cssi/SciSciGPT-SciSciNet huggingface dataset:
Circular dichroism of double-helical oligoribonucleotides☆

Abstract The ultraviolet circular dichroism and absorption of 15 double-stranded helical oligoribonucleotides have been measured. These molecules of chain-length 6 to 12 contain all 10 possible nearest neighbors of Watson-Crick base pairs. They are thus good models for short double-stranded regions in RNA molecules. The contribution to the circular dichroism of each of the nearest neighbor base pairs has been obtained. The circular dichroism is found to be very sequence-dependent and may be useful in distinguishing possible secondary structures. However, the nearest neighbor approximation for circular dichroism fails to give a quantitative measure of the circular dichroism of double-strand regions.
Voltage Dependence of Na/K Pump Current in Xenopus Oocytes

Stage V and VI (Dumont, J.N., 1972.J. Morphol. 136:153–180) oocytes ofXenopus laevis were treated with collagenase to remove follicular cells and were placed in K-free solution for 2 to 4 days to elevate internal [Na]. Na/K pump activity was studied by restoring the eggs to normal 3mm K Barth's solution and measuring membrane current-voltage (I–V) relationships before and after the addition of 10 μm dihydroouabain (DHO) using a two-microelectrode voltage clamp. Two pulse protocols were used to measure membraneI–V relationships, both allowing membrane currents to be determined twice at each of a series of membrane potentials: (i) a down-up-down sequence of 5 mV, 1-sec stair steps and (ii) a similar sequence of 1-sec voltage pulses but with consecutive pulses separated by 4-sec recovery periods at the holding potential (−40 mV). The resulting membraneI−V relationships determined both before and during exposure to DHO showed significant hysteresis between the first and second current measurements at each voltage. DHO difference curves also usually showed hysteresis indicating that DHO caused a change in a component of current that varied with time. Since, by definition, the steady-state Na/K pumpI−V relationship must be free of hysteresis, the presence of hysteresis in DHO differenceI−V curves can be used as a criterion for excluding such data from consideration as a valid measure of the Na/K pumpI−V relationship. DHO differenceI−V relationships that did not show hysteresis were sigmoid functions of membrane potential when measured in normal (90mm) external Na solution. The Na/K pump current magnitude saturated near 0 mV at a value of 1.0–1.5 μA cm−2, without evidence of negative slope conductance for potentials up to +55 mV. The Na/K pump current magnitude in Na-free external solution was approximately voltage independent. Since these forward-going Na/K pumpI−V relationships do not show a region of negative slope over the voltage range −110 to +55 mV, it is not necessary to postulate the existence of more than one voltage-dependent step in the reaction cycle of the forward-going Na/K pump.
Effects of sleep apnea and APOE ε4 status on follow-up of veterans with PTSD from the Vietnam conflict

The purpose of this ongoing study is to examine the effects of sleep apnea in veterans of the Vietnam conflict who also have Post-traumatic Stress Disorder. At the point of the first analyses of the project, 142 subjects were fully screened and 114 were found eligible. Of the 114 eligible subjects, 97 have obtained baseline Rey Auditory Verbal Learning Test (RAVLT) results and 85 have data completely scored and ready for analysis. Of these 85 completed eligible subjects, 47 have completed a 1 year follow-up, 10 have not yet been scheduled for 1 year follow-up because there has not been sufficient time elapsed since they enrolled and 28 did not complete 1 year follow-up for one of several reasons described below. This resulted in an overall drop-out rate of 28/75, or 37%, which is substantially higher than the 20% rate predicted on the basis of prior sleep studies. One of the most striking findings of the study to date is that the drop-out rate after one year for subjects who have neither SDB nor the APOE e4 allele is only 17%, but is 73% in subjects having both risk factors. Using logistic regression analyses, this effect is statistically significant for the e4-carrier status (Wald Chi-square = 4.45, p = 0.03), as well as for the effect of AHI > 20 status (Wald Chi-square = 5.76, p = 0.02) but not significant for the interaction of e4-carrier status and AHI > 20 status (Wald Chi-square = 0.003, p = 0.96). Thus, the effect of APOE e4 status and AHI appears additive with drop-out rates of 40% and 44% respectively for each risk factor alone. In short, drop-out rates increase over 20% for each factor separately. It would be extremely useful to understand why this disproportionate drop-out rate exists. Of the 85 subjects with complete data who were fully screened and entered into the study, 28 have not completed 1 year follow-up for reasons other than insufficient time elapsed since enrollment. Of these 28: 7 have been completely lost to follow-up (no telephone numbers, no recent CPRS records and no response to letters) and 5 of these 7 are e4-carriers (71%); 17 have appointments overdue more than 1 month (contact information for subjects is active and correct but there has been no responses to inquiries) and 7 of these 17 are e4-carriers (41%); and 4 consented to phone follow-ups, but would not return to the clinic and none of these are e4-carriers (0%). Further data will be presented at the time of the conference.
Cortical Neural Precursors Inhibit Their Own Differentiation via N-Cadherin Maintenance of β-Catenin Signaling

Summary Little is known about the architecture of cellular microenvironments that support stem and precursor cells during tissue development. Although adult stem cell niches are organized by specialized supporting cells, in the developing cerebral cortex, neural stem/precursor cells reside in a neurogenic niche lacking distinct supporting cells. Here, we find that neural precursors themselves comprise the niche and regulate their own development. Precursor-precursor contact regulates β-catenin signaling and cell fate. In vivo knockdown of N-cadherin reduces β-catenin signaling, migration from the niche, and neuronal differentiation in vivo. N-cadherin engagement activates β-catenin signaling via Akt, suggesting a mechanism through which cells in tissues can regulate their development. These results suggest that neural precursor cell interactions can generate a self-supportive niche to regulate their own number.
Heterogeneity of Helicobacter pylori.

