Combining NSAM and CPC concentrations to determine airborne nanoparticle count median diameter: Application to various laboratory and workplace aerosols.

Because nanomaterials have been increasingly developed and used in many technology and industry sectors over the last 20 years, an increasing number of workers is likely to be exposed to airborne nanoparticles. In addition, the question of the nanomaterial characteristics that should be assessed in epidemiological studies remains open. Thus, assessing occupational exposure to airborne nanoparticles will not only rely on mass concentration and chemical composition. Rather, key parameters, such as particle size, have to be included in measurement strategies. We previously proposed a methodology to estimate the Count Median Diameter (CMD) of an aerosol based on the simultaneous size-integrated measurement of two particle concentrations, lung-deposited surface area, and number, thanks to field-portable, commercially available aerosol instruments (Nanoparticle Surface Area Monitor/Condensation Particle Counter combination). In addition to previous work, this study investigates the case of various polydisperse metal oxides, organic oil, and salt particles with CMDs ranging from 16-410 nm. Once corrected, the CMDs derived from the NSAM/CPC agree within ±20% with regard to the reference electrical mobility equivalent diameter, regardless of aerosol composition, morphology, or geometric standard deviation (GSD). Furthermore, the field-applicability of the method was tested through 6 sets of experimental data stemming from workplace measurement campaigns where different materials were produced and handled (TiO2, SiO2, Ag, Multi-Walled Carbon Nanotubes-MWCNT), covering a range of CMDs between 40 and 190 nm. All situations considered, the approach based on the combination of a NSAM and a CPC leads to a satisfying estimation of particle CMD, within ±20% compared to reference CMD.

A laboratory study of the performance of the handheld diffusion size classifier (DiSCmini) for various aerosols in the 15-400 nm range.

In addition to chemical composition, particle concentration and size are among the main parameters used to characterize exposure to airborne ultrafine or nanoparticles. To assess occupational inhalation exposure, real-time instruments are recommended in recent strategies published. Among portable devices for personal exposure assessment in the workplace, DiSCmini (Matter Aerosol AG, Switzerland) has been identified as a potential candidate with its capacity to measure the airborne nanoparticle concentration and average particle size with good time-resolution. Monodisperse and polydisperse test nanoaerosols of varying compositions and morphologies were produced in the laboratory using the CAIMAN facility. These aerosols covered a range of particle sizes between 15 and 400 nm and number concentrations from 700 to 840,000 cm(-3). The aerosols were used to investigate the behavior of DiSCmini, comparing experimental data to reference data. In spite of a slight tendency to underestimate particle size, all particle diameters, number concentrations and surface area concentrations measured were in the same order of magnitude as reference data. Furthermore, no significant effect due to particle composition or morphology was noted.

Relation between FIGO stage, primary tumor volume, and presence of lymph node metastases in cervical cancer patients referred for radiotherapy.

The aims of this study were to determine, firstly, the relationship between FIGO stage and various tumor parameters determined by magnetic resonance imaging (MRI), and, secondly, whether any of these parameters were predictors of lymph node metastases as determined by fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in cervical cancer patients referred for radiotherapy. In 70 consecutive patients, both PET and MRI visualized all primary tumors except for one previously removed by cone biopsy. While clinical diameter and MRI-derived diameter showed a significant relationship between these two measurements (r = 0.70; P < 0.001) there was a large variability in MRI diameter for each FIGO stage and wide overlap. The average volume of primary cervical tumor on MRI was 60 cc (5-256). In FIGO stages, I, II, III and IV, uterine body involvement was present in 58%, 73%, 88%, and 100% of 19, 30, 16, and 5 patients, respectively (Ptrend= 0.015). Node positivity on FDG PET was present in 11% of patients without uterine body extension, but increased to 75% in those with uterine involvement. Average tumor volume in node-negative patients was 49 cc (5-186). Average tumor volume in node-positive patients was 69 cc (8-256). There was a significant association between nodal involvement and both FIGO stage (P = 0.018) and uterine body involvement (P < 0.001), but tumor volume and longitudinal MRI diameter were not statistically significant in unifactor predictors of nodal involvement. In multivariate analysis only uterine body extension, however, was independently related to the risk of nodal involvement. In conclusion, MRI provides noninvasive tumor size evaluation and can also demonstrate invasion of the uterine body that appears to be associated with an increased risk of nodal metastasis. This may provide clinically important prognostic information not available from current FIGO staging.

