Duration of diaphragmatic inactivity after endotracheal intubation of critically ill patients.

BACKGROUND: In patients intubated for mechanical ventilation, prolonged diaphragm inactivity could lead to weakness and poor outcome. Time to resume a minimal diaphragm activity may be related to sedation practice and patient severity. METHODS: Prospective observational study in critically ill patients. Diaphragm electrical activity (EAdi) was continuously recorded after intubation looking for resumption of a minimal level of diaphragm activity (beginning of the first 24 h period with median EAdi > 7 µV, a threshold based on literature and correlations with diaphragm thickening fraction). Recordings were collected until full spontaneous breathing, extubation, death or 120 h. A 1 h waveform recording was collected daily to identify reverse triggering. RESULTS: Seventy-five patients were enrolled and 69 analyzed (mean age ± standard deviation 63 ± 16 years). Reasons for ventilation were respiratory (55%), hemodynamic (19%) and neurologic (20%). Eight catheter disconnections occurred. The median time for resumption of EAdi was 22 h (interquartile range 0-50 h); 35/69 (51%) of patients resumed activity within 24 h while 4 had no recovery after 5 days. Late recovery was associated with use of sedative agents, cumulative doses of propofol and fentanyl, controlled ventilation and age (older patients receiving less sedation). Severity of illness, oxygenation, renal and hepatic function, reason for intubation were not associated with EAdi resumption. At least 20% of patients initiated EAdi with reverse triggering. CONCLUSION: Low levels of diaphragm electrical activity are common in the early course of mechanical ventilation: 50% of patients do not recover diaphragmatic activity within one day. Sedatives are the main factors accounting for this delay independently from lung or general severity. Trial Registration ClinicalTrials.gov (NCT02434016). Registered on April 27, 2015. First patients enrolled June 2015.

Improving carbon sequestration estimation through accounting carbon stored in grassland soil.

Based on international guidelines, the elaboration of national carbon (C) budgets in many countries has tended to set aside the capacity of grazing lands to sequester C as soil organic carbon (SOC). A widely applied simple method assumes a steady state for SOC stocks in grasslands and a long-term equilibrium between annual C gains and losses. This article presents a theoretical method based on the annual conversion of belowground biomass into SOC to include the capacity of grazing-land soils to sequester C in greenhouse gases (GHG) calculations. Average figures from both methods can be combined with land-use/land-cover data to reassess the net C sequestration of the rural sector from a country. The results of said method were validated with empirical values based on peer-reviewed literature that provided annual data on SOC sequestration. This methodology offers important differences over pre-existing GHG landscape approach calculation methods: •improves the estimation about the capacity of grazing-land soils to sequester C assuming these lands are not in a steady state and•counts C gains when considering that grazing lands are managed at low livestock densities.

Reassessing the role of grazing lands in carbon-balance estimations: Meta-analysis and review.

Assuming a steady state between carbon (C) gains and losses, greenhouse gases (GHG) inventories that follow a widely used simplified procedure (IPCC Tier 1) tend to underestimate the capacity of soils in grazing-land to sequester C. In this study we compared the C balance reported by (i) national inventories that followed the simplified method (Tier 1) of IPCC (1996/2006), with (ii) an alternative estimation derived from the meta-analysis of science-based, peer-reviewed data. We used the global databases (i) EDGAR 4.2 to get data on GHG emissions due to land conversion and livestock/crop production, and (ii) HYDE 3.1 to obtain historical series on land-use/land cover (LULC). In terms of sequestration, our study was focused on C storage as soil organic carbon (SOC) in rural lands of four countries (Argentina, Brazil, Paraguay and Uruguay) within the so-called MERCOSUR region. Supported by a large body of scientific evidence, we hypothesized that C gains and losses in grazing lands are not in balance and that C gains tend to be higher than C losses at low livestock densities. We applied a two-way procedure to test our hypothesis: i) a theoretical one based on the annual conversion of belowground biomass into SOC; and ii) an empirical one supported by peer-reviewed data on SOC sequestration. Average figures from both methods were combined with LULC data to reassess the net C balance in the study countries. Our results show that grazing lands generate C surpluses that could not only offset rural emissions, but could also partially or totally offset the emissions of non-rural sectors. The potential of grazing lands to sequester and store soil C should be reconsidered in order to improve assessments in future GHG inventory reports.

Differential effects of non-dual and focused attention meditations on the formation of automatic perceptual habits in expert practitioners.