Although many physicians view Helicobacter pylori strains as a homogenous group of organisms, it has become increasingly clear that populations in humans are highly diverse. This heterogeneity can be analyzed at two different levels: genotypic variation among strains and variations in H. pylori populations within an individual host. Genotypic variation includes point mutations in conserved genes (e.g. ureC), variation in the gene order on physical maps, mosaicism in conserved genes (e.g. vacAs1a), non-conserved genes (e.g. cagA) and extragenetic elements (e.g. IS605). Population differences include the observations that humans can be simultaneously infected with two or more H. pylori strains and that a single strain may represent a cluster of closely related organisms (a 'quasispecies'). The presence of multiple organisms within a host may occur as a result of recombination events leading to genetic shift, whereas ongoing mutation within a strain can lead to the formation of quasispecies by genetic drift. Over recent years it has become increasingly clear that observations on the fundamental biology of H. pylori have considerable clinical relevance. Several genotypic markers (e.g. cagA, vacA, sIa and iceA1) are associated with an increased risk of disease. Also, the multiplicity of infection and quasispecies indicates that analysis of a single H. pylori isolate is inaccurate for defining the genotype of H. pylori strains present in a patient. Global assays, such as serology, are more suitable. The aim of this paper is to review the general phenomenon of diversity in H. pylori and to describe particular heterogeneities that are related to clinical outcome.
Calculation of beta dosimetry in radiation synovectomy using Monte Carlo simulation (EGS4).

Using the EGS4 Monte Carlo code, absorbed dose rate factors were estimated for four radionuclides of interest in radiation synovectomy, an intra-articular radiation therapy to treat rheumatoid arthritis. The treatment consists of the injection of a beta-emitting radionuclide into the joint capsule in order to eliminate diseased synovium through irradiation. The radionuclides investigated are 32P, 90Y, 165Dy, and 198Au. Calculations reveal the absorbed dose factor (cGy cm2/MBq s) as a function of distance (mm) in an EGS4 model of the rheumatic joint. The model incorporates bone, articular cartilage, joint capsule, and tissue (synovium) components found in all synovial joints, with dimensions in the model corresponding to dimensions typically found in larger joints, e.g., the knee, shoulder, or hip. Results are compared with previous, analytical approaches to beta dosimetry in radiation synovectomy. In addition, radiation backscatter due to the presence of bone is investigated and determined to have a negligible enhancement effect on absorbed dose to synovium.
Radiation response and other characteristics of the 9l rat glioma grown as an epigastric tissue isolate

We studied the 9L tumor as a tissue isolated epigastric implant. Data supporting its applicability to this site, including tumor blood flow, glucose metabolism, plating efficiency, radiation response, and histophatologic appearance, are described. Implants were performed on 175-250 g male Fischer rats by tying 2–3 mm3 pieces of tumor onto the proximal segment of the epigastric branch of the femoral artery. Characteristics of the model include recovered cell yields of 6.1 ± 4.2 × 107 cells/g; 19–23% plating efficiency; 5% relative surviving fraction at 19.3 and 27.6 Gy in air breathing and euthanized rats, respectively; mean glucose utilization rate of 229 ± 182 nmol/min/g; and tumor blood flow of 1.9–21.3 ml/min/100 g in 0.4–303 g tumors. These characteristics, for the first time, provide a common framework for simultaneous evaluation of tumor metabolism and radiation response. © Wiley-Liss, Inc.
The effects of 17β-estradiol and ethanol on zinc- or manganese-induced toxicity in SK-N-SH cells

Serious neurodegenerative disorders are increasingly prevalent in our society and excessive oxidative stress may be a key mediator of neuronal cell death in many of these conditions. A variety of metals, such as manganese and zinc, are essential trace elements but can reach localized toxic concentrations through various disease processes or environmental exposures and have been implicated as having a role in neurodegeneration. Both manganese and zinc exist as bivalent cations and are essential cofactors/activators for numerous enzymes. Evidence suggests one action of these metals, when concentrated beyond physiological levels, may be to inhibit cellular energy production, ultimately leading to increased radical formation. Our studies were undertaken to directly investigate the toxic effects of manganese and zinc in an immortalized neuronal-like cell line (SK-N-SH) by testing interactions with the antioxidant, 17β-estradiol, and the neurotoxin, ethanol. Employing undifferentiated SK-N-SH cells, we found that these metals caused biphasic effects, enhancing cell proliferation at low doses and inducing cell death at higher doses. Zinc was both more efficacious and more potent than manganese in enhancing growth and in causing cell death. 17β-Estradiol and ethanol enhanced the proliferative actions of zinc and manganese across a wide concentration range. Furthermore, co-treatment with either 17β-estradiol or ethanol afforded protection against manganese-, but not zinc-induced toxicity. Finally, combined administration of 17β-estradiol and ethanol to SK-N-SH cells resulted in both a loss of growth enhancement and protective properties that were observed when these substances were administered individually. We also noted that the toxic effects occurred more rapidly from zinc than manganese exposure. Taken together, these data suggest that oxidative stress likely has a role in cell death resulting from toxic exposure to either zinc or manganese, but there is a difference in the precise mechanism of their effects.
Effects of unstirred layers or transport number discontinuities on the transient and steady-state current-voltage relationships of membranes

