Proteins in amorphous saccharide matrices: structural and dynamical insights on bioprotection.

Bioprotection by sugars, and in particular trehalose peculiarity, is a relevant topic due to the implications in several fields. The underlying mechanisms are not yet clearly elucidated, and remain the focus of current investigations. Here we revisit data obtained at our lab on binary sugar/water and ternary protein/sugar/water systems, in wide ranges of water content and temperature, in the light of the current literature. The data here discussed come from complementary techniques (Infrared Spectroscopy, Molecular Dynamics simulations, Small Angle X-ray Scattering and Calorimetry), which provided a consistent description of the bioprotection by sugars from the atomistic to the macroscopic level. We present a picture, which suggests that protein bioprotection can be explained in terms of a strong coupling of the biomolecule surface to the matrix via extended hydrogen-bond networks, whose properties are defined by all components of the systems, and are strongly dependent on water content. Furthermore, the data show how carbohydrates having similar hydrogen-bonding capabilities exhibit different efficiency in preserving biostructures.

Dermal substitute: a safe and effective way in surgical management of adults post-burn dorsal foot contractures.

OBJECTIVE: Neglected dorsal foοt burns may result in typical fοrefοοt defοrmities characterised by cοntractures leading tο hyperextensiοn οf the tοes and gait disturbance. These defοrmities usually cause a significant impairment in daily activities and difficulty in wearing shοes. This article presents a recοnstructiοn series οf severe fοrefοοt defοrmities by means of dermal regeneratiοn templates (also known as dermal substitutes) and split thickness skin grafts. PATIENTS AND METHODS: We retrοspectively reviewed οur institutiοnal burn database from 2010 to 2020 focusing on all those dοrsal fοοt cοntractures treated with the use οf a dermal regeneratiοn template. The patients' demοgraphics, burn injury mechanisms, depth, lοcalizatiοn, surface, treatments and fοllοw-up were described. RESULTS: Twelve patients underwent this prοcedure and the mean affected area was 75 cm2. The mean time between the dermal regeneratiοn template applicatiοn and the split thickness skin graft was 19.6 days. Just fοr one patient, an additiοnal skin grafting prοcedure was required. The mean fοllοw-up was 4.6 years. We did not register specific cοmplicatiοns at bοth the recipient (forefoot) and dοnοr sites (scalp). All patients were able tο wear shοes and walk after the procedure. Nο recurrence οf cοntractures were οbserved. All patients were satisfied with cοsmetic results, and they did not request any additiοnal prοcedure οf cοsmetic imprοvement. CONCLUSIONS: The use οf the dermal regeneratiοn template can be cοnsidered as an extremely safe and efficient treatment οf severe post-burn fοrefοοt defοrmities.

Computational methods and theory for ion channel research.

Ion channels are fundamental biological devices that act as gates in order to ensure selective ion transport across cellular membranes; their operation constitutes the molecular mechanism through which basic biological functions, such as nerve signal transmission and muscle contraction, are carried out. Here, we review recent results in the field of computational research on ion channels, covering theoretical advances, state-of-the-art simulation approaches, and frontline modeling techniques. We also report on few selected applications of continuum and atomistic methods to characterize the mechanisms of permeation, selectivity, and gating in biological and model channels.

A small molecule based on the pRb2/p130 spacer domain leads to inhibition of cdk2 activity, cell cycle arrest and tumor growth reduction in vivo.

One strategy in the development of anticancer therapeutics has been to arrest malignant proliferation through inhibition of the enzymatic activity of cyclin-dependent kinases (cdks), which are key regulatory molecules of the cell cycle. Over the past few years, numerous compounds with remarkable cdk inhibitory activity have been studied in cancer therapy, although it is very difficult to point out the best cdk to target. An excellent candidate appears to be cdk2, whose alteration is a pathogenic hallmark of tumorigenesis. The small molecule described in our study showed an inhibitory effect on the kinase activity of cdk2, a significant growth arrest observed in a colony formation assay and a reduction in the size of the tumor in nude mice, thus suggesting its potential role as a promising new type of mechanism-based antitumor drug, also for the treatment of hyperproliferative disorders.

