Dentin evaluation after Nd:YAG laser irradiation using short and long pulses

OBJECTIVE: Several reports have demonstrated the advantages of using the Nd:YAG laser to reduce dentin permeability by melting the dentin surface. A comparative study using different pulse durations can be useful to obtain further information about the laser-hard tissue interaction. MATERIALS AND METHODS: The present study pursues the evaluation of the morphological and chemical changes in human dentin surface resulting from Nd:YAG laser (lambda = 1064 nm) irradiation, with a total energy of 0.9 J distributed in 1, 2, 3, and 6 pulses with different pulse durations to promote surface melting and dentinal tubule occlusion. After irradiation, the samples were submitted to scanning electron microscopy (SEM) analysis for morphological study and energy-dispersive spectrometry (EDS) analysis for evaluation of the concentration of calcium and phosphorous in the melted layer. RESULTS: SEM analysis of the irradiated dentin surface showed surface structural changes due to laser irradiation, where the morphological changes are dependent on the laser pulse duration. EDS analysis showed an increase of calcium and phosphorous concentrations after Nd:YAG laser exposure, but no correlation with the number of pulses or pulse duration was found. CONCLUSION: Our results suggest that longer interaction times resulted in more evident effects with more melted substrate than shorter pulses, and in both cases the resultant melted layer contains a greater concentration of inorganic substances than non-irradiated dentin.     

Development of a scaled up liver device incorporating cryo-preserved pig liver micro-organs

BACKGROUND/AIMS: Currently there is no effective therapy for most patients with fulminant or end stage liver disease. METHODS: Pig liver micro-organs (LMOs), which preserve liver micro-architecture and ensure a maximal 150-200mum distance from a source of nutrients and gases have been prepared and a method to cryo-preserve them has been developed. A new scaled-up extra-corporeal liver device termed aLIVE-H in which LMOs are exposed to liver-like hemodynamic conditions has also been developed. The purpose of this work is to test the safety and function of cryo-preserved LMOs and how the hemodynamic properties of the scaled up aLIVE device affect their function. RESULTS: Pig LMOs in aLIVE-H, transcribe albumin and Factor V at similar levels, irrespective of their position within the bioreactor, indicating that the hemodynamic features of the aLIVE-H device allow for homogeneous plasma distribution and proper function at different locations. Cryo-preserved LMOs transcribe albumin and Factor V at levels comparable to those transcribed by a normal pig liver. Connecting the aLIVE-H bioreactor to normal pigs did not affect key blood components and biochemical parameters. CONCLUSIONS: An extra-corporeal liver device aLIVE-H which imitates the hemodynamic and functional properties of the normal liver and incorporates cryo-preserved LMOs has been developed and characterized. aLIVE-H was found to perform key synthetic liver functions.     

Measurement of cardiac output with indocyanine green transcutaneous fluorescence dilution technique

BACKGROUND: Cardiac output is an essential parameter for the hemodynamic assessment of patients with cardiovascular disease. The authors tested in an animal model the feasibility of measuring cardiac output by transcutaneous fluorescence monitoring of an intravenous bolus injection of indocyanine green. METHODS: Fluorescence dilution cardiac output was measured in 10 anesthetized rabbits and compared with cardiac output measured with a pulmonary thermodilution catheter and to aortic velocity measured by Doppler ultrasound. Indocyanine green fluorescence was excited with a near-infrared laser and measured with an optical probe positioned on the central ear artery. Measurements were obtained during baseline conditions as well as during short-term decreases and increases of the cardiac output. RESULTS: The fluorescence of circulating indocyanine green detected transcutaneously varied proportionally to that of arterial blood samples, which allowed for calibration in terms of blood concentration of indocyanine green. Average values of fluorescence dilution cardiac output and thermodilution cardiac output measured in baseline conditions were 412 (+/- 13) and 366 (+/- 11) ml/min, respectively. Fluorescence dilution cardiac output showed a close, one-to-one linear relation with thermodilution cardiac output in each animal and in the pooled data from all animals (slope = 0.95 x 0.03; R = 0.94). Fluorescence dilution cardiac output overestimated thermodilution cardiac output by an average of 46 (+/- 6) ml/min during baseline conditions. Fluorescence dilution cardiac output was tightly correlated with aortic velocity. CONCLUSIONS: The proposed technique yielded accurate estimates of the cardiac output in experimental animals. This study should provide an initial framework for clinical testing of this new minimally invasive method for measuring cardiac output.     