The effects of current-induced electrolyte accumulation and depletion on the electrical properties of a two-layered membrane system have been examined. The membrane consisted of a charged, ion permselective layer and an uncharged, non-selective layer. The model was designed to reveal the properties of membranes possessing long pores with ionic charges at one end or of ion-selective membranes bounded by highly unstirred aqueous layers. Electrolyte concentration profiles in the inert layer and their time-dependent changes were obtained from solutions of the diffusion equation under the condition of constant current. The profiles were then used to calculate the voltage developed across the membrane at various times after the current is switched on. The theoretical results are presented in the form of i-V curves with reduced coordinates that can be used to obtain time-current-voltage relationships for membranes of the type considered having any thickness of the non-selective layer and bathed in any concentration of any 1:1 electrolyte. Experimental results on a model composite membrane were in good agreement with calculations that assume that ion transport occurs only under the influence of electrical potential and concentration gradients, suggesting that in such systems, the combined effects of convection, osmosis, electro-osmosis, and concentration-dependence of diffusion coefficients, activity coefficients, and transference numbers are small. Voltage fluctuations in the form of periodic spikes were observed experimentally at the limiting current density (the current density at which the electrolyte concentration at one surface of the selective layer goes to 0). These phenomena were not seen when the current was in the direction leading to accumulation of electrolyte in the non-selective (unstirred) layer. Such composite membranes can exhibit S-shaped and N-shaped i-V curves under ramp-voltage and ramp-current clamps, respectively.
Properties of the moment of inertia in the problem of three bodies

Sundman's and Birkhoff's results are combined with a recently developed inequality and new qualitative results are given for the problem of three bodies.
Convective Effects in Thermal Lens Spectroscopy

Thermally induced solution stirring can cause periodic signal fluctuations which can be the sensitivity limiting factor in thermal lens spectroscopy with a chopped pump laser. Pump and probe laser fluctuations are shown to be random, while thermal lens signals are shown to have a small periodic component caused by stirring. The problem is serious in dilute solutions because of the high solvent background absorbance.
Rotationally resolved IR-diode laser studies of ground-state CO2 excited by collisions with vibrationally excited pyridine.

Relaxation of highly vibrationally excited pyridine (C5NH5) by collisions with carbon dioxide has been investigated using diode laser transient absorption spectroscopy. Vibrationally hot pyridine (...
Costly structural change and optimal growth

This paper studies the optimal growth of a developing economy that has a choice to expend a fixed amount of resource for a structural change that advances its production technology. It is shown that structural change is undertaken if capital stock is above a critical level. Economies undertaking structural change converge to a larger steady state and economies not undertaking structural change converge to a smaller steady state. The optimal policy correspondences and growth paths are characterized. The social optimum is shown implementable by a competitive equilibrium with lump-sum taxation.
PerturBoost: Practical Confidential Classifier Learning in the Cloud

Mining large data requires intensive computing resources and data mining expertise, which might not be available for many users. With the development of cloud computing and services computing, data mining tasks can now be moved to the cloud or outsourced to third parties to save costs. In this new paradigm, data and model confidentiality becomes the major concern to the data owner. Meanwhile, users are also concerned about the potential tradeoff among costs, model quality, and confidentiality. In this paper, we propose the PerturBoost framework to address the problems in confidential cloud or outsourced learning. PerturBoost combined with the random space perturbation (RASP) method that was also developed by us can effectively protect data confidentiality, model confidentiality, and model quality with low client-side costs. Based on the boosting framework, we develop a number of base learner algorithms that can learn linear classifiers from the RASP-perturbed data. This approach has been evaluated with public datasets. The result shows that the RASP-based PerturBoost can provide model accuracy very close to the classifiers trained with the original data and the AdaBoost method, with high confidentiality guarantee and acceptable costs.
SU-FF-T-159: Determination of the MLC Scatter, MLC Transmission and Dosimetric Gap in Dynamic IMRT as a Function of Field Size, Depth and Beam Energy

