RAB32 Ser71Arg in autosomal dominant Parkinson's disease: linkage, association, and functional analyses

BACKGROUND

Parkinson's disease is a progressive neurodegenerative disorder with multifactorial causes, among which genetic risk factors play a part. The RAB GTPases are regulators and substrates of LRRK2, and variants in the LRRK2 gene are important risk factors for Parkinson's disease. We aimed to explore genetic variability in RAB GTPases within cases of familial Parkinson's disease.

METHODS

We did whole-exome sequencing in probands from families in Canada and Tunisia with Parkinson's disease without a genetic cause, who were recruited from the Centre for Applied Neurogenetics (Vancouver, BC, Canada), an international consortium that includes people with Parkinson's disease from 36 sites in 24 countries. 61 RAB GTPases were genetically screened, and candidate variants were genotyped in relatives of the probands to assess disease segregation by linkage analysis. Genotyping was also done to assess variant frequencies in individuals with idiopathic Parkinson's disease and controls, matched for age and sex, who were also from the Centre for Applied Neurogenetics but unrelated to the probands or each other. All participants were aged 18 years or older. The sequencing and genotyping findings were validated by case-control association analyses using bioinformatic data obtained from publicly available clinicogenomic databases (AMP-PD, GP2, and 100 000 Genomes Project) and a private German clinical diagnostic database (University of Tübingen). Clinical and pathological findings were summarised and haplotypes were determined. In-vitro studies were done to investigate protein interactions and enzyme activities.

FINDINGS

Between June 1, 2010, and May 31, 2017, 130 probands from Canada and Tunisia (47 [36%] female and 83 [64%] male; mean age 72·7 years [SD 11·7; range 38-96]; 109 White European ancestry, 18 north African, two east Asian, and one Hispanic] underwent whole-exome sequencing. 15 variants in RAB GTPase genes were identified, of which the RAB32 variant c.213C>G (Ser71Arg) cosegregated with autosomal dominant Parkinson's disease in three families (nine affected individuals; non-parametric linkage Z score=1·95; p=0·03). 2604 unrelated individuals with Parkinson's disease and 344 matched controls were additionally genotyped, and five more people originating from five countries (Canada, Italy, Poland, Turkey, and Tunisia) were identified with the RAB32 variant. From the database searches, in which 6043 individuals with Parkinson's disease and 62 549 controls were included, another eight individuals were identified with the RAB32 variant from four countries (Canada, Germany, UK, and USA). Overall, the association of RAB32 c.213C>G (Ser71Arg) with Parkinson's disease was significant (odds ratio [OR] 13·17, 95% CI 2·15-87·23; p=0·0055; I2=99·96%). In the people who had the variant, Parkinson's disease presented at age 54·6 years (SD 12·75, range 31-81, n=16), and two-thirds had a family history of parkinsonism. RAB32 Ser71Arg heterozygotes shared a common haplotype, although penetrance was incomplete. Findings in one individual at autopsy showed sparse neurofibrillary tangle pathology in the midbrain and thalamus, without Lewy body pathology. In functional studies, RAB32 Arg71 activated LRRK2 kinase to a level greater than RAB32 Ser71.

INTERPRETATION

RAB32 Ser71Arg is a novel genetic risk factor for Parkinson's disease, with reduced penetrance. The variant was found in individuals with Parkinson's disease from multiple ethnic groups, with the same haplotype. In-vitro assays show that RAB32 Arg71 activates LRRK2 kinase, which indicates that genetically distinct causes of familial parkinsonism share the same mechanism. The discovery of RAB32 Ser71Arg also suggests several genetically inherited causes of Parkinson's disease originated to control intracellular immunity. This shared aetiology should be considered in future translational research, while the global epidemiology of RAB32 Ser71Arg needs to be assessed to inform genetic counselling.

FUNDING

National Institutes of Health, the Canada Excellence Research Chairs program, Aligning Science Across Parkinson's, the Michael J Fox Foundation for Parkinson's Research, and the UK Medical Research Council.

A pathogenic variant in RAB32 causes autosomal dominant Parkinson's disease and activates LRRK2 kinase

Background

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Mendelian forms have revealed multiple genes, with a notable emphasis on membrane trafficking; RAB GTPases play an important role in PD as a subset are both regulators and substrates of LRRK2 protein kinase. To explore the role of RAB GTPases in PD, we undertook a comprehensive examination of their genetic variability in familial PD.

Methods

Affected probands from 130 multi-incident PD families underwent whole-exome sequencing and genotyping, Potential pathogenic variants in 61 RAB GTPases were genotyped in relatives to assess disease segregation. These variants were also genotyped in a larger case-control series, totaling 3,078 individuals (2,734 with PD). The single most significant finding was subsequently validated within genetic data (6,043 with PD). Clinical and pathologic findings were summarized for gene-identified patients, and haplotypes were constructed. In parallel, wild-type and mutant RAB GTPase structural variation, protein interactions, and resultant enzyme activities were assessed.

Findings

We found RAB32 c.213C>G (Ser71Arg) to co-segregate with autosomal dominant parkinsonism in three multi-incident families. RAB32 Ser71Arg was also significantly associated with PD in case-control samples: genotyping and database searches identified thirteen more patients with the same variant that was absent in unaffected controls. Notably, RAB32 Ser71Arg heterozygotes share a common haplotype. At autopsy, one patient had sparse neurofibrillary tangle pathology in the midbrain and thalamus, without Lewy body pathology. In transfected cells the RAB32 Arg71 was twice as potent as Ser71 wild type to activate LRRK2 kinase.

Interpretation

Our study provides unequivocal evidence to implicate RAB32 Ser71Arg in PD. Functional analysis demonstrates LRRK2 kinase activation. We provide a mechanistic explanation to expand and unify the etiopathogenesis of monogenic PD.

Funding

National Institutes of Health, the Canada Excellence Research Chairs program, Aligning Science Across Parkinson's, the Michael J. Fox Foundation for Parkinson's Research, and the UK Medical Research Council.

Crucial neuroprotective roles of the metabolite BH4 in dopaminergic neurons

Dopa-responsive dystonia (DRD) and Parkinson's disease (PD) are movement disorders caused by the dysfunction of nigrostriatal dopaminergic neurons. Identifying druggable pathways and biomarkers for guiding therapies is crucial due to the debilitating nature of these disorders. Recent genetic studies have identified variants of GTP cyclohydrolase-1 (GCH1), the rate-limiting enzyme in tetrahydrobiopterin (BH4) synthesis, as causative for these movement disorders. Here, we show that genetic and pharmacological inhibition of BH4 synthesis in mice and human midbrain-like organoids accurately recapitulates motor, behavioral and biochemical characteristics of these human diseases, with severity of the phenotype correlating with extent of BH4 deficiency. We also show that BH4 deficiency increases sensitivities to several PD-related stressors in mice and PD human cells, resulting in worse behavioral and physiological outcomes. Conversely, genetic and pharmacological augmentation of BH4 protects mice from genetically- and chemically induced PD-related stressors. Importantly, increasing BH4 levels also protects primary cells from PD-affected individuals and human midbrain-like organoids (hMLOs) from these stressors. Mechanistically, BH4 not only serves as an essential cofactor for dopamine synthesis, but also independently regulates tyrosine hydroxylase levels, protects against ferroptosis, scavenges mitochondrial ROS, maintains neuronal excitability and promotes mitochondrial ATP production, thereby enhancing mitochondrial fitness and cellular respiration in multiple preclinical PD animal models, human dopaminergic midbrain-like organoids and primary cells from PD-affected individuals. Our findings pinpoint the BH4 pathway as a key metabolic program at the intersection of multiple protective mechanisms for the health and function of midbrain dopaminergic neurons, identifying it as a potential therapeutic target for PD.

