The European intercomparison of in-vivo monitoring laboratories: the EIVIC-2020 project

The EIVIC project was launched in 2020, and the main goal was the organisation of a European intercomparison of in-vivo monitoring laboratories dealing with direct measurements of gamma-emitting radionuclides incorporated into the body of exposed workers. This project was organised jointly by members of EURADOS Working Group 7 on internal dosimetry (WG7), the Federal Office for Radiation Protection (BfS, Germany) and the Radioprotection and Nuclear Safety Institute (IRSN, France). The objective was to assess the implementation of individual-monitoring requirements in EU Member States on the basis of in-vivo measurements and to gain insight into the performance of in-vivo measurements using whole-body counters. In this context, a total of 41 in-vivo monitoring laboratories from 21 countries, together with JRC (EC) and IAEA participated. The results were submitted in terms of activity (Bq) of the radionuclides identified inside phantoms that were circulated to all participants. The measured data were compared with reference activity values to evaluate the corresponding bias according to the standards ISO 28218 and ISO 13528. In general, the results of the different exercises are good, and most facilities are in conformity with the criteria for the bias and z-scores in the ISO standards. Furthermore, information about technical and organisational characteristics of the participating laboratories was collected to test if they had a significant influence on the reported results.

Common B-cell acute lymphoblastic leukaemia in a 70-year-old woman presenting 2 years after carboplatin-taxane radiotherapy for endometrial cancer

Therapy-related acute lymphoblastic leukaemia (t-ALL) is a poorly defined entity and is not featured in the World Health Organization classification as a distinct clinical entity from acute lymphoblastic leukaemia (ALL), thus differing from therapy-related acute myeloid leukaemia and myelodysplasia. We present a case of t-ALL occurring 18 months after treatment for metastatic endometrial cancer with a regimen of carboplatin, paclitaxel and radiotherapy. The patient presented with severe pancytopenia and diagnosed with common-B ALL, and the cytogenetic analysis showed a previously unreported deletion in chromosome 19 (q13.1) in 100% of the blast cells. The patient declined further therapy and died 1 month later. This rare but serious side effect of chemo-radiotherapy should be considered when deciding on treatment options for gynaecological cancers.

Effect of FOLFOX on minimal residual disease in Stage III colon cancer and risk of relapse

Introduction

25% of Stage III colon cancer patients relapse within 5 years due to minimal residual disease (MRD) not eliminated by surgery and chemotherapy. We hypothesise that sub-types of MRD, defined by circulating tumour cells (CTCs) and bone marrow micro-metastasis (mM) have different types and kinetics of relapse.

Patients and Methods

One month of curative surgery and 1 month after completing six cycles of FOLFOX chemotherapy blood and bone marrow samples were taken to detect CTCs and mM using immunocytochemistry with anti-carcino-embryonic antigen (CEA). Follow up was up to 5 years or disease progression defined as new images on CT scanning. Survival curves using Kaplan–Meier (KM) and Restricted Mean Survival Time (RMST) were calculated for three prognostic groups: CTC and mM negative, CTC negative mM positive, and CTC positive.

Results

76 patients (39 men) participated, mean age 67 years, median follow-up 3.6 years. The response to chemotherapy was heterogeneous and MRD pre-treatment did not predict response to therapy. Of 21 patients MRD (−), 20 remained MRD negative and one patient became mM (+); of 21 patients mM (+), 10 became MRD (−), 8 remained the same and 3 became CTC (+); of the 34 CTC positive, 8 became MRD (−), 8 with only mM, and 18 remained positive.

After chemotherapy, 38 patients were negative for CTC and mM, 17 were positive for only mM, and 21 for CTCs. For the whole cohort, the 5 year KM was 58%, the median survival was not reached. For the three prognostic groups, the KM 5-year survivals were 87%, 58%, and 4%, respectively, the median survival for patients MRD negative and mM only was not reached. RMST for the whole cohort was 3.6 years, for the three prognostic groups the RMST was 4.6 years, 4.0 years, and 1.5 years, respectively. Serum CEA was significantly higher pre-surgery in the CTC positive group. There were no significant differences with respect to age or sex between the three groups.

Conclusions

MRD subtypes pre-chemotherapy did not predict treatment response. Post-chemotherapy MRD subtypes were associated with the pattern of failure and time to failure. MRD negative patients had an excellent prognosis with 87% disease-free survival at 5 years. Those with only mM had a similar outcome up to 2 years and then were at increasing risk of late failure. Patients who were CTC positive had a high risk of early failure. MRD subclassification may be useful to define the risk of relapse in Stage III colon cancer patients and warrants further studies with a larger number of patients.

