Design, development and preliminary assessment in a porcine model of a novel peripheral intravenous catheter aimed at reducing early failure rates

BACKGROUND

Peripheral intravenous catheters (PIVCs) are the most commonly used invasive medical device, yet despite best efforts by end-users, PIVCs experience unacceptably high early failure rates. We aimed to design a new PIVC that reduces the early failure rate of in-dwelling PIVCs and we conducted preliminary tests to assess its efficacy and safety in a porcine model of intravenous access.

METHODS

We used computer-aided design and simulation to create a PIVC with a ramped tip geometry, which directs the infused fluid away from the vein wall; we called the design the FloRamp™. We created FloRamp prototypes (test device) and tested them against a market-leading device (BD Insyte™; control device) in a highly-controlled setting with five insertion sites per device in four pigs. We measured resistance to infusion and visual infusion phlebitis (VIP) every 6 h and terminated the experiment at 48 h. Veins were harvested for histology and seven pathological markers were assessed.

RESULTS

Computer simulations showed that the optimum FloRamp tip reduced maximum endothelial shear stress by 60%, from 12.7 Pa to 5.1 Pa, compared to a typical PIVC tip and improved the infusion dynamics of saline in the blood stream. In the animal study, we found that 2/5 of the control devices were occluded after 24 h, whereas all test devices remained patent and functional. The FloRamp created less resistance to infusion (0.73 ± 0.81 vs 0.47 ± 0.50, p = 0.06) and lower VIP scores (0.60 ± 0.93 vs 0.31 ± 0.70, p = 0.09) than the control device, although neither findings were significantly different. Histopathology revealed that 5/7 of the assessed markers were lower in veins with the FloRamp.

CONCLUSIONS

Herein we report preliminary assessment of a novel PIVC design, which could be advantageous in clinical settings through decreased device occlusion and reduced early failure rates.

Comparative analysis of novel esophageal pressure monitoring catheters versus commercially available alternatives in a biomechanical model of the thoracic cavity

Transpulmonary pressure can be estimated using esophageal balloon (EB) catheters, which come in a variety of manufacturing configurations. We assessed the performance of novel polyurethane EB designs, Aspisafe NG and NG+, against existing alternatives. We created a biomechanical model of the chest cavity using a plastic chamber and an ex-vivo porcine esophagus. The chamber was pressurized (- 20 and + 20 cmH2O) to simulate pleural pressures. We conducted tests with various EB inflation volumes and measured transesophageal pressure (TEP). TEP measurement was defined as accurate when the difference between pressure within the EB and chamber was 0 ± 1 cmH2O. We computed the minimal (Vaccuracy-min) and maximal (Vaccuracy-max) EB inflation volumes of accuracy. Inflation volumes were further validated using a surrogate method derived by the clinically validated positive pressure occlusion test (PPOT). When the esophageal balloons were filled with inflation volumes within the range provided by the manufacturers, the accuracy of TEP measurements was marginal. Our tests found median Vaccuracy-min across EB of 0.00-0.50 mL (p = 0.130), whereas Vaccuracy-max ranged 0.50-2.25 mL (p = 0.002). Post PPOT validation, median TEP was - 0.4 cmH2O (- 1.5 to 0.3) (p < 0.001 among catheters). The Aspisafe NG and NG+ were accurate in 81.7% and 77.8% of the measurements, respectively. We characterized two new EBs, which demonstrated good benchtop accuracy in TEP measurements. However, accuracy was notably influenced by the precise selection of EB inflation volumes.

A novel speckle-tracking echocardiography parameter assessing left ventricular afterload

BACKGROUND

Left ventricular stroke work index (LVSWI) and afterload-related cardiac performance (ACP) consider left ventricular (LV) afterload and could be better prognosticators in septic cardiomyopathy. However, their invasive nature prevents their routine clinical applications. This study aimed to investigate (1) whether a proposed speckle-tracking echocardiography parameter, Pressure-Strain Product (PSP), can non-invasively predict catheter-based LVSWI, ACP and serum lactate in an ovine model of septic cardiomyopathy; and (2) whether PSP can distinguish the sub-phenotypes of acute respiratory distress syndrome (ARDS) with or without sepsis-like conditions.

METHODS

Sixteen sheep with ARDS were randomly assigned to either (1) sepsis-like (n = 8) or (2) non-sepsis-like (n = 8) group. Each ARDS and sepsis-like condition was induced by intravenous infusion of oleic acid and lipopolysaccharide, respectively. Pulmonary artery catheter-based LVSWI (the product of stroke work index, mean arterial pressure and .0136), ACP (the percentage of cardiac output measured to cardiac output predicted as normal) and serum lactate were measured simultaneously with transthoracic echocardiography. Two PSP indices were calculated by multiplying the mean arterial blood pressure and either global circumferential strain (PSPcirc) or radial strain (PSPrad).

RESULTS

PSPcirc showed a significant correlation with LVSWI (r2  = .66, p < .001) and ACP (r2  = .82, p < .001) in the sepsis-like group. Although PSP could not distinguish subphenotypes, PSPcirc predicted LVSWI (AUC .86) and ACP (AUC .88), and PSPrad predicted serum lactate (AUC .75) better than LV ejection fraction, global circumferential and radial strain.

CONCLUSIONS

A novel PSP has the potential to non-invasively predict catheter-based LVSWI and ACP, and was associated with serum lactate in septic cardiomyopathy.