Secukinumab-associated localized granuloma annulare (SAGA): a case report and review of the literature

Granuloma annulare (GA) is a benign, usually self-limited inflammatory skin dermatosis characterized clinically by pink-red to brown dermal papules or annular plaques. The main histologic feature is the presence of palisading or interstitial granulomas composed of necrobiotic collagen, elastic fibers, and mucin surrounded by a lymphohistiocytic infiltrate. Granuloma annulare is commonly associated with trauma, infections, diabetes mellitus, dyslipidemia, malignancy, thyroid disease, and a variety of medications. Two cases of GA have been reported in association with the use of secukinumab, a monoclonal antibody directed against interleukin 17A (IL17A), for the treatment of moderate-to-severe plaque psoriasis. We report the third case of secukinumab-associated GA in a 52-year-old woman with a history of diabetes mellitus type II, dyslipidemia, and non-alcoholic steatohepatitis. After four months of therapy with secukinumab, she presented with pink papules coalescing to plaques involving the antecubital fossae. Histology demonstrated a lymphohistiocytic palisading granuloma with central necrobiotic collagen and mucin, consistent with GA. Physicians should be aware of the possibility of GA developing in patients receiving secukinumab, especially in those with predisposing factors for GA. A better understanding of secukinumab-associated GA may lead to discoveries in GA pathogenesis and reveal broader immunomodulatory effects of secukinumab.

DNAJC13 p.Asn855Ser, implicated in familial parkinsonism, alters membrane dynamics of sorting nexin 1

DNAJC13 (RME-8) is a core co-chaperone that facilitates membrane recycling and cargo sorting of endocytosed proteins. DNAJ/Hsp40 (heat shock protein 40) proteins are highly conserved throughout evolution and mediate the folding of nascent proteins, and the unfolding, refolding or degradation of misfolded proteins while assisting in associated-membrane translocation. DNAJC13 is one of five DNAJ 'C' class chaperone variants implicated in monogenic parkinsonism. Here we examine the effect of the DNAJC13 disease-linked mutation (p.Asn855Ser) on its interacting partners, focusing on sorting nexin 1 (SNX1) membrane dynamics in primary cortical neurons derived from a novel Dnajc13 p.Asn855Ser knock-in (DKI) mouse model. Dnajc13 p.Asn855Ser mutant and wild type protein expression were equivalent in mature heterozygous cultures (DIV21). While SNX1-positive puncta density, area, and WASH-retromer assembly were comparable between cultures derived from DKI and wild type littermates, the formation of SNX1-enriched tubules in DKI neuronal cultures was significantly increased. Thus, Dnajc13 p.Asn855Ser disrupts SNX1 membrane-tubulation and trafficking, analogous to results from RME-8 depletion studies. The data suggest the mutation confers a dominant-negative gain-of-function in RME-8. Implications for the pathogenesis of Parkinson's disease are discussed.

Altered dopamine release and monoamine transporters in Vps35 p.D620N knock-in mice

Vacuolar protein sorting 35 (VPS35) is a core component of the retromer trimer required for endosomal membrane-associated protein trafficking. The discovery of a missense mutation, Vps35 p.D620N implicates retromer dysfunction in the pathogenesis of Parkinson's disease (PD). We have characterized a knock-in mouse with a Vps35 p.D620N substitution (hereafter referred to as VKI) at 3 months of age. Standardized behavioral testing did not observe overt movement disorder. Tyrosine hydroxylase (TH)-positive nigral neuron counts and terminal expression in striata were comparable across genotypes. Fast scan cyclic voltammetry revealed increased dopamine release in VKI striatal slices. While extracellular dopamine collected via striatal microdialysis of freely moving animals was comparable across genotypes, the ratio of dopamine metabolites to dopamine suggests increased dopamine turnover in VKI homozygous mice. Western blot of striatal proteins revealed a genotype-dependent decrease in dopamine transporter (DAT) along with an increase in vesicular monoamine transporter 2 (VMAT2), albeit independent of changes in other synaptic markers. The reduction in DAT was further supported by immunohistochemical analysis. The data show that the dopaminergic system of VKI mice is profoundly altered relative to wild-type littermates. We conclude early synaptic dysfunction contributes to age-related pathophysiology in the nigrostriatal system that may lead to parkinsonism in man.

Interlaboratory comparison of epstein-barr virus viral load assays

To assess interlaboratory variability in qualitative and quantitative Epstein-Barr virus (EBV) viral load (VL) testing, we distributed a panel of samples to 28 laboratories in the USA, Canada and Europe who performed testing using commercially available reagents (n = 12) or laboratory-developed assays (n = 18). The panel included two negatives, seven constructed samples using Namalwa and Molt-3 cell lines diluted in plasma (1.30-5.30 log(10) copies/mL) and three clinical plasma samples. Significant interlaboratory variation was observed for both actual (range 1.30-4.30 log(10) copies/mL) and self-reported (range, 1.70-3.30 log(10) copies/mL) lower limits of detection. The variation observed in reported results on individual samples ranged from 2.28 log(10) (minimum) to 4.14 log(10) (maximum). Variation was independent of dynamic range and use of commercial versus laboratory-developed assays. Overall, only 47.0% of all results fell within acceptable standards of variation: defined as the expected result +/- 0.50 log(10). Interlaboratory variability on replicate samples was significantly greater than intralaboratory variability (p < 0.0001). Kinetics of change in VL appears more relevant than absolute values and clinicians should understand the uncertainty associated with absolute VL values at their institutions. The creation of an international reference standard for EBV VL assay calibration would be an initial important step in quality improvement of this laboratory tool.