METHODOLOGY AT CIEMAT WHOLE BODY COUNTER FOR IN VIVO MONITORING OF RADIOIODINE IN THE THYROID OF EXPOSED POPULATION IN CASE OF NUCLEAR EMERGENCY

Iodine-131 is one of the main concerns from the point of view of radiological protection in a short term after a nuclear accident. The WBC Laboratory of CIEMAT has developed a methodology for in vivo monitoring of radioiodine in the thyroid of exposed individuals in case of emergency. Thyroid-neck phantoms of different sizes are required for calibrating the detection systems in appropriate counting geometries for the measurement of exposed population. A Low-Energy Germanium (LEGe) detector and a Fastscan Counter were calibrated using a set of thyroid phantoms fabricated by CIEMAT. Each neck phantom consists of a Lucite cylinder with a vial source of 131I. Counting efficiencies depending on age and thyroid sizes were obtained to be used to determine the activity of 131I in internally contaminated people. DL of 131I varies with the age, being in the range of 5-8 Bq for the LEGe detector and 26-42 Bq for the Fastscan. Detection of intakes resulting in Committed Effective doses far below 1 mSv are guaranteed for thyroid monitoring in a few days after the accidental exposure assuming a scenario of acute inhalation or ingestion of 131I by members of the public.

[Massive obstetric haemorrhage in a patient with placenta percreta]

We present a case of a 38 year-old patient with prenatal diagnosis of placenta praevia. When the elective caesarean began it was found a placenta accreta. In spite of an emergency hysterectomy, embolisation using interventional radiography was needed after a massive obstetric haemorrhage. The post-operative period progressed without incidents.

Quality management system in the CIEMAT Radiation Dosimetry Service

This paper describes the activities realised by the CIEMAT Radiation Dosimetry Service (SDR) for the implementation of a quality management system (QMS) in order to achieve compliance with the requirements of ISO/IEC 17025 and to apply for the accreditation for testing measurements of radiation dose. SDR has decided the accreditation of the service as a whole and not for each of its component laboratories. This makes it necessary to design a QMS common to all, thus ensuring alignment and compliance with standard requirements, and simplifying routine works as possible.

INDIVIDUAL CRYOPRESERVATION WITH DIMETHYL SULFOXIDE AND POLYVINYLPYRROLIDONE OF EJACULATES AND POOLED SEMEN OF THREE AVIAN SPECIES

Artificial insemination (AI) has been used for avian reproduction due to the discovery of cryoprotectants extending its usefulness both in production of domestic fowl and conservation of wild species. The goal of this study was to assess the effect on domestic and wild fowl pooled semen and individual ejaculate cryopreservation with dimethyl sulfoxide (DMSO) and polyvinylpyrrolidone (PVP). Twenty ejaculates and twenty samples of pooled semen of roosters, pheasants and hawks were frozen in media containing DMSO or PVP. DMSO and PVP cryopreservation are equally effective both for ejaculates and pooled semen. Even PVP is a good alternative since no significant difference was found when compared to DMSO. The fertilizing capacity of fresh and cryopreserved pooled semen was analyzed through AI of hens and female pheasants. Similar fertility rates using DMSO, PVP or frozen-thawed samples demonstrated that reproduction is possible through the use of cryopreserved semen. In the case of female pheasants, the same values were obtained with both cryopreserved and fresh semen.

IgG antibody response against salivary gland antigens from Oestrus ovis L. larvae (Diptera: Oestridae) in experimentally and naturally infected goats

The aims of this study were to analyze the systemic IgG responses against third-instar salivary gland (L3SG) antigens by ELISA in Oestrus ovis experimentally infected kids (EIK) and in naturally exposed adult goats (NEG). Firstly, kids (n=4 per group) were assigned to receive intranasally 0, 12, 24, 36, and 48 first-instars in experimental infections. Blood samples were taken from EIK at Days 0, 14, 42 and 67 post-infection. At necropsy (Day 67), larval number and developmental instars were recorded. In an epidemiological study, blood serum samples were collected from 448 grazing NEG (n=20 flocks) in Baja California Sur, Mexico. Results showed that larval establishment rate was similar in EIK groups. Systemic IgG response reached the threshold after Day 42, but humoral response was not statistically different among EIK groups receiving experimental infections. In NEG, all surveyed flocks (100%) showed specific systemic IgG antibodies to L3SG antigens and the overall goat oestrosis prevalence was 59.2%. In conclusion, larval L3SG antigens were effective in detection of specific systemic IgG antibodies against O. ovis infected kids and goats by ELISA.

Analysis of a computational problem involving complex voxel geometries

This communication briefly summarises the results obtained from the 'International comparison on MC modeling for in vivo measurement of Americium in a knee phantom' organised within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) as a joint initiative of EURADOS working groups 6 (computational dosimetry) and 7 (internal dosimetry). Monte Carlo simulations using the knee voxel phantom proved to be a viable approach to provide the calibration factor needed for in vivo measurements.

