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Biomedical subjects

C Gatti

Publications and source records attributed to C Gatti.

At least 19 recordsLinked to original sources

Spontaneous rupture of non-parasitic hepatic cyst.

Intrahepatic cysts are generally classified as congenital, traumatic, infectious or neoplastic. Non-parasitic hepatic cysts (NPHCs) include simple cysts and adult polycystic liver disease in which the liver is diffusely occupied by cysts. NPHCs usually reach a large size before causing symptoms, unless a complication such as rupture, bleeding, infection, obstructive jaundice or neoplastic transformation occurs. We report the case of a 67-year-old man with spontaneous rupture of simple liver cyst. The clinical pictures and the unusual ultrasound features of this rare condition are discussed.

Aged↗

Subcutaneous enoxaparin following thrombolysis and intravenous unfractionated heparin in ST-elevation acute myocardial infarction: safety and efficacy of low vs full dose.

AIM: In ST-segment elevation myocardial infarction (STEMI) treated with fibrin-specific thrombolytic agents, early intravenous unfractionated heparin (UFH) is warranted. Low molecular weight heparin Enoxaparin currently represents an alternative to UFH, to be used until hospital discharge. Since optimal dosing of subcutaneous Enoxaparin is not standardized, we conducted an observational study to compare safety and efficacy of low (4,000 U once daily) vs full dose (100 U/kg twice daily) regimens. METHODS: All STEMI patients successfully treated with tenecteplase and intravenous UFH and referred to the Catheterization Laboratory between June 2002-November 2003 for predischarge coronary angiography, were evaluated. The primary end-point was the composite of hemorrhages and residual angina/reinfarction during Enoxaparin administration, whereas secondary end-points were occurrence of venous thromboembolism (VTE) during Enoxaparin administration, and infarct-related artery (IRA) patency rate at predischarge coronary angiography. RESULTS: Out of 123 patients, 57 (M/F 45/12, mean age 65.8+/-8.1 years) received low dose, and 66 (men/women 45/21, mean age 62.6+/-11.8 years) full dose subcutaneous Enoxaparin. The incidence of the composite primary end-point was comparable in both groups (19% vs 26%; P=NS). Also, null was the occurrence of VTE, whereas the IRA patency rate did not significantly differ in the 2 groups (84% vs 86% TIMI 3 and 11% vs 9% TIMI 2 flow grades; P=NS). CONCLUSIONS: In patients with STEMI undergoing successful recanalization with tenecteplase and intravenous UFH, low dose subcutaneous Enoxaparin appears preferable to full dose, in the light of comparable safety and clinical efficacy and superior easiness of use.

Aged↗

Body composition, fat distribution and metabolic characteristics in lean and obese women with polycystic ovary syndrome.

The polycystic ovary syndrome (PCOS), characterized by chronic anovulation and hyperandrogenism, has many features of metabolic syndrome and can be considered a metabolic disease. Approximately 50% of patients with PCOS are overweight or obese with abdominal fat accumulation. Some metabolic alterations and abdominal fat distribution have also been reported in lean women with PCOS. The aim of this study was to evaluate the effect, if any, of obesity on metabolic features, body composition and fat distribution in patients with PCOS. Body composition and abdominal fat distribution (evaluated by DEXA), waist circumference, blood pressure, lipid profile, glucose tolerance and homeostasis model assessment index were determined in 23 lean [mean age 23 +/- 5 yr, mean body mass index (BMI) 22 +/- 2 kg/m2] and 27 overweight-obese (mean age 21 +/- 5 yr, mean BMI 32 +/- 5 kg/m2) patients with PCOS and in 20 age- and weight-matched eumenorrhoic women. Patients exhibited slight but non-significant differences in metabolic parameters, waist circumference, blood pressure and total and abdominal fat content compared with weight-matched controls. None of the lean subjects suffered from metabolic syndrome according to the National Cholesterol Education Program--Adult Treatment Panel III (NCEP-ATPIII) criteria as opposed to 10 overweight-obese patients and three overweight-obese control subjects (37% and 33.3% of each subgroup, respectively). Our data do not show significant metabolic alterations in lean PCOS women. Results indicate that obesity seems to underpin the metabolic alterations exhibited by the overweight-obese patients. However, since women with PCOS are at increased cardiovascular risk, further studies are needed to evaluate metabolic alterations and body composition in these patients.

Adipose Tissue↗

Voiding dysfunction in x-linked adrenoleukodystrophy: symptom score and urodynamic findings.

