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Two cognate receptors (CRF(1) and CRF(2)) mediate the actions of the stress-regulatory corticotropin-releasing factor (CRF) family of peptides. Defining the respective roles of these receptors in the central nervous system is critical in understanding stress neural circuitry and the development of psychiatric disorders. Here, we examined the role of CRF(2) in several paradigms that assess coping responses to stress. We report that CRF(2) knockout mice responded to a novel setting with increased aggressive behavior toward a bulbectomized conspecific male and show increased immobility during acute swim stress compared with wild-type mice. In addition, CRF(2)-deficient mice exhibited impaired adaptation to isolation stress as evinced by prolonged hypophagia and associated weight loss. Collectively, these results point toward a role for CRF(2) pathways in neural circuits that subserve stress-coping behaviors.

As part of the authors' on-going studies aimed at reaching an understanding of biologically controlled mineralization the precipitation of strontium sulphate has been investigated in the presence of hydrophobic and hydrophilic behenic acid (CH3(CH2)20COOH) Langmuir-Blodgett (LB) films by electron microscopy and electron diffraction. The films exhibited most marked effects at low supersaturations and both nucleation and crystal growth processes were affected. In the absence of a film, tabular rhombic crystals are deposited with (001) forming the major growth face. Crystallization in the presence of hydrophobic films at low supersaturations (10 Ksp) produces thin, disc-like crystals which are nucleated on the (010) crystal face of celestite. Hydrophilic substrates of 10 Ksp and 30 Ksp produce open-floret or needle shaped crystals, respectively, deposited on the films. The diffraction patterns obtained from these crystals cannot be assigned using the orthorhombic unit cell of celestite. At higher supersaturations, three-dimensional crystals of celestite based on symmetry related (011) and (210) faces are produced which show little contact with the film surface. Substrate-ion interactions are considered in order to understand the influence of the substrate on crystal nucleation. For precipitation in the presence of the hydrophobic film it is proposed that surface topography directly affects nucleation. For precipitates formed at low supersaturations in the presence of the hydrophilic film there is no direct surface: ion spatial correlation and deformed structures of celestite are observed.

We demonstrate a high-speed tuneable, continuous wave laser source at 1550nm for Fourier domain OCT imaging. The light source was based on a pigtailed semiconductor optical amplifier and a diffraction grating and polygon mirror for fast frequency tuning. This source provides frequency scan rate of up to 20kHz over a wavelength range of 80nm (60nm FWHM) at the central wavelength of 1550nm, offering an axial resolution of ~17 microns.

Small interfering RNAs (siRNAs) potently silence expression of target genes. In principle siRNA libraries can be used to perform effective genome-scale functional genetic screens in mammalian cells, but their development has been hampered by the need to chemically synthesize thousands of oligonucleotides and to incorporate them into expression vectors. We have developed a technology to efficiently convert a double-stranded cDNA library into a retroviral siRNA library in which 21-base siRNAs are produced in infected cells at high levels and efficiently block expression of their target genes. The key steps are the generation of random cDNA fragments that are fused to a hairpin linker, cleavage with the Mme I endonuclease that creates 20- to 21-bp cDNA fragments, conversion to a double-stranded DNA that contains two copies of the cDNA insert in a head-to-head palindrome, and insertion of the construct downstream of a polymerase III promoter. We constructed a siRNA library with 3 × 10 6 clones from a mouse embryo cDNA library; siRNAs were found against many different genes; and multiple siRNAs can be generated from a single mRNA. We further showed that specific siRNAs were efficiently produced in stably infected mammalian cells and resulted in significant and specific reduction of their target mRNAs. Because no prior knowledge about target transcripts is needed, a cDNA-derived siRNA library will generate siRNAs against unknown transcripts and genes. Finally, cDNA-derived siRNA libraries can be readily generated from any cell type or species, enabling genome-wide functional screens in many biological systems.

