Deciphering interaction fingerprints from protein molecular surfaces using geometric deep learning.

Predicting interactions between proteins and other biomolecules solely based on structure remains a challenge in biology. A high-level representation of protein structure, the molecular surface, displays patterns of chemical and geometric features that fingerprint a protein's modes of interactions with other biomolecules. We hypothesize that proteins participating in similar interactions may share common fingerprints, independent of their evolutionary history. Fingerprints may be difficult to grasp by visual analysis but could be learned from large-scale datasets. We present MaSIF (molecular surface interaction fingerprinting), a conceptual framework based on a geometric deep learning method to capture fingerprints that are important for specific biomolecular interactions. We showcase MaSIF with three prediction challenges: protein pocket-ligand prediction, protein-protein interaction site prediction and ultrafast scanning of protein surfaces for prediction of protein-protein complexes. We anticipate that our conceptual framework will lead to improvements in our understanding of protein function and design.

[60]Fullerene-porphyrin [n]pseudorotaxanes: self-assembly, photophysics and third-order NLO response.

By means of different spectroscopic techniques, we investigate a novel series of porphyrin derivatives (H2TPP), connected to dibenzo-24-crown-8 (DB24C8) moieties, which undergo self-assembly with different methano[60]fullerene units bearing dibenzylammonium (DBA) cations. The formation of both [2] and [3]pseudorotaxanes was proved by means of NMR, UV-Vis-NIR absorption and emission spectroscopies. With the support of molecular modelling studies, spectroscopic investigations showed the presence of a secondary interaction between the porphyrin and the C60 chromophores leading to the formation of different types of "face-to-face" assemblies. Remarkably, investigations of the non-linear optical response of these supramolecular systems showed that individual porphyrin and fullerene derivatives exhibit significantly lower second hyperpolarizability values when compared to their pseudorotaxanes functionalised counterparts. This proves that this class of supramolecular materials possesses relevant NLO response, which strongly depends on the structural arrangement of the chromophores in solution.

Evaluation of light-touch sensation in the buccal mucosa of leprosy patients.

OBJECTIVE: The aim of this study is to evaluate the light-touch sensation of the oral mucosa in leprosy patients. MATERIALS AND METHODS: A cross-sectional study included 228 adults, 133 being leprosy patients and 95 normal controls. To assess light-touch sensation, the five-filament standard Semmes-Weinstein kit in eight regions of the oral mucosa was used. Chi-square test was used to verify the differences in responses between the studied groups. RESULTS: Normal sensation was predominant in both groups, and diminished sensation was found also in the nonleprosy group. Normal controls showed diminished light-touch sensation in at least one point, which may be attributed to the definition of sensation normality. The chi-square test revealed no significant difference between the two groups (p = 0.43171). Severe diminished sensation was detected only in the leprosy group. CONCLUSION: It is concluded that altered light-touch sensation in the oral cavity may not be a common feature in leprosy. CLINICAL RELEVANCE: Decreased or lost sensation in skin lesions is a paramount in leprosy diagnosis; however, clinicians must be aware that this seems not to be true in the oral mucosa in leprosy cases for diagnosis purpose.

Higher protein intake strategies in human milk fortification for preterms infants feeding. Auxological and neurodevelopmental outcome.

Postnatal growth restriction and failure to thrive still remain a major problem in Extremely Low Birth Weight (ELBW) infants . The goal for the nutritional care of these infants is to achieve rate of growth similar to those of the fetus in utero at the equivalent gestational age. Human milk fortified remains the best food for all these preterms. Two groups of preterm of weight 580-1250 g and gestational age 23-32 wk, were fed with different protein intake in the human/maternal milk fortified ( 3,5 g Kg-1 per day and 4,8 g Kg-1 per day in the control and intervention group respectively).The feeding tolerance, intrahospital growth, neurological outcome and anthropometric data until 12 months of corrected age, were evaluated. The protein supplemented group (PSG) showed an intrahospital highter growth rate ( mostly in head circumference, p 0,02, and length growth, p 0,04) only in the preterms with 580-980 g and 23-30 wk. In the same preterms, Griffith Development Mental Score at 3 and 12 months corrected age showed higher score than in the control group in the Performance (p 0,04) and Hearing/Language (p 0,03) items. The auxological evaluation in the postdischarge period showed in the PSG group mean z-score values for length higher than those in the control group at 9 (p 0,04) months of corrected age.