PURPOSE: Adrenoleukodystrophy is an x-linked genetic disorder characterized by the breakdown of the myelin sheath surrounding nerve cells in the brain and progressive dysfunction of the adrenal gland with 6 possible phenotypes. Lower urinary tract symptoms affect the quality of life of these patients but only sporadic cases have been previously studied by urodynamics. We report to our knowledge the first series in the literature looking at the prevalent pattern. MATERIALS AND METHODS: A total of 14 children and adults 8 to 53 years old (average age 30) with different phenotypes were referred for evaluation. Of the patients 6 had adrenomyeloneuropathy without cerebral involvement (C-) 3 had the adult cerebral form, 3 had the childhood cerebral form, 1 had cerebral involvement (C+) and 1 was asymptomatic. All patients were submitted to a screening protocol, consisting of the self-administered short form questionnaire International Conference on Incontinence Questionnaire-Short Form (ICIQ-SF) and a 3-day voiding diary. Patients were divided in group 1-no urinary symptoms, ICIQ-SF score 0 and no further investigation (3); group 2-frequency/urgency, ICIQ-SF score 1 to 5, uroflowmetry and post-voiding residual urine (4); and group 3-voiding symptoms and incontinence, ICIQ-SF score greater than 5, standard urodynamic examination (7). RESULTS: A neurogenic overactive bladder was the prevalent urodynamic finding (6 of 7 patients), while hypocontractility was found in 1 case. CONCLUSIONS: Vesicosphincteric dysfunction can be explained by spinal and/or cerebral involvement in the different neurological forms of adrenoleukodystrophy. Attempts at treatment with anticholinergics and neuromodulation in 4 of our patients provided temporary benefit with clear subjective amelioration of symptoms and improved quality of life.

Adolescent↗

Percutaneous tibial nerve neuromodulation is well tolerated in children and effective for treating refractory vesical dysfunction.

PURPOSE: We evaluated pain tolerability and the preliminary results of percutaneous tibial nerve stimulation (PTNS) in children with unresponsive lower urinary tract symptoms (LUTS). MATERIALS AND METHODS: A total of 23 children 4 to 17 years old with LUTS refractory to conventional treatment underwent PTNS at 12, 30-minute weekly sessions. Ten patients had idiopathic overactive bladder, 7 were in nonneurogenic urinary retention and 6 had neuropathic bladder. Ten children were carefully evaluated for pain during needle insertion and electrical stimulation using certain scoring systems, namely the faces pain rating scale, Children's Hospital of Eastern Ontario pain scale, visual analogue scale and Questionario Italiano del Dolore. Evaluation was done at the first, sixth and last sessions. An anxiety-depression test was administered. All 23 children underwent clinical and urodynamic evaluation before and after treatment. RESULTS: All except 1 patient completed treatment. An anxious-depressive trait was found in 7 of 10 children/parents on anxiety-depression testing. Regarding pain, the faces pain rating scale never showed the severe pain face, the Children's Hospital of Eastern Ontario scale showed signs of pain at the beginning of each stimulation but not at the end, and the visual analog scale generally showed a low score with a further decrease during the first (p = 0.05), sixth (p = 0.03) and twelfth (p = 0.02) sessions. The Questionario Italiano del Dolore score was significantly related to the affective component of pain (p = 0.002) and it decreased between the first and last sessions. The 10 children with overactive bladder had symptom improvement in 80%, incontinence was cured in 5 of 9 and urodynamics showed normalization of cystometric bladder capacity in 62.5% with no more unstable contractions in those who became continent. Symptoms improved in 71% of the children in urinary retention. One of 3 and 4 of 7 patients had incontinence and post-void residual urine cured, respectively. Urodynamics showed an improved detrusor pressure at maximum flow (p = 0.009) and flow rate (p = 0.005). Symptoms and urodynamics did not significantly change in the neuropathic bladder group. CONCLUSIONS: PTNS is safe, minimally painful and feasible in children. It seems helpful for treating refractive nonneurogenic LUTS.

Adolescent↗

Neurovesical dysfunction in children after treating pelvic neoplasms.