Stress pathways affect immune function, the most notable of these pathways being activation of the hypothalamic-pituitary-adrenal (HPA) axis. Although HPA activation has generally been relegated to an immunosuppressive role, recent evidence suggests that stress and HPA activation can be immunoenhancing in certain situations. To investigate specific effects of stress on immune function, we used a genetic model of chronic stress wherein transgenic mice overexpress corticotropin-releasing hormone (CRH), a primary mediator of the stress response. In these mice, CRH is overproduced in the brain, leading to chronic activation of the HPA axis. We found that CRH-transgenic mice have decreased leukocyte numbers in lymphoid compartments, with preferential loss of B lymphocytes. They also exhibit decreased Ab production and impaired isotype switching in response to immunization with a thymus-dependent Ag, phosphocholine-keyhole limpet hemocyanin. Despite these deficits, immunization protected CRH-transgenic and wild-type mice equally well against lethal challenge with Streptococcus pneumoniae, an encapsulated Gram-positive bacterium known to require Ab-mediated opsonization for clearance. While IgG responses are severely depressed in these mice, IgM titers are only modestly decreased. This fairly robust IgM response may be sufficient to protect against S. pneumoniae. Additionally, while total leukocyte numbers are decreased in these mice, neutrophil numbers are increased. This increase in number of neutrophils may compensate for the depressed IgG response, allowing adequate host defense during chronic stress.

The actions of corticotropin-releasing hormone (Crh), a mediator of endocrine1 and behavioural responses to stress2, and the related hormone urocortin3 (Ucn) are coordinated by two receptors, Crhr1 (encoded by Crhr) and Crhr2 (refs 4,5). These receptors may exhibit distinct functions due to unique tissue distribution6 and pharmacology4,5. Crhr-null mice have defined central functions for Crhr1 in anxiety and neuroendocrine stress responses7,8. Here we generate Crhr2−/− mice and show that Crhr2 supplies regulatory features to the hypothalamic-pituitary-adrenal axis (HPA) stress response. Although initiation of the stress response appears to be normal, Crhr2−/− mice show early termination of adrenocorticotropic hormone (Acth) release, suggesting that Crhr2 is involved in maintaining HPA drive. Crhr2 also appears to modify the recovery phase of the HPA response, as corticosterone levels remain elevated 90 minutes after stress in Crhr2−/− mice. In addition, stress-coping behaviours associated with dearousal are reduced in Crhr2–/– mice. We also demonstrate that Crhr2 is essential for sustained feeding suppression (hypophagia) induced by Ucn. Feeding is initially suppressed in Crhr2−/− mice following Ucn, but Crhr2−/− mice recover more rapidly and completely than do wild-type mice. In addition to central nervous system effects, we found that, in contrast to wild-type mice, Crhr2−/− mice fail to show the enhanced cardiac performance or reduced blood pressure associated with systemic Ucn, suggesting that Crhr2 mediates these peripheral haemodynamic effects. Moreover, Crhr2−/− mice have elevated basal blood pressure, demonstrating that Crhr2 participates in cardiovascular homeostasis. Our results identify specific responses in the brain and periphery that involve Crhr2.

Two of the genes encoding histidine utilization (hut) in Rhizobium fredii strain HH303 have been cloned in Pseudomonas putida and partially characterized. Molecular cloning of the genes was achieved by mobilizing an R. fredii cosmid library into a mutant strain of P. putida containing a Tn5 element in its histidase (hutH) gene. A number of overlapping clones were identified, all of which contain a 7.1-kbp HindIII fragment. The origin of this 7.1-kbp fragment from the chromosome of R. fredii was confirmed by Southern blotting and hybridization studies. In addition, this fragment and the two adjacent HindIII fragments of 9 and 12 kbp respectively were subcloned into pBluescript KS+ and further characterized. Although the R. fredii clones expressed histidase in Pseudomonas, they did not in Escherichia coli, suggesting that E. coli is not a suitable cloning host for Rhizobia genes.