Application of anti-inflammatory treatment in two different ovine Acute Respiratory Distress Syndrome injury models: a preclinical randomized intervention study

Whilst the presence of 2 subphenotypes among the heterogenous Acute Respiratory Distress Syndrome (ARDS) population is becoming clinically accepted, subphenotype-specific treatment efficacy has yet to be prospectively tested. We investigated anti-inflammatory treatment in different ARDS models in sheep, previously shown similarities to human ARDS subphenotypes, in a preclinical, randomized, blinded study. Thirty anesthetized sheep were studied up to 48 h and randomized into: (a) OA: oleic acid (n = 15) and (b) OA-LPS: oleic acid and subsequent lipopolysaccharide (n = 15) to achieve a PaO2/FiO2 ratio of < 150 mmHg. Then, animals were randomly allocated to receive treatment with methylprednisolone or erythromycin or none. Assessed outcomes were oxygenation, pulmonary mechanics, hemodynamics and survival. All animals reached ARDS. Treatment with methylprednisolone, but not erythromycin, provided the highest therapeutic benefit in Ph2 animals, leading to a significant increase in PaO2/FiO2 ratio by reducing pulmonary edema, dead space ventilation and shunt fraction. Animals treated with methylprednisolone displayed a higher survival up to 48 h than all others. In animals treated with erythromycin, there was no treatment benefit regarding assessed physiological parameters and survival in both phenotypes. Treatment with methylprednisolone improves oxygenation and survival, more so in ovine phenotype 2 which resembles the human hyperinflammatory subphenotype.

Donor heart ischemic time can be extended beyond 9 hours using hypothermic machine perfusion in sheep

BACKGROUND

The global shortage of donor hearts available for transplantation is a major problem for the treatment of end-stage heart failure. The ischemic time for donor hearts using traditional preservation by standard static cold storage (SCS) is limited to approximately 4 hours, beyond which the risk for primary graft dysfunction (PGD) significantly increases. Hypothermic machine perfusion (HMP) of donor hearts has been proposed to safely extend ischemic time without increasing the risk of PGD.

METHODS

Using our sheep model of 24 hours brain death (BD) followed by orthotopic heart transplantation (HTx), we examined post-transplant outcomes in recipients following donor heart preservation by HMP for 8 hours, compared to donor heart preservation for 2 hours by either SCS or HMP.

RESULTS

Following HTx, all HMP recipients (both 2 hours and 8 hours groups) survived to the end of the study (6 hours after transplantation and successful weaning from cardiopulmonary bypass), required less vasoactive support for hemodynamic stability, and exhibited superior metabolic, fluid status and inflammatory profiles compared to SCS recipients. Contractile function and cardiac damage (troponin I release and histological assessment) was comparable between groups.

CONCLUSIONS

Overall, compared to current clinical SCS, recipient outcomes following transplantation are not adversely impacted by extending HMP to 8 hours. These results have important implications for clinical transplantation where longer ischemic times may be required (e.g., complex surgical cases, transport across long distances). Additionally, HMP may allow safe preservation of "marginal" donor hearts that are more susceptible to myocardial injury and facilitate increased utilization of these hearts for transplantation.

Effect of flow change on brain injury during an experimental model of differential hypoxaemia in cardiogenic shock supported by extracorporeal membrane oxygenation

Differential hypoxaemia (DH) is common in patients supported by femoral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and can cause cerebral hypoxaemia. To date, no models have studied the direct impact of flow on cerebral damage. We investigated the impact of V-A ECMO flow on brain injury in an ovine model of DH. After inducing severe cardiorespiratory failure and providing ECMO support, we randomised six sheep into two groups: low flow (LF) in which ECMO was set at 2.5 L min-1 ensuring that the brain was entirely perfused by the native heart and lungs, and high flow (HF) in which ECMO was set at 4.5 L min-1 ensuring that the brain was at least partially perfused by ECMO. We used invasive (oxygenation tension-PbTO2, and cerebral microdialysis) and non-invasive (near infrared spectroscopy-NIRS) neuromonitoring, and euthanised animals after five hours for histological analysis. Cerebral oxygenation was significantly improved in the HF group as shown by higher PbTO2 levels (+ 215% vs - 58%, p = 0.043) and NIRS (67 ± 5% vs 49 ± 4%, p = 0.003). The HF group showed significantly less severe brain injury than the LF group in terms of neuronal shrinkage, congestion and perivascular oedema (p < 0.0001). Cerebral microdialysis values in the LF group all reached the pathological thresholds, even though no statistical difference was found between the two groups. Differential hypoxaemia can lead to cerebral damage after only a few hours and mandates a thorough neuromonitoring of patients. An increase in ECMO flow was an effective strategy to reduce such damages.

Differential Protein Expression among Two Different Ovine ARDS Phenotypes-A Preclinical Randomized Study

Despite decades of comprehensive research, Acute Respiratory Distress Syndrome (ARDS) remains a disease with high mortality and morbidity worldwide. The discovery of inflammatory subphenotypes in human ARDS provides a new approach to study the disease. In two different ovine ARDS lung injury models, one induced by additional endotoxin infusion (phenotype 2), mimicking some key features as described in the human hyperinflammatory group, we aim to describe protein expression among the two different ovine models. Nine animals on mechanical ventilation were included in this study and were randomized into (a) phenotype 1, n = 5 (Ph1) and (b) phenotype 2, n = 4 (Ph2). Plasma was collected at baseline, 2, 6, 12, and 24 h. After protein extraction, data-independent SWATH-MS was applied to inspect protein abundance at baseline, 2, 6, 12, and 24 h. Cluster analysis revealed protein patterns emerging over the study observation time, more pronounced by the factor of time than different injury models of ARDS. A protein signature consisting of 33 proteins differentiated among Ph1/2 with high diagnostic accuracy. Applying network analysis, proteins involved in the inflammatory and defense response, complement and coagulation cascade, oxygen binding, and regulation of lipid metabolism were activated over time. Five proteins, namely LUM, CA2, KNG1, AGT, and IGJ, were more expressed in Ph2.

A clinically relevant sheep model of orthotopic heart transplantation 24 h after donor brainstem death

Background

Heart transplantation (HTx) from brainstem dead (BSD) donors is the gold-standard therapy for severe/end-stage cardiac disease, but is limited by a global donor heart shortage. Consequently, innovative solutions to increase donor heart availability and utilisation are rapidly expanding. Clinically relevant preclinical models are essential for evaluating interventions for human translation, yet few exist that accurately mimic all key HTx components, incorporating injuries beginning in the donor, through to the recipient. To enable future assessment of novel perfusion technologies in our research program, we thus aimed to develop a clinically relevant sheep model of HTx following 24 h of donor BSD.

