HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells

Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.

Biliary strictures complicating pancreaticoduodenectomy

BACKGROUND

Biliary-enteric anastomotic strictures may complicate pancreaticoduodenectomy. Anastomotic ischaemia and reflux of gastric and enteric contents with secondary bacterobilia and cholangitis may contribute.

METHODS

Four patients (3 females, 1 male) with a mean age of 50 yr (range 26-73 yr) presented 1-12 yr following pancreaticoduodenectomy with features suggestive of biliary-enteric anastomotic stricture formation. These included recurrent cholangitis, obstructive jaundice, and liver abscess. Diagnosis was confirmed by percutaneous or endoscopic cholangiography. Endoscopic and radiological management were unsuccessful, and revision surgery in the form of a Roux-en-Y hepaticojejunostomy was required.

RESULTS

Three patients remain asymptomatic 10-30 mo postoperatively. Jaundice recurred at 15 mo in one patient owing to re-stricture formation and the development of secondary biliary cirrhosis; a liver transplantation is being considered.

CONCLUSION

Early diagnosis and prompt management of biliary-enteric stricture is essential if secondary biliary cirrhosis is to be avoided. Definitive therapy is best accomplished with a Roux-en-Y hepaticojejunostomy that places the gastric and biliary anastomoses onto separate jejunal limbs.

HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells

Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.

Immune responses during the acute stages of infection with the intestinal trematode Echinostoma caproni

This study investigated the nature of the immune response of C57BL/6 mice infected with the trematode Echinostoma caproni. To determine the preferential development of either a Th1 or Th2 cytokine pattern during early stages of infection, cytokine production by spleen and mesenteric lymph node (MLN) cells during the first 3 weeks of infection was followed. Whereas spleen cells failed to respond to antigen stimulation, MLN cells produced IFN-gamma and to a lesser extent IL-4. IL-5 levels were elevated throughout the period studied. The humoral response was consistent with a Th1 cytokine pattern as antigen-specific IgG2a antibodies were preferentially developed. We investigated whether IFN-gamma is critical for establishment of E. caproni infection. Worm burden in infected mice treated with a single injection of anti-IFN-gamma mAb was significantly reduced compared to that of animals treated with a control antibody.

Surface expression of HLA-C antigen by human extravillous trophoblast

In this paper definitive evidence that the classical class I product, HLA-C, is expressed on the surface of normal trophoblast cells is provided. HLA-C transcripts were sequenced from cDNA isolated from first trimester trophoblast cells obtained by flow cytometric sorting. Both paternal and maternal alleles were transcribed. HLA-C proteins were demonstrated by biochemical analysis and found on the cell surface in association with beta(2)-microglobulin. Upregulation of cell surface HLA-C but not HLA-G expression after interferon (IFN)-gamma treatment was demonstrated by flow cytometric analysis. Immunohistology has confirmed HLA-C is expressed by all extravillous subpopulations in vivo. The question of whether trophoblast HLA-C molecules interact with decidual NK cells expressing killer Ig-like receptors (KIR) has also been addressed. Our results demonstrate that extravillous trophoblast expresses at least two HLA class I molecules, HLA-G and HLA-C on the cell surface.

Effect of iron on the survival of Vibrio cholerae in water

Effect of iron in the form of ferric oxide (Fe2O3) on the survival of V. cholerae O1 was studied. V. cholerae O1 survived for 8 days in plain water whereas in presence of Fe2O3 it survived up to 15 days. Presence of organic material in the water further promoted the bacterial survival by at least 4 days. There was no difference between the behaviour of El Tor and classical biotype. These results indicate that the presence of iron in water could promote the survival of V. cholerae O1 in water and may play a significant role in the epidemiology of cholera.

Attitudes towards emotional expression, relational competence and psychological distress

The association between life events and psychological distress was found to be mediated by attitudes towards emotional expression for those with low social support but not for those with high social support. Passive interpersonal behaviour significantly accounted for additional variance in psychological distress to that accounted for by life events and attitudes.

