Heterotopic hip ossification resection: monocentric experiences of associated factors, outcomes, and complications.

PURPOSE: The exponential increase in total hip arthroplasty (THA) has led to acute and chronic surgery-related complications. Common chronic and local complications are represented by hip ossification (HO). The aim of our study was to assess the clinical and radiological correlates of patients undergoing surgical removal of heterotopic ossifications after THA and the possible association between HO and prosthetic joint infection. METHODS: Data of 26 patients who underwent surgical removal of periprosthetic calcifications after THA from 2000 to 2022 were analyzed and compared with characteristics of 156 subjects without HO. RESULTS: The preoperative radiographs of patients showed a high-grade Brooker, 3 or 4, later reduced to 1 or 2 in the postoperative radiographs. Ten (38.5%) patients underwent radiotherapy prophylaxis, administered as a single dose 24 h before surgery. In 19 (73%) patients, pharmacological prophylaxis with indomethacin was added in the 30 postoperative days. Only one patient who underwent radiotherapy had a recurrence, while new ossifications were found in three patients without prophylaxis (11.5%). Intraoperative cultures were performed for suspected periprosthetic infection in 8 study group patients. In logistic regression, the presence of HO was significantly and inversely associated with the ASA score (OR = 0.27, 95% CI = 0.09-0.82; P = 0.021) after adjusting. CONCLUSION: Surgical HO removal in symptomatic patients with high-grade disease produces good clinical and radiographic results. Radiotherapy was a good perioperative and preventive strategy for recurrence, also associated with NSAIDs and COX-2 inhibitors.

Supercooling and freezing processes in nanoconfined water by time-resolved optical Kerr effect spectroscopy.

Using heterodyne-detected optical Kerr effect (HD-OKE) measurements, we investigate the vibrational dynamics and the structural relaxation of water nanoconfined in Vycor porous silica samples (pore size ≃ 4 nm) at different levels of hydration and temperatures. At low levels of hydration corresponding to two complete superficial water layers, no freezing occurs and the water remains mobile at all the investigated temperatures with dynamic features similar, but not equal to, the bulk water. The fully hydrated sample shows the formation of ice at about 248 K. This process does not involve all the contained water; a part of it remains in a supercooled phase. The structural relaxation times measured from the decay of the time-dependent HD-OKE signal shows the temperature dependence largely affected by the hydration level; the low frequency (ν < 500 cm(-1)) vibrational spectra obtained by the Fourier transforms of the HD-OKE signal appear less affected by confinement.

The effect of myoglobin crowding on the dynamics of water: an infrared study.

Solutions containing 8 and 32 wt% myoglobin are studied by means of infrared spectroscopy, as a function of temperature (290 K and lower temperatures), in the mid- and far-infrared spectral range. Moreover, ultrafast time-resolved infrared measurements are performed at ambient temperature in the O-D stretching region. The results evidence that the vibrational properties of water remain the same in these myoglobin solutions (anharmonicity, vibrational relaxation lifetime…) and in neat water. However, the collective properties of the water molecules are significantly affected by the presence of the protein: the orientational time increases, the solid-liquid transition is affected in the most concentrated solution and the dynamical transition of the protein is observed, from the point of view of water, even in the least concentrated solution, proving that the water and myoglobin dynamics are coupled.

Optical Kerr effect of liquid and supercooled water: the experimental and data analysis perspective.

The time-resolved optical Kerr effect spectroscopy (OKE) is a powerful experimental tool enabling accurate investigations of the dynamic phenomena in molecular liquids. We introduced innovative experimental and fitting procedures, that enable a safe deconvolution of sample response function from the instrumental function. This is a critical issue in order to measure the dynamics of liquid water. We report OKE data on water measuring intermolecular vibrations and the structural relaxation processes in an extended temperature range, inclusive of the supercooled states. The unpreceded data quality makes possible a solid comparison with few theoretical models: the multi-mode Brownian oscillator model, the Kubo's discrete random jump model, and the schematic mode-coupling model. All these models produce reasonable good fits of the OKE data of stable liquid water, i.e., over the freezing point. The features of water dynamics in the OKE data becomes unambiguous only at lower temperatures, i.e., for water in the metastable supercooled phase. We found that the schematic mode-coupling model provides the more rigorous and complete model for water dynamics, even if its intrinsic hydrodynamic approach does not give a direct access to the molecular information.

Dynamics of the time-resolved stimulated Raman scattering spectrum in presence of transient vibronic inversion of population on the example of optically excited trans-ß-apo-8'-carotenal.