OBJECTIVE: To evaluate 10 years of experience, and thus define the occurrence and causes, of neurogenic lower urinary tract dysfunction in children with pelvic neoplasms treated by surgery. PATIENTS AND METHODS: From 1991 to 2000, 33 children were operated by the same surgeons for pelvic neoplasms; 11 were analysed, comprising four each with sacrococcygeal teratoma (ST) and ganglioneuroma, and one each with yolk sac tumour (YST), neuroblastoma and myofibroblastic bladder sarcoma (MBS). The other patients were not assessed because eight had died or were in severe progression, three were treated by bladder substitution and the others were lost to follow-up or refused a urological evaluation. All 11 children were evaluated at >/= 6 months after surgery with a questionnaire about bowel and voiding habits, a neurological and orthopaedic assessment, a noninvasive urodynamic study, renal ultrasonography and spinal and pelvic magnetic resonance imaging (MRI). All patients with signs of bladder dysfunction were evaluated by a pressure-flow study. The results were analysed for surgical approach and anatomical involvement, i.e. group A, extensive surgery for complete tumour excision in the sacral area (ST and YST); group B, surgery for tumour resection in the paraspinal ganglia area (neuroblastoma and ganglioneuroma); and group C, bladder tumour with partial bladder resection (MBS). RESULTS: Eight patients had signs or symptoms related to bladder sphincter dysfunction. One child refused the invasive urodynamic evaluation, leaving seven for analysis (two each ST and ganglioneuroma, one each YST, neuroblastoma and MBS). The urodynamic findings were normal in three children. On spinal and pelvic MRI a presacral lipoma with syringomyelia was discovered in one child with ST. Eight children had bladder dysfunction and two had no neurogenic damage (which was only in sacral tumours); in one child it was related to an upper motor neurone lesion from spinal dysraphism and in the other to a lower motor neurone lesion from surgical injury to the splanchnic nerves. Patients operated for paraspinal tumours had more bladder dysfunction but no signs of neurogenic damage, as did the patient with partial bladder resection. However in Group B, there may have been a transient or incomplete nerve injury in one patient. CONCLUSIONS: Deficits of parasympathetic, sympathetic and somatic innervation of the bladder and the urethra may occur in children after surgery for pelvic neoplasms, related to minor or major surgical trauma. In ST, a tethered cord may be associated with mixed neurogenic damage. Knowledge of bladder dysfunction in anorectal malformations, spinal dysraphism, etc. and the clinical protocol used in these patients also seemed to be useful for understanding the development of voiding dysfunction in patients with neoplasm.

Adolescent↗

Thoracic outlet syndrome in paediatrics: clinical presentation, surgical treatment, and outcome in a series of eight children.

BACKGROUND/PURPOSE: This report reviews the clinical presentation, surgical treatment, and outcome of 8 children treated for the thoracic outlet syndrome (TOS) during the last 3 years. METHODS: From 1998 through 2001 31 patients were admitted to our Vascular Surgery Unit with TOS. Eight of them (25.8%) were in the paediatric age group, 8 to 16 years (mean, 13 years). No sex prevalence was found. The presenting symptoms were neurologic in 2 patients (25%) and secondary to venous flow impairment in 6 (75%). At phlebography, venous thrombosis was seen in 2 cases, and functional intermittent obstruction was seen in 4. Seven patients underwent decompressive surgical partial resection of the first rib with transaxillary or supraclavicular access. One patient was treated conservatively. RESULTS: There were no major postoperative complications. Mean hospital stay was 2.7 days. In no patient were there signs of recurrence after a mean follow-up of 18 months (range, 3 to 36 months). CONCLUSIONS: In the authors' experience TOS in paediatric patients occurs with the same symptoms and thrombotic complications as in adults. The same surgical strategy adopted in adult patients is advisable for affected children.

Adolescent↗

Comparison of circulating and local adipose tissue renin-angiotensin system in normotensive and hypertensive obese subjects.

The renin-angiotensin-aldosterone system (RAAS) plays a well-recognized role in the regulation of BP and in salt and water balance. Since hypertension affects a considerable proportion of obese patients, circulating RAAS has been studied in obese subjects with and without hypertension, albeit with conflicting results. Furthermore, attention has recently focused on the expression of the components of the Renin-angiotensin system (RAS) in some organs, including adipose tissue where it seems to be involved in the regulation of growth and differentiation. The aim of our study was to investigate circulating RAAS and adipose tissue RAS in obese patients with and without hypertension and in matched controls. PRA, and plasma and urinary aldosterone levels were measured in 35 obese, 30 hypertensive obese patients and in 20 controls. In addition, the expression of angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1) genes was studied in sc adipose tissue from 8 obese, 6 hypertensive obese and 6 healthy subjects. As previously demonstrated in other studies, there were no significant differences in the levels of circulating RAAS components in the 3 groups. As regards local RAS, interestingly, we found that AT1 gene was significantly more expressed in sc adipose tissue from obese patients with hypertension than in those without hypertension and controls. By contrast, AGT levels were similar in the 3 groups. Our data do not support the hypothesis of an involvement of circulating RAAS in the development of obesity-related hypertension. On the other hand, local RAS seems to be differently regulated in sc adipose tissue from obese patients with hypertension with respect to normotensive obese patients and controls.

