First-principle molecular dynamics of the Berry pseudorotation: Insights on 19F NMR in SF4

First-principles [density-functional theory (DFT)] molecular-dynamic simulations of the Berry pseudorotation mechanism in SF4 were performed using the atom-centered density-matrix propagation method. The reaction was monitored by following the chemical shieldings of the fluorine atoms, computed on snapshots along the trajectories. In particular we compared the results obtained using a standard functional based on the generalized gradient approximation with those issuing from its hybrid Hartree-Fock-DFT counterpart using a number of basis sets. Our results show that both the basis set and the functional choice rule the quality of the molecular properties monitored as well as the trajectory over the potential-energy surface.

Helicobacter pylori infection: a new cause of anorexia in peritoneal dialysis patients

OBJECTIVE

Helicobacter pylori (HP) infection has frequently been found in dialysis patients. Chronic infections induce overproduction of pro-inflammatory substances. Inflammation has been associated with cachexia and anorexia. We explored the relationship between HP infection, anorexia, and malnutrition in peritoneal dialysis (PD) patients.

PATIENTS AND METHODS

The study included 48 clinically stable PD patients divided into four groups: HP+ with anorexia (group I, n = 12); HP+ without anorexia (group II, n = 4); HP- with anorexia (group III, n = 5); and HP- without anorexia (group IV, n = 27). Infection with HP was diagnosed by breath test. Anorexia was evaluated using a personal interview and an eating motivation scale (VAS). The VAS included five questions that are answered before and after eating. The questions concern desire to eat, hunger, feeling of fullness, prospective consumption, and palatability. Biochemical markers of nutrition and inflammation were also determined.

RESULTS

At baseline, group I showed lower scores for desire to eat, hunger sensation, prospective consumption, and palatability. They also showed lower lymphocyte counts, prealbumin, transferrin, serum albumin, normalized equivalent of protein-nitrogen appearance (nPNA), and residual renal function (RRF). In addition, the same group showed higher levels of C-reactive protein (CRP) and more sensation of fullness than the remaining groups. In the entire series, we found significant linear correlations between the following markers of nutrition and certain questions on the VAS: albumin with before-lunch desire to eat (r = 0.38, p < 0.05), and prealbumin with before-lunch hunger (r = 0.41, p < 0.05) and after-lunch hunger (r = -0.35, p < 0.05). Negative linear correlations were found between albumin and fullness before lunch (r = -0.45, p < 0.01), and between prealbumin and before-lunch desire to eat (r = -0.39, p < 0.05). Negative linear correlations were also seen between CRP and albumin (r = -0.35, p < 0.05) and between CRP and prealbumin (r = -0.36, p < 0.05). Similarly, CRP showed a negative correlation with before-lunch desire to eat (r = -0.38, p < 0.05) and afterlunch desire to eat (r = -0.45, p < 0.01). After HP eradication, group I showed a significant increase in markers of nutrition and in VAS scores for almost all questions. Simultaneously, they showed a decrease in CRP level. Significant differences were also found in lymphocyte count (1105 +/- 259.4 cells/mm3 vs 1330.8 +/- 316 cells/mm3, p < 0.05), nPNA (0.9 +/- 0.16 g/kg/day vs 1.07 +/- 0.3 g/kg/day, p < 0.05), prealbumin (26.7 +/- 6.5 mg/dL vs 33.9 +/- 56.6 mg/dL, p < 0.01), albumin (3.48 +/- 0.3 g/dL vs 3.67 +/- 0.35 g/dL, p < 0.05), CRP (1.16 +/- 1.14 mg/dL vs 0.88 +/- 1.2 mg/dL, p < 0.054), before-lunch desire to eat (56.6 +/- 6.8 vs 72.2 +/- 4, p < 0.001), after-lunch desire to eat (5.4 +/- 2.6 vs 12.3 +/- 2, p < 0.01), hunger before lunch (55.4 +/- 5.4 vs 73.1 +/- 4.6, p < 0.001), hunger after lunch (5.8 +/- 2.9 vs 11 +/- 4, p < 0.01), fullness before lunch (36.6 +/- 10.3 vs 18.7 +/- 8.8, p < 0.001), consumption after lunch (5 +/- 4.7 vs 17.5 +/- 18, p < 0.05), and palatability (61 +/- 5.3 vs 74.1 +/- 4.1, p < 0.001).

CONCLUSION

Infection with HP is associated with anorexia, inflammation, and malnutrition in PD patients. Eradication of HP significantly improves this syndrome. Residual renal function seem to have a protective effect on appetite preservation. The present study supports the hypothesis of the involvement of inflammation in the pathogenesis of malnutrition in PD patients.

[Neonatal urinary ascites secondary to posterior urethral valves]

Urine collection within the perirenal spaces and subsequent urinary ascites may be caused either by calyceal perforation or filtration through the walls of urinary tract as a consequence of urinary obstruction. The obstruction to urine deflow is more frequently secondary to the presence of posterior urethral valves (PUV) in the paediatric age group. Urine collecting within the perirenal spaces may act as a decompressive mechanism that allows endoluminal pressure to decrease, being thus glomerular function and prognosis improved. The case of a newborn in poor clinical conditions with PUV who underwent an emergency surgical procedure for the onset of urinary ascites is described. On operation, no perforation of the upper urinary tract was found, being urinary ascites probably caused by filtration secondary to increased endoluminal pressure. PUV were coagulated by means of a Bugbee electrode and a nephrostomy set in place. Congenital obstruction of the urinary tract caused by PUV may lead to renal, ureteric and vesical damages. Surgery is necessary in order to preserve and improve renal function.

[Varicocelectomy by an inguinal approach. Our experience]

Varicocele is a dilatation of the spermatic plexus due to a pathologic venous reflux in the testes. It affects about 15-18% of adolescents. The modern diagnostic tools allow an early identification and a thorough staging. Surgical treatment in this phase seems to be useful for the preservation of gonad integrity. Recently, the interest in varicocele in pediatric surgery has increased because of the close relationship of this disease to male infertility. We performed a diagnostic-therapeutic protocol with a follow-up to evaluate the trophism and functional state of testes and to identify early recurrence of venous reflux. In our Institute, the surgical treatment usually performed is resection of spermatic plexus through an inguinal approach. This technique is simple, yields good outcome and has no morbidity.

Actinic cheilitis and carcinoma of the lip

During dental examinations, the lips are readily overlooked. Dentists should routinely examine the lips visually and by palpation. Actinic cheilitis is a common condition caused by damage to the lips through exposure to sunlight, and is readily diagnosed clinically. Its progress can be minimized by the use of an appropriate sun screen when outdoors. Actinic cheilitis can undergo malignant transformation into squamous cell carcinoma. The clinical features and management of these conditions are described.