Inducible nitric oxide synthase in tangle-bearing neurons of patients with Alzheimer's disease

In Alzheimer's disease (AD), affected neurons accumulate beta amyloid protein, components of which can induce mouse microglia to express the high-output isoform of nitric oxide synthase (NOS2) in vitro. Products of NOS2 can be neurotoxic. In mice, NOS2 is normally suppressed by transforming growth factor beta 1 (TGF-beta 1). Expression of TGF-beta 1 is decreased in brains from AD patients, a situation that might be permissive for accumulation of NOS2. Accordingly, we investigated the expression of NOS2 in patients with AD, using three monospecific antibodies: a previously described polyclonal and two new monoclonal antibodies. Neurofibrillary tangle-bearing neurons and neuropil threads contained NOS2 in brains from each of 11 AD patients ranging in age from 47 to 81 years. NOS2 was undetectable in brains from 6 control subjects aged 23-72 years, but was expressed in small amounts in 3 control subjects aged 77-87 years. Thus, human neurons can express NOS2 in vivo. The high-output pathway of NO production may contribute to pathogenesis in AD.

Production of nitric oxide in the synovial membrane of rheumatoid and osteoarthritis patients

We have demonstrated spontaneous nitric oxide (NO) production by primary synovial cultures from rheumatoid (RA) and osteoarthritis patients. Increased NO production followed addition of staphylococcal enterotoxin B. Immunochemical double staining with specific anti-human inducible NO synthase (iNOS) and nonspecific esterase (NSE), or anti-CD68 (markers for tissue macrophages) showed that although many lining layer cells in RA synovium expressed iNOS, most (approximately 90%) were NSE- and CD68-, with only a minor population (approximately 10%) which were iNOS+, CD68+/NSE+. These data demonstrate the capacity for high output of NO by human synovial tissue and show that, although human macrophages can express high levels of iNOS, the majority of cells expressing iNOS are fibroblasts. We also report that synoviocytes, and macrophage cell lines, cultured with the NO donor, S-nitroso-acetyl penicillamine, produced high concentrations of tumor necrosis factor (TNF)-alpha. These results suggest that NO may mediate pathology in RA through the induction of TNF-alpha production.

The interleukin-1 beta-converting enzyme (ICE) is localized on the external cell surface membranes and in the cytoplasmic ground substance of human monocytes by immuno-electron microscopy

Interleukin-1 beta (IL-1 beta)-converting enzyme (ICE) is a novel cysteine protease that cleaves the 31-kD inactive cytoplasmic IL-1 beta precursor into active extracellular 17-kD IL-1 beta. The ICE gene product is a 45-kD proenzyme that requires proteolytic processing to activate ICE. Active ICE is a heterodimer consisting of equal amounts of p20 and p10 subunits. Generation of active ICE is affected by the removal of an 11-kD NH2-terminal precursor domain (p11) and an internal 19-amino acid sequence that separates the 20- and 10-kD subunits. Immuno-electron microscopy was performed on human monocytes with immunoglobulins recognizing the active (p20) or precursor (p11) domains of ICE. Elutriated monocytes were stimulated with 50 pM lipopolysaccharide followed by heat-killed Staphylococcus aureus under conditions that induce maximal rates of IL-1 beta secretion. Ultrathin cryosections were cut from fixed frozen pellets of these monocytes and were immunogold labeled with either antibody. Active and precursor domain ICE epitopes were localized in the cytoplasmic ground substance, but they were not detected within the endoplasmic reticulum, the Golgi apparatus, and secretory granules of activated or inactive monocytes. Importantly, numerous ICE p20 epitopes were also observed on the extracellular surfaces of the cell membrane, and were concentrated on the microvilli. Very similar patterns of ICE localization were obtained with unstimulated blood monocytes. In contrast, ICE p11 epitopes were not detected on the surfaces of these monocytes. Likewise, labeling of fixed ultrathin cryosections of monocytes with a biotinylated irreversible ICE inhibitor [Ac-Tyr-Val-Lys(biotin)-Asp-(acyloxy)-methyl-ketone] showed that the compound localized on the outer cell surface as well, and to a lesser extent, within the cytoplasmic ground substance. Furthermore, antipeptide antibodies specific for either the mature or precursor domains of IL-1 beta were both localized upon the cell membrane after stimulation of IL-1 beta secretion. Lipopolysaccaride-primed monocytes that synthesized, but did not secrete IL-1 beta, exhibited only cytoplasmic staining. The data suggests that mature IL-1 beta is generated via cleavage of the 31-kD inactive cytoplasmic IL-1 beta precursor by ICE after association with the plasma membrane during secretion.