We have studied the effect of transient vibrational inversion of population in trans-ß-apo-8(')-carotenal on the time-resolved femtosecond stimulated Raman scattering (TR-FSRS) signal. The experimental data are interpreted by applying a quantum mechanical approach, using the formalism of projection operators for constructing the theoretical model of TR-FSRS. Within this theoretical frame we explain the presence of transient Raman losses on the Stokes side of the TR-FSRS spectrum as the effect of vibrational inversion of population. In view of the obtained experimental and theoretical results, we conclude that the excited S2 electronic level of trans-ß-apo-8(')-carotenal relaxes towards the S0 ground state through a set of four vibrational sublevels of S1 state.

Structural analysis of neutral tetracycline using anharmonicity of delocalized vibrations.

While tetracyclines are in active medical use, their bioactive atomic compositions are still questionable. Here, we investigate the structural properties of neutral tetracycline in dimethyl sulfoxide - the environment used often to mimic the environment in vivo. We compare the measured linear and nonlinear infrared spectra to those calculated for a collection of stable and energetically plausible tautomers, and describe the structurally sensitive off-diagonal peaks using anharmonicities of the normal modes. The comparison of experimental and theoretical 2DIR spectra is consistent with the numerical predictions of statistical thermodynamics on the relative weights of possible tautomers. In result, we provide the systematic account of the structural realizations of neutral tetracycline in DMSO.

The role of stimulated Raman scattering in supercontinuum generation in bulk diamond.

We report on experimental results of supercontinuum generation in bulk diamond. The spectrum of supercontinuum generated with 800 nm pump extends up to 600 nm towards short wavelengths. We present the numerical model explaining the phenomenon, in which the role of different nonlinear effects including stimulated Raman scattering is discussed. Unlike in other materials, in diamond the feature of supercontinuum due to stimulated Raman response is apparently visible.

Evidence of two distinct local structures of water from ambient to supercooled conditions.

The liquid and supercooled states of water show a series of anomalies whose nature is debated. A key role is attributed to the formation of structural aggregates induced by critical phenomena occurring deep in the supercooled region; the nature of the water anomalies and of the hidden critical processes remains elusive. Here we report a time-resolved optical Kerr effect investigation of the vibrational dynamics and relaxation processes in supercooled bulk water. The experiment measures the water intermolecular vibrations and the structural relaxation process in an extended temperature range, and with unprecedented data quality. A mode-coupling analysis of the experimental data enables to characterize the intermolecular vibrational modes and their interplay with the structural relaxation process. The results bring evidence of the coexistence of two local configurations, which are interpreted as high-density and low-density water forms, with an increasing weight of the latter at low temperatures.

Knowledge of the bio-effects of ultrasound among physicians performing clinical ultrasonography: Results of a survey conducted by the Italian Society for Ultrasound in Medicine and Biology (SIUMB).

INTRODUCTION: Safety issues should always be kept in mind when using diagnostic ultrasound, which is associated with potentially hazardous bio-effects, especially with the introduction of new technologies. AIM: To assess the level of awareness and knowledge of safety issues related to the clinical use of ultrasound among physician-members of the Italian National Society for Ultrasound. MATERIALS AND METHODS: A questionnaire with 11 multiple-choice questions was sent to members of the Italian Society for Ultrasound in Medicine and Biology. The answers were forwarded from the Society's Secretariat to the investigators, who statistically analyzed the data. RESULTS: The mean age of the 105 respondents was 44 years. The most frequent kind of ultrasound examinations (in addition to conventional B-mode) were: Doppler (74%), contrast-enhanced US (43%), and pediatric studies (43%). Only 50-60% of the responders knew the correct definitions of the terms thermal index and mechanical index. Almost all respondents understood the bio-effects reflected by the thermal index, but only a minority knew the most likely organ target of bio-effects related to the mechanical index and what do indicate the units in which the thermal index is expressed. The majority knew that fetuses are at higher risk of damage. Few respondents were able to identify the correct safety statements included in the recommendations of the International Ultrasound Societies. CONCLUSION: In conclusion, the present findings indicate that greater efforts of National Ultrasound Societies are warranted in disseminating knowledge of the bio-effects of diagnostic ultrasound modalities among operators.

Real-time contrast-enhanced ultrasound--a new simple tool for detection of peritoneal-pleural communications in hepatic hydrothorax.

