Interplay of π-stacking and inter-stacking interactions in two-component crystals of neutral closed-shell aromatic compounds: periodic DFT study

This paper bridges the gap between high-level ab initio computations of gas-phase models of 1 : 1 arene–arene complexes and calculations of the two-component (binary) organic crystals using atom–atom potentials. The studied crystals consist of electron-rich and electron-deficient compounds, which form infinite stacks (columns) of heterodimers. The sublimation enthalpy of crystals has been evaluated by DFT periodic calculations, while intermolecular interactions have been characterized by Bader analysis of the periodic electronic density. The consideration of aromatic compounds without a dipole moment makes it possible to reveal the contribution of quadrupole–quadrupole interactions to the π-stacking energy. These interactions are significant for heterodimers formed by arenes with more than 2 rings, with absolute values of the traceless quadrupole moment (Q_zz) larger than 10 D Å. The further aggregation of neighboring stacks is due to the C–H⋯F interactions in arene/perfluoroarene crystals. In crystals consisting of arene and an electron-deficient compound such as pyromellitic dianhydride, aggregation occurs due to the C–H⋯O interactions. The C–H⋯F and C–H⋯O inter-stacking interactions make the main contribution to the sublimation enthalpy, which exceeds 150 kJ mol⁻¹ for the two-component crystals formed by arenes with more than 2 rings.

The interplay of π-stacking and inter-stacking interactions in two-component organic crystals without conventional hydrogen bonds.

Intracellular fate of polymer therapeutics investigated by fluorescence lifetime imaging and fluorescence pattern analysis

Nanocarriers bearing anticancer drugs are promising candidates to improve the efficacy of cancer therapy and minimize side effects. The most potent cytostatics used in the treatment of various cancers are anthracyclines, e.g. doxorubicin or pirarubicin. Recently, polymer therapeutics carrying anthracyclines have been intensively studied. The precise characterization of in vitro nanocarrier biological behavior brings a better understanding of the nanocarrier characteristics and enables prediction of the behavior of the nanocarrier during in vivo application. Advanced fluorescence detection methods, e.g. fluorescence lifetime imaging microscopy (FLIM), were successfully exploited to describe the properties of various polymeric nano-systems and contributed to a complex view of anthracyclines' intracellular transport and DNA intercalation. Here, we report the application of a specific technique for processing FLIM images, called fluorescence pattern decomposition, to evaluate early events after doxorubicin or pirarubicin treatment of cells. Moreover, we characterized changes in the intracellular localization and release of the anthracyclines during the incubation of cells with polymer nanotherapeutics based on poly[N-(2-hydroxypropyl)-methacrylamide] (pHPMA).

Correlation of peripheral blood monocyte and neutrophil direct counts with plasma inflammatory cytokines and TNF-alpha soluble receptors in the initial phase of acute pancreatitis

MATERIAL

The relationship between direct count of peripheral blood leucocyte populations and plasma concentrations of IL-6, IL-8, sTNFR-55 and sTNFR-75 during five initial days of acute pancreatitis was studied.

RESULTS

Most significant relationship was found for monocytes, which correlated with sTNFR-55 (R = 0.38, p < 0.05) and sTNFR-75 (R = 0.41, p < 0.05 and R = 0.55, p < 0.01 during 1st and 2nd day, respectively). Later, in days 2, 3 and 4 an interrelation between monocytes and IL-6 (R = 0.49 to R = 0.41, p < 0.01) was observed. Monocytes also correlated with IL-8 in days 2 and 3 (R = 0.41, p < 0.05 and R = 0.43, p < 0.01, respectively). Neutrophil count correlated with IL-6 in days 3 and 4 (R = 0.34, p < 0.05 and R = 0.56, p < 0.01, respectively) and with IL-8 in the 4th day only (R = 0.39, p < 0.05). No significant correlations of lymphocyte, eosinophil and basophil direct counts with cytokines and receptors during the initial 5 days of AP were found.

CONCLUSIONS

Observed relationships between monocyte direct counts and plasma cytokine levels reflect monocytes involvement in the development of acute pancreatitis.