GABAergic signalling in the immune system

The GABAergic system is the main inhibitory neurotransmitter system in the central nervous system (CNS) of vertebrates. Signalling of the transmitter γ-aminobutyric acid (GABA) via GABA type A receptor channels or G-protein-coupled type B receptors is implicated in multiple CNS functions. Recent findings have implicated the GABAergic system in immune cell functions, inflammatory conditions and diseases in peripheral tissues. Interestingly, the specific effects may vary between immune cell types, with stage of activation and be altered by infectious agents. GABA/GABA-A receptor-mediated immunomodulatory functions have been unveiled in immune cells, being present in T lymphocytes and regulating the migration of Toxoplasma-infected dendritic cells. The GABAergic system may also play a role in the regulation of brain resident immune cells, the microglial cells. Activation of microglia appears to regulate the function of GABAergic neurotransmission in neighbouring neurones through changes induced by secretion of brain-derived neurotrophic factor. The neurotransmitter-driven immunomodulation is a new but rapidly growing field of science. Herein, we review the present knowledge of the GABA signalling in immune cells of the periphery and the CNS and raise questions for future research.

Quantification of a matrix metalloproteinase-generated aggrecan G1 fragment using monospecific anti-peptide serum

Several members of the matrix metalloproteinase family have been reported to cleave aggrecan in the interglobular domain between Asn-341 and Phe-342. An antiserum was prepared against a peptide conjugate corresponding to the C-terminal sequence of the matrix metalloproteinase-generated aggrecan G1 fragment (Phe335-Val-Asp-Ile-Pro-Glu-Asn341). A quantitative radioimmunoassay, with a limit of detection of about 80 pM, was developed using this antiserum. This antiserum requires the free carboxyl group of the C-terminal asparagine for optimal recognition. If the C-terminal asparagine is excised from the sequence, replaced with closely related amino acids, or extended across the matrix metalloproteinase cleavage site, there is a 40-10,000-fold loss in detection. Using peptides cleaved from the N-terminus, it was determined that the antiserum requires the entire Phe-Val-Asp-Ile-Pro-Glu-Asn sequence for optimal recognition. The radioimmunoassay detects matrix metalloproteinase-generated G1 fragments with similar sensitivity to the Phe-Val-Asp-Ile-Pro-Glu-Asn peptide, but it does not recognize intact aggrecan. Immunoreactive aggrecan G1 fragments of molecular mass 50 kDa are generated by the matrix metalloproteinases stromelysin and gelatinase A. In contrast, under identical conditions, the closely related metalloproteinases, gelatinase B and collagenase, as well as cathepsin G, cathepsin B and human leucocyte elastase, did not generate a G1 fragment recognized by the antiserum. The anti-Phe-Val-Asp-Ile-Pro-Glu-Asn serum detects stromelysin-generated aggrecan G1 fragments from mouse, guinea pig, rabbit and human, indicating that the detection is not species-specific. This antiserum and radio-immunoassay should be useful for quantifying and characterizing matrix metalloproteinase-generated aggrecan G1 fragments in articular cartilage and synovial fluids from humans and various animal models of articular-cartilage destruction.

Determination of the kinetic parameters of Escherichia coli leader peptidase activity using a continuous assay: the pH dependence and time-dependent inhibition by beta-lactams are consistent with a novel serine protease mechanism