PURPOSE: Hepatic hydrothorax is defined as the accumulation of pleural effusion in a cirrhotic patient in the absence of pulmonary or cardiac disease. Peritoneal fluid can pass into the pleural space through diaphragmatic fenestrations. The demonstration of such passage is important to establish the diagnosis of hepatic hydrothorax and can be achieved by intraperitoneal injection of nuclear contrast agents. Our aim was to evaluate the ability of contrast enhanced ultrasound in the detection of peritoneal-pleural communications. MATERIALS AND METHODS: Seven patients with cirrhotic ascites and pleural effusion were studied in order to make a diagnosis of hepatic hydrothorax. SonoVue was injected into the peritoneal cavity (9.8 mL), and the peritoneal and pleural cavities were monitored by ultrasound. All patients were then studied using a nuclear scan. RESULTS: Passage of SonoVue from the peritoneal to the pleural cavities was seen in 5 patients. In 2 patients, no passage of contrast agent was detectable. Nuclear scan was consistent with contrast enhanced ultrasound in all patients. CONCLUSION: This study shows that the presence of peritoneal-pleural communications can be demonstrated by real time contrast enhanced ultrasound, whose results are comparable to those of nuclear scan. Contrast enhanced ultrasound is cheaper and could theoretically be performed wherever ultrasound facilities are available.

Electrostatic interactions in phospholipid membranes revealed by coherent 2D IR spectroscopy.

The inter- and intramolecular interactions of the carbonyl moieties at the polar interface of a phospholipid membrane are probed by using nonlinear femtosecond infrared spectroscopy. Two-dimensional IR correlation spectra separate homogeneous and inhomogeneous broadenings and show a distinct cross-peak pattern controlled by electrostatic interactions. The inter- and intramolecular electrostatic interactions determine the inhomogeneous character of the optical response. Using molecular dynamics simulation and the nonlinear exciton equations approach, we extract from the spectra short-range structural correlations between carbonyls at the interface.

Acute systemic, splanchnic and renal haemodynamic changes induced by molecular adsorbent recirculating system (MARS) treatment in patients with end-stage cirrhosis.

AIM: To evaluate the acute effect of treatment with the molecular adsorbent recirculating system (MARS) on splanchnic, renal and systemic haemodynamics in patients with end-stage cirrhosis. METHODS: Twelve patients with end-stage cirrhosis, undergoing MARS treatment, were enrolled. The following haemodynamic parameters were measured by means of Doppler ultrasonography and thoracic electrical bioimpedance, before and after each session: portal velocity, renal and splenic resistance indices, cardiac output, cardiac stroke volume, heart rate, mean arterial pressure, systemic vascular resistance. RESULTS: Median portal velocity increased significantly after treatment (23.7 vs. 20.3 cm/s, P < 0.05) while renal resistance index (0.72 vs. 0.75, P < 0.05) and splenic resistance index (0.60 vs. 0.65, P < 0.05) decreased significantly. Mean arterial pressure (83 vs. 81 mmHg, P < 0.05) and vascular resistance (899 vs. 749 dyne. s/cm5, P < 0.05) increased significantly, while cardiac output and stroke volume showed no significant changes. CONCLUSIONS: Data emerging from this investigation suggest that MARS treatment improves significantly various haemodynamic alterations in cirrhotic patients in the short term. The observed decrease in renal vascular resistance and improvement in splenic resistance index, a parameter related to portal resistance, which leads us to hypothesize that these haemodynamic effects are probably mediated by clearance of vasoactive substances during MARS treatment.

Role of real-time contrast-enhanced ultrasound in the assessment of metastatic portal vein thrombosis.

Patients with liver disease or systemic pathology are more prone to develop portal vein thrombosis. Non-neoplastic thrombosis is characterised by absence of intrathrombotic perfusion, corresponding to marked hypoechogenicity at contrast-enhanced ultrasound. We report two cases of portal vein thrombosis in which contrast-enhanced ultrasound showed marked hypoechogenicity in the late phase. This late phase perfusional contrast pattern is consistent with non-neoplastic thrombosis, but is actually similar to that of metastatic liver lesions. Echo-guided needle biopsy indeed yielded histological results consistent with carcinoma. Repeated contrast-enhanced ultrasound showed presence of intratumoural perfusion in the arterial phase, suggestive of the neoplastic nature of the thrombus. Our cases suggest that CEUS with second generation contrast agents in patients with portal thrombosis should include the evaluation of both arterial and portal phases in order to provide accurate non-invasive diagnosis of metastatic portal vein thrombosis.

Diagnosis and management of hepatic focal nodular hyperplasia.