Pollen discrimination and classification by Fourier transform infrared (FT-IR) microspectroscopy and machine learning.

The discrimination and classification of allergy-relevant pollen was studied for the first time by mid-infrared Fourier transform infrared (FT-IR) microspectroscopy together with unsupervised and supervised multivariate statistical methods. Pollen samples of 11 different taxa were collected, whose outdoor air concentration during the flowering time is typically measured by aerobiological monitoring networks. Unsupervised hierarchical cluster analysis provided valuable information about the reproducibility of FT-IR spectra of the same taxon acquired either from one pollen grain in a 25 x 25 microm2 area or from a group of grains inside a 100 x 100 microm2 area. As regards the supervised learning method, best results were achieved using a K nearest neighbors classifier and the leave-one-out cross-validation procedure on the dataset composed of single pollen grain spectra (overall accuracy 84%). FT-IR microspectroscopy is therefore a reliable method for discrimination and classification of allergenic pollen. The limits of its practical application to the monitoring performed in the aerobiological stations were also discussed.

p27 and Skp2 immunoreactivity and its clinical significance with endocrine and chemo-endocrine treatments in node-negative early breast cancer.

BACKGROUND: Low p27 and high Skp2 immunoreactivity are associated with a poor prognosis and other poor prognostic features including resistant phenotypes and antiestrogen drug resistance. We investigated these proteins in two International Breast Cancer Study Group trials studying node-negative early breast cancer. PATIENTS AND METHODS: Trial VIII compared chemotherapy followed by goserelin with either modality alone in premenopausal patients. Trial IX compared chemotherapy followed by tamoxifen with tamoxifen alone in postmenopausal patients. Central Pathology Office assessed p27 and Skp2 expression in the primary tumor by immunohistochemistry among 1631 (60%) trial patients. RESULTS: p27 and Skp2 were inversely related; 13% of tumors expressed low p27 and high Skp2. Low p27 and high Skp2 were associated with unfavorable prognostic factors including larger size and higher grade tumors, absence of estrogen receptor and progesterone receptor, human epidermal growth factor receptor 2 overexpression and high Ki-67 (each P < 0.05). Low p27 and high Skp2 were not associated with disease-free survival (P = 0.42 and P = 0.48, respectively). The relative effects of chemo-endocrine versus endocrine therapy were similar regardless of p27 or Skp2. CONCLUSIONS: We confirm the association of low p27 and high Skp2 with other poor prognostic features, but found no predictive or prognostic value, and therefore do not recommend routine determination of p27 and Skp2 for node-negative breast cancer.

White luminescence achieved by a multiple thermochromic emission in a hybrid organic-inorganic compound based on 3-picolylamine and copper(i) iodide.

Three copper(i) complexes have been obtained by the reaction of CuI with 3-picolylamine in acetonitrile solution and characterized by X-ray powder diffraction, both from synchrotron and laboratory radiation. Photophysical investigations in the solid state revealed highly efficient thermally-activated delayed fluorescence (TADF) with photoluminescence quantum yields (PLQYs) up to 18%. Notably, the complex [Cu2I2(3pica)]∞ displays a strong luminescence thermochromism due to the presence of both 1,3(X + M)LCT excited states and a lower-lying cluster-centered (3CC) one, leading to multiple emission at room temperature; as a result, a white luminescence is achieved with a PLQY of 4.5%.

Transglutaminase activity during senescence and programmed cell death in the corolla of tobacco (Nicotiana tabacum) flowers.

Corolla life span of undetached flowers of Nicotiana tabacum was divided into stages from the closed corolla (stage 1) through anthesis (stage 5) to death (stage 9). Senescence began around stage 6 in the proximal part, concomitantly with DNA laddering. Nuclear blebbing, DNA laddering, cell wall modification, decline in protein, water, pigment content and membrane integrity were observed during senescence and PCD. Transglutaminase activity was measured as mono- and bis-derivatives of putrescine (mono-PU; bis-PU) and bis-derivatives of spermidine (bis-SD). Bis-derivatives decreased with the progression of senescence, while mono-PU increased during early senescence; derivatives were present in different amounts in the proximal and distal parts of the corolla. In excised flowers, exogenous spermine delayed senescence and PCD, and caused an increase in free and acid-soluble conjugated PA levels. Bis-PU was the most abundant PA-derivative before DNA laddering stage; thereafter, bis-PU generally decreased and mono-PU became the most abundant derivative.