Interlaboratory comparison of cytomegalovirus viral load assays

To assess interlaboratory variability in qualitative and quantitative cytomegalovirus (CMV) viral load (VL) testing, we distributed a panel of samples to 33 laboratories in the USA, Canada and Europe who performed testing using commercial reagents (n = 17) or laboratory-developed assays (n = 18). The panel included two negatives, seven samples constructed from purified CMV nucleocapsids in plasma (2.0-6.0 log(10) copies/mL) and three clinical plasma samples. Interlaboratory variation was observed in both actual (range, 2.0-4.0 log(10) copies/mL) and self-reported lower limits of detection (range, 1.0-4.0 log(10) copies/mL). Variation observed in reported results for individual samples ranged from 2.0 log(10) (minimum) to 4.3 log(10) (maximum)(.) Variation was greatest at low VLs. Assuming +/- 0.5 log(10) relative to the expected result represents an acceptable result, 57.6% of results fell within this range. Use of commercially available reagents and procedures was associated with less variability compared with laboratory-developed assays. Interlaboratory variability on replicate samples was significantly greater than intralaboratory variability (p < 0.0001). The significant interlaboratory variability in CMV VL observed may be impacting patient care and limiting interinstitutional comparisons. The creation of an international reference standard for CMV VL assay calibration would be an important step in quality improvement of this laboratory tool.

Detection of varicella-zoster virus DNA by nested PCR in CSF from HIV-infected patients: A prospective evaluation

The aim of this prospective study was to determine the frequency and clinical significance of detection of varicella-zoster virus (VZV) DNA in cerebrospinal fluid (CSF) from 120 HIV-infected individuals. Six of 8 CSF samples from patients with recent (up to 8 months previously) or concurrent cutaneous zoster contained detectable VZV DNA using the polymerase chain reaction. No detectable CSF VZV DNA was present in two patients who had an encephalopathy complicating cutaneous zoster or in 112 other patients without a history of recent of concurrent zoster. In conclusion, VZV DNA may be detected in CSF of patients with neurological disease and concurrent or recent zoster. However, the absence of detectable VZV DNA in CSF does not preclude the possibility of VZV associated neurological complications.

Chronic hyperplastic and neoplastic cutaneous lesions (Marjolin's ulcer) in hot-brand sites in adult beef cattle

Linear exophytic cutaneous lesions (brand keratomas) are a chronic sequel to hot-iron branding in a small proportion of beef cattle in the western United States. Rarely, brand keratomas progress to form large ulcerated masses. Samples of chronically thickened skin were collected from 8 adult cattle with hot-brand lesions and from 2 cattle with ulcerated masses at brand sites. Cutaneous thickening was attributable to abrupt transition from normal haired skin to regular epidermal hyperplasia with marked orthokeratotic hyperkeratosis, acanthosis, hypopigmentation, and loss of adnexae. Epithelial atypia was absent. Normal dermal collagen was replaced by mature granulation tissue containing islands of dense hyalinized collagen. Two cows, aged 5 and 13 years, developed large, slow-growing squamous cell carcinomas at brand sites. Malignancy in branded skin is a rare complication of hot-iron branding in cattle and may arise because of malignant transformation of brand keratomas.

Tobacco etch virus protease: mechanism of autolysis and rational design of stable mutants with wild-type catalytic proficiency

Because of its stringent sequence specificity, the catalytic domain of the nuclear inclusion protease from tobacco etch virus (TEV) is a useful reagent for cleaving genetically engineered fusion proteins. However, a serious drawback of TEV protease is that it readily cleaves itself at a specific site to generate a truncated enzyme with greatly diminished activity. The rate of autoinactivation is proportional to the concentration of TEV protease, implying a bimolecular reaction mechanism. Yet, a catalytically active protease was unable to convert a catalytically inactive protease into the truncated form. Adding increasing concentrations of the catalytically inactive protease to a fixed amount of the wild-type enzyme accelerated its rate of autoinactivation. Taken together, these results suggest that autoinactivation of TEV protease may be an intramolecular reaction that is facilitated by an allosteric interaction between protease molecules. In an effort to create a more stable protease, we made amino acid substitutions in the P2 and P1' positions of the internal cleavage site and assessed their impact on the enzyme's stability and catalytic activity. One of the P1' mutants, S219V, was not only far more stable than the wild-type protease (approximately 100-fold), but also a more efficient catalyst.

Molecular-based strategies for assessment of CMV infection and disease in immunosuppressed transplant recipients

OBJECTIVES

Molecular assays are now considered to be the "gold standard" for assessment of human cytomegalovirus (CMV) infection and disease in those at risk from severe associated clinical manifestations. There is, however little consistency in the methods used in different centres. This study was undertaken to compare different qualitative molecular-based approaches for assessment of CMV activation from latency in samples from immunosuppressed transplant recipients.

METHODS

Nucleic acid amplification techniques based on the polymerase chain reaction (PCR) and nucleic acid sequence-based amplification (NASBA) were undertaken for the assessment of CMV replication and associated disease in immunosuppressed transplant recipients. Samples from 32 transplant recipients were tested during this study using three molecular-based strategies: (1) detection of CMV DNA in whole blood extracts (positive after a single round of PCR considered "high-level" positive, N = 55); (2) detection of cell-free CMV DNA in plasma (two methods, N = 55 for each); and (3) detection of late pp67 CMV mRNA after NASBA (N = 51). Results using a commercial pp65 antigenemia assay were available for comparison from 40 samples.

RESULTS

Seven samples were positive for CMV by all methods and 36 were negative by all methods undertaken. The other 12 samples gave discordant results using different molecular methods. The correlation between whole blood "high-level" PCR, NASBA for pp67 mRNA and antigenemia results was generally good. Results presented show that plasma PCR results do not always correlate with methods utilizing whole blood as the substrate and that inhibitors in these samples could be problematic. Whole blood PCR gave more positive results than the other assays but use of a nested assay on whole blood or plasma led to detection of CMV in individuals who had no other indicators of virus replication and who did not develop associated disease (low specificity). Although the number of confirmed CMV disease episodes was low in this study, the problems of low positive predictive value for sensitive, qualitative PCR assays was clearly demonstrated.

CONCLUSION

Assays based on qualitative detection of viral nucleic acid may provide information useful for management of CMV but caution is necessary when making comparisons between results using different molecular strategies. It remains to be proven in large, comparative clinical studies in which the approach and method give the best balance between sensitivity, specificity and clinical relevance for different patient groups.

Curing coupled-bunch instabilities with uneven fills

A new, unified theoretical description of coupled-bunch instabilities in unevenly filled storage rings is presented. Uneven-fill longitudinal dynamics are explained in terms of two physical phenomena: fill-induced tune-spread damping and modulation coupling of strong even-fill eigenmodes. The latter is also present in the transverse plane. The analysis yields simple criteria for optimizing fill shapes to reduce the growth rates of the most unstable modes. Experimental results from the ALS and PEP-II are shown to be in good agreement with the theory.

