[Developmental neurology - networked medicine and new perspectives]

Developmental neurology is one of the major areas of neuropediatrics and is among other things (legally) responsible for monitoring the motor, cognitive and psychosocial development of all infants using standardized monitoring investigations. The special focus is on infants born at risk and/or due to premature birth before 32 weeks of gestation or a birth weight less than 1500 g. Early diagnosis of deviations from normal, age-related development is a prerequisite for early interventions, which may positively influence development and the long-term biopsychosocial prognosis of the patients. This article illustrates the available methods in developmental neurology with a focus on recent developments. Particular attention is paid to the predictive value of general movements (GM). The current development of markerless automated detection of spontaneous movements using conventional depth imaging cameras is demonstrated. Differences in spontaneous movements in infants at the age of 12 weeks are illustrated and discussed exemplified by three patients (healthy versus genetic syndrome versus cerebral palsy).

Effects of active HCV replication on neurologic status in HIV RNA virally suppressed patients

BACKGROUND

Hepatitis C virus (HCV) is a frequent copathogen with HIV. Both viruses appear to replicate in the brain and both are implicated in neurocognitive and peripheral neuropathy syndromes. Interaction of the viruses is likely to be complicated and better understanding of the contributions of each virus will be necessary to make evidence-based therapeutic decisions.

METHODS

This study was designed to determine if active HCV infection, identified by quantitative HCV RNA determination, is associated with increased neurocognitive deficits or excess development of distal sensory peripheral neuropathy in HIV coinfected patients with stable HIV viral suppression. The AIDS Clinical Trials Group Longitudinal Linked Randomized Trials (ALLRT) study was the source of subjects with known HIV treatment status, neurocognitive and neuropathy evaluations, and HCV status. Subjects were selected based on HCV antibody status (249 positive; 310 negative).

RESULTS

HCV RNA viral loads were detectable in 172 participants with controlled HIV infection and available neurologic evaluations in the ALLRT. These participants were compared with 345 participants with undetectable HCV viral load and the same inclusion criteria from the same cohort. Neurocognitive performance measured by Trail-Making A or B and digit symbol testing was not dissimilar between the 2 groups. In addition, there was no significant association between active HCV replication and distal sensory neuropathy.

CONCLUSION

Clinically significant neurocognitive dysfunction and peripheral neuropathy were not exacerbated by active hepatitis C virus infection in the setting of optimally treated HIV infection.

Diagnosis of dual human immunodeficiency virus types 1 and 2 infections in a resource-limited setting

BACKGROUND

The presence of dual HIV-1/HIV-2 infection in Ghana and the different drug requirements for the treatment of HIV-1 and HIV-2 presents difficulties for the treatment of dual infections with both viruses.

OBJECTIVES

To determine the prevalence of the dual sero-positive profile in treatment naive patients at a principal ART Clinic in Accra, Ghana and to investigate if rapid screening assays could be useful for diagnosis.

DESIGN

A cross-sectional study.

SETTING

A principal antiretroviral treatment centre in Accra, Ghana.

SUBJECTS

Three hundred and twenty eight antiretroviral treatment naive patients.

RESULTS

A total of 12 (3.7%) of patients seen were dual seropositive. There was a slight tendency of dual seropositive females being older than their HIV-1 counterparts (p = 0.088, CI = -10.833 to 0.753). Eight of the 12 of the dual seropositives were reactive for Genie II and were considered as possibly infected with both HIV-I and HIV-2. Seven (87.5%) of Genie II dual seropositives had strong intensities (> 1+) on both HIV-2 specific bands (sgp105 and gp36) on Innolia. CD4 counts were not significantly different in dual seropositives as compared to HIV-1 infected patients.

CONCLUSIONS

Dual HIV-1/HIV-2 seropositives (and possibly infections) maybe common especially in older women. The Genie II will be useful as a supplemental rapid test for rapid and accurate differentiation of HIV-1 and HIV-2 antibodies at treatment centres.