Non-dual meditation aims to undo maladaptive cognitive and affective patterns by recognizing their constructed and transient nature. We previously found high-amplitude spontaneous gamma (25-40 Hz) oscillatory activity during such practice. Nonetheless, it is unclear how this meditation state differs from other practices, in terms of perceptual information processing. Here, we hypothesized that non-dual meditation can downregulate the automatic formation of perceptual habits. To investigate this hypothesis, we recorded EEG from expert Buddhist meditation practitioners and matched novices to measure two components of the auditory evoked response: the Mismatch Negativity (MMN) and the Late Frontal Negativity (LFN), a potential observed at a latency sensitive to attentional engagement to the auditory environment, during the practices of Open Presence (OP) and Focused Attention (FA), as well as during a control state, in the context of a passive oddball paradigm. We found an increase in gamma oscillatory power during both meditation states in expert practitioners and an interaction between states and groups in the amplitude of the MMN. A further investigation identified the specific interplay between the MMN and the LFN as a possible marker to differentiate the two meditation states as a function of expertise. In experts, the MMN increased during FA, compared to OP, while the opposite pattern was observed at the LFN latency. We propose that the state of OP in experts is characterized by increased sensory monitoring and reduced perceptual inferences compared to FA. This study represents a first attempt to describe the impact of non-dual meditation states on the regulation of automatic brain predictive processes.

Partition of some key regulating services in terrestrial ecosystems: Meta-analysis and review.

Our knowledge about the functional foundations of ecosystem service (ES) provision is still limited and more research is needed to elucidate key functional mechanisms. Using a simplified eco-hydrological scheme, in this work we analyzed how land-use decisions modify the partition of some essential regulatory ES by altering basic relationships between biomass stocks and water flows. A comprehensive meta-analysis and review was conducted based on global, regional and local data from peer-reviewed publications. We analyzed five datasets comprising 1348 studies and 3948 records on precipitation (PPT), aboveground biomass (AGB), AGB change, evapotranspiration (ET), water yield (WY), WY change, runoff (R) and infiltration (I). The conceptual framework was focused on ES that are associated with the ecological functions (e.g., intermediate ES) of ET, WY, R and I. ES included soil protection, carbon sequestration, local climate regulation, water-flow regulation and water recharge. To address the problem of data normality, the analysis included both parametric and non-parametric regression analysis. Results demonstrate that PPT is a first-order biophysical factor that controls ES release at the broader scales. At decreasing scales, ES are partitioned as result of PPT interactions with other biophysical and anthropogenic factors. At intermediate scales, land-use change interacts with PPT modifying ES partition as it the case of afforestation in dry regions, where ET and climate regulation may be enhanced at the expense of R and water-flow regulation. At smaller scales, site-specific conditions such as topography interact with PPT and AGB displaying different ES partition formats. The probable implications of future land-use and climate change on some key ES production and partition are discussed.

Thyroid volume measurement in external beam radiotherapy patients using CT imaging: correlation with clinical and anthropometric characteristics.

The aim of this study is to define criteria for accurate representation of the thyroid in human models used to represent external beam radiotherapy (EBRT) patients and evaluate the relationship between the volume of this organ and clinical and anthropometric characteristics. From CT images, we segmented the thyroid gland and calculated its volume for a population of 188 EBRT patients of both sexes, with ages ranging from 1 to 89 years. To evaluate uncertainties linked to measured volumes, experimental studies on the Livermore anthropomorphic phantom were performed. For our population of EBRT patients, we observed that in children, thyroid volume increased rapidly with age, from about 3 cm(3) at 2 years to about 16 cm(3) at 20. In adults, the mean thyroid gland volume was 23.5 ± 9 cm(3) for males and 17.5 ± 8 cm(3) for females. According to anthropometric parameters, the best fit for children was obtained by modeling the log of thyroid volume as a linear function of body surface area (BSA) (p < 0.0001) and age (p = 0.04) and for adults, as a linear function of BSA (p < 0.0001) and gender (p = 0.01). This work enabled us to demonstrate that BSA was the best indicator of thyroid volume for both males and females. These results should be taken into account when modeling the volume of the thyroid in human models used to represent EBRT patients for dosimetry in retrospective studies of the relationship between the estimated dose to the thyroid and long-term follow-up data on EBRT patients.

Length and cost of hospital stay of radioiodine ablation in thyroid cancer patients: comparison between preparation with thyroid hormone withdrawal and thyrogen.

