Influence of thyroid hormone disruption on the incidence of shingles.

The reactivation of dormant alpha-human herpesvirus (αHHV) has been attributed to various causes often referred to as stressors. However, no clinical study investigating the relationship between stressors and reactivation exists in humans at this time. Herpes simplex virus type-1 (HSV-1), an important αHHV, was shown to have its gene expression and replication regulated by thyroid hormone (TH) using molecular biology approaches. Varicella zoster virus (VZV) is categorized in αHHV superfamily and shares similar homology with HSV-1. We hypothesize that a history of TH imbalance may be associated with the incidence of shingles (VZV reactivation). This current pilot study, based on a hospital medical claims database, was conducted as a retrospective case-controlled investigation to determine if a putative link between TH imbalance and incidence of shingles is present. An odds ratio of 2·95 with a χ 2 value of 51·74 was calculated for the total population diagnosed with TH disruption and shingles. Further analyses indicated that African American males exhibited a much higher chance of simultaneous diagnoses. These results show that a TH imbalance history may affect VZV reactivation at different incidence rates in different races and age groups.

Induction of Transcription Factor Early Growth Response Protein 1 during HSV-1 Infection Promotes Viral Replication in Corneal Cells.

AIMS: To understand the mechanisms of Early Growth Response Protein 1 (Egr-1) induction upon HSV-1 lytic infection and its roles in regulating viral gene expression and replication. STUDY DESIGN: Rabbit corneal cell line SIRC and other cell lines were infected by HSV-1 to investigate the Egr-1 induction and its occupancy on the viral genome in different conditions. UV-inactivated HSV-1 and a recombinant virus over-expressing Egr-1 were generated to evaluate the regulatory effects on viral gene expression and replication during the infection. METHODOLOGY: Egr-1 induction triggered by viral infection was determined by Western Blot analyses and immune-fluorescent microscopy. Real-time RT-PCR and a novel Cignal™ Reporter Assay were used for quantitative measurement of Egr-1 expression. Chromatin Immuno-precipitation (ChIP) was performed to address the Egr-1 occupancy to the viral regulatory sequences and the influence on viral replication was assessed by plaque assays. RESULTS: Our results indicated that Egr-1 expression requires viral gene expression since the UV-inactivated HSV-1 failed to produce Egr-1 protein. Blockade of viral replication did not block the Egr-1 protein synthesis, supporting the hypothesis that HSV-1 replication was not essential for Egr-1 production. Chromatin immune-precipitation (ChIP) and RT-PCR assays demonstrated that induced Egr-1 was able to interact with key regulatory elements near HSV-1 immediate-early (IE) genes and promote viral gene expression. Recombinant virus overexpressing Egr-1 revealed that Egr-1 enhanced the viral replication and the release of infectious virus. CONCLUSION: Together these results concluded that HSV-1 triggers the expression of an important host transcription factor Egr-1 via a unique mechanism and benefit the viral gene expression and replication.

Stability and subcellular localization of cytadherence-associated protein P65 in Mycoplasma pneumoniae.

The surface protein P65 is a constituent of the Mycoplasma pneumoniae cytoskeleton and is present at reduced levels in mutants lacking the cytadherence accessory protein HMW2. Pulse-chase studies demonstrated that P65 is subject to accelerated turnover in the absence of HMW2. P65 was also less abundant in noncytadhering mutants lacking HMW1 or P30 but was present at wild-type levels in mutants lacking proteins A, B, C, and P1. P65 exhibited a polar localization like that in wild-type M. pneumoniae in all mutants having normal levels of HMW1 and HMW2. Partial or complete loss of these proteins, however, correlated with severe reduction in the P65 level and the inability to localize P65 properly.

Stability of Mycoplasma pneumoniae cytadherence-accessory protein HMW1 correlates with its association with the triton shell.