Clinically relevant sequence-based genotyping of HBV, HCV, CMV, and HIV

The term 'genotyping' describes the genetic characterization of a genome. The genotype analysis is performed to identify mutations that differentiate one individual or strain from another. The mutations may confer resistance to specific antiviral drugs or they may simply allow classification of a strain as to 'type' and 'subtype'. There are four human viruses for which genotype information is clinically useful. Hepatitis B virus (HBV) infections are being treated with antiretroviral drugs and resistance after prolonged treatment is common. Since HBV cannot be cultured, the only method of detecting resistance-conferring mutations in the genome is a genotypic analysis. Hepatitis C virus (HCV) infection can be cured by treatment with the combination of interferon and ribavirin but certain strains of virus are more resistant to treatment than others. The current recommendations are that all HCV type 1 infections be treated for 12 months whereas other types may be successfully treated in 6 months. Since interferon treatment may have significant side effects, the determination of HCV genotype is an important aspect of this therapeutic regimen. Treatment of cytomegalovirus (CMV) disease with nucleoside analogues occasionally results in resistant virus with mutations in the phosphotransferase gene (UL97) and/or the DNA polymerase gene (UL54) that can be tested with phenotypic or genotypic assays. Since CMV grows very slowly, it may be more clinically useful to perform a rapid genotypic assay although only the UL97 gene can be efficiently genotyped. Finally, the virus for which genotyping has become the standard of care, human immunodeficiency virus type 1 (HIV-1) can now be genotyped routinely by many clinical virology labs experienced with molecular amplification methods and automated DNA sequencing technology. All currently-available antiretroviral drugs are directed against either the protease or reverse transcriptase genes of HIV-1 and the mutations within these genes that confer resistance have been well described. Sequence-based genotyping methods are not necessarily the best approach for routine genotyping of these four viruses, but sequencing is the gold standard from which other methods are developed and against which they are compared.

Disinfection of Goldmann tonometers after contamination with hepatitis C virus

PURPOSE

To compare methods of disinfecting Goldmann tonometer tips inoculated with hepatitis C virus.

METHODS

Hepatitis C virus was placed on Goldmann tonometer tips, air dried, and then disinfected by dry gauze wipes, isopropyl alcohol wipes, cold water washes, povidone iodine 10% wipes, and hydrogen peroxide or isopropyl alcohol soaks followed by a cold water wash and dry. Hydrogen peroxide and isopropyl alcohol disinfection techniques followed the Centers for Disease Control and Prevention guidelines for prevention of possible transmission of human immunodeficiency virus (HIV). After disinfection, samples from tonometer tips were amplified by polymerase chain reaction to quantitate the amount of hepatitis C virus RNA remaining.

RESULTS

Percentage of hepatitis C virus RNA remaining after disinfection: dry gauze wipes 95.65%, isopropyl alcohol 5-second wipes 88.91%, cold water wash 4.78%, povidone iodine 10% 5-second wipes 0.72%, hydrogen peroxide soak with cold water wash 0.07%, and isopropyl alcohol soak and cold water wash 0.02%.

CONCLUSIONS

After inoculation of Goldmann tonometer tips with hepatitis C virus, a 5-minute soak in 3% hydrogen peroxide or 70% isopropyl alcohol followed by washing in cold water resulted in the greatest reduction in hepatitis C virus RNA.

Long-term persistence of Coxiella burnetii in the host after primary Q fever

After a primary infection Coxiella burnetii may persist covertly in animals and recrudesce at parturition to be shed in the products of conception and the milk. Similar latent persistence and recrudescence occurs in man: namely, infection of placenta, heart valve or mural endocardium, bone or liver. The numbers of organisms, their viability and cellular form, and the underlying organ sites of latent infection for the coxiella are obscure. During investigations of 29 patients with a chronic sequel to acute Q fever, the post-Q fever fatigue syndrome (QFS) [1-3], sensitive conventional and TaqMan-based PCR revealed low levels of C. burnetii DNA in blood mononuclear cells (5/29; 17%), thin needle liver biopsies (2/14; 14%) and, notably, in bone marrow aspirates (13/20; 65%). Irrespective of the ultimate significance of coxiella persistence for QFS, the detection of C. burnetii genomic DNA in bone marrow several years after a primary infection unveils a new pathological dimension for Q fever.

Zinc salts inactivate clinical isolates of herpes simplex virus in vitro

Using a standard plaque assay and clinical isolates of herpes simplex virus (HSV), we have tested the ability of zinc salts to inactivate HSV. Virus was treated by incubation at 37 degrees C with zinc salts in morpholinepropanesulfonic acid-buffered culture medium and was then diluted and plated onto CV-1 cells for detection and quantitation of remaining infectious virus. Of 10 randomly chosen clinical isolates (five HSV type 1 [HSV-1] isolates and five HSV-2 isolates), seven were inactivated >98% by treatment in vitro with 50 mM zinc gluconate for 2 h and nine were inactivated >97% by treatment with zinc lactate. The effect was concentration dependent. With an HSV-1 isolate, 50 mM zinc gluconate or zinc lactate caused 100% inactivation, 15 mM caused 98 to 99% inactivation, and 5 mM caused 63 to 86% inactivation. With an HSV-2 isolate, 50 and 15 mM zinc gluconate caused 30% inactivation and 5 and 1 mM caused less than 9% inactivation, whereas 50 and 15 mM zinc lactate caused greater than 92% inactivation and 5 and 1 mM caused 37 and 26% inactivation, respectively. The ability of the zinc salts to inactivate HSV was not related to pH in the pH range of 6.1 to 7.6 since inactivation by zinc gluconate or zinc lactate in that pH range was 99.7 to 100% with a 2-h treatment with 50 mM zinc salt. Short (5-min) treatments of selected isolates with zinc gluconate, zinc lactate, zinc acetate, or zinc sulfate yielded inactivation rates of 0 to 55%.