Adipose Tissue↗

Prognostic role of serum CA15.3 in 362 node-negative breast cancers. An old player for a new game.

The aims of the present investigation were to evaluate the association between serum CA15.3 levels and other biological and clinical variables and its prognostic role in patients with node-negative breast cancer. We evaluated 362 patients operated upon primary breast cancer from 1982 to 1992 (median follow-up 69 months). Serum CA15.3 was measured by an immunoradiometric assay. The association between variables was investigated by a Principal Component Analysis (PCA) and the prognostic role of CA15.3 on relapse-free survival (RFS) was investigated by Cox regression models adjusting for age, oestrogen receptor (ER), tumour stage, and ER x age interaction, with both the likelihood ratio test and Harrell's c statistic. The prognostic contribution of CA 15.3 was highly significant. Log relative hazard of relapse was constant until approximately 10 (U/ml) of CA15.3 and increased thereafter with increasing marker levels. CA15.3 showed a significant contribution using as a cut-off point a value of 31 U/ml. However, the contribution to the model of the marker as a continuous variable is much greater. From these findings, we can conclude that: (i) CA15.3 is a prognostic marker in node-negative breast cancer; (ii) its relationship with prognosis is continuous, with the risk of relapse increasing progressively from approximately 10 U/ml.

Aged↗

The unexpected and large enhancement of the dipole moment in the 3,4-bis(dimethylamino)-3-cyclobutene-1,2-dione (DMACB) molecule upon crystallization: a new role of the intermolecular CH...O interactions.

The molecular dipole moment of the 3,4-bis(dimethylamino)-3-cyclobutene-1,2-dione (DMACB) molecule and its enhancement in the crystal was evaluated by periodic RHF ab initio computations. A discrete boundary partitioning of the electronic density that allows an unambiguous partitioning of the molecular space in the condensed phase was adopted. The resulting molecular dipole in the crystal compares favorably with the experimental value obtained by a multipolar analysis of single-crystal X-ray diffraction data recorded at 20 K, using a fuzzy boundary partitioning of the derived pseudoatom densities. We show that a large and highly significant molecular dipole enhancement may occur upon crystallization, despite the lack of a strongly hydrogen bonded environment in the crystal. The 23 unique C-H...O interactions which are formed upon packing of the DMACB molecule induce an increase in the molecular dipole (over 75%) that is comparable to or greater than that found in systems which are characterized by the stronger O-H...O and N-H...O hydrogen bonds. The DMACB molecule constitutes an excellent system for the study of C-H...O interactions in the condensed phase, since no other kind of competing hydrogen bonds is present in its crystal. A simple and qualitative model for the matrix contribution to the DMACB molecular dipole enhancement in the crystal is proposed. The formation of several weak C-H...O bonds is found to yield a small (about 0.2 e) net flux of electronic charge flowing from the hydrogens of the methyl groups to the carbonyl oxygen atoms. Despite the limited increase of the intramolecular charge transfer upon crystallization, a large molecular dipole enhancement occurs because the centroids of the positive and negative induced charges are quite far apart. This work highlights a new and important role of the C-H...O bond, besides those already known in the literature.

Journal Article↗

Hydrophobicity of whey protein concentrates measured by fluorescence quenching and its relation with surface functional properties.

Surface hydrophobicity of whey protein concentrate (WPC) under heated (85 degrees C for 5, 10, 20, 30, 40, and 60 min) and unheated conditions was measured using cis-parinaric acid (CPA), 1-anilino-8-naphthalenesulfonate (ANS), and a fluorescence quenching method using acrylamide as a quencher. This last method evaluates the degree of exposure of tryptophanyl residues in proteins to the solvent. The initial slope of Stern-Volmer plots, K(app), was used as an index of protein hydrophobicity. Surface hydrophobicity of WPC exhibited good relation with surface functional properties such as emulsifying and foaming. Analysis of the data obtained in this work showed that the fluorescence quenching method gave results similar to those obtained using CPA and ANS. Therefore, this simple technique is satisfactory in effectively obtaining information about the hydrophobicity of whey proteins.