PURPOSE: Treatment of thyroid cancer consists of thyroidectomy and radioiodine ablation following thyroid-stimulating hormone (TSH) stimulation. Similar ablation rates were obtained with either thyroid hormone withdrawal (THW) or rhTSH. But with rhTSH, the elimination of radioiodine is more rapid, thus reducing its whole-body retention and potentially resulting in a shorter hospital stay. The aim of this study was to assess the financial impact of a reduced length of hospital stay with the use of rhTSH. METHODS: This was a case-control study of thyroid cancer patients treated postoperatively with 3,700 MBq (100 mCi) radioiodine; 35 patients who received rhTSH were matched with 64 patients submitted to THW according to covariates influencing radioiodine retention. The length of hospitalization (LOH) was estimated for each method according to the threshold of radioiodine retention below which the patient can be discharged from the hospital. The economic analysis was conducted from a hospital perspective. Simulations were performed. RESULTS: For a threshold of 400 MBq, the LOH was 2.4 days and 3.5 days with rhTSH and THW, respectively, and the cost for an ablation stay was, respectively, 2,146 and 1,807 . In the French context, 57% of the acquisition cost of rhTSH was compensated by the reduction of the length of hospitalization. CONCLUSION: By increasing the iodine excretion, rhTSH allows a shorter hospitalization length, which partially compensates its acquisition cost.

Effects of strength training and vascular occlusion.

The purpose of our study was to determine if vascular occlusion produced an additive effect on muscle hypertrophy and strength performance with high strength training loads. Sixteen physically active men were divided into two groups: high-intensity (HI = 6 RM) and moderate-intensity training (MI = 12 RM). An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow was reduced during the exercise. The left leg served as a control, thus was trained without vascular occlusion. Knee extension 1 RM and quadriceps cross-sectional area (MRI) were evaluated pre- and post-8 weeks of training. We only found a main time effect for both strength gains and quadriceps hypertrophy (p < 0.001). Therefore, we conclude that vascular occlusion in combination with high-intensity strength training does not augment muscle strength or hypertrophy when compared to high-intensity strength training alone.

Comparison of seven serum thyroglobulin assays in the follow-up of papillary and follicular thyroid cancer patients.

BACKGROUND: Serum thyroglobulin (Tg) is the marker of differentiated thyroid cancer after initial treatment and TSH stimulation increases its sensitivity for the diagnosis of recurrent disease. AIM: The goal of the study is to compare the diagnostic values of seven methods for serum Tg measurement for detecting recurrent disease both during L-T4 treatment and after TSH stimulation. METHODS: Thyroid cancer patients who had no evidence of persistent disease after initial treatment (total thyroidectomy and radioiodine ablation) were studied at 3 months on L-T4 treatment (Tg1) and then at 9-12 months after withdrawal or recombinant human TSH stimulation (Tg2). Sera with anti-Tg antibodies or with an abnormal recovery test result were excluded from Tg analysis with the corresponding assay. The results of serum Tg determination were compared to the clinical status of the patient at the end of follow-up. RESULTS: Thirty recurrences were detected among 944 patients. A control 131I total body scan had a low sensitivity, a low specificity, and a low clinical impact. Assuming a common cutoff for all Tg assays at 0.9 ng/ml, sensitivity ranged from 19-40% and 68-76% and specificity ranged from 92-97% and 81-91% for Tg 1 and Tg2, respectively. Using assays with a functional sensitivity at 0.2-0.3 ng/ml, sensitivity was 54-63% and specificity was 89% for Tg1. Using the two methods with a lowest functional sensitivity at 0.02 and 0.11 ng/ml resulted in a higher sensitivity for Tg1 (81% and 78%), but at the expense of a loss of specificity (42% and 63%); finally, for these two methods, using an optimized functional sensitivity according to receiver operating characteristic curves at 0.22 and 0.27 ng/ml resulted in a sensitivity at 65% and specificity at 85-87% for Tg1. CONCLUSION: Using an assay with a lower functional sensitivity may give an earlier indication of the presence of Tg in the serum on L-T4 treatment and may be used to study the trend in serum Tg without performing any TSH stimulation. Serum Tg determination obtained after TSH stimulation still permits a more reliable assessment of cure and patient's reassurance.

[Image registration for radiation therapy: Practical aspects and quality control]. / Recalage d'images en radiothérapie: considérations pratiques et contrôle de qualité.