Rapid phenotypic drug susceptibility assay for HIV-1 with a CCR5 expressing indicator cell line

Phenotypic drug susceptibility assays of human immunodeficiency virus type 1 (HIV-1) isolates generally use time-consuming, expensive assays with peripheral blood mononuclear cells. A new HIV-1 indicator cell line, MAGI-CCR5, has been developed and applied for this purpose. This cell line expresses human CD4, the two major HIV-1 coreceptors, CCR5 and CXCR4, the reporter gene beta-galactosidase driven by the HIV-1 LTR, and quantitates infection within 48 h. A panel of reference strains and primary HIV-1 isolates were all found to infect this cell line. Susceptibility assays with a nucleoside (zidovudine, ZDV) and a non-nucleoside reverse transcriptase inhibitor (nevirapine, NVP) were performed with reference and primary isolates. The assay was modified into two steps for protease inhibitor (indivinavir, IDV and ritonavir, RTV) susceptibility assays. Primary isolates derived from drug naive patients displayed mean baseline 50% effective concentrations (EC50) of 0.14 microM for ZDV, 0.33 microM for NVP, and 0.02 microM for IDV. Isolates derived from patients under treatment displayed increased EC50 concentrations. The MAGI-CCR5 cell line offers a rapid, efficient, and reproducible method of testing a wide range of HIV-1 isolates for drug susceptibility.

Methods for subtyping and molecular comparison of human viral genomes

The development over the past two decades of molecular methods for manipulation of RNA and DNA has afforded molecular virologists the ability to study viral genomes in detail that has heretofore not been possible. There are many molecular techniques now available for typing and subtyping of viruses. The available methods include restriction fragment length polymorphism analysis, Southern blot analysis, oligonucleotide fingerprint analysis, reverse hybridization, DNA enzyme immunoassay, RNase protection analysis, single-strand conformation polymorphism analysis, heteroduplex mobility assay, nucleotide sequencing, and genome segment length polymorphism analysis. The methods have certain advantages and disadvantages which should be considered in their application to specific viruses or for specific purposes. These techniques are likely to become more widely used in the future for epidemiologic studies and for investigations into the pathophysiology of virus infections.

Ehrlichia ewingii, a newly recognized agent of human ehrlichiosis

BACKGROUND

Human ehrlichiosis is a recently recognized tick-borne infection. Four species infect humans: Ehrlichia chaffeensis, E. sennetsu, E. canis, and the agent of human granulocytic ehrlichiosis.

METHODS

We tested peripheral-blood leukocytes from 413 patients with possible ehrlichiosis by broad-range and species-specific polymerase-chain-reaction (PCR) assays for ehrlichia. The species present were identified by species-specific PCR assays and nucleotide sequencing of the gene encoding ehrlichia 16S ribosomal RNA. Western blot analysis was used to study serologic responses.

RESULTS

In four patients, ehrlichia DNA was detected in leukocytes by a broad-range PCR assay, but not by assays specific for E. chaffeensis or the agent of human granulocytic ehrlichiosis. The nucleotide sequences of these PCR products matched that of E. ewingii, an agent previously reported as a cause of granulocytic ehrlichiosis in dogs. These four patients, all from Missouri, presented between May and August 1996, 1997, or 1998 with fever, headache, and thrombocytopenia, with or without leukopenia. All had been exposed to ticks, and three were receiving immunosuppressive therapy. Serum samples obtained from three of these patients during convalescence contained antibodies that reacted with E. chaffeensis and E. canis antigens in a pattern different from that of humans with E. chaffeensis infection but similar to that of a dog experimentally infected with E. ewingii. Morulae were identified in neutrophils from two patients. All four patients were successfully treated with doxycycline.

CONCLUSIONS

These findings provide evidence of E. ewingii infection in humans. The associated disease may be clinically indistinguishable from infection caused by E. chaffeensis or the agent of human granulocytic ehrlichiosis.