Focal nodular hyperplasia (FNH) is the second most common benign tumor of the liver, after hemangioma. It is generally found incidentally and is most common in reproductive-aged women, but it also affects males and can be diagnosed at any age. Patients are rarely symptomatic, but FNH sometimes causes epigastric or right upper quadrant pain. The main clinical task is to differentiate it from other hypervascular hepatic lesions such as hepatic adenoma, hepatocellular carcinoma, or hypervascular metastases, but invasive diagnostic procedures can generally be avoided with the appropriate use of imaging techniques. Magnetic resonance (MR) imaging is more sensitive and specific than conventional ultrasonography (US) or computed tomography (CT), but Doppler US and contrast-enhanced US (CEUS) can greatly improve the accuracy in the diagnosis of FNH. Once a correct diagnosis has been made, in most cases there is no indication for surgery, and treatment includes conservative clinical follow-up in asymptomatic patients.

Management of small hepatocellular carcinoma.

In the last years the incidence of hepatocellular carcinoma (HCC) is rising in cirrhotic patients worldwide. Due the importance of early and definite diagnosis of HCC, any nodular lesion detected in patients with chronic liver disease should be considered as suspicious for HCC. The screening and surveillance programs in patients with liver diseases have increased the number of small HCC detected at an early stage, when the therapeutic options available are able to provide benefit. The introduction of new imaging techniques has improved the accuracy of characterizing these nodules. According to the EASL recommendations, contrast-enhanced computed tomography (CT), contrast enhanced ultrasound (US) and magnetic resonance (MR) with different MR-contrast agents are currently used to characterize liver lesions. Imaging guided biopsy is recommended for small nodules or in lesions without typical features (arterial hypervascularization) in at least two imaging techniques. Frequently the differential diagnosis of small nodules is complicated by discordant vascularity and recent studies have also demonstrated the presence of small hypovascular HCC at perfusional US and helical CT. At present, different treatment options can be offered to patients with diagnosis of small HCC at an early stage; percutaneous techniques, surgical resection and liver transplantation can provide benefit in properly selected patients. This review describes some critical points regarding the detection, diagnosis and therapeutic management of small nodules of HCC in cirrhotic patients.

Experimental studies of the ortho-toluidine glass transition.

The thermodynamic and dynamics proprieties of ortho-toluidine, in the vicinity of a glass transition, have been studied by calorimetric and by two light scattering techniques, depolarized light scattering and time-resolved optical Kerr effect. Differential scanning microcalorimetry clearly detects a glass transition in o-toluidine and it measures some thermodynamics critical parameters, in particular, the transition temperature. The light scattering data have been analyzed according to the mode-coupling theory. This theory gives a good interpretation of our data and it allows to extract safely the critical parameters of the o-toluidine dynamics. We found a fair agreement between the analysis outputs performed in the frequency domain and in the time domain. Finally, we compared the glass transition features of o-toluidine with that of its isomer meta-toluidine, looking for some general idea about the molecular aspects of the glass transition.

Time-resolved experiments on light diffusion in anisotropic random media

Multiple light scattering in isotropic and anisotropic media is studied experimentally with an optical gating technique, as commonly used in fluorescence spectroscopy. The experimental setup permits an accurate analysis of the propagation of a short light pulse through disordered or partially ordered media. The diffusion constant of some isotropic systems is reported, and the anisotropy in the diffusion constant for light diffusion through liquid crystals is observed. For the time-resolved data, good agreement with diffusion theory is found in all cases, including the liquid crystal in the nematic phase.

Three-wave mixing in chiral liquids

Second-order nonlinear optical frequency conversion in isotropic systems is only dipole allowed for sum- and difference-frequency generation in chiral media. We develop a single-center chiral model of the three-wave mixing (sum-frequency generation) nonlinearity and estimate its magnitude. We also report results from ab initio calculations and from three- and four-wave mixing experiments in support of the theoretical estimates. We show that the second-order susceptibility in chiral liquids is much smaller than previously thought.

The photochemical behavior of colchicone and thiocolchicone.

The irradiation of colchicone 5 led to the formation of lumicolchicone 7. The same reaction cannot be obtained by using thiocolchicone 6 as substrate. Transient absorption spectroscopy of colchicone and beta-lumicolchicone showed that probably the photoisomerization occurred on colchicone in its first excited singlet state. The spectroscopic data are in agreement with the hypothesis that lumicolchicone was generated in the ground state from the S1 state of colchicone without the presence of any intermediate. Semiempirical calculations on colchicone and thiocolchicone showed that the highest single occupied molecular orbital and the lowest unoccupied molecular orbital of the singlet excited colchicone can give a disrotatory ring closure to 7, while thiocolchicone cannot give the same type of process.