Single amino acid substitutions on the surface of Escherichia coli maltose-binding protein can have a profound impact on the solubility of fusion proteins

Proteins are commonly fused to Escherichia coli maltose-binding protein (MBP) to enhance their yield and facilitate their purification. In addition, the stability and solubility of a passenger protein can often be improved by fusing it to MBP. In a previous comparison with two other highly soluble fusion partners, MBP was decidedly superior at promoting the solubility of a range of aggregation-prone proteins. To explain this observation, we proposed that MBP could function as a general molecular chaperone in the context of a fusion protein by binding to aggregation-prone folding intermediates of passenger proteins and preventing their self-association. The ligand-binding cleft in MBP was considered a likely site for peptide binding because of its hydrophobic nature. We tested this hypothesis by systematically replacing hydrophobic amino acid side chains in and around the cleft with glutamic acid. None of these mutations affected the yield or solubility of MBP in its unfused state. Each MBP was then tested for its ability to promote solubility when fused to three passenger proteins: green fluorescent protein, p16, and E6. Mutations within the maltose-binding cleft (W62E, A63E, Y155E, W230E, and W340E) had little or no effect on the solubility of the fusion proteins. In contrast, three mutations near one end of the cleft (W232E, Y242E, and I317E) dramatically reduced the solubility of the same fusion proteins. The mutations with the most profound effect on solubility were shown to reduce the global stability of MBP.

Development and application of a PCR-based method including an internal control for diagnosis of congenital cytomegalovirus infection

Cytomegalovirus (CMV) is the most common cause of congenital infection in the developed world. We have designed and evaluated an assay that includes an internal control for amplification and detection of CMV DNA in amniotic fluid and neonatal urine samples. We present data on the use of this assay in the diagnosis of congenital CMV infection. A total of 145 amniotic and fetal fluid samples were examined by this assay; 83 were from healthy pregnant women and 62 were from women who were being investigated because of concerns over the pregnancy (diagnostic group). CMV DNA was detected in three amniotic fluid samples from the diagnostic group but was not detected in any samples taken from healthy pregnant women. Thirty-nine urine samples were obtained from 19 neonates with suspected congenital infection; CMV DNA was detected in urine from 6 of these patients. The assay provides useful information about CMV infection in the fetus and the neonate; when used in conjunction with other diagnostic tools it will enable mothers and obstetricians to make informed decisions about the management of pregnancies complicated by CMV infection.

The measurement of stress-related immune dysfunction in psychoneuroimmunology

In recent years there has been a dramatic increase in research dedicated to the psycho-behavioural modulation of immune function, i.e. the field of Psychoneuroimmunology (PNI). This has led, necessarily, to the use of several in vitro and in vivo techniques in attempts to delineate the relationship between these two phenomena. However, since the field's inception, considerable uncertainty has existed over the significance of the immune outcomes detected and this has been compounded by the equivocal nature of some of the published data. A great deal of this uncertainty could, however, be overcome if a clearer understanding was achieved on the advantages and limitations conferred by the manifold immune assays described in the literature. This would, in turn, encourage their more appropriate use within PNI. Hence, in this review we describe the rationale behind, and offer an evaluation of, some of the more frequently used in vitro and in vivo immunological and virological techniques. We hope that a clear understanding of the rationale behind such assays and their inherent advantages and limitations will inform the discussion of the significance of stress-related immune impairment.

Detection of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus DNA in CSF from persons infected with HIV who had neurological disease

OBJECTIVES

To determine the frequency and clinical relevance of Epstein-Barr virus (EBV) and Kaposi's sarcoma associated herpesvirus (KSHV) DNA detection in the CSF from patients infected with HIV.

METHODS

Cerebrospinal fluid was obtained prospectively from 115 consecutive patients infected with HIV undergoing diagnostic lumbar puncture for investigation of neurological disease. Amplification of DNA was performed using a nested polymerase chain reaction (PCR) for detection of EBV internal repeat and KSHV minor capsid sequences.

RESULTS

EBV DNA was detected in the CSF supernatant of 18 patients. This included all patients with primary CNS lymphoma (seven patients) or a combination of systemic and CNS lymphoma (two patients). By contrast EBV DNA was not detected in the CSF supernatant of any patient with systemic, but not CNS, lymphoma (10 patients). EBV DNA was also detected in the supernatant of nine further patients without a diagnosis of lymphoma at the time of lumbar puncture, two of whom subsequently developed CNS lymphoma. No EBV DNA was detected in CSF supernatant from the remaining 87 samples (two of these patients subsequently developed lymphoma). KSHV DNA was detected in the CSF of two patients, one had systemic (but not CNS) lymphoma and the other did not have lymphoma.

CONCLUSION

A diagnosis of CNS lymphoma is strongly associated with the presence of EBV DNA in CSF. In the absence of clinical and radiological features of CNS lymphoma, the presence of detectable CSF EBV DNA may predict subsequent tumour development. KSHV DNA is rarely detected in CSF in this patient group and shows no correlation with lymphoma or other neurological disease.

Development and application of a new method for amplification and detection of human rhinovirus RNA

A method based on nucleic acid sequence based amplification (NASBA) was developed for detection of rhinovirus RNA. Appropriate collection and storage conditions for maintenance of rhinovirus RNA integrity in clinical samples was determined. Two silica-based extraction methods were evaluated for preparation of RNA from virus isolates and clinical samples. Primers and probes were selected from the non-translated region at the 5' end and from VP4 of sequenced rhinoviruses. Amplified products were detected by 'in-solution' hybridization, with analysis by polyacrylamide gel electrophoresis (enzyme linked gel assay or ELGA), and by a microtitre-based plate hybridization assay. Using propagated picornavirus isolates in vitro the rhinovirus NASBA, with detection of amplified sequences by ELGA or plate hybridization, was confirmed as sensitive and specific for detection of rhinovirus RNA. The method was applied successfully to analysis of rhinovirus sequences in clinical samples from individuals with respiratory-tract symptoms. Rhinovirus NASBA will be useful for studies of the molecular epidemiology of respiratory infections and monitoring of response to anti-rhinovirus therapy.

Detection of human TNF-alpha mRNA by NASBA

A method to amplify and detect TNF-alpha mRNA from primed Mono Mac 6 cells is described. A silica-based extraction system was utilised for preparation of cell extracts and specific oligonucleotide primers were designed for amplification of TNF-alpha mRNA by the NASBA process. Amplification products were detected using either a liquid hybridisation assay, with analysis by polyacrylamide gel electrophoresis, or a plate hybridisation system. The method has many potential applications for the study of inflammatory cytokines and cellular mRNAs in cell culture and clinical samples.

Consequences of live poliovirus vaccine administration in chronic fatigue syndrome

The effect of live oral polio virus vaccination on chronic fatigue syndrome (CFS) patients was examined in a double-blind study. CFS patients were allocated randomly to placebo (N = 7) or vaccine (N = 7) conditions. All controls subjects received the vaccine (9). Vaccine administration was not associated with clinical exacerbation of CFS. However, objective responses to the vaccine revealed differences between patients and controls: increased poliovirus isolation, earlier peak proliferative responses, lower T-cell subsets on certain days post vaccination and a trend for reduced gamma-interferon in the CFS-vaccine group. Polio vaccination was not found to be clinically contraindicated in CFS patients, however, there was evidence of altered immune reactivity and virus clearance.