Bacterial leader peptidase (LPase) is a potential target for the development of novel anti-infective agents, but to data only peptides based upon natural macromolecular substrates have been reported as inhibitors. In this work is described a continuous assay for Escherichia coli LPase activity, based upon Ac-WSASALAKI-AMC (I) as the substrate, that can be monitored either spectrophotometrically or spectrofluorometrically. The LPase reaction is coupled to the liberation of AMC (aminomethylcoumarin) via a nonspecific leucine aminopeptidase. LPase and a short form of the enzyme (LPase-sf) lacking the membrane spanning domains displayed saturable kinetics toward I. The second-order rate constants were approximately 2 x 10(5) M-1 h-1 at pH 7.5 and were comparable to those reported in the literature for peptide substrates based upon natural cleavage sites in preproteins. LPase was inhibited by beta-lactams. [S-(R*,S*)]-4-[(1-(((1-(5-toluoyl)butyl)amino)carbonyl)-3,3-dimethyl-4- oxo-2-azetidinyl)oxyl]benzoic acid (L-684,-248, 588 microM) inhibited the LPase-catalyzed hydrolysis of 50 microM I and 125 microM Ac-WLVP-Nleu-LSFAAEGDDPA-NH2 by 30% and 88% over 1 and 4 h, respectively. The inhibition of LPase by L-684,248 and its C-4 diasteromer was time dependent and yielded second-order rate constants (kinact/Ki) of 12 and 7.7 M-1 min-1, respectively. The process was structurally specific as the C-3 diethyl substituted beta-lactam (C-4 S-isomer) was inactive. The latter data correlate with the LPase preference for alanine at the P1 position of peptide substrates [Kuo et al. (1993) Arch. Biochem. Biophys. 303, 274-280].(ABSTRACT TRUNCATED AT 250 WORDS)

The petromastoid canal on computed tomography

The objective was to assess visibility and anatomy of the petromastoid canal in high-resolution CT. Computed tomography images of 188 patients were reviewed for delineation of the petromastoid canal. This bony canal connects the mastoid antrum with the cranial cavity and houses the subarcuate artery and vein. The diameter, obtained in the middle portion of the canal, was compared with the diameter of the vestibular and cochlear aqueduct in all patients, and absolute values measured in 20 cases. Collimation was 1 mm in 164 and 2 mm in 24 examinations. Additionally, temporal bone of a cadaver was imaged and microdissected. The petromastoid canal was identified bilaterally in all 164 scans that were obtained with a slice thickness of 1 mm. In 5 of the 24 patients imaged with a collimation of 2 mm, the canal was not visible, most probably due to partial-volume effects. The petromastoid canal had the same diameter as the cochlear aqueduct in 42/44 (right/left), exceeded it in 66/61 and was smaller in 75/78 cases. In comparison to the vestibular aqueduct it had an equal diameter in 38/41 (right/left), exceeded it in 63/61, and was rated as smaller in 82/81 temporal bones. Diameters for the canals were: petromastoid canal 0.51+/-0.04 mm; cochlear aqueduct 0.57+/-0.03; and vestibular aqueduct 0.63+/-0.06 mm. Microdissection of the specimen revealed the entire course of the canal and demonstrated a similar appearance of the structure as in the images. The petromastoid canal can easily be identified on high-resolution, thin-slice CT images. Knowledge of the anatomy of this bony canal prevents misinterpretation as pathological structure, such as fracture line, which might occur if this structure is not known.

Do automated red cell exchanges relieve priapism in patients with sickle cell anemia?

Priapism is a dramatic, painful complication for some men afflicted by sickle cell anemia. Although the natural history remains unclear, many believe replacing the patient's abnormal red blood cells (RBCs) with normal RBCs by apheresis is effective. However, no controlled trials have demonstrated its effectiveness. We exchanged 7 men after medical management failed. All procedures reduced sickle hemoglobin levels to < 30%. Two patients underwent emergency automated red cell exchanges without any detumescence or reduction of pain. The remaining 5 patients were exchanged non-emergently; 4 experienced no detumescence or relief of pain. One adult experienced resolution 8 h postexchange. However, he had a history of "stuttering" priapism. All required decompression procedures. Automated RBC exchanges were not effective in achieving detumescence or reducing pain.

Platelet membrane early activation markers during prolonged storage

The relationship between platelet aging and early markers of membrane activation have not been defined clearly. Activation markers expressed during prolonged storage are similar if not identical to those that appear after exposure to thrombin. Using flow cytometry, we investigated platelet membrane expression of CD62P, CD63, and annexin V binding (i.e., loss of membrane asymmetry) in platelets stored for up to 11 days under standard blood banking conditions. We compared five apheresis platelets to two random donor platelet concentrates, and to one pooled platelet preparation from six single platelet concentrates before and after exposure to thrombin. CD62P, CD63 expression, and annexin V binding increased during storage albeit with different kinetics. The differential increments observed between resting and thrombin (1 unit/ml) activated platelets showed an inverse correlation to storage time for CD62P, CD63, and annexin V binding, which was identical to published survival curves. A difference between apheresis platelets and platelet concentrates was observed only on day 1. Our data indicate that the in vitro platelet reserve activity to thrombin activation mirrors that of radiolabeled platelet survival in vivo and that platelet cross-sectional residual life span can explain their diminished capacity to respond to thrombin as a function of viability.

