Rapid detection of infectious cytomegalovirus in blood with the aid of monoclonal antibodies

The recently developed early antigen immunofluorescence (IF) method for the detection of infectious cytomegalovirus (CMV) in clinical specimens has hardly been applied on blood samples. We compared the CMV early antigen detection technique with the conventional cell culture method in 415 different buffy coat samples from 85 different immunocompromised patients. Duplicate coverslips were stained with two different monoclonal antibodies 4-6 days after inoculation. The conventional cultures were examined for typical cytopathic effects (CPE) during 10 weeks. Forty samples from 19 patients were positive by the IF technique, most of them with both monoclonal antibodies. Only 22 of these samples were positive in the conventional cell culture assay, on average after 15.8 days. CMV viraemia was detected exclusively by the IF method in 18 samples, 7 of which were from five patients without any further evidence of an active CMV infection. CMV viraemia was detected exclusively by the CPE method in eight samples, on average after no less than 36.6 days. CMV viraemia was not found in blood samples from 10 patients with laboratory proven active CMV infections and 53 patients without any evidence of an active CMV infection. In our hands the early antigen method for the detection of infectious CMV in blood is nearly as specific (at least 98.1%) and clearly much faster and more sensitive than the conventional cell culture method. The early CMV antigen detection method is therefore a very useful tool for the rapid detection of infectious CMV in blood.     

An international external quality assessment of nucleic acid amplification of herpes simplex virus.

BACKGROUND: There is an increasing awareness of the need for external quality control of diagnostic virology. OBJECTIVES: To assess the quality of nucleic acid amplification tests (NAT) of herpes simplex within Europe. STUDY DESIGN: Herpes simplex virus (HSV) proficiency panels were produced at the Swedish Institute for Infectious Disease Control on behalf of the European Union Concerted Action for Quality Control of Nucleic Acid Amplification in 1999 and 2000. Nine reference laboratories evaluated the production process. Each panel consisted of 12 coded samples with various concentrations of inactivated, freeze-dried HSV type 1 (HSV-1), and HSV type 2 (HSV-2), or negative controls. Positive samples included HSV-1 and HSV-2 in a range of concentrations (2 x 10(2) to 2 x 10(7) genome copies per ml) similar to those found in cerebrospinal fluids from patients with HSV encephalitis. RESULTS: Sixty-six participants reported a total of 76 data sets for panel 1, and 71 reported 78 data sets for panel 2. The majority of the participants employed qualitative 'in-house' polymerase chain reaction (PCR) methods, either in a single, nested or semi-nested format. For panel 2, 9 laboratories reported use of 'real-time' PCR in contrast to 3 for panel 1. Three laboratories submitted quantitative results on both panels. Thirty percent of the data sets had correct results for the entire panel 1. In 6 data sets (8%) a total of 11 false positive results were reported. For panel 2, 28% of the data sets had correct result. Nineteen false positive results were reported in 14 data sets (18%), but most of the incorrect results reflected a lack of test sensitivity. CONCLUSIONS: The relatively high frequency of false positive results and the large number of false-negative results, albeit at low copy number, stress the need for improvement in the quality of HSV NAT and for external quality control programmes.     

Comparison of In Vitro Lymphocyte Proliferations Induced by Cytomegalovirus-Infected Human Fibroblasts and Cell-Free Cytomegalovirus

In vitro lymphocyte reactivity (LR) to cytomegalovirus (CMV)-infected human fetal fibroblasts (CMVFF) and cell-free CMV were measured by using lymphocytes from healthy donors. Lymphocytes from all seropositive donors were stimulated by CMVFF, whereas lymphocytes from negative donors were not. The optimal stimulator cell-to-lymphocyte ratio was in the range of 1:5 to 1:50, dependent on the virus dose used. LR to cell-free CMV was positive for 15 out of 18 seropositive donors and negative for 14 out of 16 seronegative donors. In most cases LR to CMVFF was considerably higher than LR to cell-free CMV. Within the CMV seropositive group there was no significant correlation between the LR to either CMVFF or cell-free CMV and the levels of antibodies to CMV early antigens or CMV late antigens. There was no strict correlation between LR to CMVFF and to cell-free CMV, especially not in tests with lymphocytes from two patients with CMV mononucleosis. Our data suggest that CMVFF and cell-free CMV are recognized (partly) by different subpopulations of CMV-specific memory lymphocytes. We conclude that the use of CMV-infected cells, in addition to cell-free CMV, in LR tests gives more reproducible and possibly also additional information about CMV-specific cellular immunity.     

Poly(phenylenevinylene)-type conjugated alternating copolymers: Synthesis and optical properties in solution

We have synthesized a series of new conjugated alternating copolymers containing oligo(p-phenylenevinylene) units of well-defined size and structure as conjugated chromophores in their main chain. In order to interrupt the conjugation between chromophores, the oligomers were linked to each other either via non-π-conjugated silylene units or directly, but in a non-coplanar way. In this paper we describe the synthesis, the structural characterization and the optical properties in solution of these new copolymers.     