Acrylamide↗

Esophagogastric dissociation versus fundoplication: Which is best for severely neurologically impaired children?

PURPOSE: Neurologically impaired children (NIC) often have swallowing difficulties, severe gastroesophageal reflux, recurrent respiratory infections, and malnutrition. Bianchi proposed esophagogastric dissociation (EGD) as an alternative to fundoplication and gastrostomy. The authors compared these 2 approaches. METHODS: Twenty-nine consecutive symptomatic NIC refractory to medical therapy were enrolled in a prospective study and divided into 2 groups: A (n = 12), NIC who underwent fundoplication and gastrostomy; B (n = 14), NIC who underwent EGD. Three were excluded because of previous fundoplication. Anthropometric (percentage of the 50th percentile/age of healthy children) and biochemical parameters, respiratory infections per year, hospitalization (days per year), feeding time (minutes), and "quality of life" (parental psychological questionnaire, range 0 to 60), were analyzed (t test and Mann-Whitney test) preoperatively and 1 year postoperatively. Complications were recorded. RESULTS: Compared with group A, group B presented a statistically significant increase of all anthropometric and nearly all biochemical parameters with a statistical difference in terms of respiratory infections, hospital stay, feeding time, and psychological questionnaire. In group A, 2 bowel obstructions, 1 tight fundoplication, 1 dumping syndrome, and 3 failures of fundoplication occurred. Group B presented 1 anastomotic stricture, 1 paraesophageal hernia, and 1 bowel obstruction. CONCLUSIONS: Compared with fundoplication and gastrostomy, EGD offered better nutritional rehabilitation, reduction in respiratory infections, and improved quality of life. EGD can be rightfully chosen as a primary procedure.

Adolescent↗

Is the 13C-acetate breath test a valid procedure to analyse gastric emptying in children?

BACKGROUND/PURPOSE: Scintigraphy is regarded as the "gold standard" procedure in measuring gastric emptying (GE) rates. 13C-acetate breath test (ABT), which already has been validated in adults, is a noninvasive and nonradioactive alternative method. The aim of the current study was to validate ABT against technetium Tc 99m scintigraphy in children affected by delayed GE. METHODS: Sixty children were recruited and divided into 2 groups: group A, 30 healthy controls; group B, 30 patients with gastroesophageal reflux, and scintigraphy-documented DGE (15 neurologically impaired). After an overnight fast, all of them underwent ABT using 25 to 150 mg 13C-acetate. Breath samples were obtained at baseline and then every 10 minutes for 2 hours. The 13CO2 to 12CO2 ratio in breath samples was analysed by isotope ratio mass spectrometry. Data are expressed as follows: time of peak 13C exhalation (tP13CO2b) and half emptying time in ABT (t(1/2b)), and scintigraphy half emptying time (t(1/2s)). RESULTS: In controls tP13CO2b was 37 +/- 13 minutes and t(1/2b) 74 +/- 12 minutes. In patients tP13CO2b and t(1/2b) were, respectively, 65 +/- 26 minutes and 104 +/- 18 minutes t(1/2s) was 91 +/- 21 minutes. In group B tP13CO2b and t(1/2b) were delayed significantly compared with controls, respectively, P < .03 and P < .01. In group B significant correlation between t(1/2s) and t(1/2b) was noted (r1 = 0.97). A close correlation was also observed between t(1/2s) and tP13CO2b (r2 = 0.95). CONCLUSION: The 13C ABT is an easy, reliable, and less expensive procedure for measuring GE, and its results closely correlate with those of scintigraphy in a paediatric population.

Acetates↗

Quantitative measurement of soluble cytokeratin fragments in tissue cytosol of 599 node negative breast cancer patients: a prognostic marker possibly associated with apoptosis.

