High Acoustic Impedance and Attenuation Backing for High-Frequency Focused P(VDF-TrFE)-Based Transducers

Backing materials with tailored acoustic properties are beneficial for miniaturized ultrasonic transducer design. Whereas piezoelectric P(VDF-TrFE) films are common elements in high-frequency (>20 MHz) transducer design, their low coupling coefficient limits their sensitivity. Defining a suitable sensitivity-bandwidth trade-off for miniaturized high-frequency applications requires backings with impedances of >25 MRayl and strongly attenuating to account for miniaturized requirements. The motivation of this work is related to several medical applications such as small animal, skin or eye imaging. Simulations showed that increasing the acoustic impedance of the backing from 4.5 to 25 MRayl increases transducer sensitivity by 5 dB but decreases the bandwidth, which nevertheless remains high enough for the targeted applications. In this paper, porous sintered bronze material with spherically shaped grains, size-adapted for 25-30 MHz frequency, was impregnated with tin or epoxy resin to create multiphasic metallic backings. Microstructural characterizations of these new multiphasic composites showed that impregnation was incomplete and that a third air phase was present. The selected composites, sintered bronze-tin-air and sintered bronze-epoxy-air, at 5-35 MHz characterization, produced attenuation coefficients of 1.2 and >4 dB/mm/MHz and impedances of 32.4 and 26.4 MRayl, respectively. High-impedance composites were adopted as backing (thickness = 2 mm) to fabricate focused single-element P(VDF-TrFE)-based transducers (focal distance = 14 mm). The center frequency was 27 MHz, while the bandwidth at -6 dB was 65% for the sintered-bronze-tin-air-based transducer. We evaluated imaging performance using a pulse-echo system on a tungsten wire (diameter = 25 μm) phantom. Images confirmed the viability of integrating these backings in miniaturized transducers for imaging applications.

Therapeutic educational workshops for caregivers of patients with severe acquired brain injury

Abstract

Severe acquired brain injury (sABI) leads to a wide range of functional limitations in cognitive, moto and behavioural abilities. These changes impact the patient's family in terms of the feeling of emotional and physical health, social life and financial condition. Caregivers are often intensely involved in the patient's management exposing them to negative effects of caregiving including stress, mood disorders and decreased quality of life. Implementing forms of active involvement of caregivers in the rehabilitative program could be useful. Thus, in the present study, therapeutic educational workshops (TEWs) for caregivers during the post-acute intensive hospitalization were organized during the post-acute intensive hospitalization of patients with sABI. The caregivers were asked to participate in the workshops to actively involve them in the patient's care and neurorehabilitation program. Each workshop session provided indications regarding the management of the patient with aphasia, neglect, behavioural and swallowing disorders. A questionnaire of 22 items has been designed in order to represent possible indicators of usefulness and effectiveness of the TEWs. The primary aim of this study was to develop a reliable and valid questionnaire able to assess the caregivers' satisfaction with the modalities of carrying out the TEW as a novel activity during the post-acute hospitalization of patients with sABI. The second aim was to assess the caregivers' satisfaction with the utility of the TEW as a tool to enhance their skills in the management of patients' disabilities. 100 caregivers of patients with sABI who attended at least one TEW session and completed the questionnaire were included in the analysis. In conclusion the administered questionnaire has proven to be a valid and reliable tool to evaluate sABI caregivers' satisfaction with TEW. Moreover, caregivers were satisfied with the organization of the TEW and with their usefulness in the management of the patients with sABI.

Correlation between Quality of Life and severity of Parkinson's Disease by assessing an optimal cut-off point on the Parkinson's Disease questionnaire (PDQ-39) as related to the Hoehn & Yahr (H&Y) scale

PURPOSE

Strong evidence shows that symptoms in individuals with Parkinson's Disease (PD) restrict both their independence and social participation, leading to a low Quality of Life (QoL). Conversely, a reduced QoL has a negative impact on symptoms. The aim is to evaluate the correlation between QoL and severity of PD by assessing the presence of an optimal cut-off point on the Parkinson's disease questionnaire (PDQ-39) as related to the Hoehn &Yahr (H&Y) scale in a cohort of Italian adults with PD.

METHODS

A multicenter, cross-sectional study was performed. This study was conducted on a cohort of consecutive individuals. All participants were evaluated with the PDQ-39, and the severity of PD was recorded according to the H&Y scale by a neurologist. Receiver op-erating characteristic (ROC) curves and coordinates, visually inspected, were used to find cut-off points with optimal sensitivity and specificity. These were in turn used to determine the optimal PDQ-39 cut-off score for identifying disease severity according to H&Y stages.

RESULTS

513 individuals were included in the study. The ROC curve analysis showed that QoL worsened with an increase in disease severity and age. Moreover, QoL was worse in females.

CONCLUSIONS

The results of this study allowed for the correlation of QoL and disease severity in a cohort of individuals with PD. With this cut-off point, it is now possible to make a determination of QoL of an individual with PD at a certain stage of the disease, in a specific age range, and of a particular gender.