Potential of telomerase expression and activity in cervical specimens as a diagnostic tool.

AIMS: To evaluate the potential use of the immunohistochemical expression of telomerase and the measurement of its activity as diagnostic tools in the uterine cervix. METHODS: The fluorescent telomeric repeat amplification protocol (TRAP) assay was used to evaluate telomerase activity in a series of 43 cervical scrapings. Twenty five cases were cytologically classified as inflammatory, and/or metaplastic, and/or acanthotic, and 18 cases presented cell alterations compatible with mild, moderate, or severe cervical intraepithelial neoplasia (CIN). Immunohistochemistry was performed on a retrospective series of 86 archival, paraffin wax embedded blocks using a recently developed anti-hTERT (human telomerase reverse transcriptase) monoclonal antibody. RESULTS: Telomerase activity was expressed as arbitrary enzymatic units (AEU). Median values were 38.0 AEU for inflammatory non-dysplastic cell specimens, 33.5 AEU for CIN I, 41.0 AEU for CIN II, and 28.0 AEU for CIN III. The median percentage of immunoreactive dysplastic cells, as detected by immunohistochemistry, was significantly (p = 0.024) lower in CIN I (45%) than in more severe dysplastic (CIN II 70%, CIN III 80%) lesions. In contrast, no differences were seen in the enzymatic activity detected by the TRAP assay among the different dysplastic lesions. CONCLUSIONS: These data indicate that, using a molecular extra situ method, the telomerase activity of inflammatory and non-dysplastic elements masks the expected differences between mild and severe dysplasia. Conversely, an in situ approach permits the accurate identification of telomerase positive dysplastic cells.

Características clínicas e histopatológicas de los pacientes con enfermedades ampollares autoinmunes: estudio retrospectivo en el Hospital Privado Universitario de Córdoba / Clinical and histopathological characteristics of autoimmune blister diseases: a retrospective study in Private University Hospital of Córdoba

RESUMEN Las enfermedades ampollares autoinmunes (EAA) comprenden un conjunto heterogéneo de patologías de baja frecuencia de presentación con evolución crónica, remisiones, exacerbaciones y una importante morbimortalidad aun con tratamiento temprano y adecuado. Existen pocos estudios epidemiológicos en nuestra población que incluyan todo el espectro de enfermedades ampollares. Objetivos : Determinar las características clínico-epidemiológicas de las EAA, describir tratamientos realizados, tiempo de control de actividad de la enfermedad y tiempo desde iniciado el tratamiento hasta la remisión completa. Determinar recaídas de las patologías estudiadas, evaluando si existe relación entre las mismas y algún factor reconocido. Materiales y métodos : Estudio retrospectivo y descriptivo. Se incluyeron todos los pacientes con diagnóstico clínico, histopatológico y de inmunofluorescencia de las EAA que hayan tenido seguimiento por al menos un año en el servicio de dermatología del HPUC, en el período de enero de 2008 hasta noviembre de 2018. Resultados : Se incluyeron 53 pacientes de los cuales el 50,9% tenía Penfigoide Ampollar (PA), 22,6% Dermatitis Herpetiforme (DH) y 17% de Pénfigo vulgar (PV). La edad de los pacientes se encontró entre 21 y 90 años. Las ampollas tensas y erosiones fueron las presentaciones más comunes. Los tratamientos sistémicos se realizaron en el 74% de los casos. Registramos recaídas en el 63% de los casos y dos casos de muerte durante el tratamiento. Se estableció más frecuencia de enfermedad cardiovascular en los pacientes con PA. Conclusiones : Es el primer trabajo retrospectivo sobre EAA en nuestro medio. Nuestros hallazgos permiten determinar una frecuencia importante de PA en la consulta dermatológica y de DH, hecho no reportado en otros estudios con poblaciones similares.