Interlaboratory concordance of DNA sequence analysis to detect reverse transcriptase mutations in HIV-1 proviral DNA. ACTG Sequencing Working Group. AIDS Clinical Trials Group

Thirteen laboratories evaluated the reproducibility of sequencing methods to detect drug resistance mutations in HIV-1 reverse transcriptase (RT). Blinded, cultured peripheral blood mononuclear cell pellets were distributed to each laboratory. Each laboratory used its preferred method for sequencing proviral DNA. Differences in protocols included: DNA purification; number of PCR amplifications; PCR product purification; sequence/location of PCR/sequencing primers; sequencing template; sequencing reaction label; sequencing polymerase; and use of manual versus automated methods to resolve sequencing reaction products. Five unknowns were evaluated. Thirteen laboratories submitted 39043 nucleotide assignments spanning codons 10-256 of HIV-1 RT. A consensus nucleotide assignment (defined as agreement among > or = 75% of laboratories) could be made in over 99% of nucleotide positions, and was more frequent in the three laboratory isolates. The overall rate of discrepant nucleotide assignments was 0.29%. A consensus nucleotide assignment could not be made at RT codon 41 in the clinical isolate tested. Clonal analysis revealed that this was due to the presence of a mixture of wild-type and mutant genotypes. These observations suggest that sequencing methodologies currently in use in ACTG laboratories to sequence HIV-1 RT yield highly concordant results for laboratory strains; however, more discrepancies among laboratories may occur when clinical isolates are tested.

A rapid assay to screen for drug-resistant herpes simplex virus

A rapid assay was developed to screen for herpes simplex virus (HSV) isolates that are resistant to acyclovir and other antiviral agents. The assay is a modified plaque reduction assay (PRA) in which the number of plaques seen in the absence of acyclovir was compared with that seen in the presence of a single cutoff concentration of acyclovir (2 microg/mL). This assay utilizes a cell line that expresses beta-galactosidase only after infection with HSV. Since histochemically stained plaques are easily visualized, small plaques can be easily enumerated. This allows the assay to be performed on dilutions of untitered specimens in the small wells of a 24-well plate and allows the results to be read only 2 days after inoculation of the virus. The assay performed well compared with a standard PRA and should be a valuable tool in identifying drug-resistant HSV in a timely manner.

Stabilities of free and complexed human immunodeficiency virus p24 antigens during short- and long-term storage

By the standard p24 assay there was a 25 to 27% decrease in free p24 antigen in serum after storage at 4 degrees C over 14 days but no loss at -70 degrees C. There was no loss at either temperature by the immune complex dissociation (ICD) procedure. Furthermore, there was no significant loss of detectable p24 in serum by either the ICD or the standard p24 assay after 700 days of storage at -70 degrees C.

Sequence heterogeneity of Nef transcripts in HIV-1-infected subjects at different stages of disease

Nef transcripts were analyzed from peripheral blood mononuclear cells of 10 HIV-1-infected subjects with 9-822 CD4+ lymphocytes/cu mm, including 4 individuals with a probable common source infection. There was no relationship between the phylogenetic position of the various nef sequences and the disease state of the person from whom they were derived. The nef open reading frame was disrupted in all three clones from only 1 subject. Functional analyses of a representative clone from each of the remaining 9 subjects showed that all nef alleles were capable of CD4 cell surface down-regulation, but only three nef alleles suppressed the induction of IL-2 transcription.

Resistance of microorganisms to disinfection in dental and medical devices

The U.S. Centers for Disease Control and Prevention (CDC) recommends that only heat sterilization be used for all reusable devices entering the oral cavity. However, chemical disinfection is still employed for reprocessing dental devices in many areas of the world. In an analysis of a Florida dental practice responsible for nosocomial human immunodeficiency virus (HIV) transmissions, the possible role of contaminated devices was deemed unlikely in part because they were subjected to high-level disinfection with 2% glutaraldehyde. Disease transmissions have, however, been documented for endoscopes used in diagnostic and surgical procedures even after this treatment. In some dental devices, lubricants mix with potentially infectious patient materials, and organic debris has been observed in endoscopes after cleaning. We have investigated whether lubricants can render high-level chemical disinfection procedures ineffective and have addressed the role that some common devices may play in disease transmission. We report here that HIV in whole-blood samples and Pseudomonas aeruginosa in blood and plasma survived high-level disinfection when entrapped in lubricants used in dental handpieces and endoscopes. We also found that lubricated dental devices used to clean and polish teeth (prophylaxis angles) have the potential to transfer sufficient amounts of blood to infect human lymphocyte cultures with HIV. These results emphasize the need to subject reusable dental devices to a heat-sterilization protocol that penetrates the lubricant.

Nef and LTR sequence variation from sequentially derived human immunodeficiency virus type 1 isolates

Variation in HIV-1 nef and LTR DNA sequences was assessed longitudinally during disease progression in four HIV-1-infected subjects. Point mutations were found among quasispecies obtained at a single time point in each individual, with increasing diversity with disease progression in two of three patients for whom sufficient data were available for analysis. Deletions and rearrangements were more common in late than early stages of disease. Continued sequence evolution in HIV-1 quasispecies with nef deletions along with coexistence of nef-bearing quasispecies suggest that nef-deleted quasispecies are capable of replication in vivo, possibly complemented by quasispecies lacking such deletions and/or by adaptation to a specialized niche within the patients.

