PECD study of a single-conformer molecule: a critical comparison of experiment and theory.

In this work we address a specific experimental and theoretical question regarding the influence of a conformational population in the modeling of photoelectron circular dichroism (PECD) spectroscopy. In the past two decades, PECD has revealed a rich and complex phenomenology in molecular processes with unprecedented insight, especially in molecular geometry sensitivity. Since the early development of this spectroscopy, theory has pointed out the importance of conformer influence on PECD; in particular, the rotation of methyl groups was surprisingly found to be responsible for strong modulation of the PECD signal. Here, to advance understanding of the effect of rotations, we have chosen to study norcamphor, a single-conformer molecule, as a benchmark for a PECD comparison between experiment and theory at the density functional theory (DFT) and time-dependent density functional theory (TDDFT) levels. The excellent agreement between experimental data and theory for norcamphor sheds light on the influence of rotations and gives a solid explanation for the reasonable qualitative agreement in the PECD of camphor, where three methyl groups are added to the same molecular structure.

Fabrication, characterization and cell cultures on a novel composite chitosan-nano-hydroxyapatite scaffold.

This paper deals with the characterizations made during the development of a nano-HAp loaded chitosan scaffold, obtained by the freeze-drying technique combined with a novel in situ crystal growth method. The nano-composites were characterized by a highly porous and interconnected structure. The XRD patterns and calculated domain sizes of the HAp nano-crystals nucleated on the chitosan scaffolds are very similar to the ones recorded for deproteinated bone apatite. Both osteoblasts (MG63) and mesenchimal cells (hMSC) were showing good proliferation and adhesion onto the scaffolds. The presence of extensive filopodia and excellent spreading in and around the interconnected porous structure, indicated a strong cellular adhesion and growth. Moreover a good hMSC osteogenic differentiation has been verified. The observations related to well-developed structure morphology, physicochemical properties and high cytocompatibility suggest that the obtained chitosan-nHA porous scaffolds are potential candidate materials for bone regeneration.

Restorative proctectomy with colon pouch-anal anastomosis by laparoscopic transanal pull-through: an available option for low rectal cancer?

BACKGROUND: There are sporadic reports, with different verdicts, of restorative proctectomy by laparoscopic transanal pull-through (LTPT) without the use of a minilaparotomy for a part of the procedure. This study aimed to explore the applicability and advantages of LTPT with colon pouch-anal anastomosis for low rectal cancer, and to evaluate the results. METHODS: From January 2002 to July 2003, 10 of 12 patients (6 men and 4 women) undergoing a laparoscopic procedure for low rectal cancer (<6 cm from the anal verge) underwent LTPT. The mean age of these patients was 58 years. The results have been compared with those for 12 similar non-pull-through procedures performed during the same period. RESULTS: There was no operative mortality. An anastomotic leakage and a hemorrhagic gastropathy occurred in the LTPT group. During a mean follow-up period of 18 months (range, 12-26 months), there was no local relapse. Four patients manifested moderate incontinence. No significant differences in functional outcome were observed between the LTPT and control groups. CONCLUSION: The authors' experience supports use of the LTPT procedure with colonic pouch-anal anastomosis for selected lower rectal cancers with indications for a laparoscopic approach as an appropriate and reproducible surgical treatment.

Quantitative and qualitative evaluation of blood salvaged after extracorporeal circulation (ECC) in paediatric heart surgery. Study of biochemical, morphological and structural variations of RBC after ECC and after salvaging of ECC circuit priming blood.

The salvaging of ECC circuit priming blood is essential for reducing the morbidity related to homologous blood transfusions and the importance of this technique is inversely proportionate to the age and weight of the child. In infants, the washing and centrifugation of blood not only drastically reduce the risk of contracting blood-transmitted diseases and cut management costs, but are also of considerable hemodynamic importance, producing a rapid normalization of the patient's hematocrit and hemoglobin and balancing the O2 consumption/demand ratio. The marketing of miniaturized salvagin devices with 55 ml bowls by Dideco has made possible the recovery of small quantities of blood, so as to normalise the hematic crisis and permit the application of total hemodilution in low-weight patients. The salvaged blood shows an average hematocrit of 52.7+/-9.7% (max 68.1%) and an average hemoglobin of 17.6 +/- 2.9 g/dl (max 20.7 g/dl), and maintains its structural components, osmotic resistance, concentration of intraerythrocytic hemoglobin and mean corpuscular hemoglobin all intact. Washing with isoosmotic and isoionic hydroelectrolytic solutions normalizes the ionic situation in the post-operative period and activated blood salvaging after Extracorporeal Circulation. The use of solutions without nutritional substances results however in a considerable fall in the number of enzymes in the intraerythrocytic metabolic glucide chain (G6PDH: -40.7 +/- 14.3% p<0.001), (PK: -23.8 +/- 20.5% p<0.03). This drop may be responsible for erythrocytic morphological alterations (echinocytic change) and probably for the release of hemoglobin from the red blood cells. Washing with isoionic, isoosmotic solutions containing G5% and adenine could, at least in theory, improve the quality of the salvaged blood, by normalizing the morphology and the volume of the RBC and by increasing the hematocrit.

