The effect of calcipotriol on lesional fibroblasts from patients with active morphoea

We examined the responsiveness of cultured dermal fibroblasts from biopsies of 6 patients with active morphoea and a similar number of matched controls to the cell proliferation inhibition activity of calcipotriol. Cultured fibroblasts from controls showed no significant response to calcipotriol (at concentrations of 1 x 10(-8) to 1 x 10(-4) M). However, calcipotriol did inhibit the proliferation response of morphoea fibroblasts at all concentrations when compared with controls. There was 4- to 20-fold inhibition in 2 of the morphoea patients when compared with control samples. Four other morphoea samples showed inhibition but to a lesser extent compared with controls.     

Mechanisms of electrical coupling between pyramidal cells

Direct electrical coupling between neurons can be the result of both electrotonic current transfer through gap junctions and extracellular fields. Intracellular recordings from CA1 pyramidal neurons of rat hippocampal slices showed two different types of small-amplitude coupling potentials: short-duration (5 ms) biphasic spikelets, which resembled differentiated action potentials and long-duration (>20 ms) monophasic potentials. A three-dimensional morphological model of a pyramidal cell was employed to determine the extracellular field produced by a neuron and its effect on a nearby neuron resulting from both gap junctional and electric field coupling. Computations were performed with a novel formulation of the boundary element method that employs triangular elements to discretize the soma and cylindrical elements to discretize the dendrites. An analytic formula was derived to aid in computations involving cylindrical elements. Simulation results were compared with biological recordings of intracellular potentials and spikelets. Field effects produced waveforms resembling spikelets although of smaller magnitude than those recorded in vitro. Gap junctional electrotonic connections produced waveforms resembling small-amplitude excitatory postsynaptic potentials. Intracellular electrode measurements were found inadequate for ascertaining membrane events because of externally applied electric fields. The transmembrane voltage induced by the electric field was highly spatially dependent in polarity and wave shape, as well as being an order of magnitude larger than activity measured at the electrode. Membrane voltages because of electrotonic current injection across gap junctions were essentially constant over the cell and were accurately depicted by the electrode. The effects of several parameters were investigated: 1) decreasing the ratio of intra to extracellular conductivity reduced the field effects; 2) the tree structure had a major impact on the intracellular potential; 3) placing the gap junction in the dendrites introduced a time delay in the gap junctional mediated electrotonic potential, as well as deceasing the potential recorded by the somatic electrode; and 4) field effects decayed to one-half of their maximum strength at a cell separation of approximately 20 micron. Results indicate that the in vitro measured spikelets are unlikely to be mediated by gap junctions and that a spikelet produced by the electric field of a single source cell has the same waveshape as the measured spikelet but with a much smaller amplitude. It is hypothesized that spikelets are a manifestation of the simultaneous electric field effects from several local cells whose action potential firing is synchronized.     

Lovastatin decreases de novo cholesterol synthesis and LDL Apo B-100 production rates in combined-hyperlipidemic males

The effect of lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, on the kinetics of de novo cholesterol synthesis and apolipoprotein (apo) B in very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) was investigated in five male patients with combined hyperlipidemia. Subjects were counseled to follow a Step 2 diet and were treated with lovastatin and placebo in randomly assigned order for 6-week periods. At the end of each experimental period, subjects were given deuterium oxide orally and de novo cholesterol synthesis was assessed from deuterium incorporation into cholesterol and expressed as fractional synthesis rate (C-FSR) and production rate (C-PR). Simultaneously, the kinetics of VLDL, IDL, and LDL apo B-100 were studied in the fed state using a primed-constant infusion of deuterated leucine to measure fractional catabolic rates (FCR) and production rates (PR). Drug treatment resulted in significant decreases in total cholesterol (-29%), VLDL cholesterol (-40%), LDL cholesterol (-27%), and apo B (-16%) levels and increases in HDL cholesterol (+13%) and apolipoprotein (apo) A-I (+11%) levels. Associated with these plasma lipoprotein responses was a significant reduction in both de novo C-FSR (-40%; P = .04) and C-PR (-42%; P = .03). Treatment with lovastain in these patients had no significant effect on the FCR of apoB-100 in VLDL, IDL, or LDL, but resulted in a significant decrease in the PR of apoB-100 in IDL and LDL. Comparing the kinetic data of these patients with those of 10 normolipidemic control subjects indicates that lovastatin treatment normalized apoB-100 IDL and LDL PR. The results of these studies suggest that the declines in plasma lipid levels observed after treatment of combined hyperlipidemic patients with lovastatin are attributable to reductions in the C-FSR and C-PR of de novo cholesterol synthesis and the PR of apoB-100 containing lipoproteins. The decline in de novo cholesterol synthesis, rather than an increase in direct uptake of VLDL and IDL, may have contributed to the decline in the PR observed.     