Mycoplasma pneumoniae adsorbs to host respiratory epithelium primarily by its attachment organelle, the proper function of which depends upon mycoplasma adhesin and cytoskeletal proteins. Among the latter are the cytadherence-associated proteins HMW1 and HMW2, whose specific roles in this process are unknown. In the M. pneumoniae cytadherence mutant I-2, loss of HMW2 results in accelerated turnover of HMW1 and other cytadherence-accessory proteins, probably by proteolysis. However, both the mechanism of degradation and the means by which these proteins are rendered susceptible to it are not understood. In this study, we addressed whether HMW1 degradation is a function of its presence among specific subcellular fractions and established that HMW1 is a peripheral membrane protein that is antibody accessible on the outer surfaces of both wild-type and mutant I-2 M. pneumoniae but to a considerably lesser extent in the mutant. Quantitation of HMW1 in Triton X-100-fractionated extracts from cells pulse-labeled with [(35)S]methionine indicated that HMW1 is synthesized in a Triton X-100-soluble form that exists in equilibrium with an insoluble (cytoskeletal) form. Pulse-chase analysis demonstrated that over time, HMW1 becomes stabilized in the cytoskeletal fraction and associated with the cell surface in wild-type M. pneumoniae. The less efficient transition to the cytoskeleton and mycoplasma cell surface in mutant I-2 leads to accelerated degradation of HMW1. These data suggest a role for HMW2 in promoting export of HMW1 to the cell surface, where it is stable and fully functional.

Structure, function, and assembly of the terminal organelle of Mycoplasma pneumoniae.

Mycoplasmas are cell wall-less bacteria at the low extreme in genome size in the known prokaryote world, and the minimal nature of their genomes is clearly reflected in their metabolic and regulatory austerity. Despite this apparent simplicity, certain species such as Mycoplasma pneumoniae possess a complex terminal organelle that functions in cytadherence, gliding motility, and cell division. The attachment organelle is a membrane-bound extension of the cell and is characterized by an electron-dense core that is part of the mycoplasma cytoskeleton, defined here for working purposes as the protein fraction that remains after extraction with the detergent Triton X-100. This review focuses on the architecture and assembly of the terminal organelle of M. pneumoniae. Characterizing the downstream consequences of defects involving attachment organelle components has made it possible to begin to elucidate the probable sequence of certain events in the biogenesis of this structure.

Overlapping distribution of the 130- and 110-kDa myosin I isoforms on rat liver membranes.

The biochemical and mechanochemical properties and localization of myosin I suggest the involvement of these small members of the myosin superfamily in some aspects of intracellular motility in higher cells. We have determined by quantitative immunoblotting with isoform-specific antibodies that the 130-kDa myosin I (myr 1 gene product) and 110-kDa myosin I (myr 2 gene product) account for 0.5 and 0.4%, respectively, of total rat liver protein. Immunoblot analyses reveal that the 130- and 110-kDa myosins I are found in several purified subcellular fractions from rat liver. The membrane-associated 130-kDa myosin I is found at the highest concentration in the plasma membrane (28 ng/microg plasma membrane protein) followed by the endoplasmic reticulum-like mitochondria-associated membrane fraction (MAM; 10 ng/microg MAM protein), whereas the 110-kDa myosin I is found at the highest concentration in Golgi (50 ng/¿g Golgi protein) followed by plasma membrane (20 ng/microg) and MAM (7 ng/microg). Our analyses indicate that myosin I is peripherally associated with Golgi and MAM and its presence in these fractions is not a consequence of myosin I bound to contaminating actin filaments. Although found in relatively low concentrations in microsomes, because of the abundance of microsomes, in liver most of the membrane-associated myosin I is associated with microsomes. Neither myosin I isoform is detected in purified mitochondria. This is the first quantitative analysis addressing the cellular distribution of these mammalian class I myosins.

Zoster myelitis: improvement with antiviral therapy in two cases.

This report describes two patients with acquired immunodeficiency syndrome (AIDS) and herpes zoster myelopathy. Patient one had a T-8 myelitis that preceded the onset of T-8-distribution zoster and was followed by cervical myelopathy. Antibody to varicella zoster virus (VZV) was present in the CSF. He never received steroids or other immunosuppressive drugs, and his condition improved dramatically after treatment with intravenous acyclovir. The second patient had a rapidly progressive myelitis with paralysis of both legs. Detection of VZV DNA and antibody to VZV in his CSF led to successful treatment with famciclovir despite discontinuation of dexamethasone and earlier treatment failure with acyclovir. These cases support the idea that VZV myelopathy in the immunosuppressed host is caused by virus invasion. CSF analysis for antiviral antibody and for VZV DNA by polymerase chain reaction are helpful in establishing the diagnosis. Aggressive antiviral therapy is advised.