Early endoscopic sphincterotomy and early laparoscopic cholecystectomy in the treatment of severe acute biliary pancreatitis--a preliminary report

PURPOSE

The proper timing of endoscopic sphincterotomy and laparoscopic cholecystectomy in acute biliary pancreatitis is still a subject of controversies. The following rapid report presents preliminary data concerning treatment of patients with severe form of necrotizing biliary pancreatitis (SNBP) with the sequence of minimal invasive procedures (endoscopic sphincterotomy and laparoscopic cholecystectomy) performed in the first 48 hours after admission.

MATERIAL AND METHODS

Twelve patients with SNBP were included in the study. The described above procedures were performed in all of the patients within 48 hours. We evaluated clinical outcome, complications, time of stay in hospital and also some morphological (white blood cells) and liver parameters (AST, ALT, bilirubin, ALP and GGT) of these patients in the course of the disease.

RESULTS

Two patients died. Two other ones has local complications. We did not observe major complications after ERCP with ES and after laparoscopic cholecystectomy. Additionally, the lavage of the abdominal cavity was performed and drainage was established during laparoscopic cholecystectomy. Conversion in our group occurred in 1 person. Later complications in the course of the disease were caused by the its progression and not related to the performed procedures.

CONCLUSIONS

The results are very incurable, however, performing these types of procedures in the experienced centers deserves to be taken into account.

Acute biliary pancreatitis in the era of minimally invasive surgery

PURPOSE

Opinions about early endoscopic sphincterotomy and time of laparoscopic cholecystectomy in acute biliary pancreatitis are still controversial. Some authors reserved this procedure only for cases in which the stones were visualized during ERCP or patients had clinical symptoms of acute cholangitis. The aim was the assessment of the dynamic of changes of proinflammatory cytokines and white blood cells in time in patients with acute biliary pancreatitis after performed endoscopic sphincterotomy and laparoscopic cholecystectomy.

MATERIAL AND METHODS

We enrolled 43 consecutive patients with clinically diagnosed mild forms of acute biliary pancreatitis. All were treated by early endoscopic sphincterotomy and laparoscopic cholecystectomy performed during the first 48 hours after admission. The course of the disease was monitored by measurement of the level of proinflammatory cytokines.

RESULTS

Marked decrease of the level of proinflammatory interleukins within 24 hours after endoscopic sphincterotomy was observed. Mean values of IL-6 and IL-8 were statistically lower immidiately after this procedure (p < 0.001). Subsequent decrease was achieved after laparoscopic cholecystectomy. The mean values of TNF-alpha and IL-12p40 were relatively constant throughout the study period.

CONCLUSION

All patients suffering from mild acute biliary pancreatitis should be treated by using minimally invasive procedures. However, such a only treatment should be reserved for experienced centers.

Poly-C specific ribonuclease activity correlates with increased concentrations of IL-6, IL-8 and sTNFR55/sTNFR75 in plasma of patients with acute pancreatitis

Plasma pancreatic-type Poly-C specific ribonuclease (P-RNase)-enzyme activity increases in patients with acute pancreatitis (AP) who develop pancreatic necrosis and severe disease course. It is considered as a marker of pancreatic tissue destruction. The aim of this study was to estimate interrelations between major inflammatory cytokines such as: interleukin 6 (IL-6), interleukin 8 (IL-8) and tumor necrosis factor soluble receptors: sTNFR55 and sTNFR75 output, and plasma P-RNase activity. The study was carried out in a group of 56 patients with AP, where 20 developed pancreatic necrosis. It was found that serum P-RNase concentration and levels of all studied inflammatory cytokines significantly increase already in the first day from diagnose of the disease (2.5 folds for P-RNase, 20 for IL-8, about 200 for IL-6 and 1.5 for receptors, respectively). In the first day from admission to hospital, P-RNase activity significantly correlated with plasma concentration of studied inflammatory cytokines. The most pronounced correlation was found for P-RNase and IL-6 in days 1-4 from diagnose, manifested by Pearson correlation r coefficients amounting to 0.86, 0.79, 0.60 and 0.57 respectively (p<0.001). Dividing the studied AP patients into two groups, varying in severity of disease a significant differences in P-RNase and IL-6, IL-8 and sTNFR55/sTNFR75 were found. In patients with acute necrotizing pancreatitis P-RNase significantly correlate with levels of major inflammatory cytokines. Carried out studies suggest that activity of P-RNase reflects severity of inflammatory reaction, which is dependent on development of pancreatic injury and tissue necrosis in AP.