[Continuous subarachnoid analgesia and anesthesia for labor and cesarean section in a patient who had previously undergone surgery for ependymoma]

We report the case of a 38-year-old primipara who had undergone surgery 2 years earlier for an intradural ependymoma at L2-L3 and who was currently asymptomatic. A combined epidural-subarachnoid block was performed for analgesia during labor but this technique was only effective for the first 2 hours. When analgesia via epidural cannula was no longer adequate, it was decided to perform a continuous subarachnoid block. Later, the fetus's head was seen to be too large to fit through the pelvis; for cesarean section, the mother was administered fractionated doses of local anesthetic via the subarachnoid cannula until analgesia reached T4. The patient did not develop postdural puncture headache. Continuous subarachnoid anesthesia may be considered the technique of choice where the patient has a history of spinal surgery.

[Air embolism during elective cesarean section, and uterine atony due to fetal macrosomia]

We report the case of a paradoxical air embolism during a scheduled cesarean section for fetal macrosomia (7.010 kg) in a 38-year-old woman with a history of gestational diabetes and preeclampsia. Spinal anesthesia was satisfactory and well tolerated. After approximately 30 minutes (coinciding with uterine exteriorization), the patient presented a sudden episode of dyspnea, confusion, hypotension, and ST segment depression. The episode lasted approximately 10 minutes and resolved spontaneously with no sequelae. Neurological status and the electrocardiogram were normal at the end of surgery and no postoperative lesions were observed. In the immediate postoperative period, the patient presented a massive hemorrhage due to uterine atony. Echocardiography revealed a patent foramen ovale. The clinical signs in this patient are highly suggestive of a paradoxical cerebral and coronary air embolism.

[Remifentanil bolus for cesarean section in high-risk patients: study of 12 cases]

OBJECTIVES

To evaluate the utility and safety of remifentanil for hemodynamic control during cesarean section in high-risk patients ineligible for spinal anesthesia.

METHODS

One minute before induction we injected a bolus of 1 microg x kg(-1) of remifentanil, followed by propofol (2.5 mg x kg(-1)), succinylcholine (1 mg x kg(-1)), cisatracurium, sevoflurane in oxygen and nitrous oxide, and fentanyl (5 microg x kg(-1)) after clamping the umbilical cord. We recorded maternal hemodynamic variables, pulse oximetry, capnography, bispectral index, and presence of muscular rigidity. In the neonate we assessed fetal wellbeing, weight, and requirement for naloxone. Hemodynamic stability was defined as no more than 15% variation in arterial pressure with respect to baseline.

RESULTS

Twelve patients undergoing surgery because of placenta abruptio, subarachnoid hemorrhage, HELLP syndrome, or preeclampsia were enrolled. Hemodynamic variables were consistently stable during surgery in all patients. No cases of neonatal rigidity were noted and there was no need for naloxone. The mean Apgar score was 6.42 (1.5) at 1 minute and 8.42 (0.9) at 5 minutes.

CONCLUSION

Bolus injection of 1 microg x kg(-1) of remifentanil may be useful for maintaining maternal hemodynamic stability in high-risk obstetric cases. Given the risk of neonatal depression, this resource should be used selectively and the means for neonatal resuscitation should be available.

[Experience with uterine artery embolization in the treatment of massive postpartum hemorrhage]

OBJECTIVE

To analyze our experience with uterine artery embolization in the management of massive hemorrhage in obstetric patients.

PATIENTS AND METHODS

This observational, retrospective study analyzed all deliveries requiring a blood transfusion that were performed in the maternity unit of Hospital Universitario La Paz between January 1, 2000 and December 31, 2005.

RESULTS

A total of 57,835 deliveries were performed with an incidence of postpartum hemorrhage of 0.7% (406 episodes). Uterine artery embolization was performed on 51 patients and 45 patients underwent obstetric hysterectomy. Both procedures were performed on 11 patients. Ten of the patients who underwent obstetric hysterectomy subsequently required uterine artery embolization, whereas only 1 patient required an obstetric hysterectomy following embolization because the hemorrhage was not resolved. The mean consumption of blood products for patients who underwent obstetric hysterectomy was twice that for patients who underwent uterine artery embolization. There were no complications secondary to embolization.

CONCLUSIONS

Uterine artery embolization is a safe and effective procedure for managing massive postpartum hemorrhage.