Effect of seizures on cerebral blood flow measured with 15O-H2O and positron emission tomography.

To study quantitative alterations in regional cerebral blood flow (rCBF) accompanying seizures, and to assess the utility of ictal activation PET scanning as a noninvasive clinical tool for localization of epileptogenic foci, we used pentylenetetrazole (PTZ) to induce seizures during 15O-water positron emission tomography (PET) CBF measurement in 15 patients with uncontrolled complex partial seizures (CPS) who had been referred for surgical evaluation. Continuous EEG monitoring was performed during the PET scans. After baseline scans were obtained, each patient was injected with 150-300 mg PTZ. Two patients had generalized tonic-clonic seizures (GTCs). CBF increases were asymmetrical. Two patients (in 1 the seizure occurred spontaneously, without PTZ injection) who had CPS had bitemporal 70-80% increases in CBF. Thalamic CBF increased during both CPS and GTCS. Five patients had an increase in focal EEG interictal abnormality, accompanied by focal flow decreases in 3. PTZ injection not accompanied by clinical seizures did not increase CBF. Partial seizures may be associated with bilateral increases in CBF, and subcortical gray regions are involved in ictal activation.

Identification of brush border myosin-I in liver and testis.

Brush border myosin-I, or BBMI, constitutes the lateral links that connect in intestinal microvilli the core bundle of actin filaments to the membrane. Although related molecules have been identified in other higher eukaryotic tissues, northern blot analysis has indicated that the distribution of this particular myosin-I isoform is restricted essentially to intestine. Using reverse transcriptase polymerase chain reaction we have identified BBMI in a wide range of tissues including liver and testis. Our results also indicate that in testis the BBMI gene might be alternatively spliced.

IFN-alpha induces MxA gene expression in cultured human corneal fibroblasts.

Treatment of certain human cells with Interferon-alpha (IFN-alpha) induces the synthesis of a 76 kDa protein designated MxA that is involved in resistance to viral infection. We have used a specific cDNA clone and monoclonal Ab to show that MxA is induced in IFN-alpha treated human corneal fibroblast cultures. Mx RNA was increased 23-fold and 45-fold after 5 and 9 h of IFN-alpha treatment, respectively. The MxA protein was detectable by immunoblotting at 5 hr after IFN treatment and peaked at 17 hr. Concentrations of IFN-alpha as low as 1 U/ml induced detectable amounts of MxA, and expression was maximal at 1 x 10(3) U ml-1. These results confirm that MxA synthesis is induced in human corneal fibroblasts treated with IFN-alpha.

The dynamics of metabolic change following seizures as measured by positron emission tomography with fludeoxyglucose F 18.

OBJECTIVE: To examine the time course of alterations in glucose metabolism in relation to the interval from the last seizure, focus laterality, seizure frequency, and seizure type. DESIGN: Metabolic study with the use of positron emission tomography with fludeoxyglucose F 18. Blinded scan evaluation with use of a standard template. Multivariate regression analysis of positron emission tomographic data. SETTING: National Institutes of Health Clinical Center, Bethesda, Md. PATIENTS: Thirty-two adults with intractable partial epilepsy and lateralized seizure onset documented by video-electroencephalographic monitoring. MAIN OUTCOME MEASURE: Normalized metabolic rate for glucose ipsilateral and contralateral to the epileptic focus. RESULTS: The most dramatic changes occurred in inferior temporal regions; the midtemporal region was affected as well. Effects lasting 48 hours were found after both simple and complex partial seizures. The time course was different for the two types of seizures. The inferior temporal metabolic rate ipsilateral to the focus increased compared with the interictal rate during the 24-hour period following simple partial seizures; a nadir occurred in the second 24 hours. The rate then rose to an intermediate level after 48 hours. The relative to an intermediate level after 48 hours. The relative regional increase in ipsilateral metabolism following complex partial seizures persisted for 48 hours before falling. CONCLUSION: The brain may take longer than 24 hours after a partial seizure to return to its baseline state.