Methods

BSD donors (vs. sham neurological injury, 4/group) were hemodynamically supported and monitored for 24 h, followed by heart preservation with cold static storage. Bicaval orthotopic HTx was performed in matched recipients, who were weaned from cardiopulmonary bypass (CPB), and monitored for 6 h. Donor and recipient blood were assayed for inflammatory and cardiac injury markers, and cardiac function was assessed using echocardiography. Repeated measurements between the two different groups during the study observation period were assessed by mixed ANOVA for repeated measures.

Results

Brainstem death caused an immediate catecholaminergic hemodynamic response (mean arterial pressure, p = 0.09), systemic inflammation (IL-6 - p = 0.025, IL-8 - p = 0.002) and cardiac injury (cardiac troponin I, p = 0.048), requiring vasopressor support (vasopressor dependency index, VDI, p = 0.023), with normalisation of biomarkers and physiology over 24 h. All hearts were weaned from CPB and monitored for 6 h post-HTx, except one (sham) recipient that died 2 h post-HTx. Hemodynamic (VDI - p = 0.592, heart rate - p = 0.747) and metabolic (blood lactate, p = 0.546) parameters post-HTx were comparable between groups, despite the observed physiological perturbations that occurred during donor BSD. All p values denote interaction among groups and time in the ANOVA for repeated measures.

Conclusions

We have successfully developed an ovine HTx model following 24 h of donor BSD. After 6 h of critical care management post-HTx, there were no differences between groups, despite evident hemodynamic perturbations, systemic inflammation, and cardiac injury observed during donor BSD. This preclinical model provides a platform for critical assessment of injury development pre- and post-HTx, and novel therapeutic evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00425-4.

An innovative ovine model of severe cardiopulmonary failure supported by veno-arterial extracorporeal membrane oxygenation

Refractory cardiogenic shock (CS) often requires veno-arterial extracorporeal membrane oxygenation (VA-ECMO) to sustain end-organ perfusion. Current animal models result in heterogenous cardiac injury and frequent episodes of refractory ventricular fibrillation. Thus, we aimed to develop an innovative, clinically relevant, and titratable model of severe cardiopulmonary failure. Six sheep (60 ± 6 kg) were anaesthetized and mechanically ventilated. VA-ECMO was commenced and CS was induced through intramyocardial injections of ethanol. Then, hypoxemic/hypercapnic pulmonary failure was achieved, through substantial decrease in ventilatory support. Echocardiography was used to compute left ventricular fractional area change (LVFAC) and cardiac Troponin I (cTnI) was quantified. After 5 h, the animals were euthanised and the heart was retrieved for histological evaluations. Ethanol (58 ± 23 mL) successfully induced CS in all animals. cTnI levels increased near 5000-fold. CS was confirmed by a drop in systolic blood pressure to 67 ± 14 mmHg, while lactate increased to 4.7 ± 0.9 mmol/L and LVFAC decreased to 16 ± 7%. Myocardial samples corroborated extensive cellular necrosis and inflammatory infiltrates. In conclusion, we present an innovative ovine model of severe cardiopulmonary failure in animals on VA-ECMO. This model could be essential to further characterize CS and develop future treatments.

Design and rationale of the COVID-19 Critical Care Consortium international, multicentre, observational study

INTRODUCTION

There is a paucity of data that can be used to guide the management of critically ill patients with COVID-19. In response, a research and data-sharing collaborative-The COVID-19 Critical Care Consortium-has been assembled to harness the cumulative experience of intensive care units (ICUs) worldwide. The resulting observational study provides a platform to rapidly disseminate detailed data and insights crucial to improving outcomes.

METHODS AND ANALYSIS

This is an international, multicentre, observational study of patients with confirmed or suspected SARS-CoV-2 infection admitted to ICUs. This is an evolving, open-ended study that commenced on 1 January 2020 and currently includes >350 sites in over 48 countries. The study enrols patients at the time of ICU admission and follows them to the time of death, hospital discharge or 28 days post-ICU admission, whichever occurs last. Key data, collected via an electronic case report form devised in collaboration with the International Severe Acute Respiratory and Emerging Infection Consortium/Short Period Incidence Study of Severe Acute Respiratory Illness networks, include: patient demographic data and risk factors, clinical features, severity of illness and respiratory failure, need for non-invasive and/or mechanical ventilation and/or extracorporeal membrane oxygenation and associated complications, as well as data on adjunctive therapies.

ETHICS AND DISSEMINATION

Local principal investigators will ensure that the study adheres to all relevant national regulations, and that the necessary approvals are in place before a site may contribute data. In jurisdictions where a waiver of consent is deemed insufficient, prospective, representative or retrospective consent will be obtained, as appropriate. A web-based dashboard has been developed to provide relevant data and descriptive statistics to international collaborators in real-time. It is anticipated that, following study completion, all de-identified data will be made open access.

TRIAL REGISTRATION NUMBER

ACTRN12620000421932 (http://anzctr.org.au/ACTRN12620000421932.aspx).

Validation of a method for measuring (226)Ra in drinking waters by LSC

A simple method for measuring (226)Ra in drinking waters has been validated and validation parameters are provided. It is based on the measurement by LSC of (222)Rn, at equilibrium with (226)Ra, which is absorbed into a water immiscible scintillation cocktail (Ultima Gold F) inside the counting vial. The validated application field ranges between the detection limit (2·10(-3) Bq/kg) to 150 Bq/kg. The method has proven to be reliable, effective and suitable for wide-range measuring campaigns. A summary of results obtained in recent years is also given.