Inducible nitric oxide synthase expression is increased in the alveolar compartment of asthmatic patients

INTRODUCTION

Increased exhaled nitric oxide (NO) levels in asthma are suggested to be through inducible NO synthase (iNOS). The aim of this study was to investigate the expression of iNOS in bronchoalveolar lavage (BAL) cells and tissue from central and peripheral airways and compare it with the exhaled bronchial and alveolar NO levels in patients with asthma vs a control group.

METHODS

Thirty-two patients with asthma (defined as controlled or uncontrolled according to Asthma Control Test score cut-off: 20) and eight healthy controls were included. Exhaled NO was measured, and alveolar concentration and bronchial flux were calculated. iNOS was measured in central and peripheral lung biopsies, as well as BAL cells. Bronchoalveolar lavage macrophages were stimulated in vitro, and iNOS expression and NO production were investigated.

RESULTS

Expression of iNOS was increased in central airway tissue and the alveolar compartment in uncontrolled as compared to controlled asthmatics and healthy controls. There were no differences, however, in iNOS mRNA levels in total BAL cells in uncontrolled as compared to controlled asthma. Bronchoalveolar lavage cell mRNA levels of iNOS or iNOS expression in central and alveolar tissue did not relate to alveolar NO, nor to bronchial flux of NO. In vitro stimulation with leukotriene D₄ increased iNOS mRNA levels and NO production in cultured BAL macrophages.

CONCLUSION

The levels of both bronchial and alveolar iNOS are increased in uncontrolled as compared to controlled asthma. However, levels of iNOS in BAL macrophages were not reflected by alveolar NO. Both central and distal iNOS levels may reflect responsiveness to steroid treatment.

Completely converting a blood service region to the use of safer plasma

BACKGROUND

Three types of plasma are widely available for transfusion. Two plasma components, FFP donor retested (FFP-DR), and solvent/detergent-treated plasma (SDP), are now considered to be safer from infectious complications than FFP.

STUDY DESIGN AND METHODS

A large regional blood center attempted to provide FFP-DR exclusively to all its 42 hospitals. Significant planning, increases in computer capabilities, and expansion of component storage areas were completed before initiation of this program.

RESULTS

During the first 6 months of the FFP-DR program, the blood center was not able to supply the entire region exclusively with FFP-DR. Consequently, SDP was utilized to supplement the program and to successfully and completely convert the region's 42 hospitals to the use of safer plasma.

CONCLUSION

Two new plasma components were utilized to completely convert a blood service region to the use of safer plasma.

Position of the greater trochanter and functional femoral antetorsion: Which factors matter in the management of femoral antetorsion disorders?

Aims

The primary aim of this study was to define and quantify three new measurements to indicate the position of the greater trochanter. Secondary aims were to define 'functional antetorsion' as it relates to abductor function in populations both with and without torsional abnormality.

Patients and Methods

Three new measurements, functional antetorsion, posterior tilt, and posterior translation of the greater trochanter, were assessed from 61 CT scans of cadaveric femurs, and their reliability determined. These measurements and their relationships were also evaluated in three groups of patients: a control group (n = 22), a 'high-antetorsion' group (n = 22) and a 'low-antetorsion' group (n = 10).

Results

In the cadaver group, the mean anatomical antetorsion was 14.7° (sd 8.5; 0 to 36.5) and the functional antetorsion 21.5° (sd 8.1; 3.6 to 44.3): the posterior tilt was 73.3° (sd 10.8; 46.9 to 88.7) and the posterior translation 0.59 (sd 0.2; 0.2 to 0.9). These measurements had excellent intra and interobserver agreement with a range from 0.93 to 0.99. When the anatomical antetorsion decreased, the greater trochanter was more tilted and translated posteriorly in relation to the axis of the femoral neck, and the difference between functional and anatomical antetorsion increased. The results the three patient groups were similar to those of the cadaver group.

Conclusion

The position of the greater trochanter and functional antetorsion varied with anatomical antetorsion. In the surgical management of femoral retrotorsion, subtrochanteric osteotomy can result in an excessively posterior position of the greater trochanter and an increase in functional antetorsion. Cite this article: Bone Joint J 2018;100-B:712-19.