What if sharing music as a language is the key to meeting halfway? Absolute pitch, pitch discrimination and Autism Spectrum Disorder

BACKGROUND

Absolute pitch is the ability to identify a given note in the absence of a reference note. The prevalence of absolute pitch in autism is between 5% and 11% and autism involves notably enhanced abilities in pitch discrimination.

OBJECTIVES

To summarize the evidence about the role and the meaning of these special skills in autism.

METHODS

Systematic electronic database searches were conducted using Pubmed, Scopus, Psycinfo, and Web of Science. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRI-SMA) guideline was followed, and, after thorough screening by two independent reviewers, 17 articles remained eligible for inclusion in this study.

RESULTS

We have two different groups of results. Eight case-control studies discuss pitch discrimination and autism. The second group included four case reports about autistic individuals with absolute pitch and five case-control studies. These results strongly suggest that music elicits special attention for children with autism, and taken together, this evidence supports a major frequency of AP in autistic children.

CONCLUSION

Based on this evidence, future perspectives could include studies aiming to detect absolute pitch at an early age and to use this special skill to stimulate joint attention, as well as socio-communicative skills.

Development and validation of a test for the assessment of knowledge learned by healthcare students during an online course on COVID-19: cross-sectional study

Abstract

Many Italian universities during the COVID-19 pandemic had numerous students attending hospital wards. The training of health care students was necessary to prepare for good practices in implementing knowledge about COVID-19 and minimizing contagion among students who carried out the internship. In February 2020, a course aiming to guide health personnel so that they can appropriately address the health emergency posed by the new coronavirus was created, making use of the scientific evidence currently available as well as official sources of information and updates. The aim of this study was the development and validation of a useful tool to evaluate the progress in knowledge regarding COVID-19 of students in degree courses for the health care professions. The reliability of the test was assessed using Cronbach's alpha (α) coefficient, while the responsiveness of the test between T0 and T1 was measured with a student t test. The standard error of measurement was used to calculate the minimal detectable change of the tool. The test is made up of 31 items with four multiple-choice answers, one of which is correct. Fifteen bachelor's degree courses at the Sapienza University of Rome were enrolled, for a total population of 1,017 students from different course years. The test showed good internal consistency, with Cronbach's α values of 0.82. The item-total analysis also showed good results, with homogeneous α values from 0.80 to 0.82 for each item. The student t test showed a difference of 3.59 between T0 and T1 (p < 0.001). The minimal detectable change was 0.47. The test is a useful tool for assessing progress in skills regarding COVID-19 for students from bachelor's degree courses in the health professions. It allows the improvement and acquisition of skills as well as a qualitative analysis of the organization of internship degree courses.

Electrical activity at the AlN/Si Interface: identifying the main origin of propagation losses in GaN-on-Si devices at microwave frequencies

AlN nucleation layers are the basement of GaN-on-Si structures grown for light-emitting diodes, high frequency telecommunication and power switching systems. In this context, our work aims to understand the origin of propagation losses in GaN-on-Si High Electron Mobility Transistors at microwaves frequencies, which are critical for efficient devices and circuits. AlN/Si structures are grown by Metalorganic Vapor Phase Epitaxy. Acceptor dopant in-diffusion (Al and Ga) into the Si substrate is studied by Secondary Ion Mass Spectroscopy and is mainly located in the first 200 nm beneath the interface. In this region, an acceptor concentration of a few 10¹⁸ cm^-3 is estimated from Capacitance-Voltage (C-V) measurements while the volume hole concentration of several 10¹⁷ cm^-3 is deduced from sheet resistance. Furthermore, the combination of scanning capacitance microscopy and scanning spreading resistance microscopy enables the 2D profiling of both the p-type conductive channel and the space charge region beneath the AlN/Si interface. We demonstrate that samples grown at lower temperature exhibit a p-doped conductive channel over a shallower depth which explains lower propagation losses in comparison with those synthesized at higher temperature. Our work highlights that this p-type channel can increase the propagation losses in the high-frequency devices but also that a memory effect associated with the previous sample growths with GaN can noticeably affect the physical properties in absence of proper reactor preparation. Hence, monitoring the acceptor dopant in-diffusion beneath the AlN/Si interface is crucial for achieving efficient GaN-on-Si microwave power devices.

Frustration and inhomogeneous environments in relaxation of open chains with Ising-type interactions

Frustration can contribute to very slow relaxation times in large open chains, as in spin glasses and in biopolymers. However, frustration may not be sufficient to produce broken ergodicity in finite systems. Here we employ a system-plus-reservoir approach to investigate how strongly inhomogeneous environments and frustration compete in the relaxation of finite open chains. We find a sufficient condition for our inhomogeneous environments to break ergodicity. We use the microscopic model to derive a Markovian quantum master equation for a generic chain with ultrastrong intrachain couplings. We show that this microscopic model avoids a spurious broken ergodicity we find in the phenomenological model. We work out an explicit example of broken ergodicity due to the inhomogeneous environment of an unfrustrated spin chain as far as simulating a recent experiment on protein denaturation (where environment inhomogeneity is especially relevant). We finally show that an inhomogeneous environment can mitigate the effects of frustration-induced degeneracies.