A possible desensitized state conformation of the human α7 nicotinic receptor: A molecular dynamics study.

The determination of the conformational states corresponding to diverse functional roles of ligand gated ion channels is subject of intense investigation with various techniques, from X-rays structure determination to electrophysiology and computational modeling. Even with a certain number of structures becoming recently available, only few major structural features distinguishing conductive open channel from the non conductive resting protein have been highlighted, while high-resolution details are still missing. The characterization of the desensitized conformation(s) is even more complex, and only few specific characteristics have been identified. Furthermore, experimental data provide conflicting information for different ion channels, adding further complexity to the topic. Desensitization is defined as the transition of the agonist-bound open channel into an ion channel configuration inactive even in the presence of agonists. In this work, we analyze a conformation corresponding to a non conductive state obtained via molecular dynamics simulations of a homology model of the human α7 nicotinic receptor complexed with agonists. We highlight some characteristics that could associate it to a desensitized state. The obtained structure is assessed against experimental data for other ligand gated ion channels that have been putatively associated to active, inactive and desensitized conditions.

Molecular dynamics simulation of sucrose- and trehalose-coated carboxy-myoglobin.

We performed a room temperature molecular dynamics (MD) simulation on a system containing 1 carboxy-myoglobin (MbCO) molecule in a sucrose-water matrix of identical composition (89% [sucrose/(sucrose + water)] w/w) as for a previous trehalose-water-MbCO simulation (Cottone et al., Biophys J 2001;80:931-938). Results show that, as for trehalose, the amplitude of protein atomic mean-square fluctuations, on the nanosecond timescale, is reduced with respect to aqueous solutions also in sucrose. A detailed comparison as a function of residue number evidences mobility differences along the protein backbone, which can be related to a different efficacy in bioprotection. Different heme pocket structures are observed in the 2 systems. The joint distribution of the magnitude of the electric field at the CO oxygen atom and of the angle between the field and the CO unit vector shows a secondary maximum in sucrose, absent in trehalose. This can explain the CO stretching band profile (A substates distribution) differences evidenced by infrared spectroscopy in sucrose- and trehalose-coated MbCO (Giuffrida et al., J Phys Chem B 2004;108:15415-15421), and in particular the appearance of a further substate in sucrose. Analysis of hydrogen bonds at the protein-solvent interface shows that the fraction of water molecules shared between the protein and the sugar is lower in sucrose than in trehalose, in spite of a larger number of water molecules bound to the protein in the former system, thus indicating a lower protein-matrix coupling, as recently observed by Fourier transform infrared (FTIR) experiments (Giuffrida et al., J Phys Chem B 2004;108:15415-15421).

[Arterial hypertension in pregnancy: evaluation of renal damage through the study of NAG urinary activity]. / Ipertensione arteriosa in gravidanza: valutazione del danno renale attraverso lo studio dell'attività NAG-urinaria.

NAG-urinary activity was assessed in order to study the renal effects of arterial hypertension in pregnant women. The results obtained showed that there were no significant differences between mean levels of enzymuria in control subjects and normotensive pregnant women. On the contrary, significant differences were found between these two groups and hypertensive pregnant women (above all if arterial hypertension predated pregnancy). The paper stresses the usefulness of this method, which is reliable and non-invasive, for an accurate assessment of the extent of renal damage caused by arterial hypertension during the course of pregnancy.

[Human IgG and adjuvant therapy in patients with colon-rectal cancer]. / IgG umane e terapia adiuvante in pazienti con carcinoma del colon-retto.