The development of conformal radiotherapy techniques (CRT) and intensity modulated CRT requires an accurate delineation of target structures and organs at risk. Thus, additional information provided by anatomical and/or functional imaging modalities can be used for volume of interest determination combined with traditionally used Computed Tomography imaging (CT): for instance, functional or morphological Magnetic Resonance Imaging (f MRI or m MRI) or Positron Emission Tomography (PET). A prerequisite to the simultaneous use of this information is image registration. Due to the differences between the images and the information they provide, a quality control of image registration process for radiotherapy is mandatory. The purpose of this article is to present the difficulties in implementing such controls and to show the necessity for a clinical validation on patient's images. The last part of this work presents the possible interest in using f MRI to help radio-oncologists in the treatment planning for gliomas associated to image coregistration and quality control considerations.

Long-term outcome of 444 patients with distant metastases from papillary and follicular thyroid carcinoma: benefits and limits of radioiodine therapy.

AIM: The goal of this study was to estimate the cumulative activity of (131)I to be administered to patients with distant metastases from thyroid carcinoma. METHODS: A total of 444 patients were treated from 1953-1994 for distant metastases from papillary and follicular thyroid carcinoma: 223 had lung metastases only, 115 had bone metastases only, 82 had both lung and bone metastases, and 24 had metastases at other sites. Treatment consisted of the administration of 3.7 GBq (100 mCi) (131)I after withdrawal of thyroid hormone treatment, every 3-9 months during the first 2 yr and then once a year until the disappearance of any metastatic uptake. Thyroxine treatment was given at suppressive doses between (131)I treatment courses. RESULTS: Negative imaging studies (negative total body (131)I scans and conventional radiographs) were attained in 43% of the 295 patients with (131)I uptake; more frequently in those who were younger, had well-differentiated tumors, and had a limited extent of disease. Most negative studies (96%) were obtained after the administration of 3.7-22 GBq (100-600 mCi). Almost half of negative studies were obtained more than 5 yr after the initiation of the treatment of metastases. Among patients who achieved a negative study, only 7% experienced a subsequent tumor recurrence. Overall survival at 10 yr after initiation of (131)I treatment was 92% in patients who achieved a negative study and 19% in those who did not. CONCLUSION: (131)I treatment is highly effective in younger patients with (131)I uptake and with small metastases. They should be treated until the disappearance of any uptake or until a cumulative activity of 22 GBq has been administered. In the other patients, other treatment modalities should be used when tumor progression has been documented.

Radioiodine ablation of thyroid remnants after preparation with recombinant human thyrotropin in differentiated thyroid carcinoma: results of an international, randomized, controlled study.

CONTEXT: After surgery for differentiated thyroid carcinoma, many patients are treated with radioiodine to ablate remnant thyroid tissue. This procedure has been performed with the patient in the hypothyroid state to promote endogenous TSH stimulation and is often associated with hypothyroid symptoms and impaired quality of life. OBJECTIVE AND INTERVENTION: This international, randomized, controlled, multicenter trial aimed to compare the efficacy and safety of recombinant human TSH (rhTSH) to prepare euthyroid patients on L-thyroxine therapy (euthyroid group) to ablate remnant thyroid tissue with 3.7 GBq (100 mCi) 131I, compared with that with conventional remnant ablation performed in the hypothyroid state (hypothyroid group). Quality of life was determined at the time of randomization and ablation. After the administration of the 131-I dose, the rate of radiation clearance from blood, thyroid remnant, and whole body was measured. RESULTS: The predefined primary criterion for successful ablation was "no visible uptake in the thyroid bed, or if visible, fractional uptake less than 0.1%" on neck scans performed 8 months after therapy and was satisfied in 100% of patients in both groups. A secondary criterion for ablation, an rhTSH-stimulated serum thyroglobulin concentration less than 2 ng/ml, was fulfilled by 23 of 24 (96%) euthyroid patients and 18 of 21 (86%) hypothyroid patients (P = 0.2341). Quality of life was well preserved in the euthyroid group, compared with the hypothyroid group, as demonstrated by their lower pretreatment scores on the Billewicz scale for hypothyroid signs and symptoms, 27 +/- 7 vs. 18 +/- 4 (P < 0.0001) and their significantly higher Short Form-36 Health Assessment Scale scores in five of eight categories. Euthyroid patients had a statistically significant one third lower radiation dose to the blood, compared with patients in the hypothyroid group. CONCLUSIONS: This study demonstrates comparable remnant ablation rates in patients prepared for 131I remnant ablation with 3.7 GBq by either administering rhTSH or withholding thyroid hormone. rhTSH-prepared patients maintained a higher quality of life and received less radiation exposure to the blood.