Purpose: To develop a dynamic MLC test for the determination of the MLC scatter, transmission and dosimetric gap for large field size and complex geometry IMRT.Materials and Methods: A series of dynamic MLC tests was designed and performed with ionization chamber in a solid water phantom as a function of field size, depth, MLC gap size for 6,10MV 2100Ex: open beam (OB), closed MLC (cMLC), and dynamic sweeping gap (dMLCgap). Based on a generalized fluence model, MLC scatter, direct MLC transmission (no scatter) and dosimetric gap (due to rounded leaves) were determined. IMRT planning system predictions and measurement doses were compared at the central axis and outside of the field edges. Dose errors were corrected using the generalized fluence model. Results:MLC scatter is responsible for field size dependence of cMLC‐to‐OB dose ratio (1.45% for size=5cm×5cm, 1.8% for size=14cm×30cm, 6MV). MLC scatter is rather uniform within and outside of the field edges, and decreases only slightly with depth. Direct MLC transmission (no MLC scatter) changes with depth up to 10% (6MV), 5% (10MV) due to beam hardening. In dynamic MLC delivery, MLC scatter is significant for large field sizes (14cm×30cm) and low average fluence 〈φdMLC〉: MLC scatter=1%–5% for clinically realistic 〈φdMLC〉 =30%–10%, (〈φOB〉=100%, 〈φcMLC〉 ≈1.5% by definition). Dose errors of 1%–8% for large sizes and sweeping gaps 1.0cm–0.1cm were corrected when the modified fluence model (including MLC scatter) was used instead of the Eclipse fluence. Conclusions: Many commercial IMRT planning systems do not account for the MLC scatter. It is suggested that the OB‐cMLCd‐MLCgap test be used for commissioning of the IMRT when field sizes are large and average fluence 〈φdMLC〉 is low. MLC parameters in IMRT planning system may need to be adjusted separately for each IMRT class depending on field size and fluence complexity (or 〈φdMLC〉).
Dopaminergic neurons in the rat ventral tegmental area. I. Identification and characterization

By use of various histochemical techniques, it was shown that both DA and non-DA cells in the VTA project to the NAc. Of these VTA-NAc output cells, the great majority were DA-containing cells. A small number of non-DA cells were encountered most frequently in the lateral part of the VTA. Correspondingly, two distinct groups of neurons, types I and II, could be identified by antidromic stimulation of the NAc. Several lines of evidence suggest that type I cells are DA-containing neurons. The evidence may be summarized as follows: 1. (1) type I cells had a slow-bursting or regular firing pattern, slow discharge rate and wide spike duration which appears to be identical to the characteristics of DA neurons originally described by Bunney et al.16; 2. (2) the great majority of these cells could be activated antidromically by stimulation of the NAc; 3. (3) the conduction velocity and absolute refractory period of type I cells are consistent with unmyelinated fine DA fibers; 4. (4) injection of 6-OHDA, but not 5,7-DHT directly in the MFB blocked antidromic responses of these cells; 5. (5) they were extremely sensitive to intravenously administered DA agonist apomorphine (ID50 = 7 μg/kg); and 6. (6) direct fluorescence histochemical examination of serial sections from brains of animals in which type I cells have been identified by antidromic stimulation of the NAc showed that type I cells are most likely catecholamine-containi ng neurons. By contrast, type II cells possessed an entirely different spectrum of physiological characteristics; in addition, they showed no consistent response to apomorphine and their antidromic responses to stimulation of the NAc were not affected by 6-OHDA. It is concluded that (1) VTA output neurons consist of both DA and nonDA neurons, and (2) identified types I and II neurons in the VTA by antidromic stimulation of the NAc are DA and non-DA cells, respectively.
Electrokinetic Studies of Bacteria IV: Effect of Acridines on Streptococcus faecalis

The effect of the following acridines on the electrophoretic mobility of Streptococcus faecalis was studied at constant values of pH and ionic strength: acridine hydrochloride, 9-hydrazinoacridine acetate, 9-aminoacridine hydrochloride, acriflavine hydrochloride, and proflavine dihydrochloride. Increasing times of contact of the bacteria with acridines rendered the electrophoretic mobility less negative or more positive due to the interaction with nucleic acids released from the bacteria through the action of the acridines. Stirring of the bacterial suspensions minimized this effect. Hence, electrophoretic mobilities were measured on samples withdrawn from stirred bacterial suspensions at successive time intervals after the addition of the acridines, and the mobilities were extrapolated to zero time. The mobility-concentration curves had similar shapes for all acridines. With increasing concentration of the acridinium salts, the negative mobilities or ζ-potentials of the bacteria decreased slowly at first but at a much faster rate as they approached zero. When the neutralization of the carboxylate groups in the bacterial cell wall by chemisorption of acridinium ions was complete, the ζ-potential was reduced to zero because the resultant acridinium carboxylates were only slightly dissociated. Further concentration increases inverted the electric charge of the bacteria to positive by physical adsorption of the entire acridinium salts. The positive mobilities increased with the acridine concentrations. rapidly at first but at slower rates for still higher concentrations. The acridine concentrations required to reduce the mobility or ζ-potential of the bacteria to zero were lower in more acid media. For four of the five acridines, there was an inverse relationship between these concentrations and the base strength of the acridines. The acridines of highest pKa were most strongly chemisorbed by the carboxylate groups in the cell wall, saturating them at the lowest concentrations. Relatively high concentrations of acridines caused the bacteria to agglomerate. This agglutination was not due to a reduction in the absolute value of the ζ-potential; it was probably caused by nucleic acids leaked from the bacteria or by their complex coacervates with the acridines, possibly through bridging. Aminoacridine hydrochloride and proflavine dihydrochloride did not inhibit the growth of S. faecalis even at concentrations 10 times greater than those at which they reduced the ζ-potential to zero. This suggests that the primary site of attack of these acridines is not the cell wall.
On the commutativity of discrete memoryless channels in cascade

Abstract The conditions are discussed under which two square discrete memoryless channels (DMCs) in cascade commute. Two different types of channel commutativity are considered: matrix commutativity , in which changing the order of two cascaded channels results in an identical overall channel, and capacity commutativity , in which the order of two cascaded channels results in an overall channel with the same capacity as the original cascade. A theorem is presented giving necessary and sufficient conditions for a pair of square DMCs to be matrix commutative and note its implications for a number of example channel cascades. Finally, it is shown that all pairs of r -ary symmetric channels are matrix commutative, regardless of their crossover probabilities.
Binding of immunophilins to the 90 kDa heat shock protein (hsp90) via a tetratricopeptide repeat domain is a conserved protein interaction in plants.