[Cesarean section in a woman with acute blood-stage malaria]

Malaria infection during pregnancy is a serious health problem in most of the world's tropical regions. The disease has also been imported into Western countries, however, as an increasing number of infected women, who may become pregnant, emigrate from areas where malaria is endemic. Infection during pregnancy can have serious repercussions for both mother and fetus. Early diagnosis and multidisciplinary management are essential. We report the case of a woman from Guinea who debuted with severe, acute blood-stage malaria in the 32nd week of pregnancy and was admitted to the recovery care unit.

[Emergency cesarean in a patient with Coffin-Siris syndrome]

Coffin-Siris syndrome is a rare genetic disease characterized by coarse facial features, sparse scalp hair, hirsutism, hypoplasia of the distal phalanges, hypoplastic nail in the fifth digit, and mental retardation and delayed growth evident in both weight and height. Most cases are sporadic, but the possibility of recessive or dominant autosomal inheritance has been suggested. Facial abnormalities that make intubation difficult and mental retardation that interferes with cooperation are aspects of this disease that can affect the choice of type of anesthesia. We report the case of a parturient with Coffin-Siris syndrome who refused epidural analgesia for labor pain and for whom the obstetrician later decided that an emergency cesarean was necessary due to fetal distress.

A specific voxel phantom for in vivo measurements of 241Am in the knee

Calibration phantoms for in vivo measurements of low-energy photons should be anatomically realistic to minimise the uncertainties in the activity assessment. The calibration of the detection system can be performed using computational techniques based on numerical phantoms. The purpose of this work is to approach a numerical calibration by Monte Carlo (MC) technique of a Germanium detection system for the determination of 241Am in the knee. A specific voxel phantom was built from a computerised tomography of the calibration Spitz knee phantom. The phantom and the procedure to generate the associated input file for the MC code, namely MCNPX, have been described, as well as the characterisation of the detectors according to the manufacturer data and the energy calibration curves of the spectrometer. The detection efficiency and the pulse-height distribution have been determined for a homogeneous contamination of 241Am in bone.

Monte Carlo based voxel phantoms for in vivo internal dosimetry

The purpose of this communication is to describe briefly the computer programs developed to generate the MCNP input file corresponding to any segmented tomographic data and its application to the calibration procedures for in vivo internal dosimetry. The method has been applied to the determination of 241Am in bone by measurement in skull and knee using MCNP voxel models of a real human head and knee based on the tomographic Voxelman and Arms Down phantoms developed by Zubal et al. at Yale University.

Monte Carlo modelling for in vivo measurements of Americium in a knee voxel phantom: general criteria for an international comparison

The general criteria and the scientific approach adopted for an 'International comparison on Monte Carlo modelling for in vivo measurement of Americium in a knee phantom' that is being organised within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) are described her. Detection system and a knee voxel phantom based on a computerised axial tomography of the Spitz anthropometric knee phantom with a homogeneous distribution of 241Am in bone have been considered for the simulation of three specific situations: (a) a single Low Energy Germanium detector for a point 241Am source in air; (b) the calculation of photon fluence spectra in air around the voxel phantom; and (c) the calculation of the energy distribution of pulses and peak detection efficiency in the real detection system geometry.

Assessment of the internal dose of 241Am in bone by in vivo measurements of activity deposited in knee

In case of chronic exposure or long time after an acute intake of (241)Am as a consequence of an incident, the assessment of internal dose might be realised by estimating the total activity content of this element in the skeleton. For this purpose, a new methodology has been developed at the Whole Body Counting Laboratory of CIEMAT. In vivo measurements of this bone-seeker radionuclide in the knee are performed using four low energy germanium detectors inside a shielded room. The sensitivity study of this technique resulted in a minimum detectable activity of 7 Bq, for a counting time of 1800 s. Extrapolation to the total activity in the bone has been carried out by taking into account that the bone content of the knee calibration phantom is equivalent to 10.7% of the whole skeleton mass. The results of in vivo measurements of population and the procedure for internal dose evaluation are presented here.

Multiple origins of cultivated grapevine (Vitis vinifera L. ssp. sativa) based on chloroplast DNA polymorphisms

The domestication of the Eurasian grape (Vitis vinifera ssp. sativa) from its wild ancestor (Vitis vinifera ssp. sylvestris) has long been claimed to have occurred in Transcaucasia where its greatest genetic diversity is found and where very early archaeological evidence, including grape pips and artefacts of a 'wine culture', have been excavated. Whether from Transcaucasia or the nearby Taurus or Zagros Mountains, it is hypothesized that this wine culture spread southwards and eventually westwards around the Mediterranean basin, together with the transplantation of cultivated grape cuttings. However, the existence of morphological differentiation between cultivars from eastern and western ends of the modern distribution of the Eurasian grape suggests the existence of different genetic contribution from local sylvestris populations or multilocal selection and domestication of sylvestris genotypes. To tackle this issue, we analysed chlorotype variation and distribution in 1201 samples of sylvestris and sativa genotypes from the whole area of the species' distribution and studied their genetic relationships. The results suggest the existence of at least two important origins for the cultivated germplasm, one in the Near East and another in the western Mediterranean region, the latter of which gave rise to many of the current Western European cultivars. Indeed, over 70% of the Iberian Peninsula cultivars display chlorotypes that are only compatible with their having derived from western sylvestris populations.

