The pathology of posttransplant lymphoproliferative disorders occurring in the setting of cyclosporine A-prednisone immunosuppression.

Posttransplant lymphoproliferative disorders (PTLDs) were diagnosed in 43 patients from the Pittsburgh-Denver series between June 1980 and March 1987. This constitutes a detection rate of 1.7%. Major categories of clinical presentation included a mononucleosislike syndrome, gastrointestinal/abdominal disease, and solid organ disease. The median time of onset in patients initially immunosuppressed with cyclosporine-A (CsA)-containing regimens was 4.4 months after transplant, regardless of tumor clonality. A strong association of PTLD with Epstein-Barr virus (EBV) was observed. A histologic spectrum of lesions from polymorphic to monomorphic was observed. Whereas polymorphic lesions could be either clonal or nonclonal, monomorphic lesions appeared to be clonal in composition. The presence of large atypical cells (atypical immunoblasts) or necrosis did not appreciably worsen the prognosis. Twelve patients had clonal, 13 had nonclonal, and five had both clonal and nonclonal tumors. Clonality was indeterminate in 13 cases. Most patients were treated with a regimen based on reduced immunosuppression and supportive surgery. Almost all nonclonal and about half of the clonal lesions respond to this conservative therapy, indicating that it is an appropriate first line of treatment. This behavior suggests that a spectrum of lesions ranging from infectious mononucleosis to malignant lymphoma constitutes the entity known as PTLD. Some monoclonal tumors can undergo regression, however, apparently in response to host immune control mechanisms. Because of its short latency and strong association with EBV, PTLD is an important model for the study of virus-associated tumor progression in humans.     

Lingual mechanoreceptors activated by muscle twitch

1. Two groups of mechanoreceptors in the tongue have been identified by recording afferent discharges in single nerve fibres dissected from the lingual nerves of anaesthetized cats. The group of superficially situated, rapidly adapting mechanoreceptors had faster conduction velocities than the presumed deeply situated, slowly adapting endings.2. Stretch of the tongue musculature did not prove to be as efficient in activating the endings as local deformation, although it was possible to excite some of the presumed deeply situated endings in this way.3. No mechanoreceptor fibres could be identified in filaments dissected from the hypoglossal nerves in the same experiments.4. Twitches of the tongue musculature produced by stimulation of the hypoglossal nerve were able to cause discharge of superficial and presumed deeply situated mechanoreceptors during the tension change.5. The timing of the discharges in response to twitch was such that it could account for the delay in synaptic potentials produced in hypoglossal motoneurones when supramaximal stimuli were applied to the hypoglossal nerve.6. The possible significance of mechanoreceptor discharges in reflex activation of tongue motor units is discussed.     

Non-isotopic in situ hybridisation and immunophenotyping of infected cells in the investigation of human fetal parvovirus infection.

AIMS: To compare the use of biotinylated and digoxigenin labelled probes for diagnosis of human fetal parvovirus B19 infection in formalin fixed, paraffin wax embedded tissues; and to assess the cellular distribution of the virus in positive cases. METHODS: Sections of lung tissue from 23 cases of anatomically normal non-immune fetal hydrops presenting between 1984 and 1989, and from 13 control cases of hydrops due to chromosomal abnormality were probed for B19 DNA by in situ hybridisation using both biotinylated and digoxigenin labelled probes. The distribution of the virus was then investigated in all cases of fetal B19 infection confirmed in this laboratory to date (n = 11) by combining in situ hybridisation for viral DNA (using the digoxigenin system) with immunohistological labelling for a range of cellular antigens. RESULTS: Five unequivocal cases of B19 infection were identified among the 23 fetuses with unexplained hydrops using both probe labels. When combined with data from previous studies of the period 1974-1983, the results indicate that B19 infection was responsible for 27% of cases of anatomically normal non-immune hydrops and 8% of all cases, of non-immune hydrops presenting to this hospital over 15 years. False positive signal was seen in an additional three cases, using biotinylated probes. Digoxigenin labelled probes gave greater specificity and permitted detailed investigation of tissues high in endogenous biotin. Though most cells containing B19 DNA colabelled as erythroid precursors, viral DNA was frequently detected within mononuclear-phagocytic cells. In three cases viral signal was also found within occasional myocardial cells labelled by antibody to desmin. CONCLUSIONS: A relatively high proportion of cases of anatomically normal, non-immune hydrops are caused by B19 infection. Digoxigenin is a more reliable probe label than biotin for in situ hybridisation in archival fetal tissues. Double labelling for cellular antigens and viral nucleic acid is a powerful technique for investigating virus-host cell interactions, and provides evidence that cell types other than those of erythroid lineage may have a role in human fetal parvovirus infection.     

Characterisation by restriction mapping of three subtypes of molluscum contagiosum virus.

DNA from Molluscum contagiosum virus (MCV) isolates was analysed by restriction endonuclease digestion, identifying three virus subtypes. The structural features of MCV DNA are typical of poxviral DNA. Physical maps of cleavage sites for BamHI, CIaI, and HindIII were constructed for single isolates of each subtype. These differ extensively, indicating the independence of the three subtypes. However, they are closely related, as determined by molecular hybridisation and nucleotide sequence analysis, and their genomes are essentially colinear. There is marked geographical variation in the relative incidence of MCV I and II, whilst MCV III is uniformly rare.     