Temperature Coefficient of the Refractive Index of H2O and D2O and Proposed Models of Water Structure

The temperature coefficient of the refractive index, (∂n/∂T)p, has been measured for deuterium oxide. The observed values are considered together with those previously obtained for water. The experimental data cannot be explained with the best known models of molecular polarizability, at least in the approximation generally used in these models. Therfore they are discussed on the basis of a different approximation, suggested by a well-known structural model of liquid water. It is shown that the experimental results are very well explained, in a wide range of temperature, with the hypothesis of the existence of "structural voids".

Protection of ovarian tissue from radiotherapy

Advances researches in the diagnosis and treatment of childhood, adolescent and adult cancer have greatly increased the life expectancy of premenopausal women with cancer. However, one of the serious side effects of these treatments is the risk of damage to fertility. The ovaries are very sensitive to cytotoxic and radiotherapeutic treatment. The only established method of fertility preservation is embryo cryopreservation according to the Ethics Committee of the American Society for Reproductive Medicine (2005), but this option requires the patient to be of pubertal age, have a partner or use donor sperm, and be able to undergo a cycle of ovarian stimulation, which is not possible when the radiotherapy has to be initiated immediately or when stimulation is contraindicated according to the type of cancer. For patients who need immediate radiotherapy, cryopreservation of ovarian tissue is the only possible alternative. This manuscript reports the different techniques of cryopreservation and the results of transplantation of cryopreserved ovarian tissue. The current techniques allow cryopreservation of human ovarian fragments for a long time with good follicular survival rate after thawing. Numerous studies ultimately in this field have demonstrated to improve the survival rate of the oocytes and cryopreserved follicles. Moreover this manuscript includes a case of a 17-year-old girl who had to undergo pelvic irradiation for non-Hodgkin's lymphoma and the laparoscopic treatment to preserve the fertility (Fig. 2, Ref. 47).

Antibiotic treatment in patients with altered pathophysiological pathways

The pharmacokinetics of antibiotics are reviewed under particular physiological (senescence) and pathological (renal failure, liver failure) conditions. As regards the antibiotic management in the elderly, the main problems are related to the "immunosenescence" and to kinetic modifications, occurring even in the absence of an evident renal impairment. If manifest renal failure is present, the main issue is the correct dosage, and a careful consideration of the interest of the patient when they have to undergo hemodialysis. In cases of liver failure, a number of factors impairing the kinetics of antibiotics are discussed, underlining how these are too often underestimated in therapeutical approaches. The paper is focused on the behavior of new molecules, with particular regard to Teicoplanin, Carbapenems and Fluoroquinolones.

Two unusual presentations of cervicofacial actinomycosis and review of the literature

Cervicofacial actinomycosis is the most common clinical form of actinomycosis. This bacterial infection is rare. Diagnosis is difficult, often it is definitive only after surgical excision of the cervicofacial mass. Personal experience is reported concerning two cases of cervicoactinomycosis. Diagnosis, in both cases, has been based on histological findings, not on clinical symptoms. A review of the literature shows that mainly males are affected by this condition and, in fact, both patients described here are males. Symptoms of acute infection were absent. Both patients denied any history of oromaxillofacial trauma or recent dental extraction or oral manipulations. Imaging techniques--ultrasonography and computerized tomography--were not effective in making the diagnosis, in either of these patients. Furthermore, fine needle aspiration cytology did not provide a definitive diagnosis. Both patients underwent surgical excision of the mass. Penicillin was the drug of choice in post-operative long-term treatment (one month). In one of the two men, intravenous steroids were administered. As in several reports in the literature, the definitive diagnosis was histological and not clinical.

Influence of rarefaction on the flow dynamics of a stationary supersonic hot-gas expansion

The gas dynamics of a stationary hot-gas jet supersonically expanding into a low pressure environment is studied through numerical simulations. A hybrid coupled continuum-molecular approach is used to model the flow field. Due to the low pressure and high thermodynamic gradients, continuum mechanics results are doubtful, while, because of its excessive time expenses, a full molecular method is not feasible. The results of the hybrid coupled continuum-molecular approach proposed have been successfully validated against experimental data by R. Engeln [Plasma Sources Sci. Technol. 10, 595 (2001)] obtained by means of laser induced fluorescence. Two main questions are addressed: the necessity of applying a molecular approach where rarefaction effects are present in order to correctly model the flow and the demonstration of an invasion of the supersonic part of the flow by background particles. A comparison between the hybrid method and full continuum simulations demonstrates the inadequacy of the latter, due to the influence of rarefaction effects on both velocity and temperature fields. An analysis of the particle velocity distribution in the expansion-shock region shows clear departure from thermodynamic equilibrium and confirms the invasion of the supersonic part of the flow by background particles. A study made through particles and collisions tracking in the supersonic region further proves the presence of background particles in this region and explains how they cause thermodynamic nonequilibrium by colliding and interacting with the local particles.

Mixed laryngocele: a case report and review of the literature

Laryngocele is a rare, benign dilatation of the laryngeal saccule that may extend internally into the airway or externally through the thyrohyoid membrane. Many laryngoceles are asymptomatic; sometimes they may cause a cough, hoarseness, stridor, sore throat and may present as a swelling on one or both sides of the neck. Laryngocele may be associated with supraglottic squamous cell carcinoma. Computed tomography scan is the most effective imaging method for diagnosis. Surgery is the treatment of choice. A case of large mixed laryngocele in a 75-year-old male is described together with surgical management and followup. A review of the literature is also presented.

Neoplastic transformation of oral lichen: case report and review of the literature

Aim of the present investigation was to analyse the possible malignant transformation of oral lichen planus to carcinoma, especially in the atrophic erosive forms and those displaying plaques involving the top of the tongue. A review has been made of the literature, from 1986 to the present day. This search outlines the relationship between oral lichen planus, hepatitis C virus infection, Epstein-Barr virus infection and the importance of periodic follow-up in all patients with oral lichen planus. The case is described of malignant transformation of oral lichen planus to oral cancer in a female presenting asymptomatic hepatitis C virus infection. The clinical history confirms the most important aspects of the relationship between oral lichen planus and oral cancer. Oral lichen planus should be considered as a precancerous lesion, particularly in patients presenting hepatitis C virus infection, requiring follow-up, at close intervals, starting from 3 months after diagnosis.