Cortical magnetic and electric fields associated with voluntary finger movements.

Multichannel recordings of both movement-related magnetic fields (MRMFs) and movement-related cortical potentials (MRCPs) were simultaneously recorded in association with voluntary unilateral self-paced index finger abduction movement in two normal volunteers. 1) Slow magnetic field (readiness field; RF) can be detected several hundred msec before the movement onset, and its field distribution indicates the existence of the largest generator source over the contralateral primary motor area. Taken together with the vertex-maximal Bereitschaftspotential which corresponds to the earlier part of the RF, the complexity of this magnetic field suggested by relatively low correlation value in single dipole model indicates the co-activation of other underlying generators besides this largest dipole. 2) The utilization of MRMF with MRCP facilitates the separation of two distinct electrophysiological events in proximity to the movement onset, which are difficult to be determined by the technique of MRCP only. Those are the motor field (MF) and the movement evoked field I (MEFI) in MRMF, and the parietal peak motor potential (ppMP) and the frontal peak motor potential (fpMP) in MRCP, which occur approximately 20 and 100 msec after EMG onset, respectively. These two subcomponents may imply the culmination of motor cortex and sensory feedback activation, respectively. Combined study of MRMF and MRCP will provide better definition of cortical events related to voluntary movement than the study of either modality alone.

How well does a three-sphere model predict positions of dipoles in a realistically shaped head?

The electrical potential produced by a dipole in the temporal or frontal lobe was calculated for a realistically shaped scalp, skull, and brain. This potential distribution was then used with a 3-sphere model to predict the position, orientation, and strength of the dipole source. The original and predicted dipole positions differed by an average of 1.97 cm, with a difference of more than 4 cm in some cases. Control calculations demonstrated that this difference was not caused by numerical artifacts in the computation, but instead was due to a true difference between the 3-sphere and realistically shaped head models.

Interferon-alpha and interferon-gamma induced modulation of proteins in human corneal fibroblasts.

Little is known about the effects of interferon (IFN) on cell function in the eye. We have analyzed the effect of INF-alpha and IFN-gamma on the expression of proteins in cultured human corneal fibroblasts. Treatment with IFN-alpha increased the synthesis of proteins of 84, 76, 52, and 28 kD and decreased the synthesis of a 72-kD protein. Treatment with IFN-gamma increased the synthesis of proteins of 83, 66, 64, 54, and 47 kD. The effect of IFN-alpha and IFN-gamma were first detected at 5-9 h and 9 h, respectively, after the addition of the IFNs and were maximal at 17 and 24 h, respectively. Most of the changes were seen at doses of 1 x 10(1) to 1 x 10(2) U/ml of IFN-alpha or IFN-gamma and were maximal at 1 x 10(2) to 1 x 10(3) U/ml. Thus, each IFN induced distinct proteins based on apparent molecular weight and isoelectric point. These results show that IFN-alpha and IFN-gamma affect the synthesis of small groups of distinct proteins in human corneal fibroblasts.

In vivo validation of distributed source solutions for the biomagnetic inverse problem.

Probabilistic modelling of continuous current sources is applied to the analysis of MEG signals generated by current dipoles implanted in the head of a living human subject. Estimates of the distribution of activity within a circular disk are obtained from signals generated by a single implanted dipole and by a pair of simultaneously active implanted dipoles. The orientation and depth of the disc is determined in advance from the experimental geometry and the measurements. The resulting reconstructions constitute the first in vivo validation of distributed source imaging; they provide a complementary test to earlier works using computer generated data and tests using point source analysis of signals generated by a single implanted dipole. In this work we provide a literal test of spatial resolution by resolving two nearby point-like sources. Temporal resolution is addressed in a de facto manner by imaging at one millisecond intervals. Computer simulations, with controlled amount of noise, are used to demonstrate the robustness of the results, and show the interplay between high spatial accuracy and noise insensitivity.

Enhanced inhibition of herpes simplex virus type 1 growth in human corneal fibroblasts by combinations of interferon-alpha and -gamma.