Polymer of proline analogue with sustained antifibrotic activity in lung fibrosis

Inhibitors of collagen such as cis-4-hydroxy-L-proline (cHyp) may ameliorate bleomycin (bleo)-induced pulmonary fibrosis. An alternating polymer of poly(ethylene glycol) (PEG)-lysine (PEG-Lys) with cHyp attached as a pendant side chain was prepared for intratracheal delivery with bioinactive trans-Hyp (tHyp) polymer as control. To test whether the cHyp polymer has prolonged lung retention and sustained antifibrotic activity, we first instilled 3H- and 14C-labeled cHyp polymer in normal rats. Lung retention was 86 +/- 9% at 6 h and 29 +/- 3% at 7 d (n = 5). Next, rats were instilled intratracheally with either saline (sal) or 1.2 U bleo, and the following treatment groups were studied: Bleo/sal; Bleo/cHyp polymer; Bleo/tHyp polymer; and Bleo/PEG-Lys + cHyp. The dose of the test agents was 150 mg/kg polymer containing 8.5 mg/kg cHyp or tHyp instilled intratracheally at 7 and 14 d after bleo. At 21 d, hydroxyproline content (mg/lung) was: Control, 1.8 +/- 0.1; Bleo/sal 4.0 +/- 0.1*; Bleo/cHyp polymer, 2.8 +/- 0.3*+; Bleo/tHyp polymer, 4.4 +/- 0.2*; and Bleo/PEG-Lys + cHyp, 4.0 +/- 0.1* (*p < 0.05 versus Control; +p < 0.05 versus Bleo/sal; n = 5/group). The cHyp polymer also reduced lung total protein content, but the decrease was not significant. The dose required to produce 50% inhibition of lung collagen was approximately 700-fold less than monomeric cHyp. Thus, the cHyp polymer is a potent, long-acting antifibrotic agent which may be useful in treating lung fibrosis.

Polymeric carrier of proline analogue with antifibrotic effect in pulmonary vascular remodeling

The proline analogue cis-4-hydroxy-L-proline (cHyp) inhibits collagen accumulation but diffuses out of tissues. To prolong the antifibrotic effect, we used a copolymer of cHyp attached to a backbone of poly(ethylene glycol) (PEG) and lysine. The copolymer was encapsulated in liposomes conjugated with PEG or in liposomes coated with the polysaccharide amylopectin to improve uptake by lungs after intravenous infusion. Amylopectin-liposomes had approximately 3-fold greater uptake in cultured endothelial cells compared with PEG-liposomes and greater lung retention 1 wk after infusion (5.2 +/- 0.8% versus 2.7 +/- 0.2%, p < 0.05). Sustained antifibrotic activity, assayed by growth inhibition of smooth muscle cells and fibroblasts over 4 d, was greater for amylopectin-liposomes/copolymer than PEG-liposomes/copolymer. Inhibition of collagen accumulation in pulmonary arteries of hypoxic (10% O2) rats was used to assess antifibrotic activity. Amylopectin-liposomes/copolymer attenuated increased right ventricular pressure by approximately 50% and completely prevented excess vascular collagen 1 wk after a single intravenous injection. The copolymer in liposomes was > 1,000-fold more effective by weight than unencapsulated monomeric cHyp. Thus, the copolymer, a potent, long-acting antifibrotic agent, totally prevented collagen accumulation for 1 wk in pulmonary arteries undergoing vascular remodeling when delivered in amylopectin-liposomes.

Acute lumbosacral polyradiculopathy due to cytomegalovirus in advanced HIV disease: CSF findings in 17 patients

OBJECTIVES

To describe the abnormalities in CSF from HIV infected patients with acute lumbosacral polyradiculopathy (ALP) caused by cytomegalovirus (CMV) infection.

METHODS

Retrospective case notes and laboratory records were reviewed for 17 consecutive patients with CMV associated ALP admitted to specialist HIV/AIDS units at UCL Hospitals and Chelsea and Westminster Hospital.

RESULTS

Infection with CMV was confirmed by detection of CMV DNA by polymerase chain reaction amplification in 15 patients (all of whom were negative by culture), by culture in one patient, and by objective clinical response to anti-CMV treatment in one patient. Only nine patients had a CSF pleocytosis 28-1142 (median 150) cells/mm3; in seven there was a polymorphonuclear (PMN) leucocyte preponderance. Protein concentrations in CSF were moderately or considerably raised in 13 patients; CSF: plasma glucose ratios were < or = 50% in five patients. Two patients had no pleocytosis, normal CSF: plasma glucose, and normal or near normal protein values.

CONCLUSIONS

Abnormalities in CSF in CMV associated ALP are varied: only 50% of patients have a "typical" PMN preponderant pleocytosis. The diagnosis of this condition should not rely on demonstration of a PMN preponderant pleocytosis, but on identification of CMV DNA in CSF and the exclusion of other opportunistic infections and lymphoma in order that specific anti-CMV treatment may be instituted.

Characterization of the region encoding the CO-induced hydrogenase of Rhodospirillum rubrum

In the photosynthetic bacterium Rhodospirillum rubrum, the presence of carbon monoxide (CO) induces expression of several proteins. These include carbon monoxide dehydrogenase (CODH) and a CO-tolerant hydrogenase. Together these enzymes catalyze the following conversion: CO + H2O --> CO2 + H2. This system enables R. rubrum to grow in the dark on CO as the sole energy source. Expression of this system has been shown previously to be regulated at the transcriptional level by CO. We have now identified the remainder of the CO-regulated genes encoded in a contiguous region of the R. rubrum genome. These genes, cooMKLXU, apparently encode proteins related to the function of the CO-induced hydrogenase. As seen before with the gene for the large subunit of the CO-induced hydrogenase (cooH), most of the proteins predicted by these additional genes show significant sequence similarity to subunits of Escherichia coli hydrogenase 3. In addition, all of the newly identified coo gene products show similarity to subunits of NADH-quinone oxidoreductase (energy-conserving NADH dehydrogenase I) from various eukaryotic and prokaryotic organisms. We have found that dicyclohexylcarbodiimide, an inhibitor of mitochondrial NADH dehydrogenase I (also called complex I), inhibits the CO-induced hydrogenase as well. We also show that expression of the cooMKLXUH operon is regulated by CO and the transcriptional activator CooA in a manner similar to that of the cooFSCTJ operon that encodes the subunits of CODH and related proteins.

Detection of polyomaviral DNA in clinical samples from immunocompromised patients: correlation with clinical disease

Clinical samples from immunocompromised patients were screened for polyomaviral sequences by nested polymerase chain reaction (PCR) to evaluate the association of these viral infections with progressive multifocal leukoencephalopathy (PML). JC virus (JCV) DNA was detected in 19 of 23 CSF samples and all four brain samples from patients with PML. Neither BK virus (BKV) nor simian virus 40 (SV40) DNA were detected in these samples. No evidence was found to support the hypothesis that polyomaviral DNA is present in the central nervous system of immunosuppressed patients without PML (CSF n = 67, brain n = 19). JCV DNA was not detected in any peripheral blood sample included in this study. JCV DNA was detected in urine from three of eight patients with PML, but was also amplified from three of 29 urine samples from patients without PML, JCV, and not SV40 or BKV, was associated with PML in this study.