Purpose: A linac‐based SRS system with a stereotactic mask was implemented. This work aims at selecting a proper detector for small‐field beam commissions, setting up a specially designed phantom for patient‐specific plan QA, and validating the dosimetric accuracy of SRS plans based on the Varian MLC‐120 and BrainLAB cones.Methods: Four different detectors — diode, micro ion chamber, IBA chamber, and Farmer chamber, were evaluated for small field commissioning. PDD, profile, and output measurements of fields from 5×5mm to 150× 150mm were compared and discussed. A micro‐chamber was selected based on its good spatial resolution (0.016cc sensitive volume) and higher stability and sensitivity (3 and 1.5 times greater, respectively, than a diode). To reduce measurement uncertainties, both PDD and profile scans were iterated (more iterations were used for smaller fields) and summed up using commercial software. The shift of reference‐field readings was within 0.3% during the output measurements. A Lucy phantom was set up in the SRS frame and CT scanned. Treatment plans were mapped to the CTimage and measured with a calibrated micro‐chamber. The implemented SRS system was validated by comparing the planned and measured doses for targets with different volumes and shapes.Results: For a typical SRS target (1.26cc), the dose differences were 0.71% for a dynamic arc/MLC plan and 0.75% for an arc plan using a 20mm cone. For a small and spherical target (0.50cc), the differences were 2.13% for a dynamic arc/MLC plan and 0.17% for an arc plan using a 15mm cone. For a very small and irregular target (0.35cc), the differences were 2.60% for a dynamic arc/MLC plan and 4.72% for an arc plan using a 10mm cone Conclusions: Considering its dosimetric accuracy for different targets and the availability of a safety‐interlock, MLC based SRS treatment is highly recommended.

Pulmonary edema associated with transient airway obstruction was detected in 3 horses. The cause of obstruction was different in each horse, but after relief of the obstruction, clinical signs and radiographic abnormalities were indicative of pulmonary edema. In 2 of the 3 horses, pink frothy fluid was evident in the airways. The horses were treated with furosemide, nasal insufflation of O2, anti-inflammatory agents, and anti-biotics. Of the 3 horses examined, 1 horse died acutely, 1 horse recovered fully, and 1 developed pleuritis and was subsequently euthanatized.

Evidence converges from a wide range of contexts to suggest that the causal beliefs held by an individual, or predominant in a group of individuals, are of considerable practical significance and theoretical interest. A good system for analysing naturally occurring expressions of causal belief would provide the possibility of testing and exploring this supposition without having to rely on possibly artificial questionnaire responses. A rationale for such a system is described and a study of the reliability of the coding procedure is reported. It has proved possible to formulate definitions of the five major dimensions identified in the attribution literature so that, while they are not all orthogonal, each provides unique information. The coding system is shown to have adequate reliability, and to generate substantial quantities of data. The findings from these data are generally in accordance with those obtained using more traditional methodologies, and provide substantive information about the subject population. The method is proposed as an effective technique for empirical investigations of the forms, stability and significance of naturally expressed causal beliefs.

The Langmuir-Blodgett film technique is currently being researched as a deposition process for many optical applications. The performance of these coatings is dependent on both the quality of deposition and the film structure. A structural investigation, using transmission electron diffraction and microscopy, on materials with potential for second harmonic generation and optical data storage is reported on this paper. Transmission electron diffraction patterns are presented for an optically non- linear stilbene derivative. Results indicate that monolayer quality is good but for the formation of multilayers causes the film quality to deteriorate. The technique of alternating this material with tricosanoic acid has improved deposition, and electron microscopy has been used to indicate this. High quality transmission electron diffraction patterns of tricosanoic acid are interpreted in terms of a pseudo- hexagonal packing arrangement with a grain size of approximately 5 μm. Organic dyes which absorb in the near-IR have also been studied. These have potential for use in ablative optical hole burning for optical data storage. Electron diffraction results are presented, showing good structure, with a grain size suitable for this application.

Expenditure on research and development by the pharmaceutical industry in the UK has increased five-fold in real terms since 1964, whilst the rate of introduction of novel medicines and their sales, allowing for inflation, have remained approximately constant. One of the reasons the industry has been able to afford the higher investment in R&D is because its marketing has become far more international. In the UK the average effective patent life of new products has decreased to less than 5 years at launch, making it difficult to see how development expenditure for most products can be recouped before patent expiry without significant international sales.