Recognition of trophoblast HLA class I molecules by decidual NK cell receptors--a review

During placentation the extravillous trophoblast (EVT) cells migrate through the decidua towards the maternal spiral arteries. The walls of the arteries are then destroyed by trophoblast resulting in an increased blood flow to the fetus. These EVT express HLA-G, HLA-E and HLA-C, an unusual combination of two non-classical and one classical MHC class I molecules. The decidua is infiltrated by distinctive uterine natural killer (NK) cells during the time of trophoblast invasion. These cells express a variety of receptors (CD94/NKG2, KIR and ILT) which are known to recognize HLA class I molecules. There is, therefore, a mechanism for molecular recognition of the placental trophoblast cells. The possible functional consequences of this uterine NK cell-trophoblast interactions are uncertain. One possible result is in an altered NK cell cytokine profile which modulates the invasive proclivity of the EVT. In this way placentation could be controlled.

Calculation of the relative geometry of tRNAs in the ribosome from directed hydroxyl-radical probing data

The many interactions of tRNA with the ribosome are fundamental to protein synthesis. During the peptidyl transferase reaction, the acceptor ends of the aminoacyl and peptidyl tRNAs must be in close proximity to allow peptide bond formation, and their respective anticodons must base pair simultaneously with adjacent trinucleotide codons on the mRNA. The two tRNAs in this state can be arranged in two nonequivalent general configurations called the R and S orientations, many versions of which have been proposed for the geometry of tRNAs in the ribosome. Here, we report the combined use of computational analysis and tethered hydroxyl-radical probing to constrain their arrangement. We used Fe(II) tethered to the 5' end of anticodon stem-loop analogs (ASLs) of tRNA and to the 5' end of deacylated tRNA(Phe) to generate hydroxyl radicals that probe proximal positions in the backbone of adjacent tRNAs in the 70S ribosome. We inferred probe-target distances from the resulting RNA strand cleavage intensities and used these to calculate the mutual arrangement of A-site and P-site tRNAs in the ribosome, using three different structure estimation algorithms. The two tRNAs are constrained to the S configuration with an angle of about 45 degrees between the respective planes of the molecules. The terminal phosphates of 3'CCA are separated by 23 A when using the tRNA crystal conformations, and the anticodon arms of the two tRNAs are sufficiently close to interact with adjacent codons in mRNA.

Psychometric evaluation of Horowitz's Impact of Event Scale: a review

Despite being developed before the formal introduction of posttraumatic stress disorder (PTSD) within the diagnostic literature, the Impact of Event Scale (Horowitz, Wilner, & Alvarez, 1979) remains one of the most widely used self-report measures of posttraumatic stress. This paper presents an overview of research using the IES in an attempt to assess its psychometric status. It is concluded that the psychometric properties of the IES are satisfactory (although not as a PTSD diagnostic measure) and that continued use of the IES as a measure of intrusive and avoidant processes is warranted.

The Depression-Happiness Scale: test-retest data over two weeks

The present aim was to examine further the psychometric properties of the Depression-Happiness Scale. Test-retest data over 2 wk. are reported for this scale for a sample of 54 female Northern Irish university students. Stability was fairly high as r = .70, and there was no significant change between Time 1 and Time 2 (M = 49.7 and 50.8, respectively). The data suggest that the Depression-Happiness Scale might be considered a trait measure of happiness rather than a state measure.

Mouse adenovirus (MAV-1) expression in primary human endothelial cells and generation of a full-length infectious plasmid

Using RT-PCR, we show that mouse adenovirus type I (MAV-1) is capable of infecting and expressing in various cell types, specifically human endothelial cells. The capability of MAV-1 to infect and express in human endothelial cells makes it a potentially useful alternative to the use of human adenoviruses type 2/5 (Ad2/5) in virus-based gene therapy, although presently MAV-1 can only be produced at lower titers than Ad2/5. In this report, we present methods for the purification of MAV-1 DNA and use of this DNA along with a modified bacteria-based homologous recombination protocol to generate a full-length plasmid clone of MAV-1 DNA. Using various transfection procedures, we show that this plasmid MAV-1 DNA can generate plaques of MAV-1 virus, albeit at low efficiencies (about 0. 2 p.f.u./microg DNA). Furthermore, the construction of an MAV-1 plasmid along with its capability to express in human cells justifies the full development of MAV-1 into a system of gene therapy.

Posttraumatic stress disorder and traumatic brain injury: are they mutually exclusive?

It has been suggested that posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) must be mutually incompatible disorders. However, growing empirical evidence has begun to question this. Evidence suggests that although PTSD may be relatively rare among the TBI population, some TBI patients seem to develop PTSD. We suggest two theoretical routes through which PTSD might develop in TBI patients: through nonconscious processes in individuals who are subsequently amnesic, but who were conscious at the time of the traumatic episode and through subsequent appraisal processes in individuals who were unconscious during the traumatic episode.