ABSTRACT The autoimmune bullous diseases (ASD) comprise a heterogeneous group of pathologies with a low frequency of presentation that presents a chronic evolution, with remissions, exacerbations and an important morbidity and mortality even with early and adequate treatment. There are few epidemiological studies in our population that include the entire spectrum of bullous diseases. Objectives : To determine the clinical-epidemiological characteristics of AAS, describe treatments performed, control time of disease activity and time from treatment initiation to complete remission. Determine relapses of the studied pathologies, evaluating if there is a relationship between them and some recognized factor. Materials and methods : Retrospective and descriptive study. All patients with clinical, histopathological and immunofluorescence diagnosis of the AAS who had followed up for at least one year in the dermatology service of the HPUC, from January 2008 to November 2018 were included. Results: 53 were included. patients of which 50.9% had Bullous Pemphigoid (BP), 22.6% Dermatitis herpetiformis (DH) and 17% Pemphigus Vulgaris (PV). The age of the patients was between 21 and 90 years. Tense blistering forms and erosions were the most common forms of presentation. Systemic treatments were performed in 74% of the cases. We recorded relapses in 63% of the cases and two cases of death during the treatment. More frequency of cardiovascular disease was established in patients with BP. Conclusions : It is the first retrospective work on EAA in our environment. Our findings allow determining an important frequency of PA in the dermatological consultation and DH, fact this last, not reported in other studies with similar populations.

Insulin enhances endothelial alpha2-adrenergic vasorelaxation by a pertussis toxin mechanism.

To investigate whether insulin effect on endothelium is related to a specific signal transduction pathway or reflects a more generalized action of the hormone, we studied in aortic rings of Wistar-Kyoto (WKY) rats the effects of the hormone on endothelium-dependent relaxations generated by acetylcholine, adenosine diphosphate, the selective alpha2-adrenergic agonist UK 14,304, and the calcium ionophore ionomycin. The responses were evaluated both in control conditions and after 30 minutes of exposure to three different levels of insulin (30, 100, and 500 microU/mL). Insulin failed to modify the phenylephrine aortic contractions and the relaxations induced by acetylcholine, adenosine diphosphate, and ionomycin. In contrast, both 100 and 500 microU/mL insulin were able to potentiate the UK 14,304-induced vasorelaxation (+96+/-19% and +91+/-12%, respectively). Pertussis toxin, which causes alpha2-adrenergic receptor Gi uncoupling, reduced the alpha2-adrenergic vasorelaxation and prevented the insulin potentiation of the response to UK 14,304. Furthermore, in primary cultured aortic endothelial cells from WKY, we evaluated the conversion of [3H]arginine to [3H]citrulline in response to acetylcholine, ionomycin, and UK 14,304, both in control conditions and during insulin exposure. Again, insulin did not affect basal citrulline production or the increase induced by acetylcholine and ionomycin, whereas it potentiated the response to UK 14,304. Finally, in aortic rings of spontaneously hypertensive rats, insulin treatment (100 and 500 microU/mL) was unable to enhance the alpha2-adrenergic vasodilator response; in vascular endothelial cells from spontaneously hypertensive rats, insulin did not potentiate the increase in citrulline production evoked by UK 14,304. In conclusion, insulin selectively enhances alpha2-adrenergic endothelial vasorelaxation through a pertussis toxin-sensitive mechanism, by potentiating endothelial nitric oxide production. This vasorelaxant mechanism is altered in spontaneously hypertensive rats.

Prognosis and prediction of response in breast cancer: the current role of the main biological markers.

In the medical literature there are frequently conflicting reports on the utility of biological tumour markers available in the clinical management of breast cancer. In this review we analyse current information on the relationships between the most widely investigated breast cancer biological markers including oestrogen and progesterone receptors, p53, Bcl-2, c-erbB-2, cyclin expression, proliferative activity, DNA ploidy and the urokinase plasminogen activation system, as well as their relevance to prognosis and response to clinical treatment. By biological prognostic indicator, we mean a marker that correlates with survival and disease-free survival; the term predictor marker indicates a marker that is capable of predicting tumour sensitivity or resistance to various therapies. Similarly to other authors' experiences, our analysis suggests that oestrogen receptors are weak prognostic indicators and good predictors of response to endocrine therapy. Furthermore, there are consistent data suggesting that proliferation indices are good indicators of prognosis, and that they are directly related to response to chemotherapy and closely related to response to hormonotherapy. On the contrary, there is no evidence or conflicting data for all of the other biological markers. These should be considered in the context of randomized trials in order to precisely define their prognostic and predictive roles. p53 and c-erbB-2 seem to be the most promising factors, but their use in routine practice still needs validation.