[Human Metapneumovirus (hMPV) associated to severe bronchial asthmatic crisis]

Human Metapneumovirus (hMPV) is a recently reported agent of acute infection in the respiratory tract. It has been found in children as well as in young adults and elders. The clinical manifestations produced by hMPV are indistinguishable from those by common respiratory virus, and can evolve from asymptomatic infection into severe pneumonia. On the other hand, some authors have described cases of bronchial asthma exacerbation associated with hMPV infection. In this work we report a case of a child who presented a severe bronchial asthmatic crisis with a suspected viral associated infection. Immunofluorescence tests yielded negative results for sincitial respiratory virus, adenovirus, a-b influenza virus and parainfluenza 1, 2, 3, virus. In an attempt to detect the presence of hMPV, a RT-PCR was carried out to amplify sequences from both N and F genes. Using this approach, a positive result for hMPV was obtained. To our knowledge, this is the first description of a case of asthma exacerbation associated to hMPV in our region. In addition, these results are similar to previous reports where it was hypothesized that, like RSV, hMPV can trigger a respiratory chronic disease as asthma.

Intensificación de dosis con radioterapia conformacional 3D en cáncer de próstata. ¿Más dosis es mejor?

PURPOSE

The present study was undertaken to determine the effect of radiation dose on biochemical control and morbidity in prostate cancer patients.

MATERIALS AND METHODS

Between 1995 and 2003, 360 patients with T1-T3b prostate cancer were treated in a sequential radiation dose escalation trial from 66.0 to 82.6 Gy. These patients were prospectively assigned to 1 of 3 prognostic groups according to risk factors: a) low risk patients were treated with 3DCRT alone; b) intermediate risk patients were allocated to receive neoadjuvant AD (NAD) 4-6 months prior and during 3DCRT; and c) high-risk received NAD and adjuvant AD (AAD) 2 years after 3DCRT. RTOG/EORTC toxicity score was used to analyze late complications

RESULTS

Median follow-up was 48 months (12-138). The actuarial biochemical disease free survival (bDFS) at 4 years for low risk, intermediate risk and high risk patients was 88%, 68% and 79% respectively. Stratified and multivariate analysis showed that higher radiation dose (>76 Gy) (p=0.0053) and the use of AAD for high risk patients (p=0.0046) correlated significantly with an improvement of bDFS for all patients. The incidence of late grade 2 rectal and urinary bleeding were 7% and 11% respectively.

CONCLUSION

The present study confirms an independent benefit of high-dose (> 76 Gy) radiation therapy and long-term AAD in high-risk prostate cancerpatients.

Effect of wollastonite ceramics and bioactive glass on the formation of a bonelike apatite layer on a cobalt base alloy

A biomimetic method was used to promote a bioactive surface on a cobalt base alloy (ASTM F-75). The metallic substrates were alkali treated and some of the samples were subsequently heat treated. The treated samples were immersed in simulated body fluid (SBF) on granular particles of either bioactive glass or wollastonite. For comparative purposes, no bioactive system was used in some tests. Three different methods were used for the immersion of the samples in SBF: 1) 21 days in SBF, 2) 21 days in 1.5 SBF, and 3) 7 days in SBF followed by 14 days in 1.5 SBF (re-immersion method). A bonelike apatite layer was formed on all the samples placed on wollastonite and bioactive glass particles. The morphology of the apatite layer formed by using the re-immersion method and wollastonite closely resembled the existing bioactive systems. No apatite layer was observed on the samples treated without bioactive material and soaked for 21 days in SBF or 1.5 SBF, apart from the substrates treated by using the re-immersion method. The heat treatment delayed the apatite formation in all the cases studied.

