[Virtual reality and digital biomarkers: a clinical tool for early autism diagnosis]

INTRODUCTION

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition which traditional assessment procedures encounter certain limitations. The current ASD research field is exploring and endorsing innovative methods to assess the disorder early on, based on the automatic detection of biomarkers. However, many of these procedures lack ecological validity in their measurements. In this context, virtual reality (VR) shows promise for objectively recording biosignals while users experience ecological situations.

METHODS

This study outlines a novel and playful VR procedure for the early assessment of ASD, relying on multimodal biosignal recording. During a VR experience featuring 12 virtual scenes, eye gaze, motor skills, electrodermal activity and behavioural performance were measured in 39 children with ASD and 42 control peers. Machine learning models were developed to identify digital biomarkers and classify autism.

RESULTS

Biosignals reported varied performance in detecting ASD, while the combined model resulting from the combination of specific-biosignal models demonstrated the ability to identify ASD with an accuracy of 83% (SD = 3%) and an AUC of 0.91 (SD = 0.04).

DISCUSSION

This screening tool may support ASD diagnosis by reinforcing the outcomes of traditional assessment procedures.

The whole-body motor skills of children with autism spectrum disorder taking goal-directed actions in virtual reality

Many symptoms of the autism spectrum disorder (ASD) are evident in early infancy, but ASD is usually diagnosed much later by procedures lacking objective measurements. It is necessary to anticipate the identification of ASD by improving the objectivity of the procedure and the use of ecological settings. In this context, atypical motor skills are reaching consensus as a promising ASD biomarker, regardless of the level of symptom severity. This study aimed to assess differences in the whole-body motor skills between 20 children with ASD and 20 children with typical development during the execution of three tasks resembling regular activities presented in virtual reality. The virtual tasks asked to perform precise and goal-directed actions with different limbs vary in their degree of freedom of movement. Parametric and non-parametric statistical methods were applied to analyze differences in children's motor skills. The findings endorsed the hypothesis that when particular goal-directed movements are required, the type of action could modulate the presence of motor abnormalities in ASD. In particular, the ASD motor abnormalities emerged in the task requiring to take with the upper limbs goal-directed actions with low degree of freedom. The motor abnormalities covered (1) the body part mainly involved in the action, and (2) further body parts not directly involved in the movement. Findings were discussed against the background of atypical prospective control of movements and visuomotor discoordination in ASD. These findings contribute to advance the understanding of motor skills in ASD while deepening ecological and objective assessment procedures based on VR.

[Adaptive technological interventions for autism spectrum disorder: a literature review]

Individuals with autistic spectrum disorder are often described as having communication, social, emotional, nd behavioral impairments. They are often isolated and passive, with few opportunities for positive and constructive interaction with the outside world. Moreover, they may exhibit withdrawn, stereotyped and disruptive behaviors. The aforementioned conditions can seriously hamper their ability to adapt to the environment, with negative consequences on their quality of life. Phenotypic heterogeneity and manifestation, as well as symptom severity, can vary greatly from child to child. These determine the need for individualized and adaptive interventions according to specific needs, including factors such as age, intellectual ability, and specific affected areas. Early intervention would promote adaptive skills, self-determination, and autonomy towards the environment. However, wait times and costs do not allow for early assessment, and therefore intervention times are delayed, affecting the quality of life of children and parents. In addition, traditional intervention programs depend on the expertise of the therapists. One possible way to overcome this problem is by using objective adaptive technologies based on needs. This article aims to provide an overview of the empirical evidence available over the past seven years. Overall, 8 studies were selected, with 132 participants using 4 technological systems. Finally, the technological, clinical, psychological, and rehabilitative implications of the findings are discussed. Practical guidelines within this topic area are outlined as future research perspectives.

Eye gaze as a biomarker in the recognition of autism spectrum disorder using virtual reality and machine learning: A proof of concept for diagnosis

The core symptoms of autism spectrum disorder (ASD) mainly relate to social communication and interactions. ASD assessment involves expert observations in neutral settings, which introduces limitations and biases related to lack of objectivity and does not capture performance in real-world settings. To overcome these limitations, advances in technologies (e.g., virtual reality) and sensors (e.g., eye-tracking tools) have been used to create realistic simulated environments and track eye movements, enriching assessments with more objective data than can be obtained via traditional measures. This study aimed to distinguish between autistic and typically developing children using visual attention behaviors through an eye-tracking paradigm in a virtual environment as a measure of attunement to and extraction of socially relevant information. The 55 children participated. Autistic children presented a higher number of frames, both overall and per scenario, and showed higher visual preferences for adults over children, as well as specific preferences for adults' rather than children's faces on which looked more at bodies. A set of multivariate supervised machine learning models were developed using recursive feature selection to recognize ASD based on extracted eye gaze features. The models achieved up to 86% accuracy (sensitivity = 91%) in recognizing autistic children. Our results should be taken as preliminary due to the relatively small sample size and the lack of an external replication dataset. However, to our knowledge, this constitutes a first proof of concept in the combined use of virtual reality, eye-tracking tools, and machine learning for ASD recognition. LAY SUMMARY: Core symptoms in children with ASD involve social communication and interaction. ASD assessment includes expert observations in neutral settings, which show limitations and biases related to lack of objectivity and do not capture performance in real settings. To overcome these limitations, this work aimed to distinguish between autistic and typically developing children in visual attention behaviors through an eye-tracking paradigm in a virtual environment as a measure of attunement to, and extraction of, socially relevant information.

