Risk of dengue virus infection according to serostatus in individuals from dengue endemic areas of Mexico.

The variability in the host immune response directed against dengue virus (DENV) has demonstrated the need to understand the immune response associated with protection in incident infection. The objective was to estimate the association between serostatus and the risk of incident DENV infection. We used a prospective study from 2014 to 2016 in the localities of Axochiapan and Tepalcingo, Morelos, Mexico. We recruited 966 participants, of which, according to their infection history registered were categorized in four groups. To accomplish the objectives of this study, we selected to 400 participants older than 5 years of age were followed for 2.5 years. Blood samples were taken every 6 months to measure serological status and infection by ELISA. In individuals with at least two previous infections the risk of new infection was lower compared to a seronegative group (hazard ratio adjusted 0.49, 95% CI 0.24-0.98), adjusted for age and locality. Therefore, individuals who have been exposed two times or more to a DENV infection have a lower risk of re-infection, thus showing the role of cross-immunity and its association with protection.

Model based study on monitoring ketone bodies to improve safety in intensive insulin therapy.

AIM: The present study explores new signals (capillary 3betahydroxybutyrate - 3betaOHB) for improving the safety of a closed loop insulin infusion system (external wearable artificial pancreas). METHODS: Data collected during a clinical trial on diabetic subjects including a period of insulin deprivation were interpreted through mathematical models to simulate the effect of monitoring ketone bodies (capillary 3betaOHB, KB) compared to blood glucose in subjects on Continuous Subcutaneous Insulin Infusion (CSII) treatment. RESULTS: The estimation of model coefficients satisfactorily fits experimental data. The evaluation of dynamic changes of capillary 3betaOHB levels showed a more rapid response than blood glucose. CONCLUSIONS: The effect of the combination of monitoring of glucose and ketone bodies can consistently improve the safety and efficacy of the use of a closed loop system for glycemic control in dangerous situations like ketoacidosis. If a subcutaneous glucose-ketone bodies sensor were to become available in the near future it would be a key component of an external artificial pancreas.

Proposed diagnostic criteria for neurocysticercosis.

Neurocysticercosis is the most common helminthic infection of the CNS but its diagnosis remains difficult. Clinical manifestations are nonspecific, most neuroimaging findings are not pathognomonic, and some serologic tests have low sensitivity and specificity. The authors provide diagnostic criteria for neurocysticercosis based on objective clinical, imaging, immunologic, and epidemiologic data. These include four categories of criteria stratified on the basis of their diagnostic strength, including the following: 1) absolute--histologic demonstration of the parasite from biopsy of a brain or spinal cord lesion, cystic lesions showing the scolex on CT or MRI, and direct visualization of subretinal parasites by funduscopic examination; 2) major--lesions highly suggestive of neurocysticercosis on neuroimaging studies, positive serum enzyme-linked immunoelectrotransfer blot for the detection of anticysticercal antibodies, resolution of intracranial cystic lesions after therapy with albendazole or praziquantel, and spontaneous resolution of small single enhancing lesions; 3) minor--lesions compatible with neurocysticercosis on neuroimaging studies, clinical manifestations suggestive of neurocysticercosis, positive CSF enzyme-linked immunosorbent assay for detection of anticysticercal antibodies or cysticercal antigens, and cysticercosis outside the CNS; and 4) epidemiologic--evidence of a household contact with Taenia solium infection, individuals coming from or living in an area where cysticercosis is endemic, and history of frequent travel to disease-endemic areas. Interpretation of these criteria permits two degrees of diagnostic certainty: 1) definitive diagnosis, in patients who have one absolute criterion or in those who have two major plus one minor and one epidemiologic criterion; and 2) probable diagnosis, in patients who have one major plus two minor criteria, in those who have one major plus one minor and one epidemiologic criterion, and in those who have three minor plus one epidemiologic criterion.

Prevalence and risk factors for Taenia solium taeniasis and cysticercosis in humans and pigs in a village in Morelos, Mexico.