Doppler study of arterial and venous intraovarian blood flow in stimulated cycles.

OBJECTIVE: To evaluate arterial and venous intraovarian blood flow in follicle stimulating hormone-stimulated cycles. SUBJECTS AND METHODS: This was a prospective study of 76 follicle stimulating hormone-stimulated cycles carried out in 39 infertile patients who were included in a timed intercourse or intrauterine insemination program in a referral center for assisted reproduction. Transvaginal color and pulsed Doppler measurements of the follicular and luteal phase resistance index, pulsatility index, peak systolic velocity and maximum venous velocity were made and serum progesterone levels during the mid-luteal phase were recorded. Velocimetric parameters were established and then used to classify ovarian function as having a normal ovulatory cycle, or a cycle in which there was either luteal phase deficiency or a luteinized unruptured follicle. RESULTS: In 52 normal ovulatory cycles, the luteal phase peak systolic and maximum venous velocities were significantly higher and resistance and pulsatility indices were significantly lower than those found in the follicular phase. In 15 women with luteal phase deficiency we did not find any differences in arterial velocimetric parameters when compared with normal ovulatory cycles. However, luteal phase maximum venous velocities were lower in the luteal phase deficiency cycles and there was a significant correlation between luteal phase maximum venous velocity and serum progesterone levels (r = 0.36). Luteinized unruptured follicle cycles (n = 9) did not show significant changes during the ovarian cycle and no 'luteal conversion' of the Doppler signal was identified. CONCLUSIONS: Follicle stimulating hormone-stimulated cycles in infertile patients can have a high percentage of abnormal functional responses that can be diagnosed only by sonographic assessment, Doppler and the appropriate hormonal follow-up. Arterial and venous intraovarian blood flow remain unaltered during luteinized unruptured follicle cycles and serum progesterone levels correlated with luteal phase maximum venous velocity, which makes Doppler a potentially useful non-invasive test to assess ovulation and luteal function.

B-mode, utero-ovarian and intratumoural transvaginal colour Doppler ultrasonography for differential diagnosis of ovarian tumours.