Influence of chronic ethanol consumption on the muscarinic cholinergic control of rat pancreatic acinar cells

There are a number of hypothetical explanations for the actions of ethanol on the exocrine pancreas; among them, the cholinergic hypothesis has received special attention. According to this hypothesis, chronic alcohol consumption induces alterations in the control of exocrine pancreatic function resulting in cholinergic hyperstimulation of pancreatic acinar cells and their muscarinic receptors. Our aim was to investigate the cholinergic control of pancreatic enzyme secretion and the number and affinity of muscarinic receptors in the pancreatic acinar cells of rats subjected to chronic ethanol ingestion. We also investigated whether a high-fibre diet modifies the actions of ethanol on these aspects of the exocrine pancreatic function. Four groups of rats received either a standard or a high fibre diet, and either water or 20% (v/v) ethanol. After 6 months of treatment, isolated pancreatic acini were used for the determination of carbachol-stimulated amylase secretion and for the analysis of muscarinic receptors, using 1-[N-methyl-3H]scopolamine as a radioligand. Neither chronic ethanol intake nor a high fibre diet caused any apparent alteration in pancreatic histology, neither did them modify plasmatic amylase levels. Chronic alcoholization resulted in a significant increase in the amylase released from pancreatic acini in response to carbachol stimulation, but it did not affect either the number or the affinity of pancreatic acinar muscarinic receptors. The actions of ethanol are not significantly modified by the simultaneous consumption of a high fibre diet.

Nitric oxide stimulates tyrosine phosphorylation of p125(FAK) and paxillin in rat pancreatic acini

Some of the effects of several oncogenes, integrins, growth factors, and neuropeptides are mediated by tyrosine phosphorylation of the non-receptor tyrosine kinase p125(FAK) and the cytoskeletal protein paxillin. We have demonstrated that different stimuli cause tyrosine phosphorylation of p125(FAK) and paxillin in rat pancreatic acini. The aim of the present study was to determine whether exogenous NO activates this pathway. We demonstrate that in isolated rat pancreatic acini, a NO donor, sodium nitroprusside (SNP) stimulates, in a dose- and time-dependent way, tyrosine phosphorylation of p125(FAK) and paxillin. The same effects could be observed after incubating acini with 8-Br-cGMP. Moreover, the stimulation caused by SNP was completely abolished by two different guanylyl cyclase inhibitors, methylene blue, and LY-83583. These inhibitors also diminished unstimulated phosphorylation of p125(FAK) and paxillin. We conclude that in rat pancreatic acini exogenous NO causes p125(FAK) and paxillin tyrosine phosphorylation that is mediated by a guanylyl cyclase-dependent pathway.

Electrochemical immunosensor for the detection of atrazine

An amperometric immunosensor for the detection of the herbicide atrazine has been developed. A redox polymer PVPOs(bpy)2Cl was co-immobilized with the specific antibody on the surface of the electrode by crosslinking with PEGDGE to form an electron-conducting hydrogel. In a competitive assay the occurrence of the antibody-antigen reaction on the surface of the sensing film was detected through the 'electrical wiring' of the redox centres of antigen-labelled horseradish peroxidase and the electrode surface in the presence of H2O2 at 0.1 V (vsAg/AgCl).

[Comparative study between 5% prilocaine and 2% mepivacaine by the subarachnoid route in transurethral resections]

OBJECTIVE

To compare the duration of spinal block with 5% prilocaine and 2% mepivacaine in short procedures for transurethral resection and to assess possible complications in the immediate postoperative period.

MATERIAL AND METHODS

Fifty-seven patients scheduled for transurethral resection of the prostate or a vesical tumor. Patients were ASA I-III, over 55 years of age and randomly assigned to two groups to receive 5% prilocaine (1 mg/kg, n = 27) or 2% mepivacaine (0.8 mg/kg, n = 30). We collected data on anesthetic technique, levels of extension of motor and sensory blockades, duration of blockades and complications within the first 24 hours after surgery.

RESULTS

Demographic data, ASA classification and duration of surgery were similar in both groups. We found statistically significant differences (p < 0.05) in duration of sensory blockade (120.92 +/- 36.21 min with prilocaine and 145.83 +/- 35.81 min with mepivacaine) and in motor blockade (106.29 +/- 38.16 min with prilocaine and 133.16 +/- 42.21 min with mepivacaine). Five cases of hypotension and 4 of bradycardia occurred in each group and one patient in the mepivacaine group suffered slight postoperative cephalea.

CONCLUSIONS

Both local anesthetics offer good surgical conditions with hemodynamic stability and few complications. The duration of sensory and motor blockade is shorter with prilocaine than with mepivacaine, making prilocaine more appropriate for short interventions.

A rapid procedure to prepare cefotaxime

A rapid procedure is reported for the synthesis of cefotaxime, by acylation of the 7-amino cephalosporanic acid with the 2-mercaptobenzothiazolyl thioester of (Z)-2-[2-aminothiazol-4-yl]-2-methoxyimino acetic acid (MAEM) that is a commercial reagent. The reaction was carried out at room temperature for 1 h, obtaining 95% yield. 2-Mercaptobenzothiazole was recovered as a side-product with a high purity and yield. The proposed method differentiates from those reported previously for a shorter time and very mild reaction condition, as well as for a ready for use reagent.