Alterations in spliced and unspliced HIV-1-specific RNA detection in peripheral blood mononuclear cells of individuals with varying CD4-positive lymphocyte counts

Reverse transcriptase-polymerase chain amplification reactions (RT-PCR) were used to identify transcripts for HIV-1 structural and regulatory proteins in peripheral blood mononuclear cells of a cohort of 48 patients. At least one set of PCR primers was capable of detecting HIV-1 transcripts in 94% of patients. Unspliced gag-pol transcripts were detected with gag or pol primer sets in 60 and 63% of samples, respectively. A significant inverse correlation was noted between transcript identification with the gag primer set and the number of CD4-positive lymphocytes in the blood sample and the clinical stage of infection. Single-spliced env transcripts were identified in 44% of individuals. Multiple-spliced tat or nef transcripts were detected in 6.2 and 53% of individuals, respectively. These findings indicate that viral transcripts are expressed throughout the course of HIV-1 infection.

Use of probes and amplification techniques for the diagnosis and prognosis of human immunodeficiency virus (HIV-1) infections

The recent development of nucleic acid amplification methodologies has markedly improved our ability to detect very low levels of specific nucleic acids. Amplification techniques have been combined with product detection systems that are designed for high throughput and are automatable. These developments are drastically changing the face of infectious disease diagnostics and changing the character of prognostic indicators in certain diseases. The polymerase chain reaction (PCR) has been used extensively for diagnosis of human immunodeficiency virus (HIV-1) infections, and recent developments have indicated that quantitative reverse-transcriptase PCR for viral RNA has prognostic value. Self-sustained sequence replication amplification for detection of viral RNA appears comparable to plasma culture for diagnosis of pediatric infections. The ligase chain reaction is still in developmental stages, but holds promise for specific purposes.

Evolution of sequence divergence among human immunodeficiency virus type 1 isolates derived from a blood donor and a recipient

Four neonates who were infected with a single unit of blood from a human immunodeficiency virus-1 (HIV-1)-infected adult (patient 1) were studied. Two of the infected children (patients II and III) developed symptomatic HIV-1 disease and died within the first 3 y of life. One child (patient IV) died at 8 mo of age of clinical problems that may have been HIV-related. In contrast, one child (patient V) has remained asymptomatic for 7.5 y and has exhibited a very gradual decline in CD4+ cell number. A previous study had shown very limited sequence diversity of isolates from patients I, II, and III (McNearney T et al.: Proc Natl Acad Sci USA 87:1917-1921, 1990). The current study examined additional HIV-1 sequences encoding the principal neutralizing V3 loop of the surface envelope protein of isolates from patients I and V. Amplified sequences were obtained using the polymerase chain reaction from a cultured isolate and uncultured peripheral blood leukocytes, and nucleotide sequences were determined for 13 clones from patient I and 19 clones from patient V. Clones derived from the cultured isolate exhibited less predicted amino acid sequence diversity on average (0-5.2%) than did sequences from uncultured leukocytes (0-19.8% differences). All clones were more closely related to those from patients II and III (0-19.8% amino acid differences) than to other North American or European isolates (18.8-27.0% amino acid differences) or African isolates (41.0-48.0% amino acid differences). Substitutions occurred at sites predicted to modulate host cell tropism and proteolytic cleavage of the V3 loop.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-contamination potential with dental equipment

Some types of reused dental equipment, especially handpieces and their attachments for drilling and cleaning teeth, might be responsible for cross-contamination if patient material were to lodge temporarily in difficult-to-disinfect internal mechanisms. This possibility is worrisome with respect to transmission of hepatitis B and human immunodeficiency viruses (HBV, HIV). Previous cross-contamination studies have relied on laboratory experiments with bacteria or dye tracers. To assess possible risk more thoroughly, we tested 30 new prophylaxis angles and 12 new high-speed handpieces to see whether they would take up and expel contaminants in laboratory and clinical trials. In treatments of three patients, including two infected with HIV, human-specific DNA (beta-globin, HLA DQ alpha) and HIV proviral DNA were detected inside or coming back from the devices. Similarly, when handpieces were operated in contact with blood pooled from HBV-infected patients, HBV DNA was detected in samples taken from inside the equipment and from their attached air/water hoses. When we used bacteriophage phi X174 as a model virus in laboratory tests, many infective viral particles were recovered from internal mechanisms of handpieces, their connecting air/water hoses, and from water spray expelled when the equipment was reused. We recommend that reused high-speed, air-driven handpieces and prophylaxis angles should be cleaned and heat-treated between patients. Further studies are needed to determine ways of eliminating the risks associated with exhaust hoses and air/water input lines.