Validation of the Pediatric Evaluation of Disability Inventory in an Italian Population with Autism Spectrum Disorder: a Cross-Sectional Study

OBJECTIVES

To measure psychometric properties of the Italian version of the Pediatric Evaluation of Disability Inventory (PEDI-I) in a population with Autism Spectrum Disorder (ASD).

METHODS

The PEDI-I was administered to different children with ASD. The internal consistency was examined by using Cronbach's Alpha, while the intraclass correlation coefficient (ICC) was used to investigate both inter-observer and intra-observer reproducibility. Its concurrent validity was evaluated with the Italian version of the Barthel Index.

RESULTS

The PEDI-I was administered to 60 children with a diagnosis of ASD. Cronbach's Alpha showed statistically significant values (.885-.965). Inter-observer and intra-observer investigations confirm the reproducibility of the scale with a range of high and very high parameters. The Pearson Correlation Coefficient with the Barthel Index showed significant data for all PEDI-I subscales with a p<0.01.

CONCLUSIONS

The PEDI-I showed good psychometric properties and it is possible to confirm its validity and reliability in ASD population. However, for better understanding of how PEDI-I works in clinical practice, further researches are recommended.

Occupational Therapy's efficacy in children with Asperger's syndrome: a systematic review of randomized controlled trials

This systematic review of randomized controlled trials (RCTs) aims at evaluating the efficacy of Occupational therapy (OT) interventions in Asperger's syndrome (AS) pediatric patients. We conducted a systematic review according to PRISMA guidelines. The screening of the literature was carried out on PUBMED, SCOPUS, WEB OF SCIENCE and OT SEEKER databases, TO December 2018. We selected three RCTs having the common objective to evaluate whether children with AS can improve their social skills thanks to OT treatments. The interventions targeted by the three selected studies were: LEGO therapy, Social Use of Language Programme, Let's Face It! software and Parent Training combined with the administration of risperidone. All the studies showed that the intervention groups improved their overall social ability.This review shows that OT interventions can help concretely AS children in overcoming their social issues. Nevertheless, more RCTs are needed to better understand the OT's benefits and limitations in AS patients.

Impregnation of High-Magnetization FeCo Nanoparticles in Mesoporous Silicon: An Experimental Approach

This paper deals with the synthesis of high-magnetization porous silicon-based nanocomposites. Using well-controlled organometallic synthesis of ferromagnetic FeCo nanoparticles, the impregnation of mesoporous silicon has been performed by immersion of porous silicon in a colloidal solution. The technique was optimized by controlling the temperature, the immersion duration, and the solvent nature. The characterization of the nanocomposites showed a homogeneous filling of the pores and a high magnetization of 135 emu/cm3. Such composites present a great interest for many applications including data storage, medical instrumentations, catalysis, or electronics.

The effect of physiotherapy on fatigue and physical functioning in chronic fatigue syndrome patients: A systematic review

OBJECTIVE

The objectives of this work were to fill the gap in the scientific literature and to evaluate the results of physical therapy treatments in individuals affected by chronic fatigue syndrome, considering only studies that employed a randomized controlled trial.

METHODS

A systematic review was carried out according to PRISMA guidelines. Three bibliographic databases were searched: MEDLINE, Cochrane Library, and PEDro. The minimum prerequisites for papers to be included in the systematic review were that they had to (a) employ a randomized controlled trial; (b) be published in English; and (c) be published during the last ten years (2007-2017). The studies were evaluated according to Jadad score.

RESULTS

Four studies were included. This systematic review suggests that a treatment that is more effective than all the others cannot be defined. This conclusion is related to the low number of investigated studies; therefore, the collected results cannot be generalized.

CONCLUSION

Chronic fatigue syndrome is not yet a well-understood pathology, and the physical mechanisms that influence the outcomes still need more study. Rehabilitation programs that promote physiotherapy techniques such as exercise, mobilization, and body awareness (e.g., MRT and GET) are the most effective in reducing medium and long-term fatigue severity in CFS patients.

Work on a quantum dipole by a single-photon pulse

Energy transfer from a quantized field to a quantized dipole is investigated. We find that a single photon can transfer energy to a two-level dipole by inducing a dynamic Stark shift, going beyond the well-known absorption and emission processes. A quantum thermodynamical perspective allows us to unravel these two energy transfer mechanisms and to identify the former as a generalized work and the latter as a generalized heat. We show two necessary conditions for the generalized work transfer by a single photon to occur, namely, off-resonance and finite linewidth of the pulse. We also show that the generalized work performed by a single-photon pulse equals the reactive (dispersive) contribution of the work performed by a semiclassical pulse in the low-excitation regime.

