Understanding spatial and temporal patterning of astrocyte calcium transients via interactions between network transport and extracellular diffusion.

Astrocytes form interconnected networks in the brain and communicate via calcium signaling. We investigate how modes of coupling between astrocytes influence the spatio-temporal patterns of calcium signaling within astrocyte networks and specifically how these network interactions promote coordination within this group of cells. To investigate these complex phenomena, we study reduced cultured networks of astrocytes and neurons. We image the spatial temporal patterns of astrocyte calcium activity and quantify how perturbing the coupling between astrocytes influences astrocyte activity patterns. To gain insight into the pattern formation observed in these cultured networks, we compare the experimentally observed calcium activity patterns to the patterns produced by a reduced computational model, where we represent astrocytes as simple units that integrate input through two mechanisms: gap junction coupling (network transport) and chemical release (extracellular diffusion). We examine the activity patterns in the simulated astrocyte network and their dependence upon these two coupling mechanisms. We find that gap junctions and extracellular chemical release interact in astrocyte networks to modulate the spatiotemporal patterns of their calcium dynamics. We show agreement between the computational and experimental findings, which suggests that the complex global patterns can be understood as a result of simple local coupling mechanisms.

LightCycler multiplex PCR for the laboratory diagnosis of common viral infections of the central nervous system.

A conventional multiplex PCR assay that detects herpes simplex virus type 1 (HSV-1), HSV-2, varicella-zoster virus, and enteroviruses for the diagnosis of central nervous system infections was modified to be performed using the LightCycler system. The sensitivity of detection of each of the viruses using the LightCycler assay was compared to that of the conventional assay using external quality assessment material. The assays had equivalent sensitivities, but the LightCycler assay was more rapid, reduced the risk of contamination, and used an amplicon detection format that demonstrated greater discrimination than a gel electrophoresis method.

Non-convulsive status epilepticus as a complication of Mycoplasma pneumoniae infection.

Described is a confirmed case of non-convulsive status epilepticus, an unusual presentation of M. pneumoniae infection. The postulated pathological mechanisms in this infection are reviewed.

Direct sample polymerase chain reaction for the detection of Mycoplasma pneumoniae: a simple system for clinical application.

A semi-nested polymerase chain reaction system with primers derived from the P1 adhesin gene of Mycoplasma pneumoniae was evaluated for sensitivity and specificity for detection of M. pneumoniae. The method used target DNA within samples of M. pneumoniae broth cultures and clinical material, without a formal extraction process. The sensitivity for detection of DNA was found to be to a level of one copy per sample and was specific to M. pneumoniae only, discriminating from the other human mycoplasma and ureaplasma species tested. The system offers the opportunity for a simple and highly specific laboratory method for diagnosis which may be compared to currently available serological methods, and may provide another method of studying mycoplasma-induced pathology.

Neurological disease associated with Mycoplasma pneumoniae infection. PCR evidence against a direct invasive mechanism.

Aims-To investigate the pathology in patients presenting with sudden onset neurological illnesses associated with Mycoplasma pneumoniae infection.Methods-M pneumoniae infection was diagnosed by a highly rigorous interpretation of serological markers initially using complement fixation, agglutination and IgM antibodies. Confirmation of the serological diagnosis was achieved using indirect immunofluorescence for IgM, IgA, and IgG. Serum and cerebrospinal fluid (CSF) samples from these patients were examined using the polymerase chain reaction to look for evidence of M pneumoniae DNA.Results-No M pneumoniae DNA was found in any serum or CSF samples. Diagnosis of M pneumoniae infection by agglutination and complement fixation antibodies was not always confirmed by indirect immunofluorescence.Conclusion-The neurological lesions in these patients do not appear to be caused by the direct invasion of M pneumoniae into the nervous system. The lesions may be an immune response to infection. Serological diagnosis of M pneumoniae continues to be a laboratory problem.

Acute herpes hepatitis in pregnancy.

A 36 year old primigravid woman presented with a "flu-like" illness and premature labour, followed by severe pneumonitis and hepatitis in the late second trimester of pregnancy. Progressive deterioration obliged an elective delivery of twins, stillborn at 25 weeks of gestation. Herpes virus isolated from one placenta, but not from any fetal tissue, was the only indication of a systemic herpes simplex infection in which there were no mucocutaneous lesions seen before or during the illness. There was no history of herpes simplex infection and antibody studies were not helpful initially for a diagnosis that was confirmed in retrospect. Double staining for viral DNA and antigen showed that the virus was present in host monocytes.

Chicken pox infection (varicella zoster virus) and acute monoarthritis: evidence against a direct viral mechanism.

A 9 year old boy developed acute monoarthritis of the left knee concurrent with the appearance of a varicella zoster virus (VZV) rash. Repeated VZV DNA hybridisation of the cells within the synovial fluid and synovial membrane failed to show any evidence of intracellular virus. Virus was isolated from synovial fluid 24 hours after the start of clinical infection but not later. These findings suggest that the mechanism of the arthritis is not due to viral replication inside the swollen joint.

Follow-up report on 50 subjects vaccinated against herpes genitalis with Skinner vaccine.

Fifty subjects at risk of herpes genitalis received 109 immunizations with Skinner herpes vaccine and were assessed after a follow-up period of 4-48 months, representing a total follow-up period of 694 patient months. There was no evidence of contraction of herpes genitalis in 49 subjects. The risk of virus transmission and rate of contraction of disease was quantified by construction of two functions, namely a unit of exposure risk calculated per year (UYE) and standard contraction rate (SCR); in this study the SCR was 0.02. There was no evidence of significant side-effects from vaccination. Administration of Alhydrogel adjuvant with vaccine induced temporary granuloma formation in most subjects but was only detectable beyond 1 year of follow-up in one subject, in whom a painless swelling of 0.2 cm was detected 3 years after vaccination. There was no evidence of immunological reactivity to host cell or calf serum antigens in any of the subjects vaccinated.

Replication of type 2 herpes simplex virus in human endocervical tissue in organ culture.

The replication of type 2 herpes simplex virus in human endocervical tissue in organ culture was investigated. The temporal profile of virus replication was related to the initial virus inoculum; high input inocula induced a rapid increase in virus titre while lower multiplicities induced a more slow-rising increase in virus titre. Our evidence suggested that explants were capable of initiating and supporting virus replication for at least 2 weeks following establishment of the culture. Virus yields were optimal when explants were cultured at 37 degrees and in serum-supplemented medium. Explants also supported the replication of type 1 herpes simplex virus and a "non-human" herpes simplex virus (pseudo-rabies virus). The optimal conditions for replication of type 2 herpes simplex virus in human endocervical explants have been established and will provide a model permitting precise investigation of lytic or other virus-cervical cell interactions and their possible relationship to herpes virus-induced pre-invasive carcinoma of this organ.