Machine Learning and Virtual Reality on Body Movements' Behaviors to Classify Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is mostly diagnosed according to behavioral symptoms in sensory, social, and motor domains. Improper motor functioning, during diagnosis, involves the qualitative evaluation of stereotyped and repetitive behaviors, while quantitative methods that classify body movements' frequencies of children with ASD are less addressed. Recent advances in neuroscience, technology, and data analysis techniques are improving the quantitative and ecological validity methods to measure specific functioning in ASD children. On one side, cutting-edge technologies, such as cameras, sensors, and virtual reality can accurately detect and classify behavioral biomarkers, as body movements in real-life simulations. On the other, machine-learning techniques are showing the potential for identifying and classifying patients' subgroups. Starting from these premises, three real-simulated imitation tasks have been implemented in a virtual reality system whose aim is to investigate if machine-learning methods on movement features and frequency could be useful in discriminating ASD children from children with typical neurodevelopment. In this experiment, 24 children with ASD and 25 children with typical neurodevelopment participated in a multimodal virtual reality experience, and changes in their body movements were tracked by a depth sensor camera during the presentation of visual, auditive, and olfactive stimuli. The main results showed that ASD children presented larger body movements than TD children, and that head, trunk, and feet represent the maximum classification with an accuracy of 82.98%. Regarding stimuli, visual condition showed the highest accuracy (89.36%), followed by the visual-auditive stimuli (74.47%), and visual-auditive-olfactory stimuli (70.21%). Finally, the head showed the most consistent performance along with the stimuli, from 80.85% in visual to 89.36% in visual-auditive-olfactory condition. The findings showed the feasibility of applying machine learning and virtual reality to identify body movements' biomarkers that could contribute to improving ASD diagnosis.

Application of Supervised Machine Learning for Behavioral Biomarkers of Autism Spectrum Disorder Based on Electrodermal Activity and Virtual Reality

OBJECTIVE

Sensory processing is the ability to capture, elaborate, and integrate information through the five senses and is impaired in over 90% of children with autism spectrum disorder (ASD). The ASD population shows hyper-hypo sensitiveness to sensory stimuli that can generate alteration in information processing, affecting cognitive and social responses to daily life situations. Structured and semi-structured interviews are generally used for ASD assessment, and the evaluation relies on the examiner's subjectivity and expertise, which can lead to misleading outcomes. Recently, there has been a growing need for more objective, reliable, and valid diagnostic measures, such as biomarkers, to distinguish typical from atypical functioning and to reliably track the progression of the illness, helping to diagnose ASD. Implicit measures and ecological valid settings have been showing high accuracy on predicting outcomes and correctly classifying populations in categories.

METHODS

Two experiments investigated whether sensory processing can discriminate between ASD and typical development (TD) populations using electrodermal activity (EDA) in two multimodal virtual environments (VE): forest VE and city VE. In the first experiment, 24 children with ASD diagnosis and 30 TDs participated in both virtual experiences, and changes in EDA have been recorded before and during the presentation of visual, auditive, and olfactive stimuli. In the second experiment, 40 children have been added to test the model of experiment 1.

RESULTS

The first exploratory results on EDA comparison models showed that the integration of visual, auditive, and olfactive stimuli in the forest environment provided higher accuracy (90.3%) on sensory dysfunction discrimination than specific stimuli. In the second experiment, 92 subjects experienced the forest VE, and results on 72 subjects showed that stimuli integration achieved an accuracy of 83.33%. The final confirmatory test set (n = 20) achieved 85% accuracy, simulating a real application of the models. Further relevant result concerns the visual stimuli condition in the first experiment, which achieved 84.6% of accuracy in recognizing ASD sensory dysfunction.

CONCLUSION

According to our studies' results, implicit measures, such as EDA, and ecological valid settings can represent valid quantitative methods, along with traditional assessment measures, to classify ASD population, enhancing knowledge on the development of relevant specific treatments.

[Autism spectrum disorder biomarkers based on biosignals, virtual reality and artificial intelligence]

It has been observed that the stratification of Autism Spectrum Disorders (ASD) generated by the current scales is not effective for the personalization of early treatments. The clinical evaluation of ASD requires its consideration as a continuum of deficits, and there is a need to identify biologically significant parameters (biomarkers) that have the power to automatically characterize each individual at different stages of neurological development. The emerging field of computational psychiatry (CP) attempts to meet the needs of precision diagnosis by developing powerful computational and mathematical techniques. A growing scientific activity proposes the use of implicit measures based on biosignals for the classification of ASD. Virtual reality (VR) technologies have demonstrated potential for ASD interventions, but most of the work has used virtual reality for the learning / objective of interventions. Very few studies have used biological signals for recording and detailed analysis of behavioral responses that can be used to monitor or produce changes over time. In this paper the concept of behavioral biomarkers based on VR or VRBB is introduced. VRBB will allow the classification of ASD using a paradigm of computational psychiatry based on implicit brain processes measured through psychophysiological signals and the behavior of subjects exposed to complex replicas of social conditions using virtual reality interfaces.