Relationship of human immunodeficiency virus type 1 sequence heterogeneity to stage of disease

V3 envelope sequences were determined from amplified human immunodeficiency virus type 1 (HIV-1) sequences of uncultivated leukocytes obtained sequentially from four infected adults over the course of infection. Lower levels of sequence heterogeneity were noted in samples obtained early in HIV-1 infection, prior to CD4 depletion, than in samples obtained at later times during disease. The pattern of amino acid sequence divergence included nonrandom changes, with evidence of sequence variants arising from HIV-1 quasi-species present earlier in infection. Consensus sequences for isolates obtained early after infection from different patients demonstrated a high level of conservation with one another and a consensus sequence for macrophage-tropic HIV-1 isolates. These findings suggest that a highly restricted subset of HIV-1 quasi-species can be transmitted and can establish infection.

Platelet-targeted fibrinolysis enhances clot lysis and inhibits platelet aggregation

BACKGROUND

Although plasminogen activator therapy has been shown to reduce mortality in patients with severe myocardial infarction, several problems fuel the search for more potent and specific thrombolytic agents.

METHODS AND RESULTS

To explore the effect of plasminogen activator targeting to platelets, we covalently linked urokinase that had been modified with N-succinimidyl-3-(2-pyridyldithio)propionate to the Fab' of a monoclonal antibody (7E3) that selectively binds to platelet membrane glycoprotein (GP) IIb/IIIa. In an assay measuring (as reflected by plasmin generation) a plasminogen activator's ability to bind GP IIb/IIIa immobilized on plastic, urokinase-7E3 Fab' produced 31-fold more plasmin than did urokinase (p = 0.0001). The addition of solubilized GP IIb/IIIa blocked this enhancement of plasmin generation, indicating that binding was impaired. Plasmin generation reflecting binding to immobilized intact platelets was 2.4-fold greater for urokinase-7E3 Fab' than for unconjugated urokinase (p = 0.002). In a plasma clot lysis assay, urokinase-7E3 Fab' was at least 25-fold more potent than either urokinase alone or a mixture of urokinase and 7E3 (Fab')2 (p less than 0.009), and potency could be related to platelet concentration in the clot. Ex vivo, ADP-induced platelet aggregation was inhibited by a urokinase-7E3 IgG conjugate at a concentration of 8 nM, whereas a mixture of urokinase and 7E3 (Fab')2 in equimolar amounts required 60 nM and urokinase alone required 1 microM to achieve the same effect.

CONCLUSIONS

Therefore, the targeting of urokinase to the GP IIb/IIIa platelet receptor both accelerates clot lysis (when platelets are associated with a fibrin clot) and inhibits platelet aggregation.

Optimizing recovery of cytomegalovirus in the shell vial culture procedure

We have investigated three factors that may be related to the recovery of cytomegalovirus (CMV) using the shell vial culture procedure. First, we compared fluorescent-antibody staining of shell vial cultures using a monoclonal antibody to a CMV immediate early antigen at 16 vs 40 hr after inoculation. Of 332 routinely submitted specimens cultured in duplicate and stained at the different times, 25 (7.5%) were positive at 16 hr and 32 (9.6%) were positive at 40 hr. The increased yield was 28%. Second, we analyzed the effect of using duplicate shell vials (both stained at 40 hr) for all routinely submitted CMV cultures. During a 6-month period, 272 (12.5%) of the 2157 cultures processed with duplicate shell vials were positive, including 222 positive in both vials and 50 positive in only one. Assuming that a single-vial setup would have detected 50% of those positive in only one of the two vials, the increased yield attributable to the duplicate vial was estimated at 10% (25/(222 + 25)). Third, we investigated the effects of seeding density and culture age on the shell vial assay. Cell age of greater than 1 day was associated with a decrease in sensitivity both in cultures that were confluent and in those that were subconfluent at the time of inoculation. Incorporating these findings in the routine shell vial culture procedure used in our Clinical Virology Laboratory has resulted in a greater overall detection of CMV in shell vial cultures than in conventional 6-week tube cultures.