OBJECTIVES: The aim of this study was to evaluate and compare the use of B-mode transvaginal, utero-ovarian Doppler and intratumoural colour Doppler imaging in the diagnosis of ovarian tumours in order to establish whether they are organic or functional, and malignant or benign in nature prior to surgery. STUDY DESIGN: A series of 213 women between the ages of 15 and 87 presenting ovarian tumours were examined with pulsed and colour Doppler and the functional state of the ovary at the time of the exploration was also established. Size and morphology were evaluated through a new scoring system called sonographic index. This score is calculated as the sum of the points corresponding to tumoural volume (< or = 8 ml = 1 point; > 8 ml and < or = 100 ml = 2 points; > 100 ml = 3 points) and the points corresponding to morphological characteristics (negative echogenicity = 1 point; mixed echogenicity = 2 points; multilocular morphology = 3 points; complex morphology = 4 points; positive echogenicity = 5 points) varying between 2 and 8 points. The flow velocity waveform (FVW) of the utero-ovarian and intratumoural arteries were obtained and analyzed after assessing their resistance indices. Other parameters studied were the presence and location of the colour signal in the intratumoural arteries. RESULTS: Of the total, 84 of the tumours were found to be functional and had disappeared by the time later examinations took place. Surgery was performed in 129 of the patients, and posterior histopathological studies permitted classifying the tumours as benign in 107 cases and malignant in 22. The sonographic index was significantly higher in the organic (4.9 +/- 1.5) and malignant (6.9 +/- 1.0) tumours than in the functional (3.6 +/- 1.5) and the benign (4.1 +/- 1.2) tumours. The utero-ovarian and intratumoural blood flow RIs in the malignant tumours (0.48 +/- 0.12 and 0.43 +/- 0.08, respectively) was significantly lower than in the benign tumours (0.83 +/- 0.12 and 0.58 +/- 0.15, respectively). There were no significant differences in the utero-ovarian and intratumoural blood flow RIs when organic and functional tumours were compared. In all of the malignant tumours a colour signal was identified; it was centrally located in 90% of the cases. A colour signal was observed in 83% of the functional tumours, and in 52% of the organic benign tumours. In the benign tumours the colour signal was peripherally located in 98% of the cases. The variables for sensitivity, specificity, positive predictive value, negative predictive value and precision when organic tumours were diagnosed were 82.9, 65.5, 78.7, 71.4 and 76.1 for a sonographic index where the score was > or = 4; the values for the utero-ovarian RI were 48.4, 90.4, 88.4, 53.6 and 65.1 (cut-off 0.55 > or = RI > or = 0.90); the values for the intratumoural RI were 56.5, 68.6, 54.2, 70.6 and 63.8 (cut-off < or = 0.55). When malignancy was diagnosed these variables were 95.5, 82.2, 38.2, 99.4 and 83.6 for the sonographic index (score > or = 6); 90.9, 98.9, 90.0, 98.9 and 98.1 for the utero-ovarian RI (cut-off < or = 0.55) and 80.0, 66.7, 33.3, 94.1 and 69.0 for the intratumoural RI (cut-off < or = 0.50). The number of false positives diagnosed on the basis of the intratumoural RI decreased when cases that had been evaluated during the luteal phase were excluded from the study. Notwithstanding, the phase of the cycle does not seem to interfere with the diagnosis when utero-ovarian Doppler imaging is used. CONCLUSIONS: B-mode transvaginal ultrasonography and utero-ovarian Doppler velocimetry seem to complement each other to aid in differentiating between organic and functional ovarian tumours. Transvaginal ultrasonography and Doppler imaging provide good results for the diagnosis of malignancy, although the utero-ovarian RI reduces the number of false positives that occur with ultrasonography. Our group, therefore, believes that the combined use of these techniques is beneficial in the clinical d

Experience with the use of continuous positive airway pressure (CPAP) therapy in the emergency management of acute severe cardiogenic pulmonary oedema.

BACKGROUND: Acute pulmonary oedema (APO) is a frequent cause of respiratory failure and a common reason for presentation to emergency departments (EDs). To date, no paper has been published on the application of continuous positive airway pressure (CPAP) therapy for a large broad-based patient group. AIM: To report our experience with the use of CPAP in severe APO oedema, with particular reference to safety, intubation rates and impact on EDs' resources. METHOD: A retrospective chart review was undertaken of 75 patients with acute severe pulmonary oedema who were treated with adjuvant CPAP in an urban teaching hospital ED. RESULTS: Three patients (4%) required subsequent endotracheal intubation and mechanical ventilation. The average duration of CPAP was 1.9 hours. Eighty nine per cent of patients experienced no adverse events while being treated with GPAP. Five patients failed to tolerate the tight fitting mask necessitating removal of CPAP, three patients experienced arrhythmias related to underlying cardiac disease and two patients experienced mild transient hypotension. Seventy one per cent of patients were discharged from the ED to general medical wards. The in-hospital mortality for patients treated with CPAP was 15%. CONCLUSION: This series has demonstrated that CPAP therapy delivered via a face mask for the treatment of acute severe APO is safe and effective when applied to a broad range of patients. We recommend the use of CPAP therapy for all suitable patients presenting in severe APO irrespective of age or underlying pulmonary disease.

Is a standard regime for anticoagulation with heparin in unstable angina adequate?