Dynamic Stark shift induced by a single photon packet

The dynamic Stark shift results from the interaction of an atom with the electromagnetic field. We show how a propagating single-photon wave packet can induce a time-dependent dynamical Stark shift on a two-level system (TLS). A non-perturbative fully quantum treatment is employed, where the quantum dynamics of both the field and the TLS are analyzed. We also provide the means to experimentally access such time-dependent frequency by measuring the interference pattern in the electromagnetic field inside a 1D waveguide. The effect we evidence here may find applications in the autonomous quantum control of quantum systems without classical external fields, which can be useful for quantum information processing as well as for quantum thermodynamical tasks.

Non-Markovianity induced by a single-photon wave packet in a one-dimensional waveguide

The concept of non-Markovianity (NM) in quantum dynamics is still an open debate. Understanding how to generate and measure NM in specific models may aid in this quest. In quantum optics, an engineered electromagnetic environment coupled to a single atom can induce NM. The most common scenario of structured electromagnetic environment is an optical cavity, composed by a pair of mirrors. Here, we show how to generate and measure NM on a two-level system coupled to a one-dimensional waveguide with no mirrors required. The origin of the non-Markovian behavior lies in the initial state of the field, prepared as a single-photon packet. NM is shown to depend on two experimentally controllable parameters, namely, the linewidth of the packet and its central frequency. We relate the presence of NM to quantum interference. We also show how the two output channels of the waveguide provide distinct signatures of NM, both experimentally accessible.

Heat transport between two pure-dephasing reservoirs

A pure-dephasing reservoir acting on an individual quantum system induces loss of coherence without energy exchange. When acting on composite quantum systems, dephasing reservoirs can lead to a radically different behavior. Transport of heat between two pure-dephasing Markovian reservoirs is predicted in this work. They are connected through a chain of coupled sites. The baths are kept in thermal equilibrium at distinct temperatures. Quantum coherence between sites is generated in the steady-state regime and results in the underlying mechanism sustaining the effect. A quantum model for the reservoirs is a necessary condition for the existence of stationary heat transport. A microscopic derivation of the non-unitary system-bath interaction is employed, valid for arbitrary inter-site coupling regime. The model assumes that each site-reservoir coupling is local.

Fabry-Perot interferometer with quantum mirrors: nonlinear light transport and rectification

Optical transport represents a natural route towards fast communications, and it is currently used in large scale data transfer. The progressive miniaturization of devices for information processing calls for the microscopic tailoring of light transport and confinement at length scales appropriate for upcoming technologies. With this goal in mind, we present a theoretical analysis of a one-dimensional Fabry-Perot interferometer built with two highly saturable nonlinear mirrors: a pair of two-level systems. Our approach captures nonlinear and nonreciprocal effects of light transport that were not reported previously. Remarkably, we show that such an elementary device can operate as a microscopic integrated optical rectifier.

Laboratory evolution of adenylyl cyclase independent learning in Drosophila and missing heritability

Gene interactions are acknowledged to be a likely source of missing heritability in large-scale genetic studies of complex neurological phenotypes. However, involvement of rare variants, de novo mutations, genetic lesions that are not easily detected with commonly used methods and epigenetic factors also are possible explanations. We used a laboratory evolution study to investigate the modulatory effects of background genetic variation on the phenotypic effect size of a null mutation with known impact on olfactory learning. To accomplish this, we first established a population that contained variation at just 23 loci and used selection to evolve suppression of the learning defect seen with null mutations in the rutabaga adenylyl cyclase. We thus biased the system to favor relatively simplified outcomes by choosing a Mendelian trait and by restricting the genetic variation segregating in the population. This experimental design also assures that the causal effects are among the known 23 segregating loci. We observe a robust response to selection that requires the presence of the 23 variants. Analyses of the underlying genotypes showed that interactions between more than two loci are likely to be involved in explaining the selection response, with implications for the missing heritability problem.

Optimal rectification in the ultrastrong coupling regime

We study the effect of ultrastrong coupling on the transport of heat. In particular, we present a condition for optimal rectification, i.e., flow of heat in one direction and complete isolation in the opposite direction. We show that the strong-coupling formalism is necessary for correctly describing heat flow in a wide range of parameters, including moderate to low couplings. We present a situation in which the strong-coupling formalism predicts optimal rectification whereas the phenomenological approach predicts no heat flow in any direction, for the same parameter values.