High prevalence of the thermolabile methylenetetrahydrofolate reductase variant in Mexico: a country with a very high prevalence of neural tube defects

Neural tube defects (NTD) are highly prevalent in the Mexican population. According to data from the Registry and Epidemiological Surveillance of External Congenital Malformations (RYVEMCE), at least 1 in 250 conceptions that reach 20 weeks of pregnancy or more has a NTD. This number is three to four times higher than that observed in other related ethnic groups. A common novel mutation (C677T) in the methylenetetrahydrofolate reductase (MTHFR) gene is considered an associated risk factor for NTD and other malformations. Studies in different populations agree that the prevalence of the homozygote for the mutated allele is higher in cases of NTD than in controls. In a meta-analysis recently published, the mean prevalence of the homozygote for the mutation was 9.2% for different groups of European controls and 16.4% in NTD cases from the same populations. This prompted us to investigate the frequency of the normal (C) and the mutant (T) alleles and the prevalence of the expected (CC, CT and TT) genotypes in 250 healthy Mexican women from different parts of the country. The proportion of CC (17.6%), CT (47.6%), and TT (34. 8%) genotypes found, and the gene frequencies of 0.414 and 0.586% for the C and T alleles, respectively, confirmed the very high prevalence of the mutant allele and the TT genotype in the sample studied. Comparisons with studies done in Holland, Ireland, the United States, Japan, and other ethnic groups showed highly significant differences, with an average OR of 5.8 (95% Cl 3.4-10.3) for a Mexican being homozygous for the mutation. These findings may explain an important part of the high prevalence of NTD observed in our population.

[Effect of finasteride on the percentage of free PSA: implications in the early diagnosis of prostatic cancer]

OBJECTIVE

To analyze the behaviour of free PSA percentage in finasteride-treated patients and to evaluate whether this ratio allows an increased PSA specificity in the early diagnosis of prostate cancer.

MATERIAL AND METHODS

Evaluation of PSA serum levels and free PSA ratio in 336 patients initially diagnosed with prostate benign hyperplasia (PBH). A group of 82 patients were treated with finasteride for 14 to 58 months. A second group of 254 patients received no treatment. All patients were within the same age range and had similar PSA serum levels. In total, 141 prostate biopsies were performed: 19.5 (16/82) and 49.1 (125/254) respectively.

RESULTS

Median PSA level in PBH patients was 1.6 ng/mL for the finasteride-treated group and 3.5 for the untreated group, p < 0.0001. Free PSA ratio was 18.6 and 18.8%, respectively, p > 0.05. Carcinoma detection rate was 25% (4/16) for the finasteride group and 27.2% (34/125) for the untreated group. If biopsy had been requested when PSA percentage was below 25%, 17.7 and 19.8% respectively would have been prevented and all carcinoma detected.

CONCLUSION

Long-term treatment with finasteride reduces PSA serum concentration about 50% without changing the free PSA ratio. Carcinoma detection rate was similar in finasteride-treated and untreated patients. Free PSA ratio allows to increase PSA specificity and avoid unnecessary biopsied also in finasteride-treated patients.

Blood bank leukocyte infusions as remission induction therapy in a case of acute lymphoblastic leukemia

A 15-year-old female with pre-pre B ALL in third relapse was treated with administration of eight blood bank leukocyte concentrates per day for 5 days. The total number of mononuclear cells per kilogram of weight was 4.89 x 10(8). On the fifth day of infusions the patient was in complete remission (CR), asymptomatic and with a normal CBC. No secondary effects were found. The patient remained in CR without treatment for 10 weeks before relapsing again. The possibility of reaching a short-lived, clinically relevant response, using blood bank leukocyte infusions, is a promising new approach for the treatment of leukemia.

Relationship between viral genotype and viral load in patients with chronic hepatitis C

To determine the distribution of hepatitis C virus (HCV) genotypes and to related genotype to viral load, genotyping and quantification of viral RNA were carried out in 35 patients with chronic hepatitis C. Subtype 1a was most prevalent (43%), followed by subtypes 1b (23%) and 3a (14%). Mean viral load (log HCV-RNA copies/ml) for subtypes 1b, 1a and 3a was 7.1 +/- 1, 5.6 +/- 1.1 and 4.1 +/- 2.4, respectively. The presence of immunoglobulin M was related to the duration of hepatitis and genotype 1 to a more severe hepatic injury and higher viral load. Differences observed in viral load for a single HCV subtype justify the need to quantify HCV-RNA prior to establishing antiviral therapy.