Enoximone coupled to very low dose dobutamine echocardiography detects myocardial viability in akinetic and dyskinetic post-myocardial infarcted areas.

Dobutamine and enoximone stimulate independently inotropic reserve by increasing intracellular cyclic adenosine monophosphate. The potential of enoximone (0.75 mg/kg body weight over 10 minutes) followed by very low dose (2.5 microg/kg/min) dobutamine echocardiography to predict recovery of ventricular function in akinetic and dyskinetic postinfarcted areas was studied. We enrolled 22 patients with previous Q-wave myocardial infarction and regional wall motion abnormalities related to left anterior descending arterial disease, left ventricular ejection fraction <40%, and all scheduled for myocardial revascularization. A 10 microg/kg/min dobutamine test was performed 48 hours before the study protocol. Test images obtained at peak of pharmacodynamic effects were compared with those obtained at 4 months after myocardial revascularization. We used a 16-segment ventricular model and a 5-grade scoring system. Resting regional myocardial dysfunction graded > or =2 was present in 267 of 352 segments evaluated. Contractile reserve (decrease in resting wall motion score > or =2 grades) at peak effect of enoximone infusion was present in 34 of 112 severely hypokinetic, 42 of 117 akinetic, and 14 of 38 dyskinetic segments. The inotropic reserve evaluated after very low dose dobutamine was observed in 34 of 112 severely hypokinetic, 49 of 117 akinetic, and 20 of 38 dyskinetic segments. After revascularization, recovery of function was observed in 31 of 112 severely hypokinetic, 49 of 117 akinetic, and 21 of 38 dyskinetic segments. Overall, there was a significant correlation between absolute score changes of segments which were abnormal at baseline (n = 267) to enoximone peak effects (r = 0.49, p <0.001) to predict absolute changes after revascularization; after dobutamine there was progress toward identity (r = 0.62, p <0.001) and the difference was significant among correlation slopes of dobutamine alone, enoximone alone, and enoximone plus very low dose dobutamine echocardiograophy (0.45+/-0.04, 0.51+/-0.04, and 0.63+/-0.04, respectively, F = 5.25, p = 0.005). Therefore, enoximone followed by very low dose dobutamine may assess myocardial viability of postinfarcted akinetic and dyskinetic areas. This test may be useful when evaluating patients with more severe cardiac failure and/or life-threatening arrhythmias.

KATP channels and 'border zone' arrhythmias: role of the repolarization dispersion between normal and ischaemic ventricular regions.

1. In order to investigate the role of KATP channel activation and repolarization dispersion on the 'border zone' arrhythmias induced by ischaemia-reperfusion, the effects of glibenclamide and bimakalim, agents modifying action potential (AP) duration, were studied in an in vitro model of myocardial 'border zone'. 2. The electrophysiological effects of 10 microM glibenclamide and 1 microM bimakalim (n=8 each), respectively KATP channel blocker and activator, were investigated on guinea-pig ventricular strips submitted partly to normal conditions (normal zone, NZ) and partly to simulated ischaemic then reperfused conditions (altered zone, AZ). 3. By preventing the ischaemia-induced AP shortening (P<0.0001), glibenclamide reduced the dispersion of AP duration 90% (APD90) between NZ and AZ (P<0.0001), and concomitantly inhibited the 'border zone' arrhythmias induced by an extrastimulus (ES), their absence being significantly related to the lessened APD90 dispersion (chi2=8.28, P<0.01). 4. Bimakalim, which also reduced the APD90 dispersion (P<0.005) due to differential AP shortening in normal and ischaemic tissues, decreased the incidence of myocardial conduction blocks (25% of preparations versus 83% in control, n=12, P<0.05) and favoured 'border zone' spontaneous arrhythmias (75% of preparations versus 25% in control, P<0.05). 5. During reperfusion, unlike bimakalim, glibenclamide inhibited the ES-induced arrhythmias and reduced the incidence of the spontaneous ones (12% of preparations versus 92% in control, P<0.05), this latter effect being significantly related (chi2=6.13, P<0.02) to the lessened ischaemia-induced AP shortening in the presence of glibenclamide (P<0.0001). 6. These results suggest that KATP blockade may protect the ischaemic-reperfused myocardium from 'border zone' arrhythmias concomitantly with a reduction of APD90 dispersion between normal and ischaemic regions. Conversely, KATP channel activation may modify the incidence of conduction blocks and exacerbate the ischaemia-induced 'border zone' arrhythmias.

