaps: a comparison of autograft and entubulation repair methods in the rat

A study was conducted to compare the regeneration across 1.4-cm peroneal nerve gaps in rats, repaired with sutured autografts or with artificial nerve grafts. The artificial models were composed of a biodegradable passive conduit made of glycolide trimethylene carbonate, filled with either phosphate-buffered saline or a collagen extracellular matrix. Functional recovery was evaluated by walking track analysis throughout the experiment. After 9 months, the nerves were analyzed by electrophysiology and by qualitative and quantitative histology. Walking track analysis demonstrated the three repair methods to provide statistically equivalent recovery, except at day 195 post-engraftment, when the collagen-filled conduit was superior to the saline-filled conduit. Electrophysiologically, the autograft was superior to the collagen-filled conduit, while the collagen- and saline-filled conduits were equivalent. Quantitative histology demonstrated that normal intact nerve had larger mean myelinated axonal diameters but an equal number of axons to the three repair methods, and that the repair methods were statistically equivalent. While the repair methods had similar histologic and functional outcomes, combined standardized scoring demonstrated that the autograft was superior to the statistically-equivalent entubulation repairs. A collagen gel may serve as an ideal matrix in which to suspend neurotrop(h)ic factors or cells.

Treatment of nortriptyline's side effects in elderly patients: a double-blind study of bethanechol

A double-blind, placebo-controlled study of bethanechol was conducted in 26 elderly depressed patients being treated with nortriptyline. Patients receiving bethanechol had reduced subjective complaints of anticholinergic side effects and showed a trend toward improvement on an objective measure of salivary flow. The potential use of bethanechol in older patients to reduce morbidity and improve compliance with medication regimens is discussed.