Evaluation of genotyping methods and the relative cost of pharmacogenomics

Recently, several methods to assess the quality of cost-effectiveness, cost-utility and cost-benefit in the pharmacogenomic field have become available. A relevant example is the National Institute for Health and Clinical Excellence (NICE). NICE forms a diverse clinical Advisory committee, which stimulates Pharma and Academic communities to produce a robust set of data, including the design and data source, for economic models of personalized healthcare. Personalized medicine includes genomic tests of each patients and their disease into their clinical treatments, so as minimize toxicity and maximize benefits. It is well known that Pharmacogenomics (PG) tests, performed before drug treatment, lower overall medical costs and provide higher quality of life and longer life expectancy. In this issue relative costs of genotyping methods and platforms, were evaluated by "manually cured criteria" due to lack of specific guidelines. Finally, with the progress made in this scenario over the next five years, health decision-making may able to accelerating the translation of genetic technologies into routine clinical laboratory.

Antiblastic treatment of haematological malignancies during pregnancy: a crucial decision

Antiblastic treatment of hematological malignancies during pregnancy poses a number of issues related to the curability of the maternal disease, the need of a prompt treatment and the potential toxicity of chemotherapy for the fetus. Here we report the results of a systematic literature search about the management of the most frequent hematological malignancies that may occur during pregnancy, focusing on specific issues related to gestational age at diagnosis, fetal toxicity and efficacy on the maternal side. The standard approach in non-pregnant women is illustrated as reference.

Non-oxidized porous silicon-based power AC switch peripheries

We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries.

Pharmacogenomics panel test for prevention toxicity in patient who receive Fluoropirimidine/Oxaliplatin-based therapy

AIM

Both Fluoropirimidine and Oxaliplatin (FluOx) are the most common anticancer drugs used to treat lung, colorectal, ovarian, breast, head/neck, and genitourinary cancers. However, the efficacy of FluOx-based therapy is often compromised because of the severe risk of toxicity. Stratification of patients for multidrug response is a promising strategy for cancer treatment and personalized therapy.

METHODS

Here, we review the late findings on the most appropriate gene variants related to the toxicity in patients receiving FluOx chemotherapy. Several criteria were used to select a genotyping panel tests, including dihydropyrimidine dehydrogenase (DPYD), thymidylate synthase (TYMS), Glutathione S-transferase (GSTP1), and ATP-binding cassette, subfamily C member 2 (ABCC2).

RESULTS

Results of allelic status from 7 validated polymorphism assays, allow the stratification of the patients who are most likely to respond to FluOx treatments. Also, we will take in consideration the usefulness and costs of the methods used to detect these polymorphisms.

CONCLUSIONS

With these pharmacogenomics markers, the oncologists will have new means based on the genetic profile of the individual, to make treatment decisions for their patients in order to maximize benefits and minimize toxicity.

Knowledge and skills needs for health professions about pharmacogenomics testing field

BACKGROUND

Promise in the future, a disease could be ranked into genetic categories, allowing bespoke tailoring of medicine to maximize therapeutic effects and to reduce the potential for adverse drug response. This new feature requires for health professionals to have competencies not only for the basic skills of their discipline, but also for the understanding on why, when, and how that knowledge should be applied to improve personalized therapies for their patients. Current opinion on basic competences of health professions includes knowledge and skills on two fundamental features: (1) genetics of disease, to allow the understanding and the identification of diseases associated to genetic variations, and to facilitate the development of new genomic tests; and (2) ethical, social and economical implications that are fundamental to identify those factors that might contribute to a successful integration of pharmacogenomics into international health and public policy.

AIM

Briefly, we described (1) current knowledge on genetic variations that interact with therapies and the need to detect them; (2) the most common available methods for detecting mutations; and (3) ethical, social and economic issues related to pharmacogenetic testing and recording of genetic information (e.g., critical evaluation of the development of new tests, privacy, the current absence of public reimbursement, etc).

CONCLUSIONS

These could be useful recommendations for academic institutions and educational programs to prepare health professionals with the necessary abilities for their future practice.

Combination treatment of flag with non-pegylated liposomal doxorubicin (MYOCET(TM)) in elderly patients with acute myeloid leukemia: a single center experience

The incidence of acute myeloid leukemia (AML) increases with age, but results of intensive chemotherapy in elderly patients are disappointing. Non-pegylated liposomal formulations of doxorubicin (Myocet™) have been developed with the aim of reducing systemic and cardiac toxicity especially in the elderly. We evaluated the efficacy and toxicity profiles of fludarabine, cytarabine and granulocyte colony-stimulating factor (FLAG) regimen given in association with Myocet™ in 35 patients with AML, median age 69 years (range 61-83 years). Nineteen (54.3%) had newly-diagnosed AML, twelve (34.3%) patients had secondary AML (ten with Myelodisplastic Syndrome, two with Primary Myelofibrosis) and 4 (11.4%) patients had had a late relapse (>12 months) of AML. Complete remission (CR) and partial remission (PR) were obtained in twenty-two (63%) and 3 (8.5%) patients, respectively. Seven (20%) patients showed a resistant disease. There were 3 early deaths (8.5%). Six patients (17%) experienced severe cardiovascular toxicity. The median overall survival (OS) was 12 months (range 1-52 months) with a median disease-free survival (DFS) of 20 months (range 1-48 months). One-year and two-year DFS were 78.9% and 26.7%, respectively. This study demonstrates that in elderly patients with AML, FLAG-Myocet combination shows promising efficacy response with acceptable toxicity, enabling most patients to receive further treatments, including transplantation procedures.