In a Mexican village in which Taenia solium infection was known to be endemic, we selected a cluster sample of 368 households (21% of the total) for demographic, environmental, and diagnostic surveys, and medical histories for taeniasis and cysticercosis. Coproparasitologic studies of 1,531 participants revealed infection by Taenia sp. in four (0.3%) individuals; however, 5.8% of the respondents reported a history of having passed tapeworm proglottids in feces. Of 1,552 human serum specimens, 10.8% tested positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a maximum in subjects ages 46-55 years. Risk factors associated with seropositivity included a history of passing tapeworm proglottids, frequent consumption of pork, and poor personal and household hygiene (P less than 0.05). A history of seizures was also significantly associated with seropositivity (P less than 0.05); approximately one-third of persons with such histories were seropositive. Of 571 pigs examined by tongue inspection, 23 (4.0%) had cysticerci; infection rates increased with the age of pigs, and were higher in pigs that habitually ran loose or were fed human feces (P less than 0.05). Goodness of fit analysis confirmed that seropositive persons (but not infected pigs) were significantly clustered within households, particularly, in households in which a member reported a history of having passed tapeworm proglottids. The results of this study have identified community behavioral and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

Development and evaluation of a health education intervention against Taenia solium in a rural community in Mexico.

A comprehensive study was undertaken in a rural community in the state of Morelos, Mexico to evaluate health education as an intervention measure against Taenia solium. An educational program was developed to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions that foster transmission. The effects of educational intervention were evaluated by measuring changes in knowledge and practices and prevalence of human taeniasis and swine cysticercosis before and after the campaign. The health education strategy was implemented with the active participation of the population based on the information obtained from a sociologic study. A questionnaire was designed and used before, immediately after the intervention, and six months later. Statistically significant improvements occurred in knowledge of the parasite, its life cycle, and how it is acquired by humans; however, changes in behavior related to transmission were less dramatic and persistent. The prevalences of cysticercosis in pigs at the start of the education intervention were 2.6% and 5.2% by lingual examination and antibody detection (immunoblot assay), respectively, and approximately one year after the intervention they were 0% and 1.2% (P < 0.05). These changes were accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam. We conclude that health education, developed along with community involvement, reduced opportunities for transmission of T. solium in the human-pig cycle.

PIP: Neurocysticercosis is an important health problem in Mexico, as well as in many other countries of Latin America, Asia, and Africa where conditions permit completion of the cestode's life cycle in pigs and humans. A study was conducted in a rural community in the state of Morelos, Mexico, to determine whether health education could be an effective measure against Taenia solium. An educational program was developed with community input to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions which foster transmission. The effects of the educational intervention were then assessed by measuring changes in knowledge, practices, and the prevalence of human taeniasis and swine cysticercosis before and after the campaign. Statistically significant improvements occurred with regard to knowledge of the parasite, its life cycle, and how it is acquired by humans. However, changes in behavior related to transmission were less marked and persistent. Lingual examination and antibody detection found cysticercosis among 2.6% and 5.2% of pigs, respectively, at the start of the intervention. At approximately 1 year after the intervention, prevalences had declined to 0% and 1.2%. The decline was accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam.

Localization of cerebral arterovenous malformations using digital angiography.

Since 1989 we performed stereotactic radiotherapy treatments of cerebral arterovenous malformations (AVM), estimating three-dimensional (3-D) localization and shape of target volumes by the Leksell stereotactic helmet on two orthogonal radiographic projections. Due to the limitations of this method, we developed a new technique for the localization of the target volume using digital subtraction angiography (DSA) and digital image processing. To achieve this result we first developed a method to correct nonlinear distortion of DSA images using spatial relocation of image pixels based on a calibration grid. We then developed an algorithm for localization of the target volume using two independent DSA projections. Target volume coordinates in the helmet system are calculated using two DSA acquisitions taken with a free angle (approximately 90 degrees), one in the AP and the other in the LL direction. The helmet can be freely positioned between the x-ray source and the image plane. The projections of eight reference points inserted in the helmet at a known location, are used to calculate the transformation matrix between the two coordinate systems. We performed numerical and experimental validation of the system. A hypothetical random error (up to 2 mm) on image coordinates of the reference points allowed to determine that the error in target localization was less than 0.2 mm. Using DSA images of target points with a known location within a phantom, the error between calculated and actual location was, on average, 0.30+/-0.13 mm (mean+/-SD), with a maximum error of 0.49 mm. The results of numerical and experimental validations show that the system we have developed allows fast and accurate localization of the center of the target volume and it is suitable for efficient guiding during stereotactic radiosurgery of AVM.

Mass treatment against human taeniasis for the control of cysticercosis: a population-based intervention study.

