Calorimetric study of 5-trimethylsilyl-2-norbornene,of its polymerization process and of poly(5-trimethylsilyl-2-norbornene) from 5 to 600 K at standard pressure

Thermodynamic properties of 5-trimethylsilyl-2-norbornene (TMSNB) and poly(5-trimethyl-silyl-2-norbornene) (PTMSNB), viz. the temperature dependence of the isobaric heat capacity C^o_p of the monomer between 10 and 330 K and of the polymer from 7 to 600 K, were studied by adiabatic vacuum and differential dynamic calorimetry. Temperature and enthalpy of monomer melting as well as parameters of glass transition and glassy state of the monomer and the polymer were determined. From the experimental data, the thermodynamic functions H°(T)-H°(0), S°(T) and G°(T)-H°(0) were calculated for TMSNB in the range of 0 to 330 K and for PTMSNB from 0 to 380 K. In a differential automatic calorimeter, the enthalpy of polymerization of TMSNB to PTMSNB in toluene solution was measured at T = 301 K and p = 101,325 kPa. Under similar physical conditions and in the same calorimeter, enthalpies of dissolution for the monomer and the polymer were estimated. The results were used to calculate the enthalpy, entropy and Gibbs function of bulk polymerization of TMSNB in the range of 0 to 380 K at standard pressure. The ceiling temperature of the polymerization process was also evaluated.     

Individual variability in cyclosporin A sensitivity: the assessment of functional measures on CD28-mediated costimulation of human whole blood T lymphocytes.

The quantitative analysis of cyclosporin A (CsA) effects might be helpful for optimizing immunosuppressive treatment after allogeneic organ transplantation in individual patients, as rejection can occur despite the existence of CsA blood levels within therapeutic ranges. Previous investigations found that costimulation of the CD28 pathway generally mediates CsA-resistant proliferation of T cell receptor (TCR)-activated T lymphocytes. However, here we describe considerable interindividual variation regarding the immunosuppressive effects of CsA (1000 microg/L) on anti-CD3/CD28 T cell costimulation in a human whole blood assay. In the in vitro study, we found a significant reduction of T cell proliferation, activation marker expression (CD25, CD69) on the T cell surface, and interleukin-2 (IL-2) protein expression in whole blood samples of all healthy subjects (n = 11). However, the investigation of cytokine mRNA profiles revealed variable results of in vitro CsA sensitivity. Whole blood samples of 3 of 11 healthy individuals demonstrated a marked suppression of IL-2 mRNA expression (>50%) and a partial inhibition of IL-4, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) mRNA expression on addition of CsA. In contrast, the remaining 8 healthy individuals had cytokine mRNA expression levels that were unaffected or even increased when CsA was administered in vitro. In patients undergoing CsA monotherapy (ex vivo study, n = 9), we found a significant suppression of IL-2 mRNA levels in 4 of 9 patients ex vivo. Thus, we cannot confirm a universal CsA resistance of T cells on anti-CD3/CD28 costimulation. Instead, our results suggest an individual degree of CsA sensitivity that might be more consistent with clinical experience. Prospective studies are necessary to determine if individual degrees of CsA sensitivity correlate with clinical events and are associated with a low or high risk of transplant rejection.     

The ELAM-1 ligand sialosyl-Lex is present on Langerhans cells isolated from stratified epithelium

In this study we show the expression of the newly identified carbohydrate ligand, sialosyl-Le(X) on Langerhans cells. The receptor for sialosyl-Le(X) is the endothelial leukocyte adhesion molecule-1 (ELAM-1) present on activated endothelial cells. Using flow cytometry, Langerhans cells were selected due to positivity for an antibody against CD1a and low orthogonal light scatter. The CD1a antigen stained by the OKT6 antibody is considered a maturational marker of Langerhans cells in agreement with the specific labeling of dendritic cells in the epithelium only. Double immunostaining (OKT6/anti-sialosyl-Le(X)) using flow cytometry and immunohistochemistry demonstrated that almost all OKT6-positive cells in normal stratified epithelium expressed sialosyl-Le(X). Conversely, by immunohistochemistry of oral epithelium with acute inflammation, additional dendritic cells negative for OKT6 were found to express sialosyl-Le(X). In addition, sialosyl-Le(X)-positive but not OKT6-positive dendritic cells were found in the submucosa. These findings indicate that the carbohydrate antigen sialosyl-Le(X) is expressed earlier than the CD1a antigen in the maturation of the Langerhans cell lineage. Future studies should aim at investigating the importance of adhesion between sialosyl Le(X) and ELAM-1 in epithelial recruitment of Langerhans cells.     

The effect of injecting botulinum toxin type a into the calf muscles on freezing of gait in Parkinson's disease: a double blind placebo-controlled pilot study.

OBJECTIVE: To assess the effect on freezing of gait (FOG) of botulinum toxin type A (BTX-A) injections in advanced Parkinson's disease (PD) patients. METHOD: BTX-A 150 IU or normal saline was injected into each leg's calf muscles by a blinded investigator. FOG severity was assessed at set intervals (6-month follow-up). RESULTS: Eleven age- and disease severity-matched PD patients with disabling FOG participated. Six patients received BTX-A and 5 received saline. No improvement was observed in either group over time. Leg weakness and falls lead to early termination. CONCLUSION: BTX-A injections to the legs did not improve FOG and might increase fall risk.     

What are the Important Considerations in the Care of Critically III Patients with Acute Renal Failure?

With the recent progress in molecular and cellular biology, the 1990s present a unique opportunity for understanding the cellular or humoral factors responsible for accelerated catabolism in ARF. This author believes that a greater priority should be placed on funding basic research directed at understanding the pathogenesis of protein catabolism in ARF. For example, identifying the intracellular pro-teolytic pathways which are activated in experiment& ARF might lead to strategies to suppress accelerated proteolysis. Insight gained from these efforts could then be used to design clinical trials to test the efficacy of nutritional interventions in this patient population. In this era of increased economic constraints, practical solutions to this formidable problem are needed.     

Hodgkin's Disease with Primary Presentation in the Bone Marrow

A 35-year-old male patient presented with low back pain and a sclerotic lesion of the right sacroiliac joint. Nodular sclerosing Hodgkin's disease (NSHD) was diagnosed on oriented trephine biopsy from this lesion. There was no evidence of lymph node involvement at the time of diagnosis. Four months later pulmonary spread occurred. The clinical course was unusually aggressive, considering the fact that NSHD generally has a relatively favorable prognosis. The patient died 18 months after initial diagnosis with disseminated disease.