Dynamical behaviour of holographic gratings with a nematic film--Polymer slice sequence structure

We have studied the dynamical response of a new kind of holographic grating to a pulsed electric field. The structure, named POLICRYPS, consists of a sequence of homogeneous polymer slices separated by liquid-crystal films. We have found that both the rise and fall response times depend on the pulse duration and amplitude of the applied electric field. We propose a phenomenological explanation for this behaviour, outlining the possibility of getting response times of the order of 100 micros by properly choosing the pulse shape. Results are very interesting for developments in which POLICRYPS gratings could be proposed as basic elements in photonic devices for telecom applications, and induce to a deeper analysis of the microscopic interaction between liquid crystal and polymer interfaces in these samples.

Spectroscopic ellipsometry study of liquid crystal and polymeric thin films in visible and near infrared

In this work, we propose spectroscopic ellipsometry as a suitable method for measuring optical properties in soft materials, polymers and liquid crystals, specially selected for use in photonics applications. We show the results of our measurements on some multilayered samples, in the range from visible to the near-IR region, of interest for telecom applications. We point out potentialities and limits of the technique and compare the obtained results with another experimental method, the m-lines spectroscopy, and/or with existing data in the literature. The results about the optical parameters for the analysed materials (the nematic liquid crystal 5CB, one commercial and one lab made optical polymer, and an Indium Tin Oxide film) are useful and interesting by themselves. In fact, as a paradigmatic example, we briefly discuss how an incomplete knowledge of this kind of data can lead to a wrong design of a Bragg grating device. However, more than in the provided data, we put the interest of the present analysis in the warnings about spectroscopic ellipsometry utilization and eventually the necessity of getting complementary information.

Preservation of clonal heterogeneity of the Pneumocystis carinii-specific CD4 T cell repertoire in HIV infected, asymptomatic individuals

The loss of CD4 lymphocytes in HIV disease associates with opportunistic infections. Since diverse CD4 T cell clones respond to an opportunistic pathogen, we asked whether CD4 depletion deletes selected clones in the repertoire (vertical depletion) or it affects all clones by reducing the cell number in each progeny without affecting the overall number of clones (horizontal depletion). Understanding this point may help explain the mode of CD4 depletion and the mode of immunoreconstitution after therapy. Therefore we examined the CD4 T cell repertoire specific for Pneumocystis carinii, a relevant opportunistic pathogen in AIDS, in HIV-infected, asymptomatic individuals. We identified two patients of 36 asymptomatics for lack of proliferation to P. carinii, suggesting selective depletion of specific CD4 cells. To investigate clonal heterogeneity of P. carinii-responsive CD4 lymphocytes, specific CD4 T cell lines were generated and studied by TCR BV gene family usage and CDR3 length analysis (spectratyping). Clonal heterogeneity was similar in antigen-specific CD4 lines generated from P. carinii non-responding HIV seropositives and from controls. Thus, despite undetectable response to the pathogen, residual specific cells probably prevent overt infection and, when expanded in vitro, exhibit a clonal diversity similar to normal controls. These findings suggest a horizontal, rather than vertical, depletion in these asymptomatic patients.

Primary adenocarcinoma of the arytenoid: an ultrastructural study

Primary adenocarcinoma of the larynx is a rare neoplasm that tends to spread to both regional lymph nodes and distant sites. A case of primary adenocarcinoma of the arytenoid in a 74-year-old man is presented. The tumor was evaluated by light and electron microscopy. A high percentage of intranuclear pseudoinclusions (more than 20% of the neoplastic cells) was a peculiar characteristic of the tumor. To the best of our knowledge, such a feature has not been reported previously and should be considered a hallmark of more aggressive behavior.

Epidemiology of allergic occupational diseases induced by Tetranychus urticae in greenhouse and open-field farmers living in a temperate climate area

BACKGROUND

The role of Tetranychus urticae (TU) as an occupational allergen has thus far been investigated only in selected farmer samples.

METHODS

The prevalence of TU-induced sensitization and occupational diseases in a randomized sample of farmers living in a temperate climate area was investigated. Occupational/nonoccupational symptoms, skin prick test (SPT) results with common allergens and TU, specific occupational test results, and greenhouse or open-field sources of TU exposure were assessed. The study design was cross-sectional.

RESULTS

The prevalence of positive SPT to TU was 6%. TU-induced allergic/nonallergic complaints accounted for 65% of farmers with challenge-confirmed occupational disease. In all farmers, sensitization to common allergens was a risk factor for both current occupational and nonoccupational complaints, while TU sensitization was a prominent risk factor for occupational complaints. Furthermore, in SPT-positive farmers, only the presence of seasonal occupational complaints was significantly associated with TU sensitization. Common allergen sensitization was a risk factor for development of TU sensitization, which was more frequent in greenhouse than in open-field workers.

CONCLUSIONS

TU was a common nontraumatic, allergic occupational hazard for farmers. Since occupational seasonal symptoms could be directly related to the presence of TU sensitization, allergy to this mite should be routinely investigated in farmers.

Long-term absence of sensitization to mepivacaine as assessed by a diagnostic protocol including patch testing

BACKGROUND

Prospective assessment of non-reactivity to local anaesthetics is a frequent reason for allergy consultation.

OBJECTIVES

To investigate the clinical profiles of subjects referred for allergy evaluation; to prospectively reduce the frequency of evaluation by assessing the persistence, during clinical use, of non-reactivity to contaminant/additive-free mepivacaine; and to determine the usefulness of a diagnostic protocol involving patch testing.

METHODS

In a prospective study, 198 consecutive patients underwent collection of clinical data, skin prick tests and patch tests using allergens/antigens relevant for the investigation, and an intradermal/subcutaneous challenge procedure using contaminant/additive-free mepivacaine, as appropriate. Patients were followed up for 3 years for assessment of non-reactivity persistence using the same diagnostic protocol.