Characterization of the CO-induced, CO-tolerant hydrogenase from Rhodospirillum rubrum and the gene encoding the large subunit of the enzyme

In the presence of carbon monoxide, the photosynthetic bacterium Rhodospirillum rubrum induces expression of proteins which allow the organism to metabolize carbon monoxide in the net reaction CO + H2O --> CO2 + H2. These proteins include the enzymes carbon monoxide dehydrogenase (CODH) and a CO-tolerant hydrogenase. In this paper, we present the complete amino acid sequence for the large subunit of this hydrogenase and describe the properties of the crude enzyme in relation to other known hydrogenases. The amino acid sequence deduced from the CO-induced hydrogenase large-subunit gene (cooH) shows significant similarity to large subunits of other Ni-Fe hydrogenases. The closest similarity is with HycE (58% similarity and 37% identity) from Escherichia coli, which is the large subunit of an Ni-Fe hydrogenase (isoenzyme 3). The properties of the CO-induced hydrogenase are unique. It is exceptionally resistant to inhibition by carbon monoxide. It also exhibits a very high ratio of H2 evolution to H2 uptake activity compared with other known hydrogenases. The CO-induced hydrogenase is tightly membrane bound, and its inhibition by nonionic detergents is described. Finally, the presence of nickel in the hydrogenase is addressed. Analysis of wild-type R. rubrum grown on nickel-depleted medium indicates a requirement for nickel for hydrogenase activity. However, analysis of strain UR294 (cooC insertion mutant defective in nickel insertion into CODH) shows that independent nickel insertion mechanisms are utilized by hydrogenase and CODH. CooH lacks the C-terminal peptide that is found in other Ni-Fe hydrogenases; in other systems, this peptide is cleaved during Ni processing.

Detection of herpesvirus DNA by nested polymerase chain reaction in cerebrospinal fluid of human immunodeficiency virus-infected persons with neurologic disease: a prospective evaluation

A nested polymerase chain reaction-based method was used prospectively to detect herpesvirus DNA in cerebrospinal fluid (CSF) from 111 patients with AIDS, 39 of whom had a suspected diagnosis of cytomegalovirus (CMV)-associated neurologic disease (patients with encephalopathy, polyradiculopathy, or peripheral neuropathy) and 72 who had alternative diagnoses. CSF from 24 (62%) of the patients with suspected CMV-associated disease had detectable CMV DNA compared with only 8 (11%) of the patients with other diagnoses. Varicella-zoster virus DNA was detected in CSF from 3 patients (2 with myelitis and 1 with encephalitis), all of whom had recent cutaneous zoster. No CSF specimen contained detectable herpes simplex virus type 1 DNA, and none of the patients with myelitis had detectable herpes simplex virus type 2 DNA in CSF. This study demonstrates a significant association between detectable CMV DNA in CSF and suspected CMV-associated neurologic disease in patients with AIDS.

Aqueous and vitreous humor samples for the diagnosis of cytomegalovirus retinitis

PURPOSE/METHODS

Techniques for detection of viral DNA based on the polymerase chain reaction are increasingly being applied to ocular fluids; however, the clinical significance of such findings can sometimes be unclear. Two patients had the acquired immunodeficiency syndrome (AIDS) in whom different herpesviruses were detected in aqueous and vitreous fluids from the involved eye.

RESULTS/CONCLUSIONS

In both patients dual viral infections were present and the application of polymerase chain reaction-based methods to ocular fluids made a useful contribution to the treatment of the patients.

Herpes simplex virus type 2 encephalitis and concomitant cytomegalovirus infection in a patient with AIDS: detection of virus-specific DNA in CSF by nested polymerase chain reaction

A Caucasian homosexual man with AIDS and cytomegalovirus retinitis presented with facial pain and episodic confusion, had several seizures and became obtunded. An electroencephalogram was suggestive of herpes simplex encephalitis. The diagnosis was confirmed by detection of herpes simplex virus type 2 (HSV 2), but not type 1, DNA in cell-free cerebrospinal fluid (CSF) after amplification by nested polymerase chain reaction. The patient also had evidence of concomitant cytomegalovirus (CMV) infection with detectable CMV DNA in CSF. With high-dose acyclovir the patient recovered. Analysis of a follow up CSF sample taken four months later showed no detectable HSV-2 DNA.

Detection of herpesvirus DNA in cottontop tamarins: no association with colitis

Colitis occurs spontaneously in the cottontop tamarin; it shares similar clinical, endoscopic and histological features with, and has a similar response to treatment as, human ulcerative colitis. An association between human ulcerative colitis and the presence of DNA from multiple herpesviruses (human herpesvirus 6 (HHV-6), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in the colon has been described. Intestinal herpesvirus infection may be involved in the pathogenesis of this condition. In a pilot study, coded full thickness colonic specimens from 27 cottontop tamarins were examined for the presence of HHV-6, CMV and EBV DNA using the nested polymerase chain reaction. The sections represented a spectrum of disease activity ranging from histologically normal bowel to severe colitis. A low prevalence of DNA from these viruses was found, which bore no relation to the presence of inflammation. Although these herpesviruses may have a pathogenetic role in human ulcerative colitis, they are not associated with colitis in this animal model.

Progressive multifocal leukoencephalopathy in patients with AIDS: detection of JC virus DNA in CSF and brain

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Liposome encapsulation improves the effect of antifibrotic agent in rat lung fibrosis

We studied whether the therapeutic efficacy of the antifibrotic agent cis-4-hydroxy-L-proline (cHyp) in preventing bleomycin-induced pulmonary fibrosis in rats is enhanced by intratracheal delivery in liposomes. Dual-radiolabeled liposomes were used to study the distribution and stability of liposomes after intratracheal instillation. Lung retention was > 20% 1 wk after intratracheal instillation of 9 mumol phospholipid, and liposomes were intact as indicated by the ratio of the lipid and aqueous-phase markers remaining unchanged. For the fibrosis study, groups of rats were instilled with 1.2 U bleomycin (Bleo) and treated 1 and 2 wk later by single intratracheal instillation of test compounds. The control group received 0.3 ml saline (Bleo/sal). The treated groups received 9 mumol phospholipid in 0.3 ml of the following liposome preparations: empty liposomes (Bleo/lip), liposomes and 100 mg/kg of free unencapsulated cHyp (Bleo/lip/cHyp), and 100 mg/kg of liposome-encapsulated cHyp (Bleo/lip-cHyp). At 3 wk, fibrosis (mg hydroxyproline/g weight lung) by groups was as follows: control, 2.6 +/- 0.1 (SEM); Bleo/sal, 3.2 +/- 0.1, Bleo/lip, 3.2 +/- 0.1, and Bleo/lip/cHyp, 3.1 +/- 0.1, p < 0.05 compared with control; Bleo/lip-cHyp, 2.6 +/- 0.1, p < 0.05 compared with Bleo/sal, n = 3 to 6. Histologic grading of fibrosis did not show decreased fibrosis in the Bleo/lip-cHyp group, probably because of the focal nature of the fibrotic lesions. We conclude that cHyp encapsulated in liposomes prevents bleomycin-induced fibrosis by biochemical measurements. Delivery of antifibrotic agents to the lung in carrier vehicles promotes retention and may enhance their efficacy in treating bleomycin-induced pulmonary fibrosis.