Detection of rotavirus by hybridization with a nonradioactive synthetic DNA probe and comparison with commercial enzyme immunoassays and silver-stained polyacrylamide gels

Three enzyme-linked immunosorbent assays (ELISAs) (rotavirus enzyme immunoassay [EIA; International Diagnostic Laboratories], Pathfinder [Kallestad Laboratories], and Rotaclone [Cambridge Bioscience, Inc.]) and hybridization of viral RNA with a nonradioactive, synthetic oligonucleotide DNA probe (SNAP; Molecular Biosystems, Inc.) were compared with silver-stained polyacrylamide gel electrophoresis (PAGE) of viral RNA for the detection of rotavirus in fecal specimens. Hybridization was performed following column purification of the viral RNA. Of 286 specimens analyzed by PAGE, SNAP, rotavirus EIA, Pathfinder, and Rotaclone, 88 were positive by PAGE. All 88 specimens were also positive by the other four assays. Nine specimens that were positive by one or more of the assays were positive by blocking ELISAs but were negative by PAGE. If these nine specimens were considered to be true positives, the final sensitivities and specificities were as follows: PAGE, 91 and 100%; SNAP, 94 and 97%; rotavirus EIA, 96 and 97%; Pathfinder, 100 and 94%; and Rotaclone, 96 and 97%, respectively.

Effects of sonication and centrifugation of clinical specimens on the recovery of herpes simplex virus

We have analyzed frozen and fresh specimens for herpes simplex virus (HSV) to determine the effect of sonication and centrifugation on virus recovery. After sonication, titers of 24/27 specimens increased from 1.3-30.8-fold with a mean increase of 6.8-fold. One hundred seventy-four fresh specimens were inoculated before and after sonication into CV-1 tube cultures. There was not a statistically significant difference in time to positivity between the sonicated and unsonicated portions. Thus, although sonication of specimens can sharply increase the viral titer of positive specimens, sonication of fresh specimens does not significantly enhance the isolation of HSV. To determine the effect of centrifugation of clinical specimens on recovery of HSV, thirty-one culture positive frozen specimens were centrifuged, and the supernatants and resuspended sonicated pellets were titered. Twenty-five specimens had sufficient recoverable virus to titer; in 21/25 (87.5%) specimens the titers were reduced in the supernatants after centrifugation (mean reduction 38%; range of 4-92%). Two of 31 (7%) supernatants were negative in culture while the sonicated pellets were positive. Thus, centrifugation of specimens prior to cell inoculation may compromise recovery of HSV.

Remarkably homogeneous population of adenovirus type 3 and 7 genome types

A total of 270 frozen adenovirus isolates, obtained from January 1981 to December 1986, were grown in KB cells. DNA was successfully prepared from 248 of these isolates, and the prepared DNA was digested initially with SmaI restriction endonuclease and then analyzed by agarose gel electrophoresis. Restriction fragment patterns showed that 68 of these DNAs were either adenovirus type 3 (Ad3) or Ad7. Further analysis by digestion with BamHI showed that 24 isolates were Ad3a and 44 isolates were Ad7b. When Ad3 isolates were digested with SmaI or PstI, the restriction fragment patterns of the 24 isolates were identical. Of these 24 isolates, 20 (83%) also gave identical patterns when digested with HindIII, and the patterns of the remaining 4 isolates were different from that of the 20 but identical to each other. All Ad3 isolates were obtained in 1982, 1983, and 1986. All the 44 Ad7b isolates gave identical fragment patterns when digested with BglI or PvuII, and 43 of 44 (98%) isolates gave identical patterns when digested with SstII. We obtained at least two Ad7 isolates during each of the 6 years studied. Although considerable genome heterogeneity within adenovirus serotypes and subtypes has been reported, our population of isolates is remarkably homogeneous. This homogeneous set of genome types was obtained from diverse anatomical sites and was associated with a broad spectrum of clinical syndromes.

The development of the trigeminal (V) motor nucleus in normal and tubocurare treated chick embryos

The generation of cells and the naturally occurring neuronal death was studied in the trigeminal motor neuron pool in normal and tubocurare treated chick embryos between the 5th and 18th days of incubation. 3H-thymidine autoradiography revealed that the generation time extends from the 2nd to the 5th day of incubation, wherein about 50% of trigeminal motoneurons are born on the 3rd day. Maximum neuron number was found on the 7th day of incubation which steadily decreased to about 50% of the originally generated neurons by the 13th day. Nuclear pyknosis occurred from the 6th to the 13th day of incubation with a peak of neuron loss on the 7th day. Tubocurare, administered daily from the 5th day of incubation rescued most of the generated motoneurons which would otherwise have died. Cell nuclear area measurements in the motoneuron pool of the tubocurare treated animals showed a marked hypertrophy accompanying the increased neuronal survival. These observations indicate that tubocurare treatment prevents naturally occurring neuron death and causes significant nuclear hypertrophy within the trigeminal motoneuron pool innervating special, branchial arch derived muscles. Thus these neurons respond to tubocurare treatment in a manner similar to motoneurons of the spinal cord.