[Use of virtual reality for neurodevelopmental disorders. A review of the state of the art and future agenda]

To date, the diagnostic tools for autism spectrum disorder (ASD) have been mostly based on qualitative criteria from observational information in contexts with low ecological validity. We are witnessing a growing scientific activity that proposes the use of implicit measures for the evaluation and diagnosis of ASD. These measures are based on processes of a biological and unconscious nature, underlying the capacity of human cognition, and are obtained through the acquisition and treatment of brain, physiological and behavioral responses in order to obtain the behavioral structure of the ASD patient facing a stimulus. The complex relationship between physiological responses and the behavioral structure of the ASD patient requires the use of advanced techniques of signal processing based on cognitive computation. Artificial intelligence (AI) techniques, such as machine learning and neurocomputing applied to the analysis of psychophysiological signals, have demonstrated their robustness for the classification of complex cognitive constructs. Virtual reality (VR) is a tool that allows recreating real-life situations with high sensory fidelity, but at the same time individually controlling each of the situations and stimuli that influence human behavior. It also allows the measurement in real time of human reactions to such stimuli. This document analyzes the latest scientific and technological advances relevant to its applications in the diagnosis of ASD. We conclude that VR is a very valuable tool for ASD research, especially for the evaluation and diagnosis of complex skills and competencies.

[Executive functioning and evoked potentials P300 pre- and post- treatment in attention deficit hyperactivity disorder]

INTRODUCTION

Evoked potentials P300 and the analysis of executive functions have shown their utility in the monitoring of patients with symptoms of attention deficit hyperactivity disorder (ADHD).

PATIENTS AND METHODS

Neuropsychological profiles and evoked potentials P300 have been analysed for two groups of children with an ADHD treatment with atomoxetine and methylphenidate respectively. Correlations between P300 and the selected neuropsychological parameters are studied, and the differences between basal values and 1 year follow-up are analysed. Two groups were performed: a group of 22 children ADHD in the atomoxetine condition, and a group of 24 children ADHD in the methylphenidate condition.

RESULTS

The results show a global improvement of all the parameters, in terms of executive function and P300 values in both, the atomoxetine and the methylphenidate group.

CONCLUSION

Executive functions and evoked potentials P300 reflect an underlying processing and they are very useful in the clinical practice. This exploratory study shows the importance of designing personalized objective variables-based treatments.

[Pharmacological update in attention deficit hyperactivity disorder: models of intervention and new drugs]

INTRODUCTION. Attention deficit hyperactivity disorder (ADHD) is the most frequent neurodevelopmental problem in childhood, with significant repercussions that continue into adulthood. This means that an appropriate therapeutic intervention is vital to improve its prognosis. AIMS. To identify the ideal pharmacological options according to the characteristics of the patient and to report on the new drugs. DEVELOPMENT. The work analyses how therapeutic interventions can be conditioned by the anatomical substrate of the brain, the biochemical bases, genetics, neurophysiological examinations, neuropsychological studies and the clinical symptoms and subtypes. A significant amount of importance is granted to neuropsychological studies, especially those dealing with the executive functions, including evaluation of attention, impulse control, and interference and cognitive flexibility. Taking into consideration the signal-to-noise characteristics can be useful when it comes to choosing the drug. CONCLUSIONS. The development of the pharmacological therapeutic options in ADHD opens up expectations concerning applicability and greater specificity in daily practice to fit the characteristics of each patient. Psychoeducation must always be included and a thorough study of each particular child is recommended. This should involve analysing the neuropsychological features of his or her brain function in order to be able to reflect on the ideal pharmacological option that allows more favourable progress.

[Models of intervention in children with autism]

INTRODUCTION

Autism spectrum disorders make up a group of neurodevelopmental disorders that globally affect different higher brain functions in the individual, such as intelligence, the capacity to use language and social interaction. Today, although there is still no curative treatment for autism, there are a number of non pharmacological interventions that can modify the poor prognosis that is generally associated to this type of disorders.

AIM

To briefly review the different approaches to the neuro rehabilitation of patients suffering from autism spectrum disorders, which are usually known as methods of intervention.

DEVELOPMENT

From the categorical point of view, three types of methods of intervention can be distinguished, depending on whether the orientation is psychodynamic, biomedical or psycho educational. It is difficult to compare the results of the different methods of intervention, but researchers have identified several common elements that they should have if they are to be effective. At present, the psycho educational methods are preferred, since they are the only ones that, to date, have proved to be effective in research studies.

CONCLUSIONS

Early intervention by diagnostic and early care centres, with the use of mixed models of psycho educational intervention that nevertheless also include an important percentage of behavioural elements, has proved to be capable of modifying the course of patients with autism spectrum disorders and is currently the most suitable approach.

[The advantages of neuropsychological examination batteries in attention deficit hyperactivity disorder]

INTRODUCTION

The neuropsychological assessment of the functions of attention and the executive functions in patients with clinical features compatible with a diagnosis of attention deficit hyperactivity disorder (ADHD) is considered a priority study to be able to offer a basic study. It is also necessary to be able to carry out a short- and long-term developmental follow-up of patients.

DEVELOPMENT

An algorithm for diagnosing ADHD is proposed that includes both traditional and computerised tests for assessing the functions of attention and the executive functions. The development of new neuropsychological batteries for this purpose involves the use of several tests in computerised form that offer technical and methodological advantages as regards their use and the later treatment of the data obtained.