Apoptosis is associated with caspase-mediated proteolysis of Type I (K18 and K19) cytokeratins. We previously showed a positive association between the levels of tissue polypeptide antigen (TPA), that recognizes cytokeratins K8, K18, and K19 fragments, and induced apoptosis in breast cancer cell lines. The aim of the present study was to evaluate the interrelationships between TPA, steroid receptors, and p53, and their joint prognostic role in node-negative breast cancer patients not treated with adjuvant therapies. Age and pT were also considered since they are known prognostic factors. Five hundred and ninety-nine cases with N- breast cancer were evaluated (median follow-up: 60 months). TPA was measured by an immunoradiometric assay and p53 by an immunochemiluminescent assay in tumor cytosol. Multiple correspondence analysis was used to study the associations among variables. Their prognostic role (univariate analysis) and their joint effect (multivariate analysis) on RFS were investigated with Cox regression models. TPA showed a direct association with ER and PgR. Higher p53 values were weakly associated to low values of ER, PgR, and TPA. Younger age was related to low and intermediate values of ER and PgR and to low p53 values, while older age was related to high values of ER. Multivariate analysis showed a significant prognostic impact for pT, age, ER, and TPA. Among the interactions considered clinically relevant, only that between ER and age was found. RFS estimated values were poorer in cases with lower than in those with higher TPA values, both in patients expected to have a poor (pT2, young age, low ER) and a better prognosis (pT1, older age, high ER). From the findings of the present study we can draw the following conclusions: The relationship of TPA with prognosis gives an additional contribution to pT, age, and steroid receptors in N- breast cancer; TPA may be considered the first marker of apoptosis measured with a fully standardized quantitative method in tumor cytosol and could be evaluated in prognostic indexes including markers related to different biological mechanisms.

Adult↗

Gene expression of angiotensinogen in adipose tissue of obese patients.

Recently, the genes of components of the renin-angiotensin system (RAS), namely angiotensinogen (AGT), angiotensin converting enzyme and angiotensin II receptor have been described in adipose tissue. In animal models the angiotensinogen in adipose tissue has been implicated in the pathogenesis of metabolic alterations and hypertension associated with obesity. The aim of our study was to evaluate the AGT gene expression both in visceral and subcutaneous adipose tissue in obese patients and lean subjects. AGT mRNA levels were measured by reverse transcriptase polymerase chain reaction (RT-PCR) using specific primers. AGT mRNA was expressed at variable levels in obese patients. It was significantly greater in visceral than in subcutaneous adipose tissue. Positive and significant correlation was found between the expression of AGT in visceral adipose tissue and BMI. These data suggest that angiotensinogen may be determinant of fat distribution and may be involved in the plurimetabolic syndrome of central obesity.

Adipose Tissue↗

A new and successful chance in surgical treatment of gastrooesophageal reflux in severely neurologically impaired children: Bianchi's procedure.

AIM: Neurologically impaired (NI) children present with neuromuscular incoordination and severe gastroesophageal reflux (GER). In these cases, Bianchi has proposed total oesophagogastric dissociation (OGD) as a primary procedure and not only after failed fundoplication. METHODS: Anthropometric and laboratory data, incidence of respiratory symptoms, days of hospitalisation, time of feeding, stool frequency and quality of life were tested preoperatively and after OGD over a 12-month period in 13 severe NI patients. RESULTS: Results are shown in Table 1. We also recorded improvement in quality of life, based on communication by the person responsible for the care of the subject, and determined by psychological interviews. CONCLUSIONS: OGD is a successful and feasible procedure and can be included as a primary definitive surgical treatment in individualised nutritional rehabilitation planning for each severe NI child.

Adolescent↗

Evaluation of net atomic charges and atomic and molecular electrostatic moments through topological analysis of the experimental charge density

The atoms in molecules (AIM) theory may be used to derive atomic charges, atomic volumes and molecular dipole moments from the charge density. The theory is applied to theoretical periodic Hartree-Fock (PHF), density-functional (DFT) and experimental X-ray densities of p-nitroaniline using the program TOPOND and a newly developed program, TOPXD, for topological analysis of densities described by the Coppens-Hansen multipole formalism. Results show that, like dipole moments derived directly from the multipole refinement, AIM-derived atomic and molecular moments are dependent on the multipole model used. As expected, large differences are found between charges derived from the monopole parameters and those from AIM analysis of the experimental model density. Differences between the k'-restricted multipole model (KRMM) and the unrestricted multipole model (UMM) results are preserved in the AIM analysis. The enhancement of the molecular dipole moment of p-nitroaniline in the solid state is confirmed by both experiment and theory but the experimental dipole moment is in much better agreement with theoretical periodic Hartree-Fock and, especially, periodic DFT (PDFT) data when KRMM is used in the refinement. The AIM analysis allows a rigorous definition of the charges of the atoms in molecules and provides a realistic basis for comparison between molecules and between experiment and theory.

Journal Article↗