Antifungal pharmacodynamic characteristics of fluconazole and amphotericin B tested against Candida albicans

Time-kill curves were determined for three isolates of Candida albicans tested against fluconazole and amphotericin B at multiples of the MIC. Fluconazole produced fungistatic activity, with concentration-related growth effects observed over a narrow range of concentrations. Amphotericin B exhibited fungicidal activity, with enhancement of activity over a broader range of concentrations.     

Fusarium graminearum A 3/5 as a novel host for heterologous protein production

We describe a novel fungal expression system which utilizes the Quorn myco-protein fungus Fusarium graminearum A 3/5. A transformation system was developed for F. graminearum and was used to introduce the coding and regulatory regions of a trypsin gene from Fusarium oxysporum. The protein was efficiently expressed, processed and secreted by the recombinant host strain. In addition, the promoter and terminator of the F. oxysporum trypsin gene have been successfully utilized to drive the expression of a cellulase gene from Scytalidium thermophilum and a lipase gene from Thermomyces lanuginosus in F. graminearum.     

In vitro bioartificial skin culture model of tissue rejection and inflammatory/immune mechanisms

We hypothesized that an in vitro bioartificial skin rejection model using living LSEs grown in tissue culture could be developed for the study of autologous, allogenic, and/or xenogeneic inflammatory/immune mechanisms and topical immunosuppressive drugs. Human fibroblasts were mixed with type 1 rat-tail collagen to form a matrix (4 to 5 days), on which human keratinocytes were seeded. After a keratinocyte monolayer formed, CT cultures were raised to the air-liquid interface for continued growth. In the REJ LSE model, immunocytes isolated from human blood were seeded on top of the NHEK monolayer at the time of air-lifting. Thickness measurements of the acellular keratin and keratinocyte layers, and nuclear/cytoplasmic ratios, in both CT and REJ were made using digital image analysis. Immunostaining with anticytokeratin demonstrated a viable, keratin-producing epidermal layer; staining with anti-TGF-beta suggested a role for this cytokine in the rejection or wound-healing process. The LSE appeared histologically similar to normal human epidermis. Immunocytes added to the REJ cultures caused an obvious rejection response and were clearly identifiable in the gels as CD45+ staining cells. The LSE model appears promising for the study of immune/inflammatory mechanisms, thermal injury, screening antirejection agents that might be applied topically and as an in vitro replacement for skin graft studies in animals.     

Assessment of nutritional status in CAPD patients: serum albumin is not a useful measure

INTRODUCTION: In CAPD patients serum albumin is frequently used as an index of nutritional status, although it is recognized that hypoalbuminaemia may be caused by many factors. We have further examined the relationship between serum albumin and nutrition. METHODS: Nutritional status was assessed by biochemistry, anthropometry, mid-arm muscle circumference, muscle strength (hand grip and back), and lean body mass (from anthropometry, creatinine kinetics and bioimpedance) in a group of 76 stable CAPD patients. Correlations between biochemical and nutritional parameters were sought and data were compared between patient groups defined by serum albumin (> or = 37 vs < 37 g/l on two occasions 2 months apart) and separately according to subjective global assessment score (normal nutrition, A vs mild to moderate, B, and severe, C, malnutrition). RESULTS: In patients with a low SGA score, actual body weight, body mass index, mid-arm muscle circumference, lean body mass, subscapular skinfold thickness, hand grip strength (males and females) and iliac and triceps skinfold thicknesses and back strength (females only) were all significantly less than in patients with a normal SGA score. In contrast, none of these variables differed in either gender when patients were compared according to serum albumin. Serum albumin was correlated with serum creatinine (r = 0.45, P = 0.01), daily urine protein excretion (r = -0.42, P = 0.02) and uncorrected weekly creatinine clearance (r = -0.39) in females, but not with any index of body composition in either gender. CONCLUSION: Whilst SGA identified a patient group with significantly abnormal body mass, muscle mass and muscle strength, serum albumin did not. Serum albumin is not a useful marker of malnutrition in stable patients on CAPD.