AIM: To establish the proportion of patients with unstable angina in whom adequate anticoagulation is achieved using a standard regime of intravenous heparin. METHOD: A prospective series of 108 Emergency Department attendees over a six-month period with a clinical diagnosis of unstable angina for whom anticoagulation with heparin was prescribed were included in the study. The standard regime was a 5000 unit bolus followed by an intravenous infusion of 1000 units per hour (1200 units if the patient's weight was greater than 80 kg), with subsequent adjustments being made by reference to a nomogram. The activated partial thromboplastin time (APTT) was measured at six and 12 hours after treatment began. Two commonly used criteria for adequate heparinisation were compared: 1. APTT greater than 1.5 times control and 2. APTT in the range of 60-85 seconds. RESULTS: There were valid data for 90 patients at six hours and 79 at 12 hours. Compared to the criterion for adequate anticoagulation of APTT greater than 1.5 times the control, 25% of patients were subtherapeutic at six hours and 12% at 12 hours. Compared to the criterion APTT greater than 60 seconds, 53% of patients were subtherapeutic at 6 hours and 47% at 12 hours. At 6 hours, 26% of patients were over-anticoagulated as defined as APTT greater than 85 seconds. This had reduced to 13% by 12 hours. CONCLUSIONS: In the context of recent research suggesting that an APTT of greater than 1.5 times the control is sufficient to reduce complications in unstable angina, our results demonstrate that a standard regime of heparinisation will achieve this goal in the majority of patients within 6 hours of starting heparin therapy. However, if an APTT of 60-85 seconds is the goal, this standard regime is inadequate.

Color Doppler sonographic assessment of placental circulation in the first trimester of normal pregnancy.

Our aim was to study placental circulation during the first trimester of normal pregnancy. For this purpose, 108 single pregnancies from 4 to 15 gestational weeks were evaluated through conventional Doppler ultrasonography. The flow velocity waveforms from the retrochorionic arteries (spiral-radial arteries) and the umbilical artery were assessed using the peak systolic velocity, resistive index, and pulsatility index). Intervillous flow velocity waveform was evaluated from the maximum velocity. The earliest color signal from the retrochorionic circulation was registered at 4.5 weeks along with gestational sac visualization. The venous Doppler signal from the intervillous space and the Doppler signal from the umbilical artery were recorded with an embryo visible from the end of week 5 onward. The retrochorionic, intervillous, and umbilical peak systolic velocities increase, whereas the resistive and pulsatility indices decrease progressively during early pregnancy with a significant correlation with gestational age. Similarly, intervillous maximum velocity gradually increases throughout the first trimester of pregnancy. Despite some methodologic problems related to Doppler technology and the vessels studied color Doppler sonography appears to be an adequate tool to assess the physiologic changes in the placental circulation during early pregnancy.

[Rokitansky-Kuster-Hauser-Mayer syndrome. Psychological aspects in current technics in the creation of a neovagina apropos of 2 cases]. / Síndrome de Rokitansky-Kuster-Hauser-Mayer. Aspectos psicológicos y técnicas actuales en la creación de neovagina a propósito de dos casos.

A review is made of the actual status of the Rokitansky-Hauser-Kuster-Mayer Syndrome in the following aspects: clinic, diagnostic and actual techniques in the construction of a neovagina. An special remark is made on the importance of the psychologyc and psychosocial aspects in the management, diagnostic and treatment of this patients. Two cases are presented.

Effect of increased gas density on pulmonary gas exchange in man.

Pulmonary gas exchange was measured in seven resting supine subjects breathing air or a dense gas mixture containing 21% O2 in sulfur hexafluoride (SF6). The mean value of the alveolar-arterial oxygen difference (AaDO2) decreased from 12.4 on air to 7.0 on SF6 (P less than 0.01), and increased again to 13.4 when air breathing resumed (P less than 0.01). No differences occurred between gas mixtures for O2 consumption, respiratory quotient, minute ventilation, breathing frequency, heart rate, or blood pressure, and the improved oxygen transfer could not be attributed to changes in cardiac output or mixed venous oxygen content in the one subject in which they were measured. These results are best explained by an altered distribution of ventilation during dense gas breathing, so that the ventilation-perfusion ratio (VA/Q) variance was reduced. Of several considered mechanisms, we favor one in which SF6 promotes cardiogenic gas mixing between peripheral parallel units having different alveolar gas concentrations. This mechanism allows for observed increases in arterial carbon dioxide tension and dead space-to-tidal volume ratio during dense gas breathing, and suggests that intraregional VA/Q variance accounts for at least one-half of the resting AaDO2 in healthy supine young men.