Nonisotopic detection of mutations using a modified single-strand conformation polymorphism analysis

This report describes a rapid convenient screening system with improved sensitivity to detect mutations in the cystic fibrosis transmembrane regulator (CFTR) gene based on nonisotopic SSCP analysis. Because conventional SSCP analysis is often hampered by poor yield of single-stranded DNA, we applied the well-established solid-phase technique in which streptavidin-coated magnetic beads are used to immobilize biotinylated polymerase chain reaction (PCR) products. High yield of single-stranded DNA can be eluted from the solid phase by denaturation and used for SSCP analysis. An additional advantage of this procedure is that the immobilized single strand is available without any further purification steps for solid-phase sequencing.

Mental stimulation increases circulating CD4-positive T lymphocytes: a preliminary study

To stimulate the dorsolateral frontal cortex, 12 healthy, adult, human females played contract bridge for 1.5 h between initial and final blood sample collections. Flow cytometric analyses of samples, performed in triplicate, showed a significant increase in CD4-positive T lymphocytes. The dorsolateral frontal cortical thickness is significantly and bilaterally reduced in immune-incompetent female, nude mice. Thymic transplants reverse the deficient cortical thickness and CD4-positive cell numbers.

[Panorama ultrasonography of the abdominal wall for delineation of the anatomy and diagnosis of pathological findings]

PURPOSE

To assess extended field-of-view sonography for delineation of the anatomic structures of the abdominal wall and for the diagnosis of hernia.

MATERIAL AND METHODS

In 34 cases (24 probands, 10 patients with abdominal wall defects) extended field-of-view sonography of the abdominal wall was performed with a 7.5 MHz transducer. Dynamic alignment of real-time images allows for depiction of regions of up to 60 cm in a single extended field-of-view image. A standardized axial image was obtained above and below the arcuate line and at the level of the defect, respectively. All images were evaluated by two blinded readers regarding the visibility of the anatomic structures and the delineation and extent of pathological changes.

RESULTS

The abdominal wall was delineated with extended field-of-view sonography in all patients with a good image quality. The linea alba, the rectus muscle and the three lateral abdominal muscles, the rectus sheath, the peritoneum, and the subcutaneous fatty tissue were visible. In the patients with abdominal wall defects, the hernial sac with its contents, the extension of the defect, and the surrounding structures were clearly delineated.

CONCLUSION

Extended field-of-view sonography allows for easily surveyed and reproducible documentation of the ultrasound examination of the abdominal wall. It is especially useful for the preoperative planning in patients with abdominal wall defects.

Simple, inexpensive wavemeter implemented with a fused fiber coupler

A simple, inexpensive wavemeter for measuring the wavelength of optical fiber coupled light sources is described. We determined the wavelength by measuring the wavelength-dependent coupling coefficient of a fused fiber coupler. A prototype device covering the wavelength range of 1500-1600 nm was assembled and tested in the laboratory. The wavemeter had a wavelength uncertainty of less than 0.087 nm over a wavelength range of 1530-1570 nm. The dominant source of error in the test was found to be due to the presence of broadband amplified spontaneous emission (ASE) in the laser output. It is expected that the accuracy of the device can be increased significantly by the introduction of a band-limiting filter to reduce the ASE level.

Induction of single- and double-strand breaks in plasmid DNA by monoenergetic alpha-particles with energies below the Bragg-maximum

The yield of single-strand breaks (ssb) and double-strand breaks (dsb) produced by alpha-particles at the end of their track in DNA-films was determined experimentally. Helium nuclei were accelerated to 600 keV in the 400 kV ion accelerator and scattered at a carbon target. The elastically scattered alpha-particles with energies of 344 keV and 485 keV were used to irradiate supercircular plasmid DNA in vacuo. For the dosimetry of the alpha-particles a surface barrier detector was used and the energy distribution of the alpha-particles determined. The energy loss of the particles in the DNA-layer was calculated. DNA samples were separated into the three conformational isomers using agarose gel electrophoresis. After fluorochromation the number of ssb and dsb per plasmid DNA molecule was established from the band intensities assuming the validity of Poisson statistics. Linear dose effect correlations were found for ssb and dsb per plasmid molecule. In the case of 344 keV-alpha-particles the yield of dsb was (8.6 +/- 0.9) x 10(-11) breaks/Gy x dalton. The ratio of ssb/dsb was 0.5 +/- 0.2. This is at least a factor of six larger than the ratio found in experiments with higher energy alpha-particles and from model calculations. Similar experiments with protons yielded a relative biological effectiveness (rbe) value of 2.8 for the induction of double-strand breaks by track end alpha-particles.