Pretreatment with the adenosine triphosphate-sensitive potassium channel opener nicorandil and improved myocardial protection during high-potassium cardioplegic hypoxia.

We hypothesized that pretreatment with the potassium channel opener nicorandil might enhance myocardial protection achieved by cold (20 degrees C) high-potassium (16 mmol/L) cardioplegia (5 ml/min) during long-duration (120 minutes) myocardial hypoxia (average oxygen content 5.4 ml/dl). We tested a 15-minute infusion of nicorandil (1 mmol/L) given only before (group A, n = 8) or before and during cardioplegia (group B, n = 8) in guinea pig papillary muscle preparations contracting isometrically while stimulated (4 mA, 2 msec) at 1600 msec cycle length. Nicorandil was significantly negative inotropic before cardioplegia and shortened significantly action potential duration. During cardioplegia, time to arrest of contraction was shortened from 145 +/- 28 seconds (mean +/- standard error) in the vehicle group (dimethyl sulfoxide 1:100; n = 8) to 56 +/- 10 seconds (p < 0.02) and 68 +/- 5 seconds (p < 0.05) in groups A and B, respectively. Recovery of developed tension at 60 minutes of normothermic reoxygenation (expressed as percent of prehypoxia basal value) was ameliorated from 54% +/- 6% (vehicle group) to 92% +/- 4% (group A, p < 0.01) and to 119% +/- 19% (group B, p < 0.01). The specific potassium channel blocker glibenclamide (glib: 1 mumol/L, n = 8) prolonged action potential duration and was without effect on time to arrest. On reoxygenation, the glib group had prolonged time to half relaxation (versus group A, p < 0.02) and the worst percent developed tension at 60 minutes (40% +/- 4%). In the overall study, time to arrest and percent developed tension at 60 minutes were inversely correlated (r = -0.45, p < 0.01). Arrhythmias were never observed. Multivariate analysis showed that pretreatment with nicorandil (with or without drug adjunct to cardioplegic solution) was a significant factor (r2 = 0.65, p = 0.0001) to influence reoxygenation-mediated recovery of mechanical function. Neither the negative inotropic effect of nicorandil before cardioplegia nor its abbreviating action on time to arrest during cardioplegia was contributory to explain recovery of function on reoxygenation. In subgroup analysis, negative inotropism and the shortening of action potential duration were contributory factors. These data suggest that nicorandil pretreatment activates potassium channels and enhances the myocardial protection provided by cold cardioplegia an effect, which is evident after a long hypoxic period, late on reoxygenation.

Adenosine triphosphate-dependent potassium channel modulation and cardioplegia-induced protection of human atrial muscle in an in vitro model of myocardial stunning.