Antibody Responses to Haemophilus influenzae Type b and Diphtheria Toxin Induced by Conjugates of Oligosaccharides of the Type b Capsule with the Nontoxic Protein CRM197

Oligosaccharides were made from Haemophilus influenzae type b capsular polysaccharide and conjugated to CRM₁₉₇ by reductive amination. Conjugates were made with a range of lengths and multiplicities of saccharide chains. All elicited a strongly enhanced anti-H. influenzae type b capsular polysaccharide response when injected into weanling rabbits. One series of conjugates also elicited antibodies to diphtheria toxin.     

Daily stress and mood and their association with pain,health-care use,and school activity in adolescents with sickle cell disease

OBJECTIVE: To determine the extent to which daily stress and mood are associated with pain, health-care use, and school activity in adolescents with sickle cell disease (SCD). METHOD: Adolescents with SCD (n = 37; aged 13 to 17 years) completed daily diaries assessing pain, stress, mood, activity, and health-care use for up to 6 months. Multilevel modeling was used to analyze the data. RESULTS: Daily increases in stress and negative mood were associated with increases in same-day pain, health-care use, and reductions in school and social activity. Increases in positive mood were associated with decreases in pain, less health-care use, and more activity participation. Notably, pain was predictive of higher stress and lower positive mood on subsequent days. CONCLUSION: Pain in adolescents with SCD is stressful and may lead to alterations in mood states. Understanding the way in which these variables relate to health-care use and activity may lead to improved pain management approaches.     

Detection of dengue viral RNA using a nucleic acid sequence-based amplification assay

Faster techniques are needed for the early diagnosis of dengue fever and dengue hemorrhagic fever during the acute viremic phase of infection. An isothermal nucleic acid sequence-based amplification (NASBA) assay was optimized to amplify viral RNA of all four dengue virus serotypes by a set of universal primers and to type the amplified products by serotype-specific capture probes. The NASBA assay involved the use of silica to extract viral nucleic acid, which was amplified without thermocycling. The amplified product was detected by a probe-hybridization method that utilized electrochemiluminescence. Using normal human plasma spiked with dengue viruses, the NASBA assay had a detection threshold of 1 to 10 PFU/ml. The sensitivity and specificity of the assay were determined by testing 67 dengue virus-positive and 21 dengue virus-negative human serum or plasma samples. The "gold standard" used for comparison and evaluation was the mosquito C6/36 cell culture assay followed by an immunofluorescent assay. Viral infectivity titers in test samples were also determined by a direct plaque assay in Vero cells. The NASBA assay was able to detect dengue viral RNA in the clinical samples at plaque titers below 25 PFU/ml (the detection limit of the plaque assay). Of the 67 samples found positive by the C6/36 assay, 66 were found positive by the NASBA assay, for a sensitivity of 98.5%. The NASBA assay had a specificity of 100% based on the negative test results for the 21 normal human serum or plasma samples. These results indicate that the NASBA assay is a promising assay for the early diagnosis of dengue infections.     

Role of type 1 pili and effects of phase variation on lower urinary tract infections produced by Escherichia coli.

Phase variation of type 1 pili (fimbriae) was studied during the in vivo growth of Escherichia coli in two animal models. In the first, a heavily piliated urinary tract isolate (strain 149) was placed in 1-cm polypropylene chambers sealed with 0.22-micron-pore-size filters. The chambers were surgically implanted intraperitoneally in mice and recovered at various times. Piliation, as determined by electron microscopy and by measuring the minimum number of bacteria needed to produce mannose-sensitive hemagglutination, gradually decreased, and by day 5, most of the organisms were nonpiliated. In the second model, piliated and nonpiliated E. coli phase variants were inoculated into the bladders of BALB/c mice via urinary catheters, and their fate in the lower urinary tract was studied. Viable counts of bladder homogenates revealed that piliated phase variants were significantly more effective in colonizing the bladder urothelium than were their nonpiliated counterparts. Specific antibody to type 1 pili prevented colonization by the piliated organisms. After inoculation of piliated variants, the bladder-associated bacteria gave rise to approximately 80% mannose-sensitive hemagglutination-positive colonies, and immunocytochemistry of bladder lavages revealed large numbers of type 1 piliated bacteria adhering to the bladder transitional cells. Electron microscopy confirmed the presence of piliated bacteria in association with the bladder urothelium. The urine of these mice, whose bladders were colonized with piliated bacteria, frequently showed no growth, and when bacteria were present, strain 149 yielded less than 30% hemagglutination-positive colonies. The results suggest that for some E. coli strains, phase variation may be a factor in determining the fate of the E. coli in the urinary tract and that the urine may not necessarily reflect the bacteriologic state of the bladder mucosa.     

Reversed diurnal variation in depression: associations with a differential antidepressant response, tryptophan: large neutral amino acid ratio and serotonin transporter polymorphisms

BACKGROUND: Although diurnal variation of mood is a widely recognized symptom of depression, the clinical, neurobiological and psychopharmacological significance of this symptom has not previously been reported. METHOD: A total of 195 depressed out-patients underwent a detailed clinical and neurobiological assessment, and were then randomized to treatment with either fluoxetine or nortriptyline. RESULTS: Of the 195 depressed patients, 62 had a pattern of reversed diurnal variation (i.e. worse in the evening). Those with reversed diurnal variation had a poorer response to a serotonergic anti-depressant, were less likely to have bipolar II disorder, had a higher tryptophan: large neutral amino acid ratio and had different allele frequencies of the polymorphisms in the promoter region of the serotonin transporter. CONCLUSIONS: These findings raise the possibility of serotonergic influence on diurnal variation, and that the symptom of reversed diurnal variation is of relevance to antidepressant prescribing.