Impairment of intracellular calcium homoeostasis in the exocrine pancreas after caerulein-induced acute pancreatitis in the rat

1. We have measured intracellular calcium concentrations in basal conditions and in response to cholecystokinin-octapeptide and acetylcholine in pancreatic acini isolated from rats with caerulein-induced acute pancreatitis and compared them with those in control rats. 2. We also measured amylase secretion in basal conditions and in response to cholecystokinin-octapeptide in both groups. 3. In pancreatic acini from rats with pancreatitis the basal intracellular calcium concentration was significantly increased (134.9 +/- 7.1 nmol/l compared with 71.8 +/- 2.9 nmol/l, P < 0.001). Moreover, the maximum values of intracellular calcium attained during the stimulation period were equivalent in acini from control and pancreatitic rats with no statistically significant differences. 4. In acini from control rats the differences between the resting levels of intracellular calcium and the maximum intracellular calcium values (delta[Ca2+]i) in response to several concentrations of cholecystokinin-octapeptide showed a clear dose-response relationship, with a half-maximal increase at 0.1 nmol/l and a maximal difference (delta[Ca2+]i = 259 +/- 50 nmol/l) at 1 nmol/l. In contrast, a right-shifted response, with a statistically significant smaller increase, was observed in acini from pancreatitic rats. 5. Basal amylase release was significantly higher in acini from rats with pancreatitis (11.7 +/- 1.0% of total compared with 5.9 +/- 1.1% of total, P < 0.001). In contrast, cholecystokinin-octapeptide and acetyl-choline-evoked amylase secretion was reduced by more than 85% in acini from pancreatitic rats. 6. In conclusion, calcium homoeostasis in pancreatic acinar cells from rats with caerulein-induced pancreatitis seems to be impaired. These results suggest excessive release of acinar free ionized calcium, or damage to the integrity of mechanisms that restore low resting levels of intracellular free ionized calcium, and the consequent calcium toxicity could be the key trigger in caerulein-induced acute pancreatitis.

Dose-response effects of VIP on the rabbit exocrine pancreatic secretion. Comparison with PACAP-27 actions

A dose-response study of the effects of vasoactive intestinal peptide (VIP) on the exocrine pancreatic secretion of the rabbit has been made. Furthermore, the actions of VIP and pituitary adenylate cyclase activating peptide (PACAP) on the exocrine pancreatic secretion were compared at a similar molar dose. After the infusion of VIP a linear dose-response relationship for pancreatic flow rate and bicarbonate output, up to the dose of 4 micrograms/kg, was observed. VIP acts as a partial agonist of secretin, the rabbit pancreas being less sensitive to VIP compared with other mammals. Moreover, VIP did not significantly stimulate the pancreatic protein output. PACAP stimulated the hydroelectrolyte fraction of the exocrine pancreatic secretion in a similar manner to that of VIP. Unlike what was observed with VIP, PACAP, on the same molar basis, significantly stimulated the protein and amylase outputs. Furthermore, PACAP releases VIP, so that the action of PACAP on the hydroelectrolyte fraction may be partially mediated by VIP; on the other hand, VIP is not involved in the effect of PACAP on the pancreatic enzyme secretion of this species.

Cholinergic pathways are involved in secretin and VIP release and the exocrine pancreatic response after intraduodenally perfused acetic and lactic acids in the rat

The response of the exocrine pancreas to intraduodenal perfusion of acetic and lactic acids in normal and previously atropinized rats was studied. Secretin and vasoactive intestinal peptide (VIP) plasma levels in portal plasma were also measured. Intraduodenal perfusion of both acetic and lactic acids significantly stimulated flow rate (from 0.29 +/- 0.03 microliters/min to a maximum of 1.06 +/- 0.08 microliters/min after acetic and from 0.35 +/- 0.05 microliters/min to a maximum of 1.13 +/- 0.12 microliters/min after lactic acid perfusion) and protein output (from 11.16 +/- 2.33 micrograms/min to a maximum of 35.1 +/- 7.4 micrograms/min after acetic and from 8.98 +/- 0.95 micrograms/min to a maximum of 22.5 +/- 1.3 micrograms/min after lactic acid perfusion). Atropine treatment significantly inhibited pancreatic flow rate and protein output after acetic acid perfusion, but no inhibition of flow rate and a slight decrease in the protein output after lactic acid perfusion were seen. With respect to plasma peptide concentrations, significant increases in secretin and VIP levels were found after perfusion of both organic acids; atropine administration significantly decreased plasma secretin levels after acetic acid administration although it did not affect plasma VIP concentrations. By contrast, atropine significantly increased plasma secretin levels, but significantly lower values of plasma VIP concentrations were observed after lactic acid perfusion. Therefore, cholinergic mechanisms are involved in the release of secretin and VIP and different types of control of exocrine pancreatic secretion occur, depending on the features of the intraduodenal stimulant.