OBJECTIVES: Although adenosine triphosphate-dependent potassium channel openers have been shown to enhance cardioplegic protection in animal myocardium, there is a lack of data on human cardiac tissues. We aimed at determining, on human atrial muscle, whether adenosine triphosphate- dependent potassium channels are involved in protection caused by high-potassium cardioplegia and whether adenosine triphosphate-dependent potassium channel activation might improve cardioplegic protection in an in vitro model of myocardial stunning. METHODS: Human atrial trabeculae were obtained from adult patients undergoing cardiac operations. In an organ bath at 37 degrees C, the preparations were subjected to 60 minutes of hypoxia at a high stimulation rate either in Tyrode solution (control, n = 17) or in St Thomas' Hospital solution without additives (n = 6) or associated with 100 nmol/L bimakalim (n = 7) or 1 micromol/L glibenclamide (n = 7), followed by 60 minutes of reoxygenation and 15 minutes of positive inotropic stimulation with 1 micromol/L dobutamine. RESULTS: Atrial developed tension was reduced by hypoxia to 27% +/- 5% of baseline and incompletely recovered after reoxygenation to 38% +/- 7%, whereas dobutamine restored contractility to 74% +/- 7% of basal values. St Thomas' Hospital solution with or without bimakalim improved developed tension after reoxygenation and dobutamine (P <.0001 vs control), whereas glibenclamide inhibited these protective effects of cardioplegic arrest (P =.001 vs St Thomas' Hospital solution). After reoxygenation, the protective effect of bimakalim disappeared at a high pacing rate (400- and 300-ms cycle length) but recovered during dobutamine superfusion. CONCLUSIONS: Adenosine triphosphate-dependent potassium channels are likely involved in the cardioprotective effects of cardioplegia in human atrial trabeculae and adenosine triphosphate-dependent potassium channel activation with bimakalim used as an additive to cardioplegia enhanced protection.

Polynucleotide:Adenosine glycosidase is the sole activity of ribosome-inactivating proteins on DNA.

Polynucleotide: adenosine glycosidases (PNAG) are a class of plant and bacterial enzymes commonly known as ribosome-inactivating proteins (RIP). They are presently classified as rRNA N-glycosidases in the enzyme nomenclature [EC 3.2.2.22]. Several activities on nucleic acids, other than depurination, have been attributed to PNAG: in particular modifications induced in circular plasmids, including linearisation and topological changes, and cleavage of guanidinic residues. Here we describe a chromatographic procedure to obtain nuclease-free PNAG by dye-chromatography onto Procion Red derivatized Sepharose((R)). Highly purified enzymes depurinate extensively pBR322 circular, supercoiled DNA at neutral pH and exhibit neither DNase nor DNA glycolyase activities, do not cause topological changes, and adenine is the only base released from DNA and rRNA, even at very high enzyme concentrations. A scanning force microscopy (SFM) study of pBR322 treated with saporin-S6 confirmed that (i) this PNAG binds extensively to the plasmid, (ii) the distribution of the bound saporin-S6 molecules along the DNA chain is markedly variable, (iii) plasmids already digested with saporin-S6 do not appear fragmented or topologically modified. The observations here described demonstrate that polynucleotide:adenosine glycosidase is the sole enzymatic activity of the four ribosome-inactivating proteins gelonin, momordin I, pokeweed antiviral protein from seeds and saporin-S6. These proteins belong to different families, suggesting that the findings here described may be generalized to all PNAG.

Hypocaloric high-protein diet improves glucose oxidation and spares lean body mass: comparison to hypocaloric high-carbohydrate diet.

The aim of the study was to investigate the effects of two hypocaloric (800-kcal) diets on body weight reduction and composition, insulin sensitivity, and proteolysis in 25 normal glucose-tolerant obese women. The two diets had the following composition: 45% protein, 35% carbohydrate (CHO), and 20% fat (HP diet, 10 subjects), and 60% CHO, 20% protein, and 20% fat (HC diet, 15 subjects); both lasted 21 days. A euglycemic hyperinsulinemic (25 mU/kg/h) clamp lasting 150 minutes combined with indirect calorimetry was performed before and after the diet. Both diets induced a similar decrease in body weight and fat mass (FM), whereas fat-free mass (FFM) decreased only after the HC diet. 3-Methylhistidine (3-CH3-HIS) excretion was reduced by 48% after the HP diet and remained unchanged after the HC diet (P < .05). A significant correlation was found between the changes in FFM and in 3-CH3-HIS excretion after the diet (rs = .50, P < .02). Blood glucose remained unchanged, while insulin decreased in both diets. Free fatty acids (FFA) significantly increased only after the HC diet (P < .05). During the clamp period, glucose disposal and glucose oxidation significantly increased after the HP diet and significantly decreased after the HC diet. Opposite results were found when measuring lipid oxidation. In conclusion, our experience suggests that (1) a hypocaloric diet providing a high percentage of natural protein can improve insulin sensitivity; and (2) conversely, a hypocaloric high-polysaccharide-CHO diet decreases insulin sensitivity and is unable to spare muscle tissue.