Acute type B aortic dissection in elderly patients: clinical features, outcomes, and simple risk stratification rule

BACKGROUND: The clinical features and outcomes of elderly patients with acute type B aortic dissection (ABAD) are less well known. Accordingly, we sought to evaluate the clinical features and outcomes and derive a simple risk stratification rule for elderly with ABAD. METHODS: We categorized 383 patients with ABAD enrolled in the International Registry of Acute Aortic Dissection into two strata (aged less than 70 years and aged 70 years or more) and compared their clinical features and in-hospital outcomes. Further, we developed a clinical decision rule to risk-stratify elderly with ABAD. RESULTS: Forty-two percent (161 of 383) of patients with ABAD were aged 70 years or more. Hypertension, diabetes, history of prior aortic aneurysm, and arteriosclerosis were more common in the elderly patients, whereas Marfan syndrome and cocaine abuse were less common. The in-hospital complication of hypotension/shock was more common among elderly, and malperfusion of a visceral organ less frequent among elderly patients. In-hospital mortality was higher in the elderly cohort compared with the younger patients (16% versus 10%, p = 0.07). A classification tree identified that elderly patients with hypotension/shock had the highest risk of death (56%). In absence of this, any branch vessel involvement was associated with the next highest mortality rate (28.6%) followed by presence of periaortic hematoma (10.5%). In contrast, elderly patients without any of these three risk factors had an extremely low mortality rate (1.3%). CONCLUSIONS: Our study highlights important differences between older and younger patients with ABAD in their clinical characteristics, management, and outcomes. We also propose a simple decision rule that allows stepwise risk-stratification in elderly patients with ABAD.     

188Re radiopharmaceuticals for radiosynovectomy: evaluation and comparison of tin colloid, hydroxyapatite and tin-ferric hydroxide macroaggregates

BACKGROUND: Radiosynovectomy is a therapy used to relieve pain and inflammation from rheumatoid arthritis and related diseases. In this study three 188Re particulate compounds were characterized according to their physico-chemical properties and their biological behavior in rabbits. The results were compared in order to establish which was the radiopharmaceutical that better fits the requirements of this kind of radiotherapy. METHODS: Three radiopharmaceutical formulations, tin colloid, hydroxyapatite particles (HA) and ferric hydroxide macroaggregates coated with tin colloid (FHMA), were physically characterized (number, volume and surface of the particles). For this purpose laser diffraction methodology was used. To evaluate cavity leakage of activity the following studies in New Zealand rabbits were performed: scintigraphic images for 48 hr after intraarticular injection of each radiopharmaceutical, biodistribution at 48 hr and urine samples collection during the first 24 hr post-radiopharmaceutical administration. RESULTS: Labeling procedures for 188Re-HA and 188Re-Sn-FHMA were labour intensive while 188Re-Sn was easily prepared. Furthermore, 188Re-Sn colloid offered the greatest surface area in the 2-10 microm range and was obtained with a radiochemical purity over 95%, while percentage of bound activity for 188Re-HA and 188Re-Sn-FHMA were 55% and 92% respectively. Stability was verified for the three radiopharmaceuticals for 24 hr. Scintigraphic studies and biodistribution in rabbits after intraarticular administration of the radiopharmaceuticals showed relevant activity only in the knee, this being over 90% of the residual activity in the whole body at 48 hr in every case. Renal elimination of 188Re-Sn colloid and 188Re-Sn-FHMA was detected by activity measurements in urine samples, during the first 12 hr post-radiopharmaceutical injection.The percentage of activity retained in the knee was 69.1% for 188Re-Sn colloid, 55.1% for 188Re-Sn-FHMA and 33.6% for 188Re-HA. CONCLUSION: The 188Re-Sn colloid was easy to prepare, minimum facilities were required, was stable for 24 hr and showed minimal leakage from the joint after intraarticular injection into the rabbit's knee. Furthermore, 188Re-Sn colloid has greater retention in the knee when it is compared with the other radiopharmaceuticals, so it could provide the best therapeutic effect/absorbed dose ratio for the patient.     

Acute myeloblastic leukemia (M5) and aspergilloma in a 75-year-old man

We report here a case of pulmonary aspergilloma in a patient with acute myeloblastic leukemia. We present the clinical and radiological characteristics of this case. Aspergillus flavus was isolated. The antifungal treatment was unsuccessful. Pulmonary aspergillomas are associated with a high mortality in the immunocompromised host. It is important to know the diagnostic approach and the surgical and medical treatment of this disease.