CONCLUSIONS

The advantages of computerised assessment include management of answer times, minimum expression of the effect exerted by the researcher, savings in time, accurate and fast scoring, statistical management of new scores, and greater proximity to research programmes.

Effect of atorvastatin on bone mineral density in patients with acute coronary syndrome

OBJECTIVE

The aim of this paper is to evaluate the effect of atorvastatin on bone mineral density in patients with acute ischemic heart disease.

MATERIAL AND METHODS

Eighty-three patients (52 male and 31 female) with acute coronary syndrome were studied. They received treatment with atorvastatin using low doses (20 mg) and high doses (40 mg-80 mg). Initial and final cholesterol, triglyceride, calcium, phosphorus, 25-hydroxyvitamin D were obtained from every patient. Spine and hip bone mineral density were performed at the beginning and one year later.

RESULTS

Atorvastatin treatment increases vitamin D (33%, p = 0.007) and decreases the individuals with vitamin D insufficiency. Bone mineral density increased in the spine (1.31%, p = 0.02), but it was significant only in male and patients presenting vitamin D levels higher than 30 nmol/l.

CONCLUSION

Atorvastatin has a beneficial effect on bone metabolism in patients with acute ischemic heart disease (mainly males) by incrementing bone mineral density in which vitamin D levels are required to be higher than 30 nmol/l for the drug to be effective.

Tamoxifen and endometrial cancer. Is screening necessary? A review of the literature

Tamoxifen is a selective oestrogen receptor modulator (SERM) with anti-oestrogenic activity in the breast and oestrogenic effects in various tissues such as the endometrium, bone and cardiovascular territory. As adjuvant hormone therapy, it has a clear beneficial effect in patients with breast cancer, reducing relapses, contralateral breast cancer and mortality. Its most important secondary effect is a greater rate of occurrence of endometrial cancer. Although the risk/benefit ratio is clearly positive, the follow-up on these patients is still an issue. In women with metrorrhagia, it is clear that an endometrial sample must be obtained for histological examination and the best procedure today is hysteroscopic-directed biopsy. Nevertheless, the need to screen asymptomatic patients is not universally accepted. The vaginal ultrasound scan gives a great number of false positives. This entails more aggressive and more expensive procedures such as hysteroscopic-directed biopsy, meaning greater expense and more complications. As a result, the cost/benefit ratio is not very favourable. The rate of occurrence of endometrial cancer in 1026 tamoxifen-treated patients with breast cancer in our hospital between 1999 and 2001 was 1.25%. Two cases were diagnosed in asymptomatic patients. In this article, we analyse the literature on the need to screen patients on tamoxifen and about the most appropriate diagnostic protocol.

Symmetrical fetal growth retardation after gestational cocaine exposure in the rat

Cocaine use during pregnancy results in an increase in different maternal and perinatal complications. The fetal effects of cocaine could be mainly related to the disturbances in the brain development, microcephaly being the most common brain abnormality. The aim of this study was to analyze maternal outcome and fetal somatic effects of cocaine and to evaluate the hypothesis that maternal cocaine exposure would specifically impair fetal global brain development. Fifty-four timed-pregnant female Sprague-Dawley rats were daily injected with 15 or 40 mg/kg per day from gestational day (GD) 1 or 8 and sacrificed at gestational day 20. By analyzing different maternal and fetal outcomes, it could be suggested that the cocaine exposure in pregnant rats decreased maternal weight gain without significant maternal mortality, did not affect the mean number of fetuses by litter, although notably increased stillbirths, reduced fetal birth weight, and reduced the fetal central nervous system weight. Present results are globally in agreement with the literature and underline a possible selective effect of cocaine on the fetal CNS resulting in symmetrical intrauterine fetal growth retardation in contrast to the asymmetrical retardation of undernutrition.

[Levothyroxine poisoning: clinical manifestations and therapeutic management]

Intoxication with L-tyroxine has a low prevalence, high prevalence is observed in pediatric age. Toxic dose is unclear, asymptomatic patients have been observed with doses under 5 mg. Systems with high prevalence of symptoms are cardiovascular system, sympathetic nervous system and gastrointestinal tube. Symptoms could appear from hours to days after ingestion. Early hours after L-tyroxine ingestion, levels of T4 and T3 are not related with severity. However, monitoring seric levels is necessary to lead therapeutic approach and to give a prognosis. Daily determinations of T3, T4 and TSH are necessaries. Determinations of temperature, arterial pressure and blood heart rate are needed to control complications. Beta-blockers and intestinal decontamination drugs are used during therapeutic approach. Other therapeutic options are iopanoic acid and propylthiouracil. In summary, intoxication with L-tyroxine could be a severe situation. It is necessary to describe therapeutic protocols in this entity.