An intervention study with mass treatment against taeniasis to prevent neurocysticercosis due to Taenia solium in a rural community in Mexico was performed in 1991-96. Information and biological samples were obtained at the beginning of the study, at 6 months and at 42 months after mass treatment with praziquantel at a single dose of 5 mg/kg. Prevalence rates of taeniasis were measured by the detection of Taenia coproantigens and Taenia eggs in faeces; neurocysticercosis was suggested by clinical data and by serum antibodies in humans and also in swine. A reduction of 53% after 6 months and of 56% after 42 months for human taeniasis was seen after treatment. Late-onset general seizures decreased 70%. Anti-cysticercus antibodies in the human population were reduced by 75% after 42 months. Antibodies in pigs also showed a significant reduction of 55% after 6 months. In conclusion, an impact of mass chemotherapy against taeniasis to control cysticercosis in the short and long term was demonstrated. Praziquantel for tapeworm treatment should not be given at doses lower than 10 mg/kg. Late-onset convulsive crisis and specific antibodies are good indicators of neurocysticercosis and of exposure to the parasite, respectively.

Epidemiological investigation of Taenia solium taeniasis and cysticercosis in a rural village of Michoacan state, Mexico.

We performed a survey for taeniasis and cysticercosis among persons living in a Mexican village where Taenia solium infection in pigs was known to be enzootic. A standardized questionnaire was administered in all 577 households to obtain medical histories and information on demographic and environmental factors and on risk factors associated with transmission of infection. Serum and/or stool specimens were obtained from 1005 volunteers and examined for cysticercosis antibodies and intestinal parasites. Faecal examination of 828 participants revealed infection by Taenia sp. in 2 (0.2%). Three additional cases of taeniasis were detected in individuals who evacuated proglottids after treatment with praziquantel. Of 1005 human serum specimens, 49 (4.9%) were positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a peak in subjects aged 46-55 years (P < 0.05). A history of seizures was significantly associated with seropositivity (P < 0.05); approximately 25% of persons with such histories were seropositive. Histories of headache, dizziness, trembling, blurred vision, and vomiting were also significantly associated with positive immunoblot assays. This study has demonstrated previously undiagnosed morbidity associated with T. solium neurocysticercosis and identified community behavioural and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

First branchial cleft cysts: clinical update.

First branchial cleft cysts develop as a result of incomplete fusion of the cleft between the first and second branchial arches and give rise to two distinct anomalies, termed type I and type II anomalies. Type I anomalies are purely ectodermal while type II anomalies exhibit ectodermal and mesodermal elements. The type II anomaly incorporates some portion of the first and second arch as well as the cleft. Type I lesions are extremely rare. They appear histologically as cysts lined by squamous epithelium. Clinically, they present as a cystic mass or fistula posterior to the pinna and concha. The cyst is usually superior to the main trunk of the facial nerve and ends in a cul-de-sac on or near a bony plate at the level of the mesotympanum. Type II lesions are more numerous and represent a duplication of both membranous and cartilaginous portions of the external auditory canal. They contain skin as well as adnexal structures and cartilage and may be associated with the parotid gland. Most frequently they are associated with fistulae in the concha or external auditory canal as well as fistulous openings in the neck.

Paranasal sinus disease with intracranial extension: aspergillosis versus malignancy.

Aspergillus is a fungus with world-wide distribution and a common endogenous contaminate of the upper respiratory tract. It has become an increasingly recognized pathogen in the paranasal sinuses. In its pathologic state it presents in one of several forms that may represent a continuum of the disease: allergic, noninvasive, invasive, and fulminant. The progression and prognosis of these disease depends on the location and immunologic status of the patient. This case represents the fourth reported case of a nonimmunologic compromised patient with intracranial extension of aspergillosis. The patient presented with unilateral pansinusitis and radiographic evidence of orbital and anterior cranial fossa invasion. This case illustrates the difficulty of establishing the diagnosis of invasive aspergillosis and differentiating it from neoplastic entities. Radiographs and photomicrographs will be presented to establish this premise.

Theoretical study for use of Leksell's stereotactic frame in radiosurgery.

The authors examine all the problems connected with the use of Leksell's frame. These problems were studied specifically for the treatment of artero-venous malformation of the brain using small fields and movement therapy of a 10 MV linear accelerator. The technique allows the administration of high radiation doses (25-30) Gy into a very small target within a fraction. In this way the surrounding tissue receives a low dose. The treatment was initially simulated with a dummy. The dosimetry gives an accuracy of +/- 1.5%. This study has been able to resolve all the theoretical and practical problems demonstrating the feasibility of the project which has already been put into effect.

Rationale of treatment in Graves ophthalmopathy.