[Optimal reconstruction after resection of the rectum in cancer surgery]. / Sulla ricostruzione ottimale dopo escissione del retto per cancro.

The efficacy of colon-J-pouch anal anastomosis (CPAA) in reducing defecatory frequency and urgency and the incidence of anastomotic fistulas has been proved by several studies but only as compared to straight colo-anal anastomosis (CAA) of the end-to-end type. We investigated the role played by the colon pouch in the strict sense, without the influence of a different CAA model, in a randomised prospective study comparing CPAA and straight side-to-end CAA. Over the period from 1994 to 1998 we selected 66 of 118 patients operated on for rectal cancer: a CPAA was constructed in 35 (group P) and a direct side-to-end CAA in 31 (group D). The two groups were well matched for surgeon, type of patient, stage of disease and incidence of radiotherapy and presented no differences in operative mortality, general and anastomotic morbidity, or need for reoperation. Functional results: after 3, 12 and 36 months, defecatory frequency > or = 4 movements/day was observed in 93.4, 67.7 and 41.6% of cases, respectively, in group D as against 25.7, 14.2 and 13%, respectively, in group P (P < 0.05), while defecatory urgency was recorded in 77.4, 35.4 and 27.9% of cases, respectively, in group D as against 34.2, 17.1 and 9%, respectively, in group P (p < 0.05). In the long term, incontinence was also significantly lower in group P. The colon pouch improves sphincter rehabilitation after anal recanalization compared to straight side-to-end CAA. It does not affect anastomotic morbidity but affords a protective effect on function in irradiated patients. CPAA proves to be the optimal reconstruction option after excision of the rectum.

Solvent effects on the conformational distribution and optical rotation of gamma-methyl paraconic acids and esters.

A computational investigation of the optical rotatory power of cis and trans 2-methyl-5-oxo-tetrahydro-3-furancarboxylic acids and the corresponding methyl and ethyl esters is presented. Solvent effects on both the conformational space and the rotatory power are analyzed by comparing results obtained in vacuo with those computed--using the Polarizable Continuum Model--in methanol. A comparison with experimental observations for the optical rotatory power of the title compounds in methanol is also carried out, in a few cases also for several wavelengths. Agreement between theory and experiment is in all cases excellent, in particular when solvent effects are included both in the geometry optimization and in the calculation of the OR, thus confirming the validity of the computational procedure adopted, even for this challenging family of floppy molecules.

Optical rotation calculation of a highly flexible molecule: the case of paraconic acid.

The absolute configuration of (S)-(-)-paraconic acid is correctly assigned on the basis of ab initio calculations of the specific optical rotation (OR) at the sodium D line, carried out both in vacuum and in methanol. Density functional theory (DFT) and Møller-Plesset second-order perturbation theory (MP2) are used to determine the most stable conformational structures, whose OR values are then calculated using DFT linear response theory and London atomic orbitals. The total OR is obtained by averaging these values using the population fractions determined from Boltzmann's statistics. The total OR of the MP2 structures has the correct sign both in vacuum and in solution, whereas only the solvent-relaxed DFT structures correctly reproduce the experimental sign. The strong solvent effect on the total OR is shown to arise primarily due to the variations in the relative energies of the various conformations.

A survey in Puglia: the attitudes and opinions of specialists, general physicians and patients on follow-up practice. G.S.Bio.Ca.M.

BACKGROUND: The follow-up for breast cancer patients is a well established routine practice requiring the organization and coordination of many professional figures and a large expenditure of national health funds. To study the problems in practical clinical management of such a complicated health program in a typical population, a questionnaire survey of the opinions and attitudes of specialists, general practitioners and patients directly involved in clinical follow-up was performed in the Puglia region of Southern Italy. MATERIALS AND METHODS: A representative sample of specialists (n = 285), general practitioners (n = 263) and patients (n = 284) involved in the management of follow-up practice for breast cancer in Puglia received different questionnaires to ascertain their behaviour, attitudes, opinions, perception of the disease and the organizational requirements for treatment. A total of 57.4% of questionnaires were returned. RESULTS AND DISCUSSION: The most important results were: (a) about one-third of cases complained of difficulties in follow-up management due to the lack of cooperation and integration of follow-up procedures among specialists; (b) the general practitioners preferred to have a more active role in follow-up; (c) the patients reported that being managed by more than one physician or living far from follow-up facilities resulted in an inferior quality of life.