In animal cell lysates, multiprotein complexes containing hsp90, hsp70, p60, p23, and several immunophilins can assemble steroid receptors and oncogenic protein kinases, such as v-Src and v-Raf, in...
Isolation of histidyl peptides of the steroid-binding site of human placental estradiol 17β-dehydrogenase

Abstract Human placental estradiol 17β-dehydrogenase (E.C. 1.1.1.62) was inactivated at pH 6.3 by 3-bromo[2′- 14 C]acetoxy-1,3,5(10)estratrien-17-one, a known substrate. The affinity-alkylated enzyme was then hydrolyzed by trypsin. Radioactive peptides were initially isolated by gel filtration and identified according to which residue was alkylated. Tryptic peptides containing radioactive 3-carboxymethylhistidyl residues were further purified by cation-exchange chromatography. The population of these peptides varied, depending upon the conditions of enzyme inactivation. With 60 μM 3-bromo[2′- 14 C]acetoxy-1,3,5(10)estratrien-17-one four major peptides (a,b,c,d) each containing radioactive 3-carboxymethylhistidine, were eluted from the cation-exchange column. The alkylation of all of these peptides was completely suppressed when the enzyme was inactivated in the presence of excess estradiol-17β. The presence of equimolar NADPH during incubation greatly enhanced the alkylation of all four peptides. In the presence of NADPH, estradiol-17β most significantly decreased the formation of peptide d. Peptide d was the only peptide identified when the concentration of the alkylating steroid was lowered to 6 βM, a value approaching the Km. These observations indicate that peptide d is a histidyl-bearing peptide from the steroid-binding site which proximates the steroid A-ring. They further suggest that with the affinity labeling steroid at higher concentrations other nonspecific, hydrophobic sites on the enzyme are occupied and labeled.
Omission and Inspiration in Noverre’s Lettres sur la danse

This essay examines Noverre’s strategic naming and omission of sources in the Lettres sur la danse, et sur les ballets as a way of building his credibility as a writer and ballet master. Although Noverre was a pioneer of the ballet d’action, he was certainly not its creator, as he would have liked his reader to believe. His creation of a poetics of the ballet d’action, however, was fundamentally new. This essay focuses in particular on the passages of his work inspired by Cahusac, Diderot, and Garrick, and shows how Noverre, by naming or omitting these writers’ names, attempted to frame his Lettres sur la danse not as a historical, but as a literary project: the theoretical construct of dance as a theatrical art.
THE EFFECT OF SOLUBLE STREPTOTOXINS ON THE THYROID GLANDS OF RABBITS

The role of infections as etiological factors in the causation of thyroid disorders has been the subject of study by various investigators for a number of years. Although much information has come to light as to the various influences of environment, diet, functional disorders, and the particular role of iodine, it has always been held that micro-organisms must be considered as influencing thyroid disorders if not actually causing them. Halstead (1), while attempting to explain the hypertrophy occurring in the stumps of the thyroid glands of dogs upon which thyroidectomies had been done, suggested the possible role of intoxication from the infected wounds of these animals. This observation was based upon his own previous experiments and those of Munk, whom he quotes (2). Halstead later repeated the experiment under conditions of asepsis and variations in diet but was unable to obtain hyperplasia of the remaining gland. This he thought was suggestive of the possible influence of infections obtained in his ...
Interferon γ increases sensitivity to endotoxin

Abstract Interferon-γ (IFN-γ) has been proposed for use following severe trauma to reverse depressed macrophage (Mφ) function and thereby reduce infection, sepsis, and subsequent multiple organ failure syndrome (MOFS). However, an excessive inflammatory response by Mφs and other components of the inflammatory cascade is thought to be central to the underlying pathophysiology of MOFS. Endotoxin (LPS) has been implicated as a principal mediator of sepsis-induced MOFS by stimulating Mφs and leukocytes (WBC). This study addresses the following question: Does IFN-γ predispose normal rabbits to a pathophysiologic response to LPS infusion? Four groups of New Zealand White rabbits ( n = 6, each group) were prepared for measurement of cardiac output, arterial pressure, arterial PO 2 , and WBC counts over a 6-hr period. Group I (control) was instrumented alone, Group II (LPS alone) was given a subclinical dose of 1.0 μg/kg of Escherichia coli LPS iv, Group III (IFN-γ alone) was given recombinant rabbit IFN-γ (5.0 μg/kg subcutaneous) for 3 days prior to preparation for measurements, and Group IV (IFN-γ + LPS) received 3 days of IFN-γ followed by LPS. One hour prior to sacrifice 5.0 μCi of 125 I-albumin was given and bronchoalveolar lavage was performed at death to determine the lavage/plasma 125 I ratio as an index of pulmonary permeability. The results indicate that IFN + LPS animals had significant decreases in cardiac output, PO 2 , and WBC counts, and increased lavage/plasma ratio of 125 I-albumin when compared to all other groups ( P t test). Neither LPS alone nor IFN-γ alone had a significant effect on measured variables. In contrast to immunosuppressed animals, IFN-γ pretreatment of normal animals increases the host pathophysiologic response to endotoxin.
Misdiagnosis of stroke in tissue plasminogen activator-treated patients: characteristics and outcomes.

