Smooth muscle myosin light chain kinase is transiently expressed in skeletal muscle during embryogenesis and muscle regeneration both in vivo and in vitro

Byusing a polyclonal antibody raised against smooth muscle MyosinLight Chain Kinase of adult chicken we show that the 135 kDasmooth muscle Myosin Light Chain Kinase isoform is present inneonatal and regenerating rat skeletal muscle, as well as inadult atrial myocardium. No reaction was evident in adultskeletal muscle fibres. In neonatal and in early regeneratingmuscle smooth muscle Myosin Light Chain Kinase is associated withembryonic myosin as revealed by their co-presence in musclefibres. Experiments in vitro show the same results in myotubes.In atrial myocardium there is a patchy positivity in certaingroup of myocytes. Immunoblotting experiments show in muscle cellcultures, in neonatal and in regenerating skeletal muscle aprotein band with electrophoretic mobility corresponding to thatof smooth muscle Myosin Light Chain Kinase. These results suggestthat the expression of smooth muscle Myosin Light Chain Kinase isnot fully tissue-specific and that regulation of the contractilemachinery could be different during myogenesis and in adulthood,in relation to the peculiar dynamic characteristics of developingmuscles     

p53 OVEREXPRESSION AND HUMAN PAPILLOMAVIRUS INFECTION IN TRANSITIONAL CELL CARCINOMA OF THE URINARY BLADDER: CORRELATION WITH HISTOLOGICAL PARAMETERS

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladder (25 grade 1, 22 grade 2, and 32 grade 3 tumours) were examined for p53 overexpression by immunohistochemistry with a monoclonal antibody and for human papillomavirus (HPV) infection by the polymerase chain reaction (PCR). Positive immunostaining for p53 was detected in 40·5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours (10·6 per cent vs. 84·4 per cent; P <0·0001). The overall rate of HPV infection was 32·9 per cent; 20·3 per cent of the cases were positive for HPV 16, 3·8 per cent for HPV 18, and 8·9 per cent for both. Consensus primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection. The prevalence of HPV 16 and/or HPV 18 infection was significantly higher in low-grade than in high-grade tumours (44·7 per cent vs. 15·6 per cent; P =0·0061). p53-positive cases were more common among papillary, deeply infiltrating tumours, and HPV-positive cases among papillary, non-infiltrating lesions. According to these data, p53 overexpression and HPV 16/18 infection are common findings in bladder TCC and there appears to be an inverse correlation of p53 overexpression and of HPV infection with tumour aggressiveness. The possibility of different molecular pathways in superficial low-grade and in invasive high-grade tumours is suggested.     

Salbutamol pretreatment does not change eosinophil percentage and eosinophilic cationic protein concentration in hypertonic saline-induced sputum in asthmatic subjects

BACKGROUND: Sputum induction by inhalation of hypertonic saline (HS) is usually preceded by beta2-agonist pretreatment, to prevent severe bronchoconstriction. OBJECTIVE: To evaluate whether salbutamol pretreatment may influence cell counts and concentrations of soluble mediators in induced sputum. METHODS: We studied 22 patients who randomly underwent HS sputum induction after pretreatment with either 200 microg salbutamol or placebo. Sputum was induced by means of HS inhalation (3, 4, 5% NaCl, 10 min each), measuring FEV1 every 5 min until it fell >/= 20% from baseline. Collected sputum was diluted 1 : 1 with 0.1% DTT, incubated at 37 degrees C for 20 min, and total and differential cell counts were measured. ECP and histamine levels were measured in the supernatant. RESULTS: Sputum volume, percentages of inflammatory cells, squamous cell counts and quality of the slides were not different after the two pretreatments, while sputum total inflammatory cells after salbutamol tended to be higher than after placebo (8.3 [1-41] 10(6) vs 6.3[0.2-40] x10(6); P = 0.09). Eosinophilic cationic protein (ECP) did not significantly change (260 [8-900] microg/L after salbutamol vs 200 [8-800] microg/L, n = 19), while histamine levels tended to be lower after salbutamol (140.9 [39.9-236.5] nm) than after placebo (190.4 [72. 2-322.6] nm, P = 0.09, n = 17). The airway response to HS inhalation was significantly greater after placebo and the duration of the test was significantly different (median: 15 min after placebo and 30 min after salbutamol). Similar results were obtained when patients who differed for more than 15 min in the duration of HS-inhalation in the two tests were selected (n = 11). CONCLUSION: Salbutamol pretreatment reduces the severity of bronchoconstriction induced by HS inhalation without significantly affecting the percentages of inflammatory cells and the levels of soluble mediators in induced sputum.     