Light symptoms following a high-dose intentional L-thyroxine ingestion treated with cholestyramine

Adult exposure to L-thyroxine has a wide range of presentations: most adults either do not develop symptoms or only become minimally symptomatic. Appropriate treatments after exposure to L-thyroxine have yet to be established. A 26-year-old woman with a suicidal intention was witnessed to ingest approximately 50 L-thyroxine tablets, each containing 0.1 mg L-thyroxine (total dose 5 mg). Cholestyramine was administered (4 g every 8 h p.o.). Vital signs were monitored every 6 h and the hormone levels (L-thyroxine and thyroid-stimulating hormone) every 24 h. The thyroxine levels increased, and the thyroid-stimulating hormone levels decreased, with a normalization of the L-thyroxine level on postingestion day 6. Hypertension, dysrhythmias, and delusions did not appear in our patient. Only distal tremor and diaphoresis appeared on day 1 after ingestion. Cholestyramine has been used in cases of iatrogenic hyperthyroidism, in patients with Graves' disease, and in patients with digoxin intoxications, with good responses in all cases and a low incidence of side effects. This case illustrates the potential utility of cholestyramine to treat L-thyroxine intoxications.

[The course of behaviour changes in children with attention deficit and hyperactivity after drug treatment]

INTRODUCTION

Several studies have reported differences in behaviour in patients with various subtypes of attention deficit with hyperactivity and the benefits of psychostimulant medication in the treatment of behaviour problems of patients with the attention deficit hyperactivity syndrome (TDAH).

OBJECTIVES

1. To determine possible differences in behaviour between patients with subtypes of the attention deficit hyperactivity disorder; 2. To analyze the efficacy of methylphenidate on behaviour in three subtypes of TDAH, evaluated on the opinions of patients and teachers.

PATIENTS AND METHODS

A total of 90 children were studied: 39 children with TDAH-C; 36 with TDAH-1 and 15 with TDAH-H/I. All patients were given 0.5 mg/kg of methylphenidate for a period of three months, once in the morning and once in the afternoon.

RESULTS

The results show that the children with the three subtypes of TDAH have significant differences in all the behaviour variables studied except for the variable timidity anxiety, in which no differences were observed between the subtypes of TDAH. Statistical analysis also showed that children with all three subtypes of TDAH improved significantly with regard to most of the aspects of behaviour studied after psychostimulant medication, in the opinions of parents and teachers.

CONCLUSIONS

Our findings are similar to those of other studies and give fresh data on the behaviour and advantages of methylphenidate in the new subtype included in the DSM-1V, the predominantly hyperactive impulsive type.

Effect of angiotensin-converting enzyme inhibitor on renal function in ovarian hyperstimulation syndrome in the rabbit

OBJECTIVE

To investigate renal function and whether captopril prevents alterations in the handling of sodium and water in the ovarian hyperstimulation syndrome (OHSS) in the rabbit.

DESIGN

Experimental study

SETTING

Physiology laboratory.

ANIMAL(S)

Six female New Zealand white rabbits were used as controls, and 13 were hyperstimulated with gonadotropins.

INTERVENTION(S)

Saline or captopril.

MAIN OUTCOME MEASURE(S)

Renal excretory and hemodynamic variables.

RESULT(S)

The 3% extracellular volume expansion in OHSS animals induced a significant elevation in mean arterial pressure by 27%, although increments in natriuresis and diuresis were similar to those observed in controls. The OHSS group had impaired pressure-natriuresis sensitivity compared with controls (0.36 +/- 0.07 microEq/min/g of Na excreted per mm Hg vs. 1.74 +/- 0.45 microEq/min/g of Na excreted per mm Hg; P<.05. Captopril significantly reduced mean arterial pressure (P<.05) and shifted the pressure-natriuresis response to the left by 0.85 +/- 0.17 microEq/min/g of Na excreted per mm Hg (P<.05).

CONCLUSION(S)

In OHSS in the rabbit model, pressure-natriuresis sensitivity is impaired. Angiotensin II may play a significant role in this phenomenon, since angiotensin-converting enzyme inhibition normalized the pressure-natriuresis relationship.

[Scintigraphy with 99mTc-MIBI in the diagnosis of axillary lymph node invasion of breast cancer]

The presence of affected locoregional lymph nodes should be considered as one of the most important prognostic factors of breast cancer. At present, the clinician is conditioned by an absolute lack of an efficient methodology to evaluate the possible invasion of the axillary lymph nodes, which if negative, would make it possible to avoid surgical excision. In this study, we will evaluate the use of the 99mTc-MIBI scintigraphy in the pre-surgical diagnosis of axillary lymph node invasion and will analyze the relationship between the 99mTc-MIBI uptake and the number of lymph nodes affected.

MATERIAL AND METHODS

84 patients diagnosed of breast cancer were analyzed in this study. All of them underwent a 99mTc-MIBI scintigraphy, and the tumor/background ratio was determined semiquantitively for each image. The axillary lymph node invasion was determined following surgery.

RESULTS

The sensitivity of the breast scintigraphy with 99mTc-MIBI for detection of lymph node invasion is 36% and the specificity is 100%. The positive predictive value is 100% and the negative one 48%. In the current study, we failed to detect correlation between the intensity of 99mTc-MIBI uptake in the primary tumor and the number of affected axillary lymph nodes.

CONCLUSION

99mTc-MIBI breast scintigraphy can provide complementary information for the presurgical diagnosis of breast cancer axillary lymph node invasion. 99mTc-MIBI breast scintigraphy shows high specificity and a high predictive value.

[99m Tc-MIBI scintigraphy compared to mammography in the diagnosis of breast cancer in dense, operated and young women breasts]

Breast scintimammography with 99mTc-MIBI has proven to be a useful complement to mammography in the diagnosis of breast cancer in the female population. Although the mammography, along with a physical examination, is the backbone of breast cancer diagnosis, there are groups of patients in whom the mammography has an even lower specificity.