Abstract Study objective Misdiagnosis of acute ischemic stroke is a risk inherent in treating patients with acute deficits, yet few data exist on the problem. We report an evaluation of emergency department misdiagnoses in patients treated with tissue plasminogen activator for acute ischemic stroke. Methods We conducted an observational study of 151 consecutive patients treated without an acute stroke team. Initial diagnosis was compared with interim and hospital discharge diagnoses. Separate analyses were performed for patients without a final diagnosis of acute ischemic stroke and for those without a final diagnosis of either acute ischemic stroke or transient ischemic attack, combined. Results Ten of 151 patients (7%; 95% confidence interval [CI] 3% to 12%) had final diagnoses that did not include acute ischemic stroke. Six of 151 (4%; 95% CI 1% to 8%) had a final diagnosis other than acute ischemic stroke or transient ischemic attack (conversion disorder [4], complex migraine [1], and Todd's paralysis [1]). These "stroke mimics" had no intracranial hemorrhage (0%; 95% CI 0% to 31%), had less disability at discharge (modified Rankin Scale score mean±SD, 2.2±1.3 versus 3.2±1.8), and were younger (mean age±SD, 47±21 years versus 68±15 years) than patients with acute ischemic stroke or transient ischemic attack. An additional 4 (3%) patients had interim diagnoses other than acute ischemic stroke, all subsequently changed to acute ischemic stroke after magnetic resonance imaging or computed tomography. Conclusion These data show that in a 4-hospital system without an acute stroke team, thrombolytic treatment of patients with diagnoses mimicking stroke was infrequent, and hemorrhagic complications did not occur in any patients without an acute ischemic stroke. However, because the number of mimics was small, safety cannot be ensured with statistical confidence.
Biomechanical evaluation of the quadriceps tendon autograft for anterior cruciate ligament reconstruction: a cadaveric study.

Background:Recently, many surgeons have chosen the quadriceps tendon (QT) as an autograft for anterior cruciate ligament (ACL) reconstruction. However, there have not been biomechanical studies that quantitatively evaluated knee function after reconstruction using a QT autograft.Purpose:To measure the 6 degrees of freedom knee kinematics and in situ graft forces after reconstruction with a QT autograft compared with a quadrupled semitendinosus and gracilis (QSTG) tendon autograft.Study Design:Controlled laboratory study.Methods:Ten human cadaveric knees (age, 54-64 years) were tested in 3 conditions: (1) intact, (2) ACL deficient, and (3) after ACL reconstruction using a QT or QSTG autograft. With use of a robotic/universal force-moment sensor testing system, knee kinematics and in situ forces in the ACL and autografts were obtained at 5 knee flexion angles under externally applied loads: (1) 134-N anterior tibial load, (2) 134-N anterior tibial load with 200-N axial compression, and (3) 10-N·m valgus and...
Compliance Changes in Venous Insufficiency

In 37 patients (69 limbs) referred to Mayo Clinic's Vascular Center for possible venous valvular insufficiency in the lower limb, calf muscle pump function, calf compliance, and venous refilling times were measured by strain gauge plethysmography techniques. Patient limbs were separated into four categories based on 90% refilling time (T90) following fifteen deep knee bends: normal (n = 16), mild/moderate (n = 28), severe (n = 16), and edema of nonvenous origin (n = 9). Pump function was assessed in actual pumping volumes (mL) and in percent pumping volumes (mL/100 mL), and was reduced in all noncontrol categories. Calf compliance was assessed in actual volume change (mL/mmHg) and in percent volume change (mL/100 mL/mmHg) and was increased in the severe reflux category. Ten study patients had 1 normal category limb and 1 reflux category limb. Paired analysis of these limbs showed pump function to be decreased and calf compliance to be increased in the diseased group limbs.
Synthesis of Carnosine-d7 and Anserine-d4 for Use as Internal Standards in Liquid Chromatography–Mass Spectrometry

Abstract A convenient synthesis of carnosine-d7 and anserine-d4 is described. Coupling of N-Boc-β-alanine-d4 with L-histidine-d3 or 1-methyl-L-histidine using isobutyl chloroformate afforded the corresponding Boc-protected dipeptide. Subsequent Boc group deprotection with hydrochloric acid yielded carnosine-d7 and anserine-d4 in 46% and 69% overall yield, respectively.
The cutaneous manifestations and common mimickers of physical child abuse

The cutaneous manifestations of physical child abuse are some of the most common and easily recognized forms of injury. To make an accurate assessment and diagnosis, it is important to differentiate between inflicted cutaneous injuries and mimickers of physical abuse. Likewise, an understanding of reporting guidelines helps guide practitioners in their decision making.
Unprotected anal intercourse in HIV-positive and HIV-negative gay men: the relevance of sexual arousability, mood, sensation seeking, and erectile problems.