Structural analysis and sheep pituitary receptor binding of GnRH and its complexes with metal ions

Binding of GnRH and its metal complexes to a sheep pituitary receptor have been investigated showing that Cu(II)-GnRH complex is more effectively bound to the receptor than the metal-free ligand, while Ni(II) and Co(II) complexes are less effective than the metal-free GnRH. Earlier studies have explained reasonably well the complex formation with cupric ion, while in this work extensive 1H NMR measurements have been performed for free gonadotropin-releasing hormone (GnRH) and its complexes with Ni(II) in DMSO (dimethyl sulfoxide) solution. This study shows the high order of organization of the metal-free peptide in DMSO solution with two structured 'domains' whose relative orientation is modulated by the mobility of the central glycine. Furthermore, theoretical calculations were performed for the Ni(II)-GnRH complex. The data obtained in this work supports previous studies on the co-ordination of Ni(II) ions with GnRH in aqueous solutions at high pH [J. Inorg. Biochem. 33 (1988) 11] and suggest an experimental procedure to reproduce high pH in DMSO solution. In the Ni(II) complex, the metal ion was found to co-ordinate with four nitrogen atoms inducing a well definite arrangement of aromatic side-chains and a rigid backbone structure.

Serum free fatty acid concentration in patients with acute pancreatitis

BACKGROUND

The involvement of lipolytic enzymes and liberated fatty acids in ethiology of acute pancreatitis (AP) has been implicated.

AIM

To analyze the level of FFA in the patients with AP in relation to severity of the disease.

MATERIAL AND METHODS

The study included 36 patients with acute edematous AP (group I), 29 patients with necrotizing AP: 16 without (group IIA) and 13 with complications (group IIB), and 12 control subjects. Serum levels of total FFA (by enzymatic method) and the individual fatty acids of the FFA pool (by gas-liquid chromatography) were measured during the first 4 days after admission.

RESULTS

A significant increase in the mean total serum FFA was noted for all the groups with the highest values on admission (p < 0.02-0.01). The per cent contribution was significantly higher as compared to control group for oleic acid (group I, p < 0.02, group IIA, p < 0.05, group IIB, p < 0.005), linoleic acid (group IIB, p < 0.02) and arachidonic acid (group IIA, p < 0.05, group IIB, p < 0.02). Significantly lower percentage was noted for stearic acid (all three groups: p < 0.01, p < 0.005, p < 0.01, respectively) and for palmitic acid (only group IIB: p < 0.005). The ratio of saturated to polyunsaturated fatty acids was significantly lower than in control group on each day of study for group IIB only (p < 0.005-p < 0.001).

CONCLUSION

Polyunsaturated fatty acids, mainly linoleic and arachidonic, may be involved in the development of complications in acute pancreatitis.

[Thyroid crisis diagnosed on the basis of anatomic-pathologic examination]

Graves-Basedow disease is the most common cause of hyperthyroidism. Rhabdomyolysis is occasionally associated with metabolic coma or severe electrolyte disturbances. We describe rhabdomyolysis accompany ing thyroid crisis. A 48-years old man admitted with hypovolemic shock developed rhabdomyolysis, congestive heart failure, hepatic failure and renal failure and then died. It is interesting that correct diagnosis was done on the basis of microscopic examination of specimens of the thyroid gland.

Red cell deformability in patients with chronic atheromatous ischemia of the legs

BACKGROUND

It has been shown that atherosclerosis can cause not only lowering of the perfusion pressure gradient at the macro/micro circulation level, but can bring about untoward rheological changes such as e.g. loss of the red blood cells (RBC) elasticity. This can participitate in mechanism of impairment of the blood flow through the microcirculation as well. The aim of this study was to measure RBC elasticity in the claudicants, and to evaluate the effect of the applied treatment either conservative or surgical revascularisation on this rheological parameter.

