Characterization of and functional antigen presentation by central nervous system mononuclear cells from mice infected with Theiler's murine encephalomyelitis virus

We examined the phenotype and function of cells infiltrating the central nervous system (CNS) of mice persistently infected with Theiler's murine encephalomyelitis virus (TMEV) for evidence that viral antigens are presented to T cells within the CNS. Expression of major histocompatibility complex (MHC) class II in the spinal cords of mice infected with TMEV was found predominantly on macrophages in demyelinating lesions. The distribution of I-As staining overlapped that of the macrophage marker sialoadhesin in frozen sections and coincided with that of another macrophage/microglial cell marker, F4/80, by flow cytometry. In contrast, astrocytes, identified by staining with glial fibrillary acidic protein, rarely expressed detectable MHC class II, although fibrillary gliosis associated with the CNS damage was clearly seen. The costimulatory molecules B7-1 and B7-2 were expressed on the surface of most MHC class II-positive cells in the CNS, at levels exceeding those found in the spleens of the infected mice. Immunohistochemistry revealed that B7-1 and B7-2 colocalized on large F4/80(+) macrophages/microglia in the spinal cord lesions. In contrast, CD4(+) T cells in the lesions expressed mainly B7-2, which was found primarily on blastoid CD4(+) T cells located toward the periphery of the lesions. Most interestingly, plastic-adherent cells freshly isolated from the spinal cords of TMEV-infected mice were able to process and present TMEV and horse myoglobin to antigen-specific T-cell lines. Furthermore, these cells were able to activate a TMEV epitope-specific T-cell line in the absence of added antigen, providing conclusive evidence for the endogenous processing and presentation of virus epitopes within the CNS of persistently infected SJL/J mice.     

Multiple-spell, discrete-time survival analysis of developmental data: object concept in pigtailed macaques

To measure cognitive development in 123 pigtailed macaques, we calculated medians and quartiles for the milestones of classical (Piagetian) object concept development (plain reach, partial-hide, full-hide, and A-not-B) in both 2-dimensional (screen) and 3-dimensional (well) tasks. Using multiple-spell, discrete-time survival analysis, we examined the influence of 4 independent variables (starting age, sex, birth weight, and task) on the probability of completing the milestones on any given test. The significant predictors for completion of the well sequence were birth weight and task. The best predictors for completion of the screen sequence were birth weight, number of test sessions, and interaction between birth weight and task. Birth weight had a greater predictive relationship in the earlier stages. This analysis provided information that cannot be obtained with traditional parametric methods.     

Transposition flaps adn full-thickness skin grafts used as interposition tissue: progressive physiological expansion

Expressing proteins and polypeptides as fusions to ubiquitin offers the advantage of an often dramatic increase in yield, and the ability to produce any desired amino-terminal residue upon ubiquitin cleavage. The recent availability of cloned ubiquitin-cleaving enzymes has enhanced this technique for both bacterial and eukaryotic host systems.     

Predictability of sacral base levelness based on iliac crest measurements

The pharmacokinetic profile of the melanotropic peptide, melanotan-II (MT-II), was determined in rats following a 0.3 mg kg-1 intravenous dose. Regression analysis of the plasma MT-II concentrations determined using HPLC and bioassay methods indicated the existence of a significant linear correlation (r = 0.90, p < 0.001). The plasma concentration versus time plots determined using the two assay methods yielded biphasic disposition profiles that were essentially superimposable. The following pharmacokinetic parameters were assessed from plasma concentration versus time data using both methods: Cmax, AUC, CLs, t1/2 beta, MRT, Vd beta, and Vss. Statistical comparison showed that the parameters measured by each method were not significantly different (at the 0.05 level) except for t1/2 beta, MRT and Vss. The presence of even one aberrant data point in the beta-phase can significantly influence t1/2 beta when only a few data points are available in the beta-phase. Since MRT and Vss were calculated from t1/2 beta it is not surprising that these two parameters also differed between methods.     

The orlA gene from Aspergillus nidulans encodes a trehalose-6-phosphate phosphatase necessary for normal growth and chitin synthesis at elevated temperatures

A cosmid carrying the orlA gene from Aspergillus nidulans was identified by complementation of an orlA1 mutant strain with DNA from the pKBY2 cosmid library. An orlA1 complementing fragment from the cosmid was sequenced. orlA encodes a predicted polypeptide of 227 amino acids (26360 Da) that is homologous to a 211-amino-acid domain from the polypeptide encoded by the Saccharomyces cerevisiae TPS2 gene and to almost the entire Escherichia coli otsB-encoded polypeptide. TPS2 and otsB each specify a trehalose-6-phosphate phosphatase, an enzyme that is necessary for trehalose synthesis. orlA disruptants accumulate trehalose-6-phosphate and have reduced trehalose-6-phosphatate phosphatase levels, indicating that the gene encodes a trehalose-6-phosphatate phosphatase. Disruptants have a nearly-wild-type morphology at 32 degrees C. When germinated at 42 degrees C, the conidia and hyphae from disruptants are chitin deficient, swell excessively, and lyse. The lysis is almost completely remedied by osmotic stabilizers and is partially remedied by N-acetylglucosamine (GlcNAc). The activity of glutamine:fructose-6-phosphate amido-transferase (GFAT), the first enzyme unique to aminosugar synthesis, is reduced and is labile in orlA disruption strains. The findings are consistent with the hypothesis that trehalose-6-phosphate reduces the temperature stability of GFAT and other enzymes of chitin metabolism at elevated temperatures. The results extend to filamentous organisms the observation that mutations in fungal trehalose synthesis are highly pleiotropic and affect aspects of carbohydrate metabolism that are not directly related to trehalose synthesis.     

Fusion of the nucleoporin gene NUP98 to HOXA9 by the chromosome translocation t(7;11)(p15;p15) in human myeloid leukaemia

The parasympathetic nervous system plays a major role in the pathophysiology of many cardiovascular disease, particularly in modulating myocardial electrical stability. Measurements of heart rate variability have been widely used to assess parasympathetic activity. The reproducibility of measurements obtained from 24-hour ambulatory electrocardiograms has not been well documented. We have developed a technique for measuring parasympathetic activity from clinical quality 24-hour ambulatory electrocardiograms by counting beat-to-beat increases in RR interval that are > 50 ms. To determine the reproducibility and sensitivity of our technique, we analyzed repeated 24-hour electrocardiograms of 173 subjects (19 normal subjects, 67 patients with ischemic heart disease, and 87 diabetics) followed up over periods of 2 to 16 weeks. In all subject groups, mean values for repeated measurements were virtually identical. Measurements were stable in all 3 groups throughout the course of the study, as assessed by intraclass correlation coefficients. This technique is sensitive enough to detect relatively small changes in parasympathetic activity in subjects, as demonstrated by the calculated Bland and Altman coefficients of repeatability. Reproducibility and sensitivity of our technique are particularly good in normal subjects and in patients with ischemic heart disease. The results obtained with this technique imply that other related measurements of parasympathetic activity will show similar excellent short- and long-term reproducibility and sensitivity.