Conjugates of cis-4-hydroxy-L-proline and poly(PEG-Lys), a water soluble poly(ether urethane): synthesis and evaluation of antifibrotic effects in vitro and in vivo

Synthetic approaches for the preparation of macromolecular conjugates of the antifibrotic agent cis-4-hydroxy-L-proline (cHyp) were explored, and the efficacy of the conjugates in inhibiting collagen accumulation was investigated in vitro and in vivo. In one approach, poly(PEG-Lys), an alternating copolymer of poly(ethylene glycol) (PEG) and lysine, was used as the carrier. To prepare pendent chain systems, cHyp was attached to poly(PEG-Lys) through an amide linkage [poly(PEG-Lys-cHyp amide)] or through an ester linkage [poly(PEG-Lys-cHyp ester)]. In an alternative approach, cHyp was incorporated into the backbone of a linear copolymer consisting of PEG, succinic acid, and cHyp units [poly(PEG-succinate-cHyp)]. Bioactivity in vitro was assessed by the ability of the cHyp conjugates to inhibit growth of cultured smooth muscle cells (SMC) and rat lung fibroblasts (RLF). Cell numbers were compared to control experiments in the presence of biologically inactive trans-4-hydroxy-L-proline (tHyp). After a 5 day period, the presence of 8 micrograms/mL of cHyp delivered by poly(PEG-Lys-cHyp amide) resulted in a 47% reduction in the number of SMC (p < 0.05), the presence of 36 micrograms/mL of cHyp delivered by poly(PEG-Lys-cHyp ester) resulted in a 38% reduction in the number of SMC (p < 0.05), while the presence of 118 micrograms/mL of cHyp delivered by poly(PEG-succinate-cHyp) resulted in a 31% reduction in the number of cells (p < 0.05). An identical trend was observed for the inhibition of RLF growth. In general, poly(PEG-Lys-cHyp amide) was most active, followed by poly(PEG-Lys-cHyp ester) and the backbone system, poly(PEG-succinate-cHyp). Specifically, poly(PEG-Lys-cHyp amide) was over 100-fold more active in inhibiting cell growth than free cHyp. Bioactivity in vivo was evaluated by measuring collagen accumulation in subcutaneously implanted poly(vinyl alcohol) sponges in rats. Among the tested conjugates, poly(PEG-Lys-cHyp amide) was most active, reducing collagen accumulation in the sponge by 33% after 14 days relative to controls (p < 0.05). This result indicates that the covalent attachment of cHyp to poly(PEG-Lys) carries may be a useful strategy for the local inhibition of collagen accumulation in tissues.

Varicella zoster gastritis in a bone marrow transplant recipient

A case is reported of a patient who had previously undergone autologous bone marrow transplantation for recurrent Hodgkin's disease. The patient developed a generalised vesicular skin eruption. The clinical diagnosis was of disseminated shingles. Herpes viral particles were identified within the vesicular fluid by electron microscopy and using a specific monoclonal antibody to varicella zoster virus (VZV), positive immunofluorescence was detected in scrapings from the base of a vesicle. Gastroscopy and biopsy were performed because of severe abdominal pain and vomiting. The histological features were of non-specific active inflammation. Despite the histological absence of viral inclusions electron microscopy of the gastric biopsy revealed the presence of intranuclear herpes viral particles with a diameter of 90-100 nm. VZV specific DNA was detected by the polymerase chain reaction in the gastric biopsy extract. The patient was treated with acyclovir and made a full recovery.

Detection of varicella-zoster virus DNA in ocular samples from patients with uveitis but no cutaneous eruption

Herpes zoster ophthalmicus is a well-recognised cause of intraocular inflammation, which may become recurrent or chronic after the acute phase has elapsed. Although it commonly presents with the typical rash, cases of ocular zoster with no cutaneous eruption have been well documented. We present two patients with unilateral anterior uveitis complicated by cataract, in whom molecular techniques based on the polymerase chain reaction detected varicella-zoster virus DNA in intraocular material obtained during cataract surgery. Neither patient gave a history of cutaneous eruption.

Vitreous fluid sampling and viral genome detection for the diagnosis of viral retinitis in patients with AIDS

Cytomegalovirus (CMV) causes severe necrotizing retinitis in patients with the acquired immune deficiency syndrome (AIDS) and other herpesviruses have been implicated in the acute retinal necrosis syndrome (ARN), seen in both the immunocompetent and the immunosuppressed. At present the diagnosis of viral retinitis relies solely on clinical appearances. In order to assess whether the detection of herpesvirus-specific DNA in cell-free vitreous biopsy samples could be useful in the early diagnosis of viral retinitis, vitreous fluid samples were taken from 100 patients. Fifty patients had AIDS as defined by the Centers for Disease Control, (MMWR 36 (suppl 1S):1S-15S, 1987) and retinal disease. The remainder were not known to be HIV infected and had no clinical evidence of retinal infection. Each sample was tested for the presence of CMV, herpes simplex virus 1 (HSV-1), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV6), by amplification of viral DNA using a sensitive and specific nested polymerase chain reaction (PCR). The presence of detectable CMV or VZV DNA was clearly associated with clinical disease whereas the presence of HSV-1, EBV, and HHV6 sequences were not. Clinical discrimination between CMV- and VZV-associated retinitis was greatly enhanced when the PCR results were taken into consideration.

Detection of varicella-zoster virus DNA using the polymerase chain reaction in an immunocompromised patient with transverse myelitis secondary to herpes zoster

A case of herpes zoster transverse myelitis is described in which the clinical diagnosis was confirmed by demonstrating the presence of varicella-zoster virus (VZV) DNA in the cerebrospinal fluid (CSF) by amplification using the polymerase chain reaction. This case illustrates the potential role of the selective amplification of VZV DNA from CSF in contributing to the diagnosis of neurological complications associated with VZV infection.