Limb salvage with isolated perfusion for soft tissue sarcoma: could less TNF-alpha be better?

BACKGROUND: The optimal dose of TNF-alpha delivered by isolated limb perfusion (ILP) in patients with locally advanced soft tissue sarcoma is still unknown. PATIENTS AND METHODS: Randomised phase II trial comparing hyperthermic ILP (38-40 degrees ) with melphalan and one of the four assigned doses of TNF-alpha: 0.5 mg, 1 mg, 2 mg, and 3/4 mg upper/lower limb. The main end point was objective tumour response on MRI. Secondary end points were histological response, rate of amputation and toxicity. Resection of the remnant tumour was performed 2-3 months after ILP. The sample size was calculated assuming a linear increase of 10% in the objective response rates between each dose level group. RESULTS: One hundred patients (25 per arm) were included. Thirteen per cent of patients had a systemic leakage with a cardiac toxicity in six patients correlated with high doses of TNF-alpha. Objective tumour responses were: 68%, 56%, 72% and 64% in the 0.5 mg, 1 mg, 2 mg and 3 or 4 mg arms, respectively (NS). Sixteen per cent of patients were not operated, 71% had a conservative surgery and 13% were amputated with no difference between the groups. With a median follow-up of 24 months, the 2 year overall and disease-free survival rates (95% CI) were 82% (73% to 89%) and 49% (39% to 59%), respectively. CONCLUSION: At the range of TNF-alpha doses tested, there was no dose effect detected for the objective tumour response, but systemic toxicity was significantly correlated with higher TNF-alpha doses. Efficacy and safety of low-dose TNF-alpha could greatly facilitate ILP procedures in the near future.

Effects of rate of force development on EMG amplitude and frequency.

The purpose of this study was to compare the amplitude and frequency of the gastrocnemius EMG during ramp and ballistic contractions in highly trained sprint athletes. Sixteen female sprinters performed ramp and ballistic isometric contractions on a Biodex dynamometer. RMS and median frequency of the gastrocnemius EMG signals were obtained at the following torque levels: 25 +/- 5 %, 50 +/- 5 %, 75 +/- 5 %, 100 % MVC. The average rate of force development (RFD), was 610.2 +/- 123.1 N . m/s and 212.3 +/- 155.6 N . m/s for the ballistic and ramp contractions, respectively. In the ramp contractions the EMG amplitude increased as a function of torque. In the ballistic contractions the EMG amplitude decreased from 25 % to 100 % MVC. The highest RFD of 889.45 N . m/s was generated in ballistic contractions by a muscular activation pattern with high EMG amplitude (475.7 microV) and low frequency (116.7 Hz) at 25 % MVC. The findings suggest that the CNS utilizes different muscular activation patterns to modulate RFD in ramp and ballistic contractions. In ramp contractions the EMG amplitude increased linearly with force. In ballistic contractions a high RFD is generated with a muscular activation pattern consisting of high amplitude and low frequency at the start of the contraction.

Neural, metabolic, and performance adaptations to four weeks of high intensity sprint-interval training in trained cyclists.

The purpose of this study was to investigate the effects of short-term, high-intensity sprint training on the root mean squared (RMS) and median frequency (MF) derived from surface electromyography (EMG), as well as peak power, mean power, total work, and plasma lactate levels in trained cyclists when performed concurrently with endurance training. Seventeen trained cyclists were randomly assigned to a sprint training (S) group (n = 10, age 25 +/- 2.0 y) or a control (C) group (n = 7, age 25 +/- 0.5 y). Sprint training was performed bi-weekly for four weeks, comprising a total of 28 min over the training period. EMG measurements were taken before and after training during a series of four 30-s sprints separated by four minutes of active recovery. Plasma lactate, peak power, mean power, and total work were measured during each sprint bout. Following sprint training a significant increase occurred in the RMS of the vastus lateralis with a decrease in MF of the same muscle. Values for the vastus medialis did not change. Pre training exercising plasma lactate values were higher (p < 0.05) in C compared to S, but did not change with training. Exercising plasma lactate values increased (p < 0.05) from pre to post training in S, but were not different from C post training. Total work output increased from pre to post in S (p = 0.06). Peak power, mean power, and V.O (2)max increased (p < 0.05) pre to post training in S and C, indicating C was not a true control. In conclusion, these data suggest that four weeks of high-intensity sprint training combined with endurance training in a trained cycling population increased motor unit activation, exercising plasma lactate levels, and total work output with a relatively low volume of sprint exercise compared to endurance training alone.