The lymphopenia mutation of the BB rat causes inappropriate apoptosis of mature thymocytes

BB rats develop autoimmune diabetes mellitus at a high frequency. A key factor in the development of the disease is an autosomal recessive mutation determining peripheral T cell lymphocytopenia. Previous studies have suggested that the lymphopenia could be caused by increased cell death. Here we demonstrate that the lyp mutation dramatically reduces the in vitro lifespan of the TCRhi single-positive thymocytes and peripheral T cells, without abolishing their capacity to proliferate. The reduced lifespan is due to an increased rate of apoptosis, and is detected in single-positive thymocytes displaying characteristics of cells which have undergone positive selection. The cell death defect does not affect the in vitro lifespan of peripheral B cells. Interestingly, stimulation can rescue peripheral lyp/lyp T cells from immediate cell death. We propose that the lymphopenia mutation prevents the accumulation of a normal T cell pool, including regulatory subsets, without preventing the activation and proliferation of reactive T cells, thereby creating conditions appropriate for the development of uncontrolled autoimmune responses.

Neuropsychological factors associated with borderline pathology in children

OBJECTIVE

To determine whether children with borderline pathology have a specific pattern of neuropsychological risk factors.

METHOD

The subjects were 94 school-age children in day treatment, divided into borderline (n = 41) and nonborderline (n = 53) groups according to results of the Child version of the Diagnostic Interview for Borderlines. All children were assessed with the Child Behavior Checklist, the Schedule for Affective Disorders and Schizophrenia for School-Age Children, and a neuropsychological battery.

RESULTS

Children with borderline pathology had abnormal scores on the Wisconsin Card Sorting Test and on the Continuous Performance Test, both of which suggested problems with executive function. Although borderline pathology was highly comorbid with conduct disorder, most results were independent of this comorbidity.

CONCLUSIONS

Borderline pathology in children has a unique pattern of neuropsychological risk factors that may reflect a diathesis for this syndrome.

Site-directed hydroxyl radical probing of 30S ribosomal subunits by using Fe(II) tethered to an interruption in the 16S rRNA chain

Two in vitro transcripts, one corresponding to the 5' and central domains (residues 1-920) of 16S rRNA and the other corresponding to its 3' domain (residues 922-1542), assemble efficiently in trans with 30S ribosomal proteins to form a compact ribonucleoprotein particle that cosediments with natural 30S subunits. Isolated particles are similar in appearance to natural 30S subunits with electron microscopy and contain a full complement of the small subunit ribosomal proteins. The particles have a reduced ability to bind tRNA (attributable to the location of the discontinuity in a conserved region of the rRNA) near features that have been implicated in tRNA binding. Association of these two halves of 16S rRNA in trans must be stabilized by either previously unidentified RNA-RNA contacts or interactions mediated by ribosomal proteins because there are no known direct interactions between them. The trans construct was used to probe the three-dimensional RNA neighborhood around position 922 of 16S rRNA by generating hydroxyl radicals from Fe(II) tethered to the 5' end of the 3' transcript. Hydroxyl radical-induced cuts in the 16S rRNA chain were localized by primer extension to nucleotides 923-929 and 1192-1198, providing evidence for the mutual proximity of the 920 and 1192 regions.

Haemorrhage during cranial CT : spontaneous or contrast related?

Two cases of haemorrhage during cranial computed tomography (CT) occurring during the enhancement phase of CT examination immediately after the administration of intravenous contrast medium are reported. In both cases, the preceding unenhanced scansshowed evidence of haemorrhage. The risk of aneurysmal rupture as a result of retching and vomiting induced by intravenous contrast is stressed. Judicious use of contrast enhanced CT is suggested in patients with suspected aneurysmal subarachnoid haemorrhage.

Drug metabolism biosensors: electrochemical reactivities of cytochrome P450cam immobilised in synthetic vesicular systems

Biosensors containing cytochrome P450cam in a didodecyldimethylammonium bromide vesicular system were prepared by cross-linking onto a glassy carbon electrode (GCE) with glutaraldehyde in the presence of bovine serum albumin. Cyclic voltammetric responses of the sensor in air-free buffer solution showed that the sensor exhibited reversible electrochemistry due to direct electron exchange between the haem Fe(3+/2+) redox system and the GCE surface. In air-saturated solution containing camphor, the biosensor gave an irreversible electrocatalytic current which is compatible with the monooxygenation of the substrate. Steady state amperometric experiments with camphor, adamantanone and fenchone were performed with a biosensor prepared by cross-linking P450cam with glutaraldehyde onto a Pt disc electrode. The sensor was characterised by fast amperometric responses, attaining steady-state in about 20 s in a cobalt sepulchrate mediated electrochemical system. The kinetic parameters of the biosensor were analysed using the electrochemical Michaelis Menten equation. The estimated apparent Michaelis-Menten constant, Km, values for the biosensors were in the range of 1.41-3.9 mM.

