Magnetic resonance imaging characteristics of multiple sclerosis plaques imaged with two-dimensional and three-dimensional Fourier transform techniques at low and mid field strengths

A total of 58 multiple sclerosis lesions from 16 patients were used to characterize the performance of a low field system for the detection of edematous (e.g., water-elevating) brain lesions. Contrast, signal-to-noise, and their product (signal difference to noise) were measured for two-dimensional and three-dimensional Fourier transform techniques at low field strength (640 G) and compared to two-dimensional sequences at mid field strength (3,500 G). The results showed numerically that low-field strength magnetic resonance imaging can reliably detect multiple sclerosis lesions, and, by extension, other water-elevating lesions, although with lower confidence levels.

Major histocompatibility complex binding and T cell recognition of a viral nonapeptide containing a minimal tetrapeptide

The primary immune response of cytotoxic T lymphocytes in H-2d and H-2q mice to infection with lymphocytic choriomeningitis virus is directed mostly towards the common major T cell epitope of amino acids 112-132 on the viral nucleoprotein (NP). The molecules responsible for presentation of the T cell epitope NP112-132 are in both haplotypes the MHC class I L antigens (Ld, Lq). Truncations of the amino and carboxy termini of the NP 112-132 sequence revealed the nonapeptide RPQASGVYM (NP118-126) as a most effective peptide antigen, but even the tetrapeptide GVYM was recognized by CTL of both haplotypes in a class I antigen-restricted specificity. When tyrosine (Y) or methionine (M) were substituted with alanine, CTL recognition of the altered nonamer required 10(6) to 10(8) times higher peptide concentrations and in one case (Y----A on Ld) the peptide was not recognized at all. Up-modulation of the expression of Ld and Lq class I antigens as measured by flow cytometry correlated with the ability to present the peptide antigens. The only exception was peptide NP118-126 (M----A), which was recognized by T cells on L-Ld and L-Lq target cells but failed to up-regulate Ld and Lq antigens.

Assessment of pretransplant prognosis in patients with cirrhosis

The objective of this prospective study was to assess the prognostic value of dynamic liver function tests and traditional methods of evaluating liver function in potential candidates for hepatic transplantation. Patients who underwent orthotopic liver transplantation within the follow-up period of 120 days were excluded. The study included 107 adult and 57 pediatric patients with cirrhosis. Postnecrotic cirrhosis was present in 107 and biliary cirrhosis in 57 of 164 patients. During the follow-up period, 26 of 164 patients died of their liver disease. At the time of inclusion, we recorded monoethylglycinexylidide (MEGX) formation from lidocaine, indocyanine green (ICG) half-life, bilirubin and albumin serum concentration, activity of cholinesterase and alkaline phosphatase, prothrombin time, the clinical complication of ascites, and--in adults--the Pugh score also. These variables were subjected as covariates to a survival analysis (Cox proportional hazards regression model) using separately the data from adults, pediatric patients, all patients with postnecrotic cirrhosis, and all patients with biliary cirrhosis. In all of these four subgroups there was a significant relationship between MEGX and ICG test results and the 120-day survival. In the stepwise analysis, none of the remaining parameters contributed to a further relevant improvement of our predictive ability when added to the values of ICG and MEGX. Our results suggest that the ICG and the MEGX test are superior to conventional liver function tests and the Pugh score in assessing short-term prognosis in cirrhotics independently from the etiology of the underlying liver disease. These findings may have important implications for determining the optimum timing of transplantation.

[Therapeutic and toxic plasma concentrations and elimination half-lives of commonly used drugs]

For 253 frequently used drugs therapeutic and, if data were available, toxic, and fatal plasma concentrations as well as elimination half-lives were compiled in a table. To assess the significance of drug levels for the therapeutic monitoring of patients, it is essential that a collection of data is readily available. In addition, this list can assist the diagnostic assessment in case of intoxications.

A retinal ganglion cell neurotrophic factor purified from the superior colliculus

Dissociated neonatal rat retinal ganglion cells can be maintained by the addition of an extract from the neonatal superior colliculus. This extract can support 95% of ganglion cells over 24 h in culture; in addition it promotes the expression of neurites from these cells. This report describes the purification of a neurotrophic factor from the superior colliculus which supports the survival of 80% of retinal ganglion cells over 24 h in vitro. The purification procedure involves a combination of dye-ligand, anion-exchange, and molecular sieve chromatography. The purified neurotrophic factor has a Stokes radius of approximately 200 A using molecular sieve chromatography in the presence of a chaotropic agent. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified factor indicates that it is a glycoprotein that migrates with a molecular mass greater than 400 kDa. Further characterization of this high-molecular-mass glycoprotein by enzymatic digestion demonstrated that it is a chondroitin sulfate proteoglycan. This factor is clearly distinguishable from other neurotrophic factors that have an effect on retinal ganglion cells such as brain-derived neurotrophic factor and fibroblast growth factor. The chondroitin sulfate proteoglycan from the neonatal superior colliculus is the first proteoglycan to be identified as a neurotrophic factor.