Graves ophthalmopathy is a chronic and multisystem disorder caused by an autoimmune process, characterized by the presence of antibodies that stimulate a general fibroblastic reaction (thyroid gland and lower extremities), and involves orbital fat tissue and muscles. The clinical findings and therapy for the treatment of the exophthalmos, such as changes in extrinsic eye motility, diplopia, optic nerve involvement, and lid retraction, were analyzed, and the various types of surgical treatment currently available for Graves ophthalmopathy were evaluated. The aim was to choose the best option to treat each case. The surgical techniques were transpalpebral decompression by removal of intraorbital fat, three-wall osseous expansion, and zygomatic osteotomy. Adjunctive procedures were lengthening of the levator muscle of the upper eyelid, lengthening of the retractor of the lower eyelid (if necessary), and surgery of the extrinsic muscles to correct diplopia. All these techniques were useful in treating the disease, which is characterized by chronic evolution and, at times, a "malignant" outcome. A total of 39 orbits were treated using different techniques of decompression and secondary adjunctive procedures. Results were analyzed after a minimum 6-month follow-up. It was evident that surgery greatly reduced the degree of exophthalmos and improved eye motility, diplopia, and visual acuity. Close cooperation among a team of specialists, including an endocrinologist, ophthalmologist, neuroradiologist, surgeon, anesthesiologist, and radiotherapist, is essential to manage and to quantify the postoperative results of this complex disorder. The authors' experience and application of different surgical strategies, as based on clinical data and histopathological classification, are presented.

Cyclophosphamide, epirubicin, etoposide, cis platinum (CEVP) in combination with radiotherapy: evaluation of a protocol adopted for 6 years in 148 cases of small cell lung cancer.

The present study was carried out with the purpose of assessing and evaluating the responsiveness of small cell lung cancer (SCLC) to combined treatment (i.e., chemotherapy and radiotherapy). This approach was applied to all patients observed in our Institution during the last 6 years with the exclusion of patients more than 65 years old, with Karnofsky performance status less than 60, and with concomitant non-neoplastic diseases. One hundred and forty-eight patients were selected and treated with a combination chemotherapy regimen including cyclophosphamide, etoposide, epirubicin and cisplatinum. For patients with limited disease, treatment consisted of 3 cycles of chemotherapy (induction), followed by radiation therapy and then by another 3 cycles of chemotherapy (consolidation). For those with extensive disease, treatment consisted only of 6 consecutive cycles of chemotherapy. Results, besides showing the good activity and tolerability of the chemotherapeutic regimen employed (which induced 80% overall response), indicated that some prognostic factors such as the number of metastatic sites, brain and liver involvement and performance status are essential in determining the outcome of response and, particularly, of survival. In addition, the efficacy and tolerability of the combination chemotherapy-radiotherapy were confirmed, as was the evidence of a synergistic pharmacologic effect between cis-platinum and etoposide.

Minimal requirements in prostate cancer irradiation: a consensus document by the AIRO Lombardia Cooperative Group.

PURPOSE: With the aim of establishing clinical and technical criteria to homogenize radiotherapy practice, a working group of AIRO-Lombardia (Associazione Italiana di Radioterapia Oncologica--Gruppo regionale della Lombardia) has tried to define minimal requirements for radical and postoperative irradiation in prostate cancer. The document has been structured in such a way as to be also of interest to the urological and medical oncology communities. METHODS: The working group, composed of representatives of most of the regional radiotherapy departments in the Lombardy region, had monthly meetings during 1996 and 1997. The document on minimal requirements has been derived from the participants' combined experience and knowledge, from review of the literature, and from a 1995 regional survey on current practice of prostate irradiation. RESULTS: Minimal requirements for radical and postoperative irradiation of prostate cancer have been defined with respect to treatment strategies, pre-treatment diagnostic evaluation and staging, treatment prescription, preparation and execution, and quality assurance procedures. CONCLUSION: Standards of reference for minimal requirements in prostate cancer irradiation adapted to the regional structures and resources have been defined.

The role of radiotherapy in the treatment of carcinoma of the prostate: a survey of clinical practices in Lombardy, Italy, by the AIRO-Lombardia Cooperative Group. Italian Association for Radiation Oncology.

AIMS AND BACKGROUND: We report the results of a survey performed in 1994 by the AIRO-Lombardia Cooperative Group, on the clinical patterns of radiation treatment for prostatic carcinoma in Lombardy, Italy, involving all radiotherapy centers serving an overall local population of about 8,800,000 people. METHODS: A questionnaire was sent to all 13 radiotherapy centers throughout Lombardy, asking for demographic and treatment details concerning the local population of patients with a localized (T1-4, N0-1, M0) carcinoma of the prostate treated with radiotherapy; 12 centers responded, making the basis for the present report. RESULTS: Analysis of collected data showed that in Lombardy: a) approximately 400 patients per year are irradiated for a localized carcinoma of the prostate, accounting for less than 30% of the total expected number of patients with this disease presentation; b) a complete staging (with PSA, transrectal ultrasonography, abdomino-pelvic CT or MRI scan and total-body bone scan) is performed in over 95% of patients before initiating radiotherapy; c) significant differences exist between radiotherapy centers as regards treatment planning and delivery. CONCLUSIONS: An urgent need exists for implementing procedures aimed at standardizing radiotherapy procedures within Lombardy.