UNLABELLED: It is well known that, in patients with carcinoma, chemotherapy produces an increase of the incidence of infections and changes the immune defences of the patient. Since 1952 human immunoglobulins have been used for pathologies with immune deficiency. This study aims to evaluate the immunologic efficacy of purified human immunoglobulins in patients with colon-rectal cancer undergoing chemotherapy. MATERIALS AND METHODS: In 60 patients of both sexes, with colon-rectal cancer after surgical operation and who underwent chemotherapy with 5-FU and folinic acid, about thirty of them were treated with purified human IgG. In particular, the hemochrome and the microbiologic parameters were evaluated. RESULTS: The percentage of infections in patients treated with purified human immunoglobulins was less in comparison to patients treated only with chemotherapy and in this sphere, a prevalence of sepsis sustained by Gram-, was observed in the control group in respect to patients treated with purified human IgG. DISCUSSION AND CONCLUSIONS: The authors have observed a positive qualitative variation in the functional state of the immunocompetent cells; the IgG would play the role of functional stimulation of immediate immunity, pointed out by an inferior number of infections in patients treated with IgG. Therefore, it is evident that the use of such therapeutic factors that can help in the reintegration of a slackened control of immunity represented by neutropenic leucocytes, might contribute to rendering the diffusion of the tumour more difficult.

[Effect of antibiotic chemotherapy on urinary N-acetyl-B-D-glucosaminidase activity in patients with chronic pyelonephritis]. / Effetti della terapia chemio-antibiotica sull'attività NAG-urinaria in pazienti affetti da pielonefrite cronica.

The behaviour of N-acetyl-B-D-Glucosaminidase (NAG) was studied in the urine of patients with chronic pyelonephritis under pharmacological treatment for renewed attacks of acute renal inflammation. It was noted that by the end of target chemo-antibiotic treatment all patients presented a reduction in the inflammation and hence the tubular distress. Once treatment was suspended several patients showed an increase tendency in the activity of the enzyme followed by the reappearance of significant bacteriuria and/or leukocyturia. The acute attack of renal inflammation would not have been recognised if the enzymuria technique had been used to monitor the patients.

[Purified human IgG administration, after chemotherapy, to patients with colorectal carcinoma]. / La somministrazione, dopo chemioterapia, di IgG umane purificate in pazienti affetti da carcinoma del colon-retto.

The authors, in the present study try to test the prophylactic effect of human IgG on surgical patients affected by colorectal cancer and undergoing chemotherapy in order to prevent microbial infections, supporting immunological host defences.

[Use of ultrafiltration in refractory cardiac decompensation]. / Impiego dell'ultrafiltrazione nello scompenso cardiaco refrattario.

Traditional therapy for heart failure (diuretics, digitalic compound, vasodilators, inodilatory ACE-inhibitors) cannot arrest the progressive overloading of the circulatory system so that it is inevitable that a refractory stage to all forms of treatment will be reached when more specialised techniques, such as heart transplant and ultrafiltration will be needed. The paper reports the results obtained in 13 patients in ultrafiltration treatment for refractory heart failure: in the majority of these, a marked improvement in general conditions (edema, dyspnea) was recorded together with a regression from class 5 to class 3 NYHA in 5 patients, and to class 2 for others. The ultrafiltration method in spite of not altering the prognosis which remains negative in these patients, allow those waiting for heart transplant to survive and may improve their chances of surviving heart surgery.

[Changes in urinary NAG activity in patients with climacteric syndrome treated with estrogens]. / Variazioni dell'attività NAG-urinaria in pazienti con sindrome climaterica trattate con estrogeni.

The behaviour of urinary NAG activity was studied in patients during menopause, some of whom were given estrogen therapy due to severe vasomotor symptoms (hot flushes etc.). One group of these patients revealed slightly higher than normal blood pressure. A second group had slight arterial hypertension and pancreatic diabetes. The third group consisted of apparently healthy menopausal women. The significant increase in enzymuria in the first two groups suggests that blood pressure should be carefully checked before starting estrogen therapy. Furthermore this treatment should be given very cautiously and under constant surveillance in the presence of slight hypertension. In patients with diabetes or more severe hypertension, estrogens should never be given.

[Urinary NAG activity and diabetic microangiopathy]. / Attività NAG-urinaria e microangiopatia diabetica.

The behaviour of urinary NAG was monitored in diabetic patients some of whom presented more or less severe vascular alterations. The results showed a relationship between urinary NAG levels and the severity of the vascular condition (in fact the greatest NAG activity was found in patients with overt kidney damage). NAG may therefore reveal the existence of a vascular nephropathy that is still too slight to be identified by the standard non-invasive clinical examinations.