MATERIAL AND METHODS

RBC deformability was examined in claudicants 83 of them (mean claudication distance 400 m) were treated conservatively (walking exercise on a treadmill and Pentoxyphilline 600 mg b.i.d.) 44 claudicants with the critical leg ischemia (mean claudication distance below 50 m or rest pain) underwent surgical revascularisation. The measurements of RBC elongation (under selected values of the shear stress) were made on entry to the study, after 6 weeks, and 12 weeks of observation.

RESULTS

After 12 weeks of conservative treatment, RBC elasticity both at rest and after walking exercise significantly increased. In the patients undergoing surgery mean RBC elasticity both at rest and after walking exercise 12 weeks following surgery was not significantly different compare with the respective levels at the beginning of the study.

CONCLUSIONS

In the group of claudicants with less advanced atherosclerosis (conservative group), the treatment brought about significant increase of RBC elasticity. On the contrary in case of the patients with advanced atherosclerosis and critical leg ischemia revascularisation alone appeared to be ineffective in correction of untoward rheologic alteration such as rigidity of the erythrocytes.

Composition of free fatty acid and triglyceride fractions in human necrotic pancreatic tissue

BACKGROUND

Lipolytic enzymes, such as lipase, phospholipase A(2), lipoprotein lipase, and hormone-sensitive adipocyte lipase are probably implicated in the pathogenesis of acute pancreatitis. The increased activity of these enzymes can cause specific changes in fatty acid composition, both to free fatty acid (FFA) and triglyceride (TG) fractions in necrotically changed pancreatic tissue.

MATERIAL AND METHODS

Specimens of necrotically changed pancreatic tissue taken intraoperatively from 13 patients operated for serious necrotic acute pancreatitis were analysed. The Fölsch extraction method and separation of lipids by thin-layer chromatography was used, and the final fatty acid composition was determined after methylation by gas liquid chromatography.

RESULTS

The changes in the FFA fraction are more definite than those for the triglyceride fraction and refer mostly to the increased percentage distribution of unsaturated fatty acids.

CONCLUSIONS

These studies lead to the hypothesis that fatty acids released in the process of lipolysis play a key role in the pathogenesis of acute pancreatitis.

[Unusual complication in the course of acute pancreatitis]

Rare neurological complication in course of severe acute pancreatitis was described. A 38-year old woman developed Multiple Organ Dysfunction Syndrome ((MODS) and neurological complications such as transient encephalopathy and polineuropathy in a form of tetraplegy.

[The cause of upper gastrointestinal bleeding and the value of emergency endoscopic hemostasis]

Introduction of endoscopy and endoscopic hemostasis had substantial impact on the treatment of diseases of stomach and duodenum complicated by bleeding. We compared two 4-years' periods analysing etiology of bleeding and influence of endoscopic haemostasis on outcome of patients with upper gastrointestinal haemorrhage. Number of patients in both groups were comparable. Ratio of bleeding related to gastric and duodenal ulcer didn't change substantially. Number of patients with haemorrhagic gastritis decreased somehow while those with bleeding oesophageal varies increased. Number of patients submitted to emergency operation for bleeding ulcer decreased significantly. Mortality was lower in the second period of time only in patients with haemorrhage requiring transfusion of 4-7 units of blood.

Autoxidation of stored soybean lecithin (short communication)

Soybean phospholipid concentrates, generally called lecithins, can be stored for long time in a refrigerator or even at room temperature, without apparent changes of sensory properties, and their peroxide value usually remains low. This behaviour is related to the antioxidant activity of phospholipids in refined vegetable oils [1] which was attributed to their synergistic effect in presence of tocopherols [2, 3]. Both the low peroxide content and the inhibitory activity may be explained, at least partially, by the hydroperoxide decomposing activity of phospholipids [4], the rate of hydroperoxide decomposition being proportinal to the square root of the hydroperoxide content [5]. Therefore, we have analysed several samples of lecithin to find out whether the presence of phospholipids only affects the rate of hydroperoxide accumulation or the formation of total oxidation products, respectively.