OBJECTIVE

Our study has aimed to assess the usefulness of breast 99mTc-MIBI scintimammography in those situations in which the mammography was indeterminate, such as, in dense breasts, young females or breasts with architectural distortion after surgery or radiation therapy.

MATERIALS AND METHODS

We studied 109 females with mammographically dense breasts, 8 young females under 30 and 24 patients who had undergone previous surgery or radiation therapy. All cases were studied to rule out breast cancer. Final diagnosis was established with excisional biopsy.

RESULTS

In dense breasts MIBI scintimammography sensitivity was 88% and the mammography one 81%. MIBI scintimammography specificity was 90% and the mammography 28%. In young females MIBI scintimammography sensitivity was 100% and the mammography 50%, MIBI scintimammography specificity 100% and the mammography 20%. In previous surgery, MIBI scintimammography sensitivity was 80% and the mammography 80%, MIBI scintimammography specificity 100% and the mammography 42%.

CONCLUSION

Breast scintimammography with 99mTc-MIBI is an excellent diagnostic technique with high specificity. Undoubtedly it is complementary to mammography in those cases where mammography has major limitations such as dense breasts, young females and breasts with severe scarring after surgery or radiation therapy.

[Usefulness of the quantification of (99M)Tc-MIBI uptake in breast neoplasms in the preoperative assessment of tumor aggressiveness]

(99m)Tc-MIBI has been proposed as an imaging diagnostic method in a large variety of human malignant tumors. At present, the mechanism by which (99m)Tc-MIBI is uptaken and concentrated by the malignant cells is not totally known. Some mammary neoplasms do not show any uptake of (99m)Tc-MIBI. This study aims to determine if there is any correlation between the uptake of (99m)Tc-MIBI by the tumor and the different histopathological parameters involved in tumoral aggressiveness. To do so, we have studied 100 patients with breast cancer. All of them underwent a breast scintimammography with (99m)Tc-MIBI with semiquantitative analysis by means of a tumor-to-background ratio calculated in every projection. After surgery, an experienced pathologist determined tumor size, axillary lymph node metastases, histological grade (Scarff Bloom Richardson) (SCBR), nuclear grade, mitotic index, presence of cellular atypia and estrogen and progesterone receptor expression.

RESULTS

A statistically significant correlation (p < 0.005) has been found between tumor-to-background (T/B) ratios of (99m)Tc-MIBI uptake and tumor SCBR histological grade. A correlation between (99m)Tc-MIBI uptake and the mitotic index, cellular atypia and nuclear grade has also been found. No correlation was found in our study with tumor size, hormone receptor expression or axillary lymph node metastases.

CONCLUSIONS

(99m)Tc-MIBI uptake in breast cancer is correlated with the tumoral differentiation grade: the smaller the tumoral cellular differentiation (greater aggressiveness), the greater the uptake. On the other hand, no correlation was found between the uptake of (99m)Tc-MIBI and the classical pathological parameters that define tumoral aggressiveness, such as size and axillary lymph node metastasis.

Vertebral osteomyelitis caused by Streptococcus agalactiae

Streptococcus agalactiae is a rare cause of vertebral osteomyelitis. We present four cases of spondylitis caused by this micro-organism and a review of 20 cases previously described in the literature. Only seven patients (29%) were under 50 years of age. Diabetes mellitus and neoplasms were the most frequent underlying conditions, although 37.5% of the patients did not have any predisposition. Neck or back pain was the most common symptom. Diagnosis depended mainly on magnetic resonance imaging. Blood cultures were positive in 50% of the patients. The duration of antibiotic therapy was 6 weeks for most patients. The outcome was favourable, with none of the patients suffering serious sequelae.

[Usefulness of quantification and visual analysis of the uptake of (99m)Tc-MIBI in the diagnosis of mammary lesions]

OBJECTIVE

Scintigraphy studies with (99m)Tc-MIBI are widely used in the diagnosis of non-invasive breast cancer and their results have been verified by many studies. However, the scintigraphic technique produces erroneous false negative and positive results. This study aims to verify how the different characteristics of the uptake of (99m)Tc-MIBI (intensity, size, morphology, etc.) can help to increase sensitivity and specificity of breast scintigraphy.

MATERIALS AND METHODS

We have studied 201 patients (84 breast cancer and 117 benign lesions). All of them underwent a breast scintigraphy with (99m)Tc-MIBI and anatomopathological study. A semiquantitative analysis (by T/F indexes) and visual study were performed in the lesions that presented radiodrug uptake.

RESULTS

Eleven false positive results and 8 false negative results were obtained in the study of the 201 patients. The analysis of the T/F indexes did not demonstrate any significant differences between the benign and malignant lesions (p>0,05). There is a statistically significant correlation (p<0.05) between the tracer uptake morphology and the AP diagnosis and between the localization of the lesion in a breast quadrant and the uptake intensity.

CONCLUSIONS

Quantification of (99m)Tc-MIBI uptake by T/F indexes does not provide any conclusive data on the lesion's malignancy, however, a more detailed analysis of the characteristics of the tracer uptake would permit us to make the correct diagnosis and would reduce the false positive and negative results of this technique.