Trials testing the topical treatment of herpes simplex virus (HSV) ocular infections with single interferons (IFN) have provided mixed results. To determine if combination therapy with IFN may be more effective, the ability of combinations of IFN-alpha and IFN-gamma to inhibit HSV growth in human corneal fibroblasts (HCF) was assessed. Virus yields were reduced 282-fold and 37-fold, respectively, in HCF treated with either IFN-alpha or IFN-gamma (10(3) units/mL each). In cells treated with a combination of IFN-alpha and IFN-gamma (10(3) units/mL each), an average reduction of 5.1 x 10(5)-fold in the yield of infectious virus was achieved. Combinations of IFN-alpha and IFN-gamma considerably enhanced the antiviral effect in HCF, suggesting that combination treatment may be efficacious against ocular HSV infections; these findings provide a possible explanation at the cellular level for the poor results achieved in previous clinical trials.

Temporal lobectomy for uncontrolled seizures: the role of positron emission tomography.

We evaluated the role of positron emission tomography (PET) with [18F]deoxyglucose (FDG) (FDG-PET) for planning surgery in 53 patients who had temporal lobectomy for uncontrolled seizures at National Institutes of Health from 1981 to 1990. Investigators blinded to PET data used results of telemetered video-electroencephalographic ictal monitoring and other standard criteria to decide whether subdural electrodes (22 patients, i.e., the "invasive" group) should be implanted or surgery performed. PET scans were analyzed using a standard regional template. Mean lateral but not mesial temporal asymmetry was significantly higher in patients who became seizure free (p < 0.03). Patients with > or = 15% hypometabolism were significantly more likely to be seizure free in the entire study population and the invasive subgroup. Visual identification of hypometabolism was less accurate. When a clear temporal ictal surface electroencephalographic focus was present, FDG-PET provided less additional information. FDG-PET may be particularly valuable if the surface electroencephalographic scan is nonlocalizing. In addition to helping to identify the seizure focus, it may allow limitation of invasive electrode placement to those necessary for functional mapping. When PET is used to identify epileptic foci, quantitative measurements of asymmetry should be made.

Comparison of PET measurements of cerebral blood flow and glucose metabolism for the localization of human epileptic foci.

We compared the relative sensitivity of two interictal PET techniques, bolus injection of [15O] labeled water for estimation of cerebral blood flow (H2(15)O CBF-PET), and 18F 2-deoxyglucose (18FDG-PET) for cerebral glucose metabolism (CMRglc), and T2-weighted magnetic resonance imaging, in 28 patients with medically intractable complex partial seizures undergoing evaluation for surgery. There were statistically significant associations between lateralization by 18FDG-PET, and MRI, but not H2(15)O CBF-PET, and lateralization of the epileptic focus as defined by scalp-sphenoidal ictal EEG. Fifteen patients had surgery or subdural electrodes. 18FDG-PET was more closely associated with a good outcome than H2(15)O CBF-PET, which, in addition, showed hypoperfusion contralateral to the epileptic temporal lobe in several cases. H2(15)O sensitivity may have been reduced by technical factors, but 18FDG-PET appears to be more specific for localization of epileptic zones.

Cerebral metabolism and depression in patients with complex partial seizures.

Twenty-three patients with complex partial seizures were evaluated with 18F-2-deoxyglucose positron emission tomography and with the Beck Depression Inventory. Five of 10 patients with left and zero of eight with right temporal electroencephalographic foci had depressive symptoms; one of five patients with poorly localized electroencephalographic foci also scored in the depressed range. Temporal, frontal, caudate, and thalamic normalized glucose metabolic rates among five patients with depressive symptoms and well-localized left temporal epileptogenic regions were compared with five patients without depressive symptoms but with similar electroencephalographic characteristics. Multifactorial analysis of variance yielded a significant nonlateralized mood by region interaction. Of nine individual regions compared, only inferior frontal cortex showed a significant difference in normalized regional metabolic rate between depressed and nondepressed patients. Metabolism in this region also distinguished patients with depressive symptoms from normal control subjects. Depressive symptoms in patients with complex partial seizures are associated with a bilateral reduction in inferior frontal glucose metabolism, compared with patients without depressive symptoms and normal control subjects. The frontal lobe hypometabolism observed in patients with depressions associated with epilepsy, Parkinson's disease, and primary affective disorder suggests that similar frontal lobe metabolic disturbances could underlie these conditions.