Reduction of unprotected anal intercourse (UAI) in gay men infected with HIV is important in preventing further spread of this infection. In previous studies, personality trait measures relevant to sexual arousability and the effects of anxiety have been shown to relate to UAI in both gay and heterosexual men. Are HIV+ gay men similar in these respects or are there other personality-related factors that influence their sexual risk taking? This question was addressed using a convenience sample of 156 HIV+ gay men and 155 HIV− gay men, matched for age and UAI risk. There were no significant differences between these two groups on measures of sexual arousability, inhibition of sexual arousal in risky situations, sensation seeking, depression and anxiety proneness, or tendency to increased sexual interest in negative mood states. HIV+ men were, however, more likely to report erectile problems and higher scores on an associated trait measure, inhibition of arousal due to threat of performance failure. As this association was not anticipated, questions about whether erectile problems preceded the seroconversion were not asked. Such problems could be associated with reluctance to use condoms, thus increasing the likelihood of seroconversion and/or disease transmission. Alternatively, erectile problems could be a consequence of HIV infection. In each case, this has implications for prevention. The associations among HIV status, erectile problems, and UAI need to be specifically addressed in future research.
Effects of auditory stimuli on sucking behavior in the human neonate

Abstract The effect of a moderately intense (90 db) auditory stimulus on the sucking response of 48 full-term, newborn infants was investigated. Frequency of tone (400 and 4000 cps), stimulus duration (2 and 10 seconds), and intertrial interval (2 and 10 seconds) were varied. Response measures employed were cessation and initiation of non-nutritive sucking. Subjects who received longer stimulus durations responded significantly more to the stimuli initially than did the 2-second groups, then responded less as trials were continued. No significant effect of interval or frequency was found.
Situational Salience and Cultural Differences in the Correspondence Bias and Actor-Observer Bias

Two studies examined the correspondence bias in attitude attributions of Koreans and Americans. Study I employed the classic attitude attribution paradigm of Jones and Harris and found that both Korean and American participants displayed the correspondence bias in the no-choice condition. This lack of difference might have been due to weak salience of the situational constraints. Study 2 was designed to make the situational constraints of the no-choice condition salient in two ways: (a) by asking participants to write an essay on a topic regardless of their genuine attitude toward the topic or (b) by also making it clear to participants that the essay by the target person was almost a copy of the arguments provided by the experimenter. The results showed that (a) American attributions were unaffected by the two salience manipulations, whereas Koreans' correspondence bias decreased with increasing salience of the constraints, and (b) Koreans were less susceptible to the actor observer bias.
Vitamin A metabolism: α-Tocopherol modulates tissue retinol levels in vivo, and retinyl palmitate hydrolysis in vitro

Abstract The steady-state concentrations of retinol in rat tissues varied as a function of dietary α-tocopherol. The liver, kidney, and intestinal retinol concentrations increased in animals fed an α-tocopherol-deficient diet despite a decrease (liver) or no change (kidney and intestine) in the concentrations of total vitamin A. In contrast, in lung the concentrations of both retinol and total vitamin A decreased. α-Tocopherol inhibited retinyl palmitate hydrolase in vitro in liver, kidney, and intestine; had minimal effect on the testes hydrolase; and stimulated the lung hydrolase. Fifty percent inhibition of the liver hydrolase was provided by an α-tocopherol concentration (100 μ m ), close to that reported in livers of rats fed a purified diet, constituted with moderately low amounts of α-tocopheryl acetate. Phylloquinone (vitamin K 1 ) inhibited the retinyl palmitate hydrolase in vitro in all tissues tested, and was about fivefold more potent than α-tocopherol. The effects of phylloquinone and α-tocopherol on the liver hydrolase were additive, not synergistic. The antioxidant N,N′ -diphenyl- p -phenylenediamine, the most effective synthetic vitamin E substitute known, had little effect on the hydrolase. These data show that α-tocopherol effects vitamin A metabolism in several tissues, and suggest that it may be a physiological effector of tissue retinol homeostasis.
Electron microscopy of the 50-S ribosomes of Escherichia coli

Abstract 50-S ribosomes from Escherichia coli, strain B, have been examined in frozen-dried and air-dried preparations by electron microscopy. The frozen-dried particles were found to be somewhat asymmetrical, measuring approx. 160 A and 230 A along their shortest and longest dimensions. Volumes of4.6·10 A3 and 3.3 ·106 A3 are estimated for the frozen-dried and air-dried ribosomes, respectively. The internal hydration of wet ribosomes is estimated to be 0.9 g water/g ribonucleoprotein. A method is described for estimating the mean volume of a sample of particles from their shadow shapes.
Optimization of Pressure Response in HPDLC Gratings Based on Polymer Composition

This paper reports on the pressure response of Bragg gratings formed by reflective Holographic Polymer Dispersed Liquid Crystals (HPDLCs) as a function of polymer composition. Pressure response is determined by measuring the variation in reflected wavelength intensity in response to hydrostatic pressure applied parallel to the HPDLC grating vector. The pressure response of di- and tri-functional urethane polymer HPDLCs is reported here. These polymer gratings demonstrate a correlation between pressure response sensitivity and polymer functionality and polymer composition. A maximum response of 1.6 nm of wavelength shift over 20 psi of pressure variation is recorded for a di-functional polymer HPDLC.
Automaticity training for dyslexics: An experimental study.