Brucellar spondylitis: review of 35 cases and literature survey

Thirty-five patients aged 14-74 years (average, 54 years) who had brucellar spondylitis were treated between January 1991 and December 1997. The time from onset of symptoms to diagnosis of spondylitis ranged from 1 week to 8 months (median, 9 weeks). Back or neck pain (100% of patients), fever (66%), and constitutional symptoms (57%) were the most common symptoms. Cultures of blood specimens from 26 patients (74%) were positive for Brucella melitensis. The duration of antimicrobial therapy (median, 120 days; range, 45-535 days) varied according to clinical response and the presence of epidural and paravertebral masses. One of the 35 patients underwent surgical treatment of a spinal epidural abscess. Therapy failed for 9 patients (26%; 95% confidence interval [CI], 12%-43%), and 5 (14%; 95% CI, 5%-30%) had a relapse. There were no deaths or severe sequelae in this study. Brucellar spondylitis causes considerable suffering and absenteeism from work, but long-term clinical responses are favorable.

Effect of N-acetylcysteine on vascular endothelium function in aorta from oophorectomized rats

1. Experiments were performed to examine and to compare vascular endothelial function in aortic rings from oophorectomized and from ovary-intact rats and to test the effect of thiol compound as N-acetylcysteine on endothelial function. 2. In precontracted aortic rings from oophorectomized and intact rats, vascular endothelial function was evaluated by measuring changes in isometric force in response to cumulative doses of superoxide dismutase, acetylcholine and sodium nitroprusside. 3. In studies designed to assess the tone-related release of nitric oxide from aortic rings moderately precontracted with phenylephrine, superoxide dismutase produced a lower concentration-related relaxant response in aortic rings from oophorectomized rats than from ovary intact rats. 4. Acetylcholine caused a concentration- and endothelium-dependent relaxation of less magnitude in aortic rings from oophorectomized animals compared with those from ovary-intact rats. Addition of N-omega-nitro-L-arginine methyl ester eliminated the relaxation induced by both superoxide dismutase and acetylcholine. 5. No differences between groups were noticed in the concentration-relaxation curve induced by sodium nitroprusside. 6. Preincubation with N-acetylcysteine normalized the depressed vasorelaxant response to acetylcholine in the aortic rings from oophorectomized rats, whereas the concentration-response curve for acetylcholine in aortic rings from ovary-intact rats did not alter. 7. These results suggest that the absence of ovary estrogens is associated with a vascular endothelium dysfunction that can be reverted by addition of N-acetylcysteine, a thiol-containing compound with a free radical scavenger effect.

Role of nitric oxide on the central hemodynamic response to acute volume expansion in the pregnant rat

OBJECTIVES

Our hypothesis was that during pregnancy nitric oxide acts as mediator in the hemodynamic response to volume expansion.

STUDY DESIGN

The study was performed on 12 rats on days 19 to 20 of pregnancy. Six rats were injected intravenously with hexamethonium bromide plus the inhibitor of nitric oxide synthase L-nitro-arginine methyl ester. For a control group, six rats were injected with hexamethonium bromide plus the L-nitro-arginine methyl ester vehicle. A volume expansion (1.2% body weight) was performed in both groups by intravenous infusion of bovine albumin (6%) solution.

RESULTS

In the control group volume expansion induced a hyperdynamic circulation characterized by increased cardiac output, decreased total vascular resistance, and no change in arterial pressure; however, in the study group volume expansion induced a pressor response without hyperdynamic circulation.

CONCLUSION

During pregnancy volume expansion induces a hyperdynamic circulatory state possibly mediated by nitric oxide release. A defect in the release of nitric oxide may be responsible for an inadequate hemodynamic response to volume expansion.

[MUltiple sclerosis and obstetric epidural analgesia]

A prior diagnosis of multiple sclerosis (MS) has been considered a contraindication for performing epidural blocks due to the possible negative impact of the course of disease. For this reason, women with MS who given birth have rarely benefited from obstetric epidural analgesia. We report the case of a woman giving birth at full-term who had been diagnosed one year before the pregnancy of "probable" MS. She was given epidural analgesia with a mixture of bupivacaine and fentanyl at low doses. Both the birth and the immediate postpartum period transpired without complications and no new signs of disease were reported over the following years. We conclude that obstetric epidural analgesia with bupivacaine administered at a low concentration is safe for women with MS.

Novel osmotically induced antifungal chitinases and bacterial expression of an active recombinant isoform

NaCl (428 mM)-adapted tobacco (Nicotiana tabacum L. var Wisconsin 38) cells accumulate and secrete several antifungal chitinases. The predominant protein secreted to the culture medium was a 29-kD peptide that, based on internal amino acid sequence, was determined to be a class II acidic chitinase with similarity to PR-Q. The four predominant chitinases (T1, T2, T3, and T4) that accumulated intracellularly in 428 mM NaCl-adapted cells were purified. Based on N-terminal sequence analyses, two of these were identified as class I chitinase isoforms, one similar to the N. tomentosiformis (H. Shinshi, J.M. Neuhaus, J. Ryals, F. Meins [1990] Plant Mol Biol 14:357-368) protein (T1) and the other homologous to the N. sylvestris (Y. Fukuda, M. Ohme, H. Shinshi [1991] Plant Mol Biol 16:1-10) protein (T2). The other two proteins (T3 and T4) were determined to be novel chitinases that have sequence similarity with class I chitinases, but each lacks a chitin-binding domain. All four chitinases inhibited Fusarium oxysporum f. sp. lycopersici and Trichoderma longibrachiatum hyphal growth in vitro, although the isoforms containing a chitin-binding domain were somewhat more active. Conditions were established for the successful expression of soluble and active bacterial recombinant T2. Expression of soluble recombinant T2 was achieved when isopropyl beta-D-thiogalactopyranoside induction occurred at 18 degrees C but not at 25 or 37 degrees C. The purified recombinant protein exhibited antifungal activity comparable to a class I chitinase purified from NaCl-adapted tobacco cells.