Mathematical model to analyse urea synthesis following alanine infusion in control subjects and in patients with liver cirrhosis.

A three-compartment model was used to analyse the urea response to an alanine infusion in control subjects and patients with liver cirrhosis. Discriminant analysis showed a good separation between model coefficients of the two groups. A single parameter was derived, able to quantify the liver functional capacity. The method provides a useful diagnostic tool in patients with liver disease.

A simulation study on a self-tuning portable controller of blood glucose.

A self-tuning, nonlinear controller was developed to drive portable or implantable micro-pumps for blood glucose control in diabetic subjects. The parameter estimation is based on a recursive least-square algorithm applied to a discrete time simplified mathematical model of the glucose system; the controller, which is integrated with the estimator, uses an extended minimum-variance method. The software was designed to drive a micro-controller wearable unit, operating with different kinds of glucose sensors, in order to perform chemical and biological experimentations. Some strategies were introduced to avoid hypoglycaemia, even tolerating a reduction in control speed and accuracy. The whole system was tested in a simulation study, performed on a mathematical model implemented on a personal computer. The tests were performed while simulating different controller structures and settings, and patient responses. They showed a satisfactory control behaviour, mostly as far as stability and robustness are concerned, in all simulated conditions.

Wearable system for acquisition, processing and storage of the signal from amperometric glucose sensors.

A wearable device for the acquisition, processing and storage of the signal from needle-type glucose sensors has been designed and developed as part of a project aimed at developing a portable artificial pancreas. The device is essential to assess the operational characteristics of miniaturized sensors in vivo. It can be connected to sensors operating at a constant potential of 0.65 Volts, and generating currents in the order of 10(-9) Amp. It is screened and equipped with filters that permit data recording and processing even in the presence of electrical noise. It can operate with sensors with different characteristics (1-200 nA full scale). The device has been designed to be worn by patients, so its weight and size have been kept to a minimum (250 g; 8.5 x 14.5 x 3.5 cm). It is powered by rechargeable Ni/Cd batteries allowing continuous operation for 72 h. The electronics consists of an analog card with operational amplifiers, and a digital one with a microprocessor (Intel 80C196, MCS-96 class, with internal 16-bit CPU supporting programs written in either C or Assembler language), a 32 Kb EPROM, and an 8 Kb RAM where the data are stored. The microprocessor can run either at 5 or 10 Mhz and features on-chip peripherals: an analog/digital (A/D) converter, a serial port (used to transfer data to a Personal Computer at the end of the 72 h), input-output (I/O) units at high-speed, and two timers. The device is programmed and prepared to operate by means of a second hand-held unit equipped with an LCD display and a 16-key numeric pad.(ABSTRACT TRUNCATED AT 250 WORDS)

A digital computer model for optimal programming of hemodialytic treatment.

A mathematical model of hydroelectrolyte exchanges and arterial pressure regulation in the human body during dialysis has been set up. It is conceived as a tool for a new dialysis unit which will be able to "interpret" the signals supplied by suitable instruments connected to the patient and modify the machine set-points in real time in order to obtain clinical results defined by the physician. The main aim is the prevention of hypotensive episodes during treatment. An experimental protocol has been developed for parameter estimation of each patient during a single dialysis. Clinical tests illustrated the model's ability to fit the patient's state during dialysis. This is the first step in the more general task of validation of the model, necessary for the achievement of a closed-loop dialysis unit.

A mathematical model describing the glycemic response of diabetic patients to meal and i.v. infusion of insulin.

Nine type 1 diabetic patients were studied for 24 hours. During this period they were given three calibrated meals. The glycemia was feedback-controlled by means of an artificial pancreas. The blood concentration of glucose and the infusion speed of the insulin were measured every minute. The experimental data referring to each of the three meals were used to estimate the parameters of a mathematical model suitable for describing the glycemic response of diabetic patients at meals and at the i.v. infusion of exogenous insulin. From the estimate a marked dispersion of the parameters was found, both interindividual and intraindividual. Nevertheless the models thus obtained seem to be usable for the synthesis of a feedback controller, especially in view of creating a portable artificial pancreas that now seems possible owing to the realization (so far experimental) of sufficiently reliable glucose concentration sensors.