Langmuir-Blodgett (LB) films have been produced using a novel near-IR- absorbing dye based on 1,4-naphthoquinone. Wavelength compatibility with semiconductor diode lasers makes it particularly suitable for optical storage applications. Ablative data marks have been recorded using 830 nm light with a pulse energy of 3.6 nJ. The sensitivity is dependent on heat flow within the film and substrate, and can be increased using LB film buffer layers.

The interaction between methyl p-hydroxybenzoate and polysorbate 80 has been determined using a molecular sieve technique. At 25° and at surfactant concentrations of 2·86 and 1·43% respectively, the ratios of total to free preservative were 2·9 and 1·9. These results are comparable with published data.

Surface tension, conductivity and dye solubilization experiments show that, in aqueous solution, chlorhexidine diacetate forms micelles and has a molar critical micellar concentration (CMC) of 0·010–0·011 at 25°. Similarly, the digluconate salt has a molar CMC of 0·0066. Above its CMC, the freely soluble digluconate salt solubilizes the less soluble diacetate salt. The formation of micelles does not affect the rate of hydrolysis of chlorhexidine to p-chloroaniline. It is suggested that the micelles formed by chlorhexidine resemble those formed by many dyes rather than those of colloidal surfactants. Equilibrium dialysis experiments show that 1·0 and 3·0% polysorbate 80 inactivates 37·5 and 70·0% respectively of the chlorhexidine in a 0·10% solution of the diacetate salt.

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A case of partial heart-block is reported in the course of which there occurred frequent attacks of syncope with convulsive seizures (Adams-Stokes' syndrome). During the period of observation barium chloride, epinephrin and atropine were administered,—all without appreciable effect. The patient died during an attack of ventricular asystole. Postmortem examination showed a lesion involving junctional tissues and consisting of a fatty and lymphocytic infiltration of the atrioventricular node and the first part of the bundle of His together with a fibrotic process involving both left and right bundle-branches. The bundle fibers showed degeneration. That this degeneration was active, was evidenced by the finding of endotheliocytes which were phagocyting the degenerating Purkinje fibers. We suggest that our failure to establish an idioventricular rhythm might have been due to the presence of extensive destruction of junctional tissues in a patient in whom the lower pacemaker had never been dominant.

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The epizootic Trinidad donkey strain of Venezuelan equine encephalomyelitis virus (VEE) was cleared slowly from the circulation of rhesus monkeys following intravenous inoculation, while the live, attenuated vaccine strain, TC-83, was cleared rapidly. The efficient clearance of TC-83 vaccine may be a factor in the lower viremia and benign course of TC-83 virus infection in rhesus monkeys.

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IN a recent preliminary communication, R. Tschesche1 has directed attention to the similarity between adenine hydrochloride and the crystals isolated by Barnes, O'Brien and Reader2. These crystals were specifically stated by them to have vitamin B4 activity (10γ per diem per rat), but no claim was made that they were actually vitamin B4. Tschesche does not state whether the specimen of crystals obtained by him was biologically active.

Auricular flutter is that condition in which the auricles contract rhythmically and coordinately at a greatly accelerated rate, the lower limit of which has been arbitrarily placed by Lewis 1 at 200. The rate of the ventricles is usually slower than that of the auricles. This difference in rate is due to the fact that the ventricles fail to respond to every impulse originating in the auricles. The term "auricular flutter" was first applied clinically by Jolly and Ritchie 2 in 1911; but the condition had been previously described as occurring in both humans 3 and animals. 4 Before the term was generally accepted, we find auricular flutter referred to as "jugular embryocardia," "auricular tachysystole," "auricular tachycardia," and "auricular tachyrhythmia." 5 From the time that this disturbance in mechanism had been first recorded, until 1914, when Ritchie published his book, fifty-three cases, including those of Ritchie, had been reported. This fact, especially in view of