Non-surgical treatment of ectopic pregnancy in the sole remaining tube

We reported on three successive cases of intrauterine term pregnancy obtained in patients with an ectopic gestation in their solitary remaining tube who were treated by three different non-surgical conservative methods: parenteral methotrexate, local injection of methotrexate combined with systemic administration, and expectant management respectively. The opposite tube had been removed because of previous tubal ectopic pregnancy. The cases, which were at a high risk of repeated ectopic implantation, are unequivocal proof of intact function of a tube after conservative non-surgical procedures for ectopic pregnancy. Thus, our report adds further evidence favouring the feasibility, the safety and fertility potential of these procedures for selected unruptured tubal gestations.

Immunoradiometric studies with a monoclonal antibody against an estrogen-receptor-related protein in human breast cancer

The concentration of P29, a phosphoprotein related to estradiol receptor (RE), was measured by an immunoradiometric assay in human breast cancer cytosol and the results compared with the levels of RE and progesterone receptors (RP), as measured by the classical ligand-binding assay. Good linear correlation was found between P29 and RE, but not RP. Tumors which were positive for both RE and RP had a higher P29 mean value than RE-negative, RP-negative tumors. Menopausal status of the patients influenced the result, since premenopausal women had lower mean concentrations or were P29-positive less frequently than postmenopausal women. RE-negative, RP-positive tumors tended to have positive P29 levels. The correlation between RE and P29 corroborates results obtained with other techniques and supports a role for P29 in predicting response to hormonal treatment.

Effect of exogenous and endogenous gonadotropin-releasing hormone on prolactin secretion in perimenopausal women

Serum concentrations of PRL, LH and FSH were examined in 17 perimenopausal women with dysfunctional uterine bleeding (PDUB group), after stimulation with exogenous GnRH (a 100-micrograms i.v. bolus dose), and endogenous GnRH (as induced by an estrogen challenge test). Five normal cycling women during the follicular phase of the cycle were used as control (FP group). Exogenous GnRH induced increments in the concentration of PRL, FSH and LH in PDUB and FP women. Increases were statistically higher for FSH (p less than 0.001) and LH (p less than 0.01), but not for PRL, in the FP group. No significant correlation was found between LH-PRL or FSH-PRL in PDUB women. A positive correlation was found when the maximal LH percent change for each case was compared with the simultaneous PRL percent value (r = 0.83, p less than 0.001) during the estrogen test. We conclude that, as shown by previous studies in both hypogonadal and normal women, also in this perimenopausal model exogenous GnRH induces secretion of PRL, LH and FSH, and that a positive correlation exists between LH and PRL under the finely modulated stimulation of gonadotrophs by endogenous GnRH.

Response to clomiphene citrate in the polycystic ovarian syndrome according to different LH/FSH ratios

Twenty-nine clomiphene tests were carried out, 19 on subjects with polycystic ovarian syndrome (PCO) who did not wish to conceive and 10 on women with correct ovarian function (control women). The intention was to determine if the response of the hypothalamic-pituitary-ovary axis varies according to different LH/FSH ratios. The results indicate that with repeated LH/FSH ratios of less than 3, the positive and negative feedback systems are preserved in most subjects, but when the ratio is higher than 3, both systems are significantly altered (P less than 0.01). In the control group, both systems were preserved in all subjects. In another group composed of 26 infertile patients with PCO, the rate of ovulation and pregnancy after administration of clomiphene citrate (CC) was correlated according to different LH/FSH ratios. A significant (P less than 0.0001) reduction in the rate of ovulation and a lesser reduction in pregnancy was found with increasing LH/FSH ratios. In conclusion we suggest that the LH/FSH ratio is a good marker of this syndrome, and can be used to give a prognosis on the severity of the syndrome, as well as the ovulatory capacity of the subject after administration of CC.

The positive feedback of estradiol on gonadotropin secretion in women with perimenopausal dysfunctional uterine bleeding

The functionality of the hypothalamic-pituitary-ovarian axis was explored in 27 women with perimenopausal dysfunctional uterine bleeding. The positive feedback effect of estradiol on LH and FSH was studied by the estrogen challenge test, which was performed by a single i.m. injection of estradiol benzoate. An early decline of both LH and FSH was followed by an increase of LH, mainly due to the cases in which the estrogen test was positive. FSH remained low through the whole period tested. The results were compared with those found in 5 normal menstruating women. The frequency of positive estrogen tests, defined by an acute estradiol-induced discharge of LH, was lower in the perimenopausal patients (P less than 0.025). The results of the tests used in our study showed an impairment of the positive feedback system in the perimenopausal-dysfunctional-bleeding group.