Management of occult adrenocorticotropin-secreting bronchial carcinoids: limits of endocrine testing and imaging techniques

The differential diagnosis and the identification of the source of ACTH in occult ectopic Cushing's syndrome due to a bronchial carcinoid still represents a challenge for the endocrinologist. We report our experience in six patients with occult bronchial carcinoid in whom extensive hormonal, imaging, and scintigraphic evaluation was performed. All patients presented with hypercortisolism associated with high plasma ACTH values. The CRH test and high dose dexamethasone suppression test suggested an ectopic source of ACTH in three of six patients. During bilateral inferior petrosal sinus sampling, none of the patients showed a central to peripheral ACTH gradient. At the time of diagnosis, none of the patients had radiological evidence of the ectopic source of ACTH, whereas pentetreotide scintigraphy identified the lesion in two of four patients. Finally, a chest computed tomography scan revealed the presence of a bronchial lesion in all patients, and pentetreotide scintigraphy identified four of six lesions. In all patients a bronchial carcinoid was found and removed. In one patient with scintigraphic evidence of residual disease after two operations, radioguided surgery, using a hand-held gamma probe after iv administration of radiolabeled pentetreotide, was performed; this allowed detection and removal of residual multiple mediastinal lymph node metastases. In conclusion, our data show that there is not a single endocrine test or imaging procedure accurate enough to diagnose and localize occult ectopic ACTH-secreting bronchial carcinoids. Radioguided surgery appears to be promising in the presence of multiple tumor foci and previous incomplete removal of the tumor.

Microdialysis study of bromocriptine and its metabolites in rat pituitary and striatum

Bromocriptine, a D2 receptor agonist, was administered intravenously (1mg/kg) to anesthetized rats. Microdialysis probes were implanted in the pituitary and the striatum, known sites of D2 agonist action. Bromocriptine and its metabolites were monitored in plasma and tissue dialysates for 4 h. Drug analyses were performed using two different enzyme immunoassays specific for untransformed bromocriptine or a pool of parent drug plus hydroxylated metabolites. The metabolites/parent drug ratio for areas under the curve was 5.5 in plasma and 1 in the pituitary. No metabolites could be detected in the striatum. Bromocriptine penetration was at least 10-fold greater in the pituitary than in the striatum. The kinetics of bromocriptine in the pituitary and striatum did not parallel those in plasma, indicating that the prolonged action of bromocriptine reported by other authors may be due to slow dissociation from receptors.

Bromocriptine modulates P-glycoprotein function

The multidrug resistance (MDR)-associated P-glycoprotein (P-gp) is a membrane transporter which carries, at the expense of MgATP hydrolysis, many amphiphilic molecules, such as the MDR-related cytotoxic drugs vincristine and vinblastine, and the MDR-reversing agents verapamil and progesterone. We have tested the effects on P-gp function of bromocriptine (BCT), an ergot alkaloid known as a D2 dopaminergic receptor agonist. BCT (at 4 microM) partially reverses the P-gp-mediated vincristine resistance of the Chinese hamster lung fibroblasts DC-3F/ADX, a MDR cell line. P-gp containing membrane vesicles prepared from the DC-3F/ADX cells exhibit, in the absence of any added drug, a basal MgATPase activity due to P-gp. BCT inhibits this basal ATPase activity, with a half-inhibiting concentration of 0.30 +/- 0.15 microM. BCT also inhibits the verapamil-induced P-gp ATPase stimulation competitively (Ki approximately 0.2 microM), and the progesterone-induced P-gp ATPase stimulation non-competitively (Ki approximately 0.07-0.10 microM). BCT also non-competitively inhibits the vinblastine-dependent P-gp ATPase activity within the same concentration range. Hydroxylated metabolites of BCT have different effects on P-gp ATPase, only the monohydroxylated being able to modulate both the basal and the drug-stimulated ATPase activities. In conclusion, these effects of BCT on P-gp function can be linked to a specific interaction with P-gp, probably involving inhibition of P-gp-mediated drug transport.