Less-skilled readers may experience a processing bottleneck in reading comprehension produced by a failure to automate word recognition. The automaticity hypothesis predicts that training which increases rapid and automatic word recognition will improve comprehension. To date few studies have tested this hypothesis. Our goal was to test the automaticity hypothesis by training dyslexic readers (n=35) to access the meaning of words more rapidly. Training consisted of speeded word games implemented on a microcomputer that provided feedback concerning subjects’ speed and accuracy using sound and graphics. Three experimental tasks were administered both before and after training in which trials with trained and untrained stimuli were randomly intermixed. The measures were latency and accuracy of word vocalization, sentence comprehension, and a dual-task procedure designed to measure automaticity. Although pre/post improvement was larger for trained than untrained stimuli, reaction time on the word vocalization and sentence comprehension tasks improved significantly for both trained and untrained stimuli. In contrast, automaticity and sentence comprehension accuracy improved significantly for trained but not untrained stimuli. The training effect in comprehension remained when controlling for increases in word knowledge. The results support the automaticity hypothesis and further suggest that severely disabled readers may benefit from training in automatic word recognition.
Rural development planning in Pakistan

Most of the rural development plans and green revolution technology attempted in Pakistan between the years 1950 and 1970 were a part of “induced transformations and institutional innovations.” These attempts did bring some advances in productivity in Pakistan. In recent years, Panjab broke the international records in wheat production. But, a review of rural development efforts and wide application of induced innovations provide mixed results. Since 1972, the Integrated Rural Development has been adopted as a model for country's agrarian reforms, because of the gains at Shadab Project. The success of Shadab was impressive indeed, but Pakistan's economy, history, and society call for caution and raise scepticism, as were rightly pointed out by Ruttan (12) for Integrated Rural Development Program.
Lumbosacral ependymomas: a review of the management of intradural and extradural tumors.

Object. The goal of this study was to review the management of intra- and extradural ependymomas. Spinal ependymomas most commonly occur as intramedullary tumors throughout the spinal axis. In the lumbosacral region, ependymomas are most commonly associated with the conus medullaris and cauda equina, but can also occur extradurally in the sacrum, presacral tissues, or subcutaneous tissues over the sacrum. These two tumor locations produce different management concerns. Intradural ependymomas, especially those in the lumbosacral region, are now recognized for their potential to spread throughout the central nervous system (CNS), whereas extradural tumors elicit more concern for their association with extraneural metastases. Methods. The authors have reviewed the literature regarding both of these distinct tumors and have summarized recommendations for the management of intra- and extradural lumbosacral ependymomas. For both tumors, it appears that gross-total resection is the treatment of choice when feasible. The role of radiation therapy has not been adequately studied for either tumor location, but most clinicians use this modality in patients with subtotal resection of intradural ependymomas, local recurrence, or CNS dissemination. Data supporting the use of radiation therapy for extradural ependymomas are lacking. There does not appear to be a significant role for chemotherapy in either tumor location. Conclusions. Despite the risk for local recurrence and CNS dissemination, the prognosis for intradural lumbosacral ependymomas is good, with a greater than 90% 10-year patient survival in most series. The prognosis for extradural ependymomas does not appear to be as good. Much depends on extradural tumor location, however; the outlook is better for dorsal sacral tumors than presacral tumors.
The Reception of the Council of Florence in Moscow

As the Council of Florence concluded its deliberations, the Greek Orthodox participants had a number of choices open to them. The Byzantine metropolitan and newly created cardinal of the Roman Church, Bessarion, elected to remain in the Roman West where his intellect and knowledge were so well appreciated, after a short visit to a Constantinople unreconciled to the idea of Union. The Metropolitan of all Russia, Isidore, likewise adorned with the red hat and invested by the Pope with legatine power over Russia, chose another solution. Proud Greek that he was, Isidore trusted his superiority over the Russians and decided to return to his see, bringing with himself the new faith. According to the Tale of Isidore's Council by the monk Simeon of Suzdal', the metropolitan explained to Pope Eugene IV the reasons for his confidence that Moscow would accept the Union: “They are all in my hands, all the princes and bishops,” Isidore told the Pope; “Not one of them dares argue with me; the Grand Prince is young and is under my will… their bishops are ignorant and they, too, fear me.”
Naturalistic Observation of Behavior: A Model System Using Mice in a Colony

Despite their importance, techniques of naturalistic observation are rarely taught in undergraduate research methods courses. This article describes exercises designed to give students experience in using methods of naturalistic observation to quantify behavior. Students construct a coding system (ethogram) of the behaviors observed in a small mouse colony. This behavioral catalog is then used to gather data by two techniques: instantaneous and focal animal sampling. The data can be used to calculate interrater reliability and then subjected to sequence analysis. The application of naturalistic observation to the quantification of human behavior is considered.