RESULTS

Only one-third of the patients had a history of previous adverse local anaesthetic reactions. Absence of sensitization to contaminant/additive-free mepivacaine persisted in all subjects completing the follow-up. Controlled challenge with mepivacaine was negative in 196 patients with both negative specific skin prick tests and patch tests but it was eventful in two subjects with positive specific patch tests. A few subjects displayed positive skin prick tests and/or patch tests for latex and/or additives.

CONCLUSIONS

A few patients had a relevant history for potential local anaesthetic-induced adverse reactions. Upon assessment of absence of sensitization and reactivity, contaminant/additive-free mepivacaine could safely be given for as long as 3 years. The patch testing was shown to be useful and safe for prediction of challenge outcomes. True allergic reactions to contaminant/additive-free mepivacaine were not observed in our patient series.

Bilateral femoral osteomyelitis with knee arthritis due to Salmonella enteritidis in a patient with systemic lupus erythematosus

A bilateral knee septic arthritis due to Salmonella enteritidis developed in a female patient affected by long-standing systemic lupus erythematosus (SLE) with cardiac and renal involvement treated with immunosuppressants and corticosteroids. Because avascular necrosis and multiple osteomyelitic areas were detected at the same time in both right and left femoral condyles, an early localisation of Salmonella into the bone was assumed. Involvement of the joints was regarded as consequence of local dissemination of infection. Ampicilline (0.2 g/kg body weight daily for 2 months) plus ciprofloxacin (1.5 g daily for 12 months) and withdrawal of immunosuppressants appeared to be effective in preventing complications of infection.

Peptic ulcer occurrence in follow-up of chronic gastritis in patients with treated and not eradicated CagA-positive Helicobacter pylori infection

The aim of the present prospective investigation was to study 49 dyspeptic Helicobacter pylori (HP)-positive (HP+) or -negative (HP), CagA+ and CagA- patients with a normal pattern or pure chronic gastritis at initial histology as well as normal features or hyperemic gastropathy at initial endoscopy in a two-year follow up. All the HP+ patients were treated with omeprazole 20 mg twice a day plus amoxicillin 1 g twice a day for two weeks. No substantial change was seen in gastritis in CagA+ patients in whom the infection was not eradicated, and, in contrast, a progressive improvement in 13/14 successfully treated patients was found. At endoscopy, a progressive change to a normal picture was seen in 8 and no change in 6 of 14 patients whose HP infection was eradicated, in contrast a worsening in the 9 HP+ patients who were still infected was observed. In particular, peptic lesions arose in 6 of 21 CagA+ patients in whom the infection was not eradicated. In conclusions, the lack of change in chronic gastritis at histology and the progressive worsening of endoscopic hyperemic gastropathy (with peptic lesions arising in 28,6%) when HP+ CagA+ infection is not eradicated, unlike the progressive improvement of the anatomoclinical condition in the patients whose infection was eradicated, draws attention to the relevance of eradicating HP in CagA+ patients even when no peptic lesion is found at initial endoscopy.

[Choanal atresia: personal surgical technique]

Choanal atresia is a rare otorhinolaryngological pathology. It occurs in 1 out of 5,000 children born alive and can be associated with other major or minor congenital abnormalities. The most important associations go under the acronym of C.H.A.R.G.E. (Coloboma, Heart disease, Atresia choanae, Retarded growth and/or development, Genital hypoplasia and Ear anomalies and/or deafness). The authors briefly describe the most salient clinical features and possible, though rare, complications of this anomaly (i.e., prolonged apnea, ab ingestis pneumonia, sinusitis, all the way to death by asphyxia). They also mention the current embryogenic theories advanced to explain the etiology. Foremost of these is the theory based on the persistence or inadequate development of the Hochstetter bucconasal membrane which is normally resorbed between the 35th and the 42nd day of intrauterine life, giving rise to the posterior nostril and primitive choana. The authors then present their personal experience with seven clinical cases of monolateral atresia in children ranging in age from 7 to 13 years, plus one case of bilateral atresia treated surgically 8 days after birth. They describe their surgical technique using intranasal and transseptal microsurgery. The patient undergoes general anesthesia in controlled hypotension. A surgical microscope with a 200-300 mm lens is used as well as the normal instrumentation for endonasal surgery. Access to the atresia lamina is gained through the floor of the nose and the lamina is perforated with a micro-osteotome. The excess bone tissue is removed and the neo-choana is calibrated and lined with the two mucosal flaps previously prepared. Then a silicone tube is positioned and anchored to the septum with a suture and left in place for approximately three weeks. Finally the authors indicate the most salient points of the other surgical techniques currently in use and they discuss their post-surgical treatment to prevent restenosis, comparing it with the experience of other authors.

Peptic ulcer occurrence in follow-up of chronic gastritis in patients with treated and not eradicated CagA-positive Helicobacter pylori infection

The aim of the present prospective investigation was to study 49 dyspeptic Helicobacter pylori (HP)-positive (HP+) or -negative (HP), CagA+ and CagA- patients with a normal pattern or pure chronic gastritis at initial histology as well as normal features or hyperemic gastropathy at initial endoscopy in a two-year follow up. All the HP+ patients were treated with omeprazole 20 mg twice a day plus amoxicillin 1 g twice a day for two weeks. No substantial change was seen in gastritis in CagA+ patients in whom the infection was not eradicated, and, in contrast, a progressive improvement in 13/14 successfully treated patients was found. At endoscopy, a progressive change to a normal picture was seen in 8 and no change in 6 of 14 patients whose HP infection was eradicated, in contrast a worsening in the 9 HP+ patients who were still infected was observed. In particular, peptic lesions arose in 6 of 21 CagA+ patients in whom the infection was not eradicated. In conclusions, the lack of change in chronic gastritis at histology and the progressive worsening of endoscopic hyperemic gastropathy (with peptic lesions arising in 28,6%) when HP+ CagA+ infection is not eradicated, unlike the progressive improvement of the anatomoclinical condition in the patients whose infection was eradicated, draws attention to the relevance of eradicating HP in CagA+ patients even when no peptic lesion is found at initial endoscopy.