A Common Variant in ERBB4 Regulates GABA Concentrations in Human Cerebrospinal Fluid

The neuregulin 1 (NRG1) receptor ErbB4 is involved in the development of cortical inhibitory GABAergic circuits and NRG1-ErbB4 signaling has been implicated in schizophrenia (SCZ). A magnetic resonance spectroscopy (¹H-MRS) study has demonstrated that a single-nucleotide polymorphism in ERBB4, rs7598440, influences human cortical GABA concentrations. Other work has highlighted the significant impact of this genetic variant on expression of ERBB4 in the hippocampus and dorsolateral prefrontal cortex in human post mortem tissue. Our aim was to examine the association of rs7598440 with cerebrospinal fluid (CSF) GABA levels in healthy volunteers (n=155). We detected a significant dose-dependent association of the rs7598440 genotype with CSF GABA levels (G-allele standardized β=−0.23; 95% CIs: −0.39 to −0.07; P=0.0066). GABA concentrations were highest in A homozygous, intermediate in heterozygous, and lowest in G homozygous subjects. When excluding subjects on psychotropic medication (three subjects using antidepressants), the results did not change (G-allele standardized β=−0.23; 95% CIs: −0.40 to −0.07; P=0.0051). The explained variance in CSF GABA by rs7598440 in our model is 5.2% (P=0.004). The directionality of our findings agrees with the aforementioned ¹H-MRS and gene expression studies. Our observation therefore strengthens the evidence that the A-allele of rs7598440 in ERBB4 is associated with increased GABA concentrations in the human central nervous system (CNS). To our knowledge, our finding constitutes the first confirmation that CSF can be used to study genotype–phenotype correlations of GABA levels in the CNS. Such quantitative genetic analyses may be extrapolated to other CSF constituents relevant to SCZ in future studies.     

NMDA-receptor coagonists in serum,plasma, and cerebrospinal fluid of schizophrenia patients: A meta-analysis of case–control studies

Serine and other amino acids that function as coagonists at the N-methyl-d-aspartate receptor (NMDAR) have been extensively investigated in schizophrenia (SCZ). However, studies comparing amino acid levels in body fluids of SCZ patients with healthy controls have yielded inconsistent results. We therefore conducted a meta-analysis (search: May 9, 2013) of serine, l-serine, d-serine, glycine, alanine, proline, and aspartate levels in blood and cerebrospinal fluid (CSF) obtained from adult SCZ patients and healthy controls. Standardized differences of means (SDMs) were computed, and heterogeneity, subgroup, sensitivity, and publication bias analyses were conducted. Blood serine levels were found to be significantly higher in SCZ patients compared to healthy controls (SDM = 0.280 (0.021–0.540), p = 0.034; N = 1671 subjects), whereas CSF serine, l-serine, d-serine, glycine, alanine, proline, and aspartate levels did not differ. Stratification by sex suggested that the case–control difference in blood serine levels particularly applies to male subjects. These results provide support for blood serine level aberrations in SCZ patients and warrant further research to disentangle the involvement of serine with SCZ in both sexes.     

Optimal Doses of Specific Antipsychotics for Relapse Prevention in a Nationwide Cohort of Patients with Schizophrenia

Background and HypothesisOptimal doses of most antipsychotics in the maintenance treatment of schizophrenia are unknown. We aimed to study the risk of severe relapse indicated by rehospitalization for different dose categories of 15 most frequently used antipsychotics in monotherapy in Finland. Study MethodsWe studied the risk of rehospitalization (Adjusted Hazard Ratio, aHR) associated with six antipsychotic monotherapy dose categories (as time-varying dose, measured in defined daily dose, DDDs/day) in a nationwide cohort of persons diagnosed with schizophrenia (n = 61 889), using within-individual analyses to eliminate selection bias. Study ResultsAmong the 15 most widely used antipsychotics, 13 had a U- or J-shaped dose-response curve, showing the lowest risks of relapse for doses of 0.6–<1.1 DDDs/day vs nonuse of antipsychotics. The exceptions were oral perphenazine (aHR = 0.72, 95% CI = 0.68–0.76, <0.6 DDDs/day), and olanzapine-long-acting injectable (LAI), which had the lowest aHR of any antipsychotic (aHR = 0.17, 95% CI = 0.11–0.25, 1.4–<1.6 DDDs/day). Certain risperidone and perphenazine doses <0.9 DDD/day were associated with 21%–45% lower risk of rehospitalization (P < .001) than the standard dose of 0.9–1.1 DDD/day (ie, 5 mg for risperidone and 30 mg for perphenazine). ConclusionsFor most antipsychotics, the risk of severe relapse was the lowest during use of standard dose. Our results suggest that olanzapine LAI is highly effective in dose ranges >0.9 DDD/day, and especially at 1.4–<1.6 DDDs/day (405 mg/4 weeks) associated with substantially lower risk of rehospitalization than any dose of any other antipsychotic. The current WHO standard dose definitions appear to be clearly too high for perphenazine and somewhat too high for risperidone.     

Ultrasound to stimulate mandibular bone defect healing: a placebo-controlled single-blind study in rats.

PURPOSE: Because of the limitations of the body to heal large maxillofacial bone defects, an attempt was made to stimulate mandibular defect healing with low intensity pulsed ultrasound in rats. This ultrasound consists of a 1.5-MHz pressure wave administered in pulses of 200 microsec, with an average intensity over space and time of 30 mW. cm(-2). MATERIALS AND METHODS: In 72 rats, a 5.0-mm-diameter circular mandibular defect was created. Three groups were studied: an ultrasound treatment group, a placebo treatment group, and a control group. Ultrasound and placebo treatment involved a daily treatment for 20 minutes at the site of the defect under general anesthesia. At 2 and 4 weeks, the region of bone growth within the defect was measured using microradiographs and the amount of defect healing was expressed as the percentage of defect closure. RESULTS: At 2 and 4 weeks, there was no statistical significant difference in the percentage of defect closure between the groups. CONCLUSION: Low-intensity pulsed ultrasound does not stimulate bone defect healing in the case of a large mandibular defect in the rat.