Long-Term Results of Hybrid Therapy in Patients with Atrial Fibrillation Who Develop Atrial Flutter During Flecainide Infusion

The flecainide infusion test has been proposed to screen candidates for hybrid pharmacological and ablation therapy. We report the long-term follow-up of 154 consecutive patients with paroxysmal or persistent atrial fibrillation (AF) who developed atrial flutter (AFL) during flecainide infusion (IC AFL), treated with inferior vena cava-tricuspid annulus isthmus catheter ablation and oral flecainide (hybrid therapy). Over a mean of 54.1 ± 13.1 months 82 patients (53%) remained free of AF and AFL. Flecainide was discontinued because of adverse effects in 6 patients (4%). A history of persistent AF, and the documentation of ≥1 spontaneous AFL episode before the flecainide test were independent predictors of successful hybrid therapy. In patients with paroxysmal AF without documented spontaneous AFL, the long-term efficacy of hybrid therapy was 38.5% (P = 0.03). The flecainide infusion test reliably detects candidates for hybrid therapy. The efficacy of this therapy is maintained over the long-term with a high patient compliance.     

FAILURE OF INHIBITION BY TRH OF L-DOPA STIMULATED GH SECRETION IN PATIENTS WITH ALCOHOLIC CIRRHOSIS OF THE LIVER

We have investigated the effects of a single oral dose of L-Dopa (500 mg) or of an i.v. infusion of TRH (1 mg dissolved in 400 ml of saline solution) or both administered together, on GH release in men with alcoholic cirrhosis of the liver, and compared them with responses in normal subjects. The results obtained in normal subjects confirm that TRH does not modify plasma GH levels, L-Dopa elevates GH concentrations, while the administration of these two drugs together significantly inhibits GH release induced by oral L-Dopa. In contrast, in patients with alcoholic cirrhosis of the liver, the following results were obtained:

• 1 TRH infusion significantly increased plasma GH levels which were steadily elevated throughout the experiment;
• 2 oral administration of L-Dopa provoked a significant rise in blood GH over the basal values similar to that observed in normal subjects;
• 3 when TRH and L-Dopa are administered at the same time a GH increase like that observed after L-Dopa alone was obtained.

These results clearly demonstrate that in patients with alcoholic cirrhosis of the liver the normal inhibitory effect of TRH on L-Dopa induced GH release is completely lost.     

Potential Distributions Generated By Point Stimulation in a Myocardial Volume:

Potential Patterns in a 3-D Cardiac Depolarization Model, introduction: We present simulations of extracellular potential patterns elicited by delivering ectopic stimuli to a parallelepipedal slab of ventricular tissue represented as an anisotropic bidomain incorporating epiendocardial fiber rotation.
Methods and Results: Simulations were based on an eikonal model that determines wave-front shapes throughout the slab at every time instant during the depolarization phase, coupled with an approximate model of the action potential profile. The endocardial face of the slab was in contact with blood and the composite volume was surrounded by an insulating medium. The effect of a simplified Purkinje network was also studied. Results: (1) For all pacing depths, except endocardial pacing, a central negative area and two potential maxima were observed at QKS onset in all intramural planes parallel to the cpicardium. In all planes, the axis joining the two maxima was approximately aligned with the direction of fibers in the plane of pacing. Endocardial pacing generated a different pattern, but only when blood was present; (2) During later stages of excitation, outflowing currents (from the wavefront toward the resting tissue) were always emitted, at all intramural depths, only from those portions of the wavefront that spread along fibers. At any given instant, the position of the two potential maxima in a series of planes parallel to the epicardium and intersecting the wavefront rotated as a function of depth, following the rotating direction of intramural fibers. Purkinje involvement modified the above patterns.
Conclusion: Epicardial and endocardial potential maps provided information on pacing site and depth and on subsequent intramural propagation by reflecting the clockwise or counterclockwise rotation of the deep positivity. Results may be applicable to epicardial and endocardial potential maps recorded at surgery or from endocavitary probes.     

A pseudopeptide incorporating the tetrahydrophthalazine nucleus,a constrained Aza analog of phenylalanine

Replacement of the α-carbon with a nitrogen in α-amino acids gives rise to azaamino acids. Most examples of azaamino acids that have been incorporated into peptides are linear analogs, in which conformational effects are restricted to the immediate vicinity of the urea bond. In contrast to the linear azaamino acids, the heterocyclic analogs might be expected to exhibit stronger conformational preferences, but examples of this class of azaamino acids are very limited. We synthesized tetrahydrophthalazine (THPhth) as a constrained phenylalanine analog and elaborated it into the model pseudotripeptide N-{([N-alanyl]-1,2,3,4-tetrahydro-2-phthalazinyl)carbonyl)}-L-alanine (1). As shown by NMR studies, tetrahydrophthalazine 1A has a secondary structure in which ψTHPhth is fixed at 16–18° and there are two equal populations of cis and trans amide bonds from the N-terminal alanine. © Munksgaard 1996.