Herpes simplex encephalitis in a patient with complex partial epilepsy: confirmation by the polymerase chain reaction with necropsy studies

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Detection of herpesvirus DNA in the large intestine of patients with ulcerative colitis and Crohn's disease using the nested polymerase chain reaction

The prevalence of herpesvirus DNA was examined in inflammatory bowel disease tissue. DNA was extracted from resection and biopsy specimens of the large intestine from patients with ulcerative colitis (n = 21), patients with Crohn's disease (n = 29), and patients with noninflammatory bowel disease (controls) (n = 21). The nested polymerase chain reaction was used to detect viral DNA using primer pairs specific for either cytomegalovirus (CMV), herpes simplex virus 1 (HSV1), human herpesvirus 6 (HHV6), varicella zoster virus (VZV), or Epstein Barr virus (EBV). HSV1 and VZV DNA were not detected in any of tissue samples. There was a high prevalence of CMV (81%), HHV6 (76%), and EBV (76%) DNA in ulcerative colitis tissue compared to Crohn's disease tissues (CMV 66%, HHV6 45%, EBV 55%). Control tissue had a relatively low frequency of CMV (29%) and EBV (19%) DNA but a prevalence of HHV6 DNA similar to that of ulcerative colitis (86%). However, the simultaneous presence of HHV6 and CMV and/or EBV DNA in ulcerative colitis tissue (76%) was much greater than in either Crohn's disease tissues (38%) or control tissue (29%) (P < 0.05). There was a low prevalence of CMV, HHV6, and EBV DNA in peripheral blood mononuclear cells from all patient groups. CMV and EBV are capable of reactivating HHV6: the high prevalence of coexistent HHV6 infection with either or both of these two viruses in ulcerative colitis tissue suggests that they may play a synergistic role in the pathogenesis of this disease.

Comparison of three immunoassays for the detection of anti-HHV6

Sera from 96 blood donors were tested for antibody to human herpesvirus 6 by indirect immunofluorescence (IF), circle immunoassay (CIA) and competitive radioimmunoassay (RIA). The correlation between the three assays was good but the CIA and competitive RIA were more sensitive for the detection of HHV6 antibody than indirect IF. The crossreaction of HHV6 antibody with that to the other human herpesviruses was also studied in this blood donor group. No correlation was found between antibody to human herpesvirus 6 by any of the methods described and antibody to any of the other human herpesviruses in these sera.

Liposome-entrapped antifibrotic agent prevents collagen accumulation in hypertensive pulmonary arteries of rats

We studied the therapeutic efficacy of an intravenously injected antifibrotic agent encapsulated in liposomes on inhibiting collagen accumulation in hypertensive blood vessels. cis-4-Hydroxy-L-proline (cHyp) in liposomes was injected into rats exposed to 10% O2, and drug effect was evaluated by measuring right ventricular pressure and hydroxyproline content of the pulmonary artery. Right ventricular pressure was 11 +/- 1 mm Hg (mean +/- SEM) 5 days after a single intravenous injection of 200 mg/kg cHyp in liposomes compared with 14 +/- 1 mm Hg in rats injected with empty liposomes; hydroxyproline content was also reduced by cHyp treatment (87 +/- 6 versus 107 +/- 7 micrograms per vessel) (p less than 0.05 for both, n = 6-9). Injections of cHyp in liposomes every 5 days partially prevented hypertension and vascular collagen accumulation during a 3-week exposure to hypoxia, and the dose required was one tenth the dose of unencapsulated cHyp. Therapeutic doses of cHyp in liposomes injected for 6 months affected tensile properties of main pulmonary artery and aorta, but there were no apparent histological effects on other organs. Liposomes injected intravenously were identified in pulmonary artery endothelial cells. The prolonged effect of a single injection of cHyp in liposomes may be due to uptake of the liposomes by the endothelium. Liposome delivery of drugs to the arterial wall may be useful in the study and treatment of hypertensive vascular disease.

Miniaturization of three carbohydrate analyses using a microsample plate reader

Three carbohydrate analyses (reducing value by copper-bicinchoninate, total carbohydrate by phenol-sulfuric acid, and D-glucose by glucose oxidase) have been miniaturized using a microsample plate reader. The use of the reducing-value procedure to measure the hydrolysis of starch by alpha-amylase and the use of the glucose oxidase method to measure the hydrolysis of lactose by lactase are illustrated.

Human herpesvirus 6 in salivary glands

In an investigation of the role of saliva in the transmission of human herpesvirus 6 (HHV6) sections of salivary gland tissue were screened for HHV6-specific DNA by in-situ hybridisation and for HHV6-specific protein by immunohistochemical staining with monoclonal antibodies against the virus. All of nine submandibular glands and one of four parotid glands showed the presence of HHV6 genome and expressed protein by these techniques. The findings are consistent with transmission of HHV6 by saliva and suggest that salivary gland tissue is a site of replication of the virus and a potential site for HHV6 persistence.

Production of IgM antibody to HHV6 in reactivation and primary infection

The cross-reaction of HHV6 antibody with that to the other herpesviruses was studied in 96 blood donors whose sera were tested for IgG antibody to human herpesvirus type 6 (HHV6), cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zostervirus (VZV) and herpes simplex virus (HSV). No correlation was found between IgG antibody to HHV6 and that to any of the other herpesviruses in these individuals. Antibodies to HHV6 and CMV were measured in patients undergoing documented serological responses to HHV6. Eleven cases of primary HHV6 infection associated with roseola infantum in babies, 1 of whom suffered from gastroenteritis as well as pyrexia and rash, are reported. Three cases of HHV6 reactivation, 1 in a 3-year-old child and 2 in adults, 1 of whom simultaneously underwent a primary CMV infection are also reported. Our results suggest that indirect immunofluorescence is a specific way of measuring HHV6 antibody, that HHV6 IgG and IgM can be detected in the absence of antibody to CMV and that HHV6 IgM is present both in primary HHV6 infections and in reactivations.

Cytomegalovirus and human herpesvirus-6 in sudden infant death syndrome: an in situ hybridization study

Thirty lung, spleen, and thymus sections and four lymph node sections from 40 sudden infant death syndrome (SIDS) cases were probed with biotinylated DNA probes specific for human herpesvirus-6 (HHV-6) and cytomegalovirus (CMV). Control material gave a strong, distinct signal with little or no background staining and no cross-reactivity. No staining was found with the SIDS material. We find no evidence to implicate an overwhelming infection by either virus in SIDS.

Serological prospects for peptide vaccines against foot-and-mouth disease virus

Antibodies to a synthetic peptide corresponding to the 141 to 160 amino acid sequence of the protein VP1 of type O foot-and-mouth disease virus (FMDV) neutralize a wider range of type O isolates than anti-virion serum. Extending this peptide at the amino terminus reduced the number of strains neutralized by the antipeptide sera. Reactions with antisera to peptides representing non-contiguous native sequences showed that it was also possible to increase the number of strains effectively neutralized. Selected substitutions of a single amino acid at position 148 markedly altered the neutralizing specificity of antibodies elicited by the 141 to 160 peptide. In particular, a peptide with an L----S substitution at this position induced antibodies which neutralized a type O and a type A virus equally, and guinea-pigs inoculated with it were protected from challenge with either virus. Attempts to isolate variant viruses resistant to neutralization with anti-peptide antibody indicated that these occurred at low frequency, and there was some evidence that resistance may be partially conferred by mutations outside the peptide sequence.