Metabolite involvement in bromocriptine-induced prolactin inhibition in rats

Bromocriptine (BCT) is a dopamine D2 receptor agonist used for the treatment of Parkinson's disease and hyperprolactinemic disorders. After oral administration, BCT is metabolized into mono- or dihydroxylated metabolites. To study how these metabolites influence parent drug pharmacodynamics, we administered BCT to rats intravenously (1 mg/kg i.v.) and orally (10 mg/kg p.o.) and measured the inhibition of prolactin secretion. Despite similar areas under the curve for BCT, the duration of the effect was 36 h after oral and only 18 h after intravenous administration. Pharmacokinetic/pharmacodynamic models were used to correlate the concentration of BCT in the effect compartment with the lowering of prolactin. One of these models (effect compartment model) showed that the effective concentration (EC50) at the site of action was much lower after oral (0.56 nM) than after intravenous administration (3.68 nM). In contrast, the EC50 values based on BCT metabolite data were in the same range for both administrations. These observations suggested the activity of one or more BCT metabolites. To confirm this hypothesis, hydroxylated metabolites of BCT (produced in vitro by rat liver microsomes) were administered i.v. (100 microg/kg) in rats. We found that monohydroxylated BCT was able to lower prolactin secretion like BCT. Dihydroxylated metabolites, as well as monohydroxylated metabolites, were effective in reducing in vitro prolactin secretion. Because we demonstrated that the concentration of hydroxylated metabolites after oral administration is 55-fold that of BCT, it can be concluded that BCT activity in the pituitary after oral administration is mediated by its metabolites.

Effect of variability of plasma interferences on the accuracy of drug immunoassays

Most immunoassays applied to drugs in human plasma do not use an extraction of analyte. To compensate for interferences due to plasma proteins or salts, standards are prepared in drug-free plasma. Because the concentration of plasma components varies from one subject to another, it is likely that the drug-free plasma is not representative of the potential interference in each plasma. Using two immunoassays, for a steroid (nomegestrol acetate) and a heptapeptide (BN 52080), the authors have shown that tracer binding to the antibody may vary significantly between plasma from different subjects. Intersubject variability of tracer-antibody binding was 21.6% (coefficient of variation for 25 subjects) for nomegestrol acetate. When the same plasma were spiked with the steroid at a concentration corresponding to the central part of the standard curve, the recovery was between 39 and 215%. Intersubject variability in tracer binding was lower (7.7%) for the peptide immunoassay, but still affected accuracy. The authors show that this problem is common to direct immunoassays for other drugs and must be solved in assay development.

Enzyme immunoassays for bromocriptine and its metabolites

We have developed two bromocriptine enzyme immunoassays with different specificities for applications in human and animal pharmacokinetic studies. The first assay uses antibodies directed against the cyclopeptide structure of bromocriptine, and is specific for untransformed bromocriptine. The second assay uses antibodies directed against the bromolysergic part of the molecule and allows the measurement of both bromocriptine and its metabolites. Enzymatic tracers were obtained by covalent coupling of bromocriptine analogs to acetylcholinesterase from the electric eel Electrophorus electricus. Both assays have a limit of detection of 10 pg/ml and a limit of quantification of 50 pg/ml. The specificity of the assays was determined following fractionation by high-performance liquid chromatography of rat samples obtained after administration of bromocriptine.

Study of mediators of anaphylaxis in nasal wash fluids after aspirin and sodium metabisulfite nasal provocation in intolerant rhinitic patients

Nasal histamine (H), leukotriene C4 (I-LTC4) and SRS-A activity were studied in seven aspirin-(ASA)-intolerant patients (AIR) with rhinitis and in five ASA-tolerant control patients with chronic rhinitis after nasal provocation (NP) with a lysine acetylsalicylate solution. The same parameters were also studied after metabisulfite (MBS) NP in four sulfite-intolerant patients with rhinitis and in six control patients with chronic rhinitis. In six ASA-intolerant subjects and in four controls, we studied the PGD2 levels in nasal washes after ASA NP 0.2 mL of lysine acetylsalicylate solution (10 mg/mL) was sprayed intranasally in ASA-intolerant patients and controls and a 25-mg/mL MBS solution in sulfite intolerant patients and controls. Nasal wash fluids were obtained using 5 mL of 0.15 M saline before and 7 1/2, 15, 30, and 60 minutes after nasal provocation. The nasal provocation with ASA induced itching and sneezing in four out of seven intolerant subjects. In this subgroup histamine values in nasal wash fluids were significantly higher versus the remaining ASA-intolerant patients at 30 and 60 minutes (P less than .05 and P less than .01, respectively) and versus controls at 60 minutes (P less than .01). We found significantly higher I-LTC4 (P less than .01) and SRS-A levels in nasal washes collected from ASA-intolerant subjects versus controls at 60 minutes after nasal provocation. There was no significant increase in the mean PGD2 values in either the ASA-intolerant or control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Radiation-induced intestinal injuries]

Postoperative radiation after the removal of radiosensitive tumours may cause acute or chronic intestinal lesions. In some cases severe complications requiring one or more operations may arise even years later and unfortunately the morbidity and mortality rates are high. The paper presents a discussion of the clinical onset of these pictures as well as diagnostic and therapeutic possibilities in the light of personal experience and information obtained from the literature.