Validation of the EGS usercode DOSE3D for internal beta dose calculation at the cellular and tissue levels.

Internal radiotherapy is currently focusing on beta emitters such as 90Y or 131I because of their high-energy emissions. However, conventional dosimetric methods (MIRD) are known to be limited for such applications. They are unable to take into account microscopic radionuclide distribution because standardized anthropomorphic phantoms are used, and absorbed dose is calculated at the organ level. New tools are therefore required for dose assessment at cellular and tissue level (10-100 microm). The purpose of this study was to validate, at this scale, a Monte Carlo usercode (DOSE3D), based on the MORSE combinatorial geometry package and the EGS code system. Dose point-kernel calculations in water were compared to those published by Cross et al and Simpkin and Mackie. They confirm that DOSE3D is a reliable tool for cellular dosimetry in various geometric configurations.

[Significance of sentinel lymph node biopsy in Merkel cell carcinoma. Analysis of 11 cases]. / Intérêt du ganglion sentinelle dans le carcinome de Merkel. Analyse de 11 cas.

BACKGROUND: Merkel cell carcinoma is an aggressive cutaneous neoplasm with a high propensity for nodal metastases. Regional lymph node involvement develops in 45 to 65 p. 100 of patients. We evaluated in Merkel cell carcinoma the use of sentinel lymph node biopsy which allows the identification of occult nodal metastases. PATIENTS AND METHODS: Eleven patients diagnosed with Merkel cell carcinoma without clinical nodal involvement underwent pre-operative lymphoscintigraphy followed by sentinel lymphadenectomy with histologic analysis. Identification of microscopic nodal metastases led to complete lymph node dissection and adjuvant radiation therapy to the lymph node basin. RESULTS: The sentinel lymph node was successfully identified in 9 patients. Two patients demonstrated metastatic disease in their sentinel lymph nodes. At subsequent complete node dissection, one of two patients had an additional metastatic lymph node. None of the eleven patients experienced recurrent disease at a follow-up varying from 1 to 42 months. One patient with a negative sentinel lymph node experienced lymphoedema. COMMENTS: Our results are consistent with the 14 published studies which totalled 93 patients with Merkel cell carcinoma and identified 29 patients (30 p. 100) with nodal involvement. Metastatic disease was identified only after immunohistochemical analysis in 20 p. 100 of these patients (n=6). Lymph node involvement appears to be a bad prognostic factor with 29.6 p. 100 of disease recurrence, as opposed to 3 p. 100 in patients with an uninvolved sentinel lymph node. Although the prognostic significance of this technique seems interesting, there is no optimal therapeutic approach to sentinel lymph node involvement.

Optimizing the use of LiF:Mg,Cu,P (GR-200 P) to measure low dose irradiation in nuclear medicine.

We undertook a study in order to determine the optimal conditions under which thermoluminescent powder LiF:Mg,Cu,P (GR-200 P) could be used for applications in nuclear medicine and for dosimetric needs. First, we defined the conditions chiefly related to the readout chain, namely the optimal mass of GR-200 material used for each readout, which is between 15 and 30 mg, and the optimal glow curve readout, which corresponds to heating in two phases: a rise in temperature at the rate of 10 degrees C s(-1) up to 150 degrees C followed by a plateau lasting 10 s and then another rise in temperature at the rate of 25 degrees C s(-1) up to 260 degrees C followed by a second plateau lasting 6 s. The optimum conditions for using TL material were also studied: using GR-200 P without annealing and performing two successive readouts of the same sample only led to a 0.1% loss in sensitivity per re-use cycle, and the good reproducibility of measurements was preserved with stable and weak residual TL signal. The response of the sample irradiated at three different dose levels with a 60Co gamma photon beam remained constant over 40 d. Sensitivity was preserved to within +/-4% between a few tenths of a microGy and 1 Gy. Our observations concur with the results of the literature and show how to optimize the conditions for using the GR-200 thermoluminescent dosimeter to measure low doses with a simple procedure that preserves the sensitivity of material.

Clinical use of recombinant human TSH in thyroid cancer patients.

Recombinant human TSH (rhTSH) is an effective and safe alternative to thyroid hormone withdrawal during the post-surgical follow-up of papillary and follicular thyroid cancer. Its clinical efficiency for the detection of persistent and recurrent disease is similar to that of thyroid hormone withdrawal. The main purpose for its use is to avoid hypothyroidism.