Encounter dynamics of a small target by a polymer diffusing in a confined domain.

We study the first passage time for a polymer, that we call the narrow encounter time (NETP), to reach a small target located on the surface of a microdomain. The polymer is modeled as a freely joint chain (beads connected by springs with a resting non zero length) and we use Brownian simulations to study two cases: when (i) any of the monomer or (ii) only one can be absorbed at the target window. Interestingly, we find that in the first case, the NETP is an increasing function of the polymer length until a critical length, after which it decreases. Moreover, in the long polymer regime, we identified an exponential scaling law for the NETP as a function of the polymer length. In the second case, the position of the absorbed monomer along the polymer chain strongly influences the NETP. Our analysis can be applied to estimate the mean first time of a DNA fragment to a small target in the chromatin structure or for mRNA to find a small target.

Palatability of crushed ß-blockers, converting enzyme inhibitors and thiazides.

WHAT IS KNOWN AND OBJECTIVES: A problem that often affects antihypertensive drugs is the lack of formulations appropriate for childhood. Parents, therefore, crush tablets and administer the antihypertensive drug mixed with solid food or a palatable drink. Because palatability is a major modulator of adherence to prescribed medication, the palatability of crushed ß-blockers, converting enzyme inhibitors and thiazides was assessed among adult volunteers. METHODS: The palatability of crushed atenolol, bisoprolol, enalapril, lisinopril, ramipril, chlorthalidone and hydrochlorothiazide was evaluated by means of a facial hedonic scale among 20 volunteers. The calcium channel-blockers amlodipine and lercanidipine whose tastes are disliked and liked, respectively, by children were also tested. A concealed random allocation procedure was used. RESULTS: The palatability scores assigned to chlorthalidone, hydrochlorothiazide and lisinopril were superior (P < 0·002) to those assigned to atenolol, bisoprolol, enalapril and ramipril. As with children, the palatability score of lercanidipine was superior to that of amlodipine (P < 0·002). The scores assigned to the various agents were similar in women and in men and were age-independent. WHAT IS NEW AND CONCLUSION: Pulverized atenolol, bisoprolol, enalapril and ramipril are poor tasting. From the perspective of palatability, pulverized chlorthalidone, hydrochlorothiazide and lisinopril are preferable.

[Nephrotic syndrome after treatment with d-penicillamine in a pediatric patient with Wilson's disease]. / Sindrome nefrosica da penicillamina in un caso pediatrico di Morbo di Wilson.

We describe a case of nephrotic syndrome (NS) after a 7 months treatment with D-penicillamine in a 14 years old girl with Wilson's disease, with a prompt regression at the discontinuation of the drug. Kidney function, proteinuria in particular, must be always monitored during the chelating therapy, and the drug must be discontinued as soon as signs of renal injury are detected.

[Pediatric steatohepatitis: is it only obesity?]. / Steatoepatite in un bambino obeso: solo questione di peso?

We describe the case of an 11-year-old obese child with nonalcoholic steatohepatitis and Wilson's disease. Nonalcoholic steatohepatitis, although frequently found in patients with obesity, can also be caused by other etiologies, including Wilson's disease, which must therefore always be ruled out in the obese child.

[Hepatitis type A with atypical course]. / Epatite A ad evoluzione atipica.

Hepatitis A virus infection is usually asymptomatic in children. Classic symptomatic forms and atypical clinical manifestations are known. We report a paediatric case of hepatitis A with marked cholestasis, treated with steroids, and with an unusual prolonged course.

[Acute acalculous cholecystitis as a complication of hepatitis A: report of 2 pediatric cases]. / Colecistite acuta acalcolotica in corso di epatite A: 2 casi pediatrici.

Acute acalculous cholecystitis (CAA) is very rare in children and it is usually related to infectious agents. We report 2 paediatric cases of CAA complicating hepatitis type A, with a favourable evolution with conservative treatment.

Diagnostic value of carcinoembryonic antigen (CEA) assay in pleural effusions.