A tetrodotoxin-like substance found in the Brazilian frog Brachycephalus ephippium

A tetrodotoxin-like substance, denoted ephippiotoxin, was obtained from the tissue of Brachycephalus ephippium, a small pumpkin-coloured frog collected in the Atlantic Forest of the southeast region of Brazil. Ephippiotoxin is a dialyzable substance soluble in water, methanol and ethanol, but insoluble in organic solvents such as chloroform and other apolar solvents. After treatment with active charcoal (Norit-A) and purification with ion-exchange Amberlite IRC-50 resin (NH4 + form), a freeze-dried residue was obtained, with a toxicity of c. 117 micrograms/kg (mice, i.p.). Ephippiotoxin showed the same mobility as crystalline tetrodotoxin (Sankyo) when submitted to thin-layer chromatography (silica gel G) using seven different solvent systems. White mice (20 +/- 1 g) injected i.p. with either B. ephippium tissue extracts or semi-purified toxin showed partial paralysis of the hind limbs, lethargy, altered breathing rhythm and clonic convulsions. Death occurred within 1.5-30 min after injection, depending on the dose. Ephippiotoxin induced atrioventricular diastolic blockade in the toad heart. It also inhibited the response of toad striated muscle to direct and indirect electric stimulation and blocked the compound action potential of isolated frog sciatic nerve.

Early detection of pregnancy by new beta-hCG monoclonal urine test

1,066 urine samples were assayed by beta-human chorionic gonadotrophin (beta-hCG) monoclonal pregnancy test with a sensitivity of 150 IU hCG/l. Tests were performed in 5 independent laboratories and results were compared with those of pregnancy tests which were used routinely. Urine samples which showed discordant results under evaluation were reassayed for beta-hCG using radioimmunoassay. 569 urine samples were from nonpregnant women, and a consistent result with comparison pregnancy tests was achieved in 97.19% of urine samples. The trial test from 389 urine samples of pregnant women was 99.49% in accordance with routine pregnancy tests. Results from 108 urine samples of women over 40 years of age indicate the high specificity of the new beta-hCG monoclonal pregnancy test. Titration experiments showed 63% positive tests at 150 IU beta-hCG/l. Data presented combine to suggest that this new monoclonal pregnancy test is a valuable aid in diagnosing early pregnancy. It may also be used in the diagnosis of tubal pregnancy and in other ectopic processes.

A study on melanophore receptors of Papiliochromis ramirezi (Teleostei, Cichlidae)

Melanophores of Papiliochromis ramirezi aggregate their melanosomes in the presence of catecholamines. Their order of potency are: at 10(-4) M, norepinephrine greater than isoproterenol = epinephrine; at 10(-6) and 10(-8) M, norepinephrine = isoproterenol greater than epinephrine. These effects are antagonized not only by phentolamine but also by propranolol. The catecholamines are unable to induce pigment dispersion. Melanosome dispersion is obtained with cholinergic drugs and the order of potency is nicotine greater than acetylcholine = pilocarpine. Their effects are inhibited by atropine and also by d-tubocurarine and potentiated by physostigmine. The evidences suggest the presence of undifferentiated adrenoceptors, related to the melanosome aggregation and undifferentiated cholinoceptors related to the melanosome dispersion.

Detection of morphine in urine by hemagglutination inhibition, with use of lyophilized reagents

We describe a modified test of hemagglutination inhibition for the detection of morphine in urine, similar to the well-known test for pregnancy. The reaction takes place in test tubes or ampoules containing carefully matched amounts of lyophilized morphine antiserum and tanned human erythrocytes coated with morphine conjugated to rat serum albumin. The reagents are reconstituted by adding 100 microL of urine and 400 microL of water, and the result is read after 60 min. The detection limit, tested with the method of Gorodetzky (Clin Chem 19:753, 1973), was about 200 ng of total morphine per milliliter of urine. For more than 2000 samples, results by our test agreed satisfactorily with those obtained by an accepted RIA method. The test is suitable for rapid screening in field work, monitoring subjects during detoxication, and use in nonspecialized laboratories. Confirmatory analysis is needed for quantitative measurements, forensic purposes, and discrimination between morphine and cross-reacting opiates.

Detection of morphine in urine by hemagglutination inhibition, with use of lyophilized reagents

We describe a modified test of hemagglutination inhibition for the detection of morphine in urine, similar to the well-known test for pregnancy. The reaction takes place in test tubes or ampoules containing carefully matched amounts of lyophilized morphine antiserum and tanned human erythrocytes coated with morphine conjugated to rat serum albumin. The reagents are reconstituted by adding 100 microL of urine and 400 microL of water, and the result is read after 60 min. The detection limit, tested with the method of Gorodetzky (Clin Chem 19:753, 1973), was about 200 ng of total morphine per milliliter of urine. For more than 2000 samples, results by our test agreed satisfactorily with those obtained by an accepted RIA method. The test is suitable for rapid screening in field work, monitoring subjects during detoxication, and use in nonspecialized laboratories. Confirmatory analysis is needed for quantitative measurements, forensic purposes, and discrimination between morphine and cross-reacting opiates.