[Carcinoma of the gallbladder. State of the art]. / Il carcinoma della colecisti. Stato dell'arte.

The authors examine the most interesting data about gallbladder cancer. They emphasize the difficulties of an useful approach to this pathology: an early diagnosis is quite impossible and the surgical treatment very disappointing.

[Carcinoma of the gastric stump]. / Il carcinoma del monocone gastrico.

After having emphasized that carcinoma of the gastric stump represents a "major" risk in patients undergoing gastric resection, the authors describe the physiopathology of the new anatomical and functional status of the gastroenteric apparatus and underline the probable etiopathogenetic stages attributable to carcinogenesis. They then describe the treatment of this neoplasia with a marked aggressive character and conclude with the affirmation that the surgeon's efforts must be focused on the correct execution of gastroresection and the follow-up of gastro-resected patients in order to allow the early identification of precancerous conditions and therefore the commencement rational oncological prophylaxis.

[Laparoscopic cholecystectomy: the complications]. / La colecistectomia per via laparoscopica: le complicanze.

The authors report their experience of 48 consecutive cases of colecystectomy performed using a videolaparoscopic technique. Laparoscopic surgery was not successful in only two patients in whom it was necessary to resort to laparotomy; bile duct injury occurred in one patient. On the basis of their experience the authors conclude by affirming that this videolaparoscopic technique may be applied to almost all patients requiring cholecystectomy since it offers considerable advantages over traditional techniques.

[Breast cancer today]. / Il carcinoma della mammella, oggi.

Authors, after a short dissertation about evolution, trough out the years, of the diagnosis and the therapy of the mammary carcinoma, specify the leading role of primary prevention. Self palpation and the mammography reduce of about 30% the mortality. Modern pharmacology and radiotherapy allow a surgical preservative approach, produce better esthetic and functional results. Preservative therapy (QUART) also warrants a good quality of life, and allows the excellent control of primary disease.

Molecular dynamics simulation of carboxy-myoglobin embedded in a trehalose-water matrix.

We report on a molecular dynamics (MD) simulation of carboxy-myoglobin (MbCO) embedded in a water-trehalose system. The mean square fluctuations of protein atoms, calculated at different temperatures in the 100-300 K range, are compared with those from a previous MD simulation on an H2O-solvated MbCO and with experimental data from Mössbauer spectroscopy and incoherent elastic neutron scattering on trehalose-coated MbCO. The results show that, for almost all the atomic classes, the amplitude of the nonharmonic motions stemming from the interconversion among the protein's conformational substates is reduced with respect to the H2O-solvated system, and their onset is shifted toward higher temperature. Moreover, our simulation shows that, at 300 K, the heme performs confined diffusive motions as a whole, leaving the underlying harmonic vibrations unaltered.

Shift from noradrenaline to adrenaline production in the adrenal gland of the lizard, Podarcis sicula, after stimulation with vasoactive intestinal peptide (VIP).

The aim of this study was to investigate the distribution and function of VIP in the adrenal gland of the lizard, Podarcis sicula. We have shown by immunohistochemistry that VIP fibers were localized exclusively around clusters of chromaffin cells in the dorsal ribbon of the lizard adrenal gland. Moreover, a strong positivity for this peptide was observed within ganglial cells and within most chromaffin cells of the gland. To investigate the effects of VIP on the adrenal gland, we have treated lizards with several doses of this peptide and we have shown that injections of exogenous VIP increased plasma levels of catecholamines and corticosteroids, but not of ACTH. This probably suggests a direct effect of VIP on the control of adrenal hormone secretion without the involvement of the hypothalamo-hypophyseal axis. Our results also establish that the increased levels of the hormones were modulated in a time- and dose-dependent manner. Therefore, our morphological studies showed a clear increased function of steroidogenic cells. In the medullary region, VIP administration induced not only a functional enhancement of adrenaline release from adrenergic cells, but also a shift of noradrenaline cells to adrenaline ones.