Organophosphate poisoning: predicting the need for ventilatory support

The present study evaluated 103 consecutive patients of organophosphate poisoning with special reference to the need for ventilatory support. Of 103 patients, 36(34.95%) required assisted ventilation. The need for ventilatory support was significantly more with greater time duration for institution of specific treatment, low level of sensorium at admission, pin-point pupils and generalized fasciculations, presence of convulsions, presence of respiratory insufficiency at admission, and higher initial atropine requirement for atropinization. The study also proposes a system of grading of severity, modified from the existing systems proposed.

Additive anticonvulsant effect of flunarizine and sodium valproate on electroshock and chemoshock induced seizures in mice

The efficacy of Flunarizine (FLU), a calcium channel blocker, in combination with conventional antiepileptic drugs, phenytoin (PHT), carbamazepine (CBZ), sodium valproate (VPA), and ethosuximide (ESM), at ED50 doses, were examined for protective effects against maximal electroshock seizures (MES) and pentylenetetrazol (PTZ) induced seizures in mice. In both models, only VPA and FLU showed significantly enhanced protection, which was additive ie. 100% protection. In the MES test, though FLU combined with PHT did show a slightly enhanced protection (66.6%), with CBZ there was no enhancement as compared to either drug alone. In the PTZ test, FLU with ESM showed 83% protection this however was not statistically significant. The findings of this study in mice suggest that FLU would be a suitable candidate for add-on therapy with VPA for clinical epilepsy.

EF-G-catalyzed translocation of anticodon stem-loop analogs of transfer RNA in the ribosome

Translocation, catalyzed by elongation factor EF-G, is the precise movement of the tRNA-mRNA complex within the ribosome following peptide bond formation. Here we examine the structural requirement for A- and P-site tRNAs in EF-G-catalyzed translocation by substituting anticodon stem-loop (ASL) analogs for the respective tRNAs. Translocation of mRNA and tRNA was monitored independently; mRNA movement was assayed by toeprinting, while tRNA and ASL movement was monitored by hydroxyl radical probing by Fe(II) tethered to the ASLs and by chemical footprinting. Translocation depends on occupancy of both A and P sites by tRNA bound in a mRNA-dependent fashion. The requirement for an A-site tRNA can be satisfied by a 15 nucleotide ASL analog comprising only a 4 base pair (bp) stem and a 7 nucleotide anticodon loop. Translocation of the ASL is both EF-G- and GTP-dependent, and is inhibited by the translocational inhibitor thiostrepton. These findings show that the D, T and acceptor stem regions of A-site tRNA are not essential for EF-G-dependent translocation. In contrast, no translocation occurs if the P-site tRNA is substituted with an ASL, indicating that other elements of P-site tRNA structure are required for translocation. We also tested the effect of increasing the A-site ASL stem length from 4 to 33 bp on translocation from A to P site. Translocation efficiency decreases as the ASL stem extends beyond 22 bp, corresponding approximately to the maximum dimension of tRNA along the anticodon-D arm axis. This result suggests that a structural feature of the ribosome between the A and P sites, interferes with movement of tRNA analogs that exceed the normal dimensions of the coaxial tRNA anticodon-D arm.

The Depression-Happiness Scale: reliability and validity of a bipolar self-report scale

This article reports two studies aimed at validating the 25-item self-report McGreal and Joseph (1993) Depression-Happiness Scale (D-H S). In the first study, principal component data are reported on the D-H S with 194 respondents. A forced 1-factor solution confirmed the unidimensionality of the scale (item loadings ranged from .38 to .77) and thus the feasibility of a statistically bipolar measure. In the second study, data on the convergent validity of the D-H S with the Beck Depression Inventory (r=-.75) and the Oxford Happiness Inventory (r=.59) with 100 respondents are reported confirming the construct validity of the scale. Implications for research in social and clinical psychology are discussed along with the possible uses of the D-H S in a clinical setting.