Regulation and cellular localization of the membrane-bound thyrotropin-releasing hormone-degrading enzyme in primary cultures of neuronal, glial and adenohypophyseal cells

Using monolayer cultures from murine brain and reaggregate cell cultures of rat anterior pituitary we observed that TRH (pyroGlu-His-Pro-NH2) added to the culture medium was not taken up by these cells but hydrolyzed at the pyroGlu-His bond by an enzyme obviously located at the cell surface. This enzyme exhibited a high degree of substrate specificity and other characteristics of the membrane-bound TRH-degrading enzyme. Relatively high enzymatic activity was associated with cultured neuronal cells from embryonic rat brain while glial cells were almost devoid of this peptidase activity. Rather low, but significant activity was found on anterior pituitary cell aggregates. In agreement with previous in vivo studies we observed that the TRH-degrading ectoenzyme on adenohypophyseal cells was regulated by estradiol and stringently controlled by T3, but that the activity of the brain enzyme was not. When pituitary cells were separated according to their size and density and established in reaggregate cell culture, a close correlation was always observed between enzyme activity and the distribution of lactotrophic cells regardless of the animal models (eu- and hypothyroid adult male rats) used and the cell fractionation techniques (velocity sedimentation and sequential velocity/buoyant density sedimentation) employed. Such a close correlation was not observed with other cell types, such as the somatotrophic cells, the folliculo-stellate cells, the ACTH-producing AtT20 pituitary cells, or thyrotrophic cells. In conclusion, the high degree of substrate specificity, the tissue-specific regulation, and the very heterogeneous distribution of the TRH-degrading ectoenzyme on brain and pituitary cells strongly support the hypothesis that this enzyme serves very specialized functions in the transmission of TRH signals at specific target sites.

Antiviral cytotoxic T cell response induced by in vivo priming with a free synthetic peptide

Induction in vivo of antiviral cytotoxic T cell response was achieved in a MHC class I-dependent fashion by immunizing mice three times with a free unmodified 15-mer peptide derived from the nucleoprotein of lymphocytic choriomeningitis virus in IFA. The effector T cells are CD8+, restricted to the class I Ld allele of the analyzed mouse strain, and are specific both at the level of secondary restimulation in vitro and at the effector T cell level. These results suggest that cocktails of viral peptides may be used as antiviral T cell vaccines.

Lidocaine metabolite formation as a measure of liver function in patients with cirrhosis

A method for rapid assessment of hepatic function in cirrhotics based on the formation of the lidocaine metabolite, monoethylglycinexylidide (MEGX), was evaluated. The formation kinetics and urinary excretion patterns of MEGX clearly distinguished cirrhotics (n = 12) from healthy volunteers (n = 16). In a prospective study, we compared the prognostic value of the MEGX test with that of traditional parameters in transplant candidates. Patients who underwent transplantation during follow-up were excluded. The study included 58 adult patients with biopsy-proven posthepatitic or biliary cirrhosis. During the follow-up period of 120 days, 10 of 58 patients died of their liver disease. At the time of inclusion, we recorded MEGX formation, indocyanine green (ICG) half-life, caffeine clearance, and the Child-Pugh score. These variables were subjected as covariates to a survival analysis (Cox proportional hazards regression model). The results of the MEGX and the ICG test were significantly related to the 120-day survival. In the stepwise analysis, none of the parameters evaluated contributed to a further significant improvement of our predictive ability when added to the values of ICG (improvement: p less than 0.0005) and MEGX (improvement: p less than 0.0005). These findings suggest that the ICG and MEGX tests were the best short-term prognostic indicators. The easy handling favors the MEGX test over the ICG test as a tool for assessment of hepatic function and short-term prognosis in transplant candidates with cirrhosis.

[Treatment of chronic hepatitis B with interferon alpha-2b]

In a prospective randomized trial 58 patients (46 men, 12 women; mean age 41 [18-65] years) with histologically proven chronic hepatitis B and demonstration of HBs antigen and hepatitis B virus DNA in serum were randomly divided into two groups: 30 patients were treated with recombinant alpha 2b interferon. The interferon was administered subcutaneously, 3 x 10(6) IU, three times weekly for four months. 28 patients served as untreated controls. There was a six-month post-treatment follow-up. Two patients in the treatment group and one in the control group had to be excluded later. In the treatment group one patient responded completely (HBs antigen, HBe antigen and HBV-DNA negative) and eight partially (HBe antigen and HBV-DNA negative). In three patients of the control group, HBe antigen and HBV DNA were no longer demonstrated (P less than 0.05). The loss of HBV features was associated with normalization of serum transaminases activity. Reactivation of liver inflammation after seroconversion was not observed.