An outbreak of herpes simplex virus type I gingivostomatitis in a dental hygiene practice

An outbreak of herpes simplex virus (HSV) type I gingivostomatitis occurred in a dental hygiene practice in November 1981. An epidemiologic investigation disclosed that 20 of 46 patients seen by the dental hygienist during a four-day period had this illness, whereas none of 26 patients seen by the dentist alone became ill. One day after the outbreak, the hygienist was found to have a herpetic whitlow. Identical endonuclease restriction enzyme type I HSV was isolated from the left index finger of the hygienist and from nine of 16 patients. The nine patients with positive cultures all had at least a fourfold increase in complement fixing antibody titer. A similar significant increase in titer indicated another seven cases.

Characterization of hepatitis B virus DNA polymerase

Hepatitis B virus (HBV) particles were separated from the blood-plasma containing HBe and HBs antigens (subtype adr) and the nature of the endogenous DNA polymerase in the HBV core particles was studied. The HBV endogenous DNA polymerase activity was examined under the conditions used for preparation of HBV vaccine. The endogenous DNA polymerase activity was reduced slowly upon the heat treatment or the formalin treatment. The reductions of the activity were 65% and 70% upon the heat treatment at 60 C for 10 hr and the formalin treatment at 37 C for 90 hr, respectively. Properties of the HBV endogenous DNA polymerase were studied by utilizing specific inhibitors against the eukaryotic DNA polymerases. Our results showed that the HBV endogenous DNA polymerase is resistant to aphidicolin and N-ethylmaleimide, and sensitive to 2',3'-dideoxythymidine 5'-triphosphate, phosphonoformic acid and 9-beta-D-arabinofuranosyladenosine 5'-triphosphate.

[Enzyme-linked immunosorbent assay (ELISA) for IgG- and IgM antibodies in chlamydial infections of humans]

The development and evaluation of an indirect ELISA for IgG and IgM antibodies in human sera against the genus-specific chlamydial antigen is described. Application of commercial anti-immunoglobulins for production of conjugates usually resulted in direct conjugate/antigen reactions. Therefore, all immunoreagents had to be prepared by the authors. Using anti-immunoglobulins purified by affinity chromatography for the production of anti-human IgG(H + L)-peroxidase conjugates, these conjugates showed high specific activity and could be diluted 1/10,000 for the test, whereby direct reactions with antigens were negligible (12 +/- 12 ELISA units). Results with the mu-chain-specific IgM ELISA could be verified additionally by rheumatoid factor analysis and gel-chromatographic investigations. Reactions with sodium deoxycholate extracted antigen from cells not infected with chlamydiae ("negative antigen") were observed with sera from persons working with cell cultures. In comparison with microimmunofluorescence (MIF) test and radioimmunoassay (RIA), the ELISA was the most sensitive method. However, for differentiation of urogenital infections associated with chlamydiae, the type-specific MIF test was superior to the genus-specific ELISA. In comparison to persons with chlamydia-associated prostatitis, the high percentage of IgM-positive reactions in patients with nongonococcal urethritis (10% and 56%, respectively) pointed to a predominant participation of genus-specific IgM antibodies in recent infections. As compared to ELISA values of patients with infections of the urogenital tract (up to 875 ELISA units), in some apparently healthy blood donors significantly higher ELISA values (up to 1400 ELISA units) were recorded. Such reactions may be attributed to systemic infections, e.g. chlamydial pneumonias. The importance to differentiate between IgG and IgM antibodies in such infections is discussed.

Significance of Chlamydia trachomatis in "abacterial" prostatitis

Chlamydia (C.) trachomatis was isolated in McCoy cell cultures from urethral swabs after prostatic massage, of 43 out of 233 patients (18.5%) with symptoms of "abacterial" prostatitis, but also from 5 out of 65 control persons (7.7%). Numbers of granulocytes in sediments of cytocentrifuged urine voided after prostatic massage were normal (less than or equal to 2, magn. 400 X) in all 65 control persons, but were increased in 26 out of 43 patients with symptoms of "abacterial" prostatitis (greater than or equal to 4, magn. 400 X). Using an (H + L) chain specific anti-IgG FITC conjugate, microimmunofluorescence tests for detection of antibodies against C. trachomatis could be performed with the sera of all 65 control persons and with those of 37 out of the 43 patients. All control persons, even those five with positive C. trachomatis culture, were serologically negative (titer less than 1:8), while in 13 out of 15 C. trachomatis positive patients with a definitive diagnosis of "abacterial" prostatitis, humoral antibodies with titers of greater than or equal to 1:8, predominantly against serotypes I, J, E, and G, were detected. Serological results correlated well with granulocyte counts in urines after prostatic massage. Patients with symptoms of "abacterial" prostatitis with normal granulocyte counts (less than or equal to 2) and negative serology (titer less than 1:8) were considered suffering from "prostatodynia".