Carcinoembryonic antigen (CEA) levels were evaluated by a direct radioimmunoassay in the effusion fluids and plasma samples from 107 patients with pleural effusions of unknown etiology. CEA levels higher than 20 ng/ml were detected in 55% of pleural effusions from patients with malignant disease: 40% of the patients in this group had values of plasmatic CEA lower than 20 ng/ml. With the only exception of 4 patients with empyema, CEA levels were uniformly lower than 20 ng/ml in the effusion fluid of patients with benign disease. Moreover, CEA levels higher than 20 ng/ml were observed in 81.2% of pleural effusions and 31.2% of plasma samples from patients with cytology positive for malignancy, whereas increased CEA levels were observed in 37.5% of effusion fluids and 33.3% of plasma samples from patients with malignant disease but negative cytology in the pleural effusion. CEA assay in the effusion fluid represents a useful tool of high specificity and good sensitivity to discriminate between benign and malignant etiology of pleural effusions.

Conformal invariance and stochastic Loewner evolution processes in two-dimensional Ising spin glasses.

We present numerical evidence that the techniques of conformal field theory might be applicable to two-dimensional Ising spin glasses with Gaussian bond distributions. It is shown that certain domain wall distributions in one geometry can be related to that in a second geometry by a conformal transformation. We also present direct evidence that the domain walls are stochastic Loewner (SLE) processes with kappa approximately 2.1. An argument is given that their fractal dimension d(f) is related to their interface energy exponent theta by d(f) - 1 = 3/[4(3 + theta)], which is consistent with the commonly quoted values d(f) approximately 1.27 and theta approximately -0.28.

Scalings of domain wall energies in two dimensional Ising spin glasses.

We study domain wall energies of two dimensional spin glasses. The scaling of these energies depends on the model's distribution of quenched random couplings, falling into three different classes. The first class is associated with the exponent theta approximately -0.28; the other two classes have theta=0, as can be justified theoretically. In contrast to previous claims, we find that theta=0 does not indicate d=d(c)(l) but rather d< or =d(c)(l), where d(c)(l) is the lower critical dimension.

Relationship between plasma and hepatic cytosolic levels of ornithine decarboxylase (ODC) and thymidine kinase (TK) in 70% hepatectomized rats.

Ornithine decarboxylase (ODC) and thymidine kinase (TK) are enzymes important for DNA synthesis, a process that is critical for cell renewal and regeneration. As such, they already have been used as surrogate markers of regeneration in tissue. In the present study, the activity of these two enzymes in plasma of rats and regenerating hepatic tissue following a 70% hepatectomy were determined. The results demonstrate that the changes in these enzyme activities in plasma reflect the changes obtained in the liver tissue. Thus, blood levels of ODC and TK can be used as a less invasive and nondestructive means of monitoring the regenerative response of the liver and possibly other tissues.

Circadian rhythm of hepatic cytosolic and nuclear estrogen and androgen receptors.

Mammalian liver is a sex steroid-responsive tissue. The effects of these hormones presumably are mediated by hepatic estrogen receptors (ER) and androgen receptors (AR). Serum levels of sex hormones display circadian rhythms. Further, estrogens and androgens are commonly administered; administration of these agents is associated frequently with liver disease. Therefore, we investigated whether the cytosolic and nuclear sex steroid receptors also display a similar circadian rhythm, and whether variations occurred in the distribution of receptors between cytosolic and nuclear compartments. Animals were killed every 4 h from midnight till the following midnight; cytosolic and nuclear levels of both ER and AR were measured. Cytosolic ER reached a maximum level at 4 AM, and a minimum at 8 PM and midnight of both days. Nuclear ER was highest at 8 AM and lowest at 4 PM and 8 PM, a pattern which parallels variations in serum estradiol levels. Cytosolic AR was highest at 8 PM and lowest at midnight and 4 AM. Nuclear AR was highest at 4 AM and lowest at 4 PM and 8 PM. The highest level of nuclear AR does not correspond to the maximum serum testosterone level, which occurred at 4 PM. The total hepatic content of both ER and AR was not constant over the 24-h period, but varied considerably with time of day. These studies suggest that both ER and AR show a distinct circadian rhythm in subcellular compartmentalization, and that total hepatic content of ER and AR varies significantly during a 24-h period.