Time course of 21-hydroxylase antibodies and long-term remission of subclinical autoimmune adrenalitis after corticosteroid therapy: case report

Subclinical Addison's disease is characterized by the presence of adrenal autoantibodies (ACA) and steroid 21-hydroxylase autoantibodies (21OHAb) with or without adrenal function failure. In our previous longitudinal study some patients with high titers of ACA and at stage 2 of subclinical adrenocortical failure showed disappearance of ACA with recovery of normal adrenocortical function after corticosteroid treatment for Graves' ophthalmopathy. To investigate whether corticosteroid-induced modification of the adrenal autoimmune markers can also involve 21OHAb and to evaluate whether the remission of subclinical adrenocortical failure can persist over a long period of time, we followed-up for 100 months the levels of 21OHAb and ACA as well as the metabolic markers of adrenal function in one patient with Graves' ophthalmopathy and at stage 2 of subclinical adrenocortical failure before and after corticosteroid therapy. A 34-yr-old woman with Graves' disease and active ophthalmopathy who was found to be positive for ACA and to have high PRA, low aldosterone levels, and normal basal ACTH and cortisol levels, but impaired cortisol response to ACTH was studied. The patient was treated with oral corticosteroid therapy for 6 months. After corticosteroid therapy, 21OHAb, initially positive, became negative in concomitance with the disappearance of ACA and the restoration of normal adrenal function. The disappearance of both 21OHAb and ACA and their prolonged absence during the follow-up suggest that corticosteroid treatment can induce long-term remission of subclinical adrenal insufficiency and prevent the onset of the clinical phase of the disease. Our pilot study may pave the way to future trials aimed at preventing the onset of the clinical signs of Addison's disease in ACA/21OHAb-positive patients.

Determination of uranium isotopes in food and environmental samples by different techniques: a comparison

The uranium concentration in 59 samples of bottled and tap water, mainly from northern Italy, was measured by different techniques. Results obtained by inductively coupled plasma mass spectrometry (ICP-MS), semiconductor alpha spectrometry and low level liquid scintillation counting with alpha/beta discrimination (LSC) have been compared. High resolution gamma spectrometry and semiconductor alpha spectrometry have been used to analyse uranium in a variety of organic and inorganic samples. Isotopic secular equilibrium in the 238U series may be lacking or hidden by auto-absorption phenomena, so caution should be used in evaluating gamma spectrometry data. Alpha spectrometry has also been used to ascertain the possible pollution from depleted uranium in the environment.

[Epistaxis: emergency treatment approach]

After a brief summary of the causes of severe epistaxis and the surgical choices available for treatment, the authors present their own cases study. Starting from a brief description of the anatomy involved in the system of arterial irrigation of the nasal cavities, they focus on two fundamental concepts: the basis for a proper topographic picture of the site of bleeding and the success of surgery. First and foremost is the emergence of two arterial branches from the sphenopalatine formen; this differs from what is asserted in the classical treatise on anatomy and in line with what has been stated in the Nomina Anatomica, approved during the X World Congress on Anatomy (Tokyo 1975). Secondly, focus is placed on the existence of two important anastomotic systems in the arterial circulation of the nasal cavities: the one between nasal septum and anterior-posterior ethmoid arteries and the one between the lateral-posterior nasal and nasoseptal arteries. In the literature the failure of surgery in treating severe epistaxis is explained by the onset of supplementary anastomotic circulation. The indications for surgical treatment of epixstaxes are: copious bleeding in hospital or after the packing has been removed; underlying pathology or general status which has been aggravated by the packing; patient which has already been staunched several times. The results of 31 epistaxis procedures are presented: 8 (25.81%) upper and 23 (74.19%) posterior. The upper epistaxes were treated as follows: 3 cases with anterior ethmoid ligature, two of which failed; 2 cases with combined ligature of the anterior and posterior ethmoid; 3 cases of successful septoplasty. The posterior epistaxes were treated as follows: 11 cases of ligature of the lateral-posterior nasal artery, 2 of which failed; 12 cases of successful combined ligature of lateral-posterior nasal and nasoseptal arteries. These results confirm that it is possible to effectively resolve surgically severe epistaxis using microsurgery or transnasal endoscopy based on in depth knowledge of the complex architecture of the arterial circulation within the district of the paranasal sinuses, possible anatomic variations and collateral circulation.

[Description of a particular case of the so-called Schmincke lymphoepithelioma and study of the correlation with Epstein-Barr virus]

For poorly differentiated rhinopharyngeal carcinomas, the clinical presentation (association with the Epstein-Barr virus, paraneoplastic syndromes, onset of lymphoma) and the histopathological features can be polymorphous and they can confound or delay diagnosis and preparation of an adequate treatment plan (radio-chemotherapy). Often these neoplasms arise as clinically primitive laterocervical metastases, masked by clinical findings and a history that can lead to the mistaken diagnosis of systemic lymphoproliferative processes such as Hodgkin's disease. Here an observation of this type is presented in a young patient (19 years old) who came under observation for a laterocervical tumefaction recurrent from a previous exeresis performed at another hospital and symptoms of serotine febricula, dysphagia and serology positive for the Epstein-Barr virus (EBV). The patient underwent surgery and then radiotherapy and has been under close post-operative follow-up for two years. To date the patient's condition--both local and general--is good. The particular histology of the neoformation lies in the abundant infiltration of plasma cell and lymphocyte eosinophils, at times in blastic form. Moreover, elements with a large clear nucleus and evident nucleolus (Hodgkin-like) and scattered multinucleate Langhans-type giant cells can be seen. Immunohistologically the tumor cells markedly express for cytokeratin and the latent membrane protein (LMP1) of the Epstein-Barr virus (EBV) and show a high growth fraction. Under the electron microscope, the plurinucleate giant cells present large nuclei with morphology similar to that of tumor cells. The clear cytokeratin-positivity of the tumor elements and the histological and ultrastructural features mentioned led to the diagnosis of a massive metastasis from lymphoepithelial carcinoma, the Schmincke variant, plus EBV infection of the neoplastic cells. The authors conclude assuming that the particular granulomatous reaction is due to the host's reaction to the tumor cells, but also to the reaction to the viral antigens. In the former case we find an attempt to limit the carcinomatous process; in the latter it is a response caused by the EBV and is not, apparently, aimed at protecting against the neoplasm rather it facilitates the neoplastic process.

[Biphasic hypopharyngeal synovial sarcoma: ultrastructural, cytofluorometric and immunohistochemical study and brief review of the literature]

Synovial sarcomas account for 7-10% of all soft tissue malignancies and the rare head and neck region location accounts for an average 5% of them. A brief review of the data in the Literature has shown that not more than one hundred cases of cervical-facial synovial sarcoma have been reported. In the head and neck locations this form of tumor is significantly less aggressive, with a higher survival rate and a recurrence rate much lower than the 60-70% shown for other locations in the limbs. After a brief review of the Literature, Authors present a rare clinical case of hypopharyngeal synovial sarcoma which recently came under observation. Despite the accurate diagnostic procedure, after surgical removal of the tumor by CO2 laser microlaryngoscopy, diagnosis required the use of histological and ultrastructural techniques. CT and NMR of the neck using contrast medium showed that the structure of the neoformation was similar to that of the soft tissues, it was 3-4 cm in diameter, located in the hypopharynx and had an extensive surface in contact with the left glossoepiglottic groove. The lesion appeared to involve the free edge of the aryepiglottic fold, coming into contact with the free edge of the epiglottis; it could not be dissociated form the epiglottis and obliterated both the homolateral glossoepiglottic vallecula and the pyriform sinus. Structural analysis after radiography with a contrast medium showed a marked impregnation of the lesion, indicative of high degree of vascolarization. Ultrastructural, cytofluormetric and immunohistochemical analyses were performed on the neoplasm in order to process all these data together with the clinical parameters; in other words a multi-parameter evaluation was performed, as suggested by other Authors, to determine the therapy and arrange more accurate monitoring of this patient, victim of a neoplasm with a high potential for metastases.

[Upper maxillary cysts: embryogenic and surgical considerations in our cases]

Upper maxillary cysts are a chapter in otorhinolaryngological pathology which have been relatively neglected by the Literature. The reason for this most likely lies in the difficulty in producing a nosographic picture of these pathologies which border on other surgical fields (dentistry, maxillofacial surgery), and because they show significant clinical and etiopathogenic polymorphism. The elements that characterize upper maxillary cysts as a separate clinical entity are basically their cystic nature and origin within the upper maxillary bone, although they can expand widely within the medio-facial region (nasal vestibule, oral vestibule, nasolabial region, palate, maxillary sinus). After having reviewed the various classification schemes proposed over the years, and briefly examining the main clinical and etiopathogenic characteristics and principles for surgical treatment, the present work offers a surgical case study, together with the related iconography. Moreover this work does not neglect embryogenic considerations which are indispensable for the study of some of these pathologies. In this manner the results for 35 surgical procedures on upper maxillary cysts performed from 1989 to 1996 are presented and classified following the Cudennec classification module (1991). This study shows the variety of possible clinical manifestations for these pathologies. Such a variety makes correct diagnosis imperative--today facilitated by modern imaging techniques--and requires diversifying the surgical approach, conditioned not only by the site, extension and nature of the specific lesion, but also by the related symptoms. The significant progress in surgical techniques has made increasingly functional surgery possible and led to the abandonment of such conventional radical techniques as the Caldwell-Luc procedure. Moreover, CT and NMR have provided good image definition, specifying precisely the limits and extensions and, in most cases, facilitating diagnosis of the nature of the disorder with direct and indirect signs of the cystic nature of the lesions whenever the clinical data proves inadequate.

[Morphological study of the palatine tonsils: clinical and histopathological considerations]

This study examined 71 pediatric tonsillectomy patients through accurate case history and clinical examination, placing particular emphasis on pathologies concomitant to tonsillopathy. In an attempt to find anatomo-clinical correlations, these data were processed together with the results of a histomorphological study of thetonsil epithelium, performed on all tonsillectomy samples. The majority of these patients were females and none more than 13 years of age. Numerous pathologies were found associated with the tonsillopathy and in varying combinations, first and foremost of which was adenoid hypertrophy. Only approximately one fifth of the patients did not show any concomitant pathology of note. All patients presented a history of recurrent pharyngotonsillitis (at least 4 episodes a year) with symptoms arising from 1 to 10 years prior to surgery. The concomitant pathologies included: respiratory, cutaneous and food allergies, asthma, obstructive sleep apnea, rheumatic diseases, etc. From the histomorphological point of view, particular modifications were found in the follicle epithelium and interstitial cells of the palatine tonsil. An exasperated fibrotic interstitial reaction and chronic duration of the disease appeared to prevent tonsil filter function, facilitating chronicization of the tonsillopathy or onset of recurrent infections and concomitant allergies. In the allergic patients the tonsil epithelium was thickened and compact and showed various degrees of chorion edema, in agreement with what is found in the literature. On the contrary, few morphostructural palatine tonsil mutations were found in those subjects which did not present any concomitant pathology or were affected by tonsillopathy of brief duration. All the histomorphological modifications encountered appear related to the individual patient history, confirming the hypothesis that tonsil epithelium can not only condition the evolution of tonsillopathy--reflecting the effect of various factors--but, above all, it directs the immune response, thus playing a role in the development of various concomitant pathologies.

Theory for a new full-vectorial beam-propagation method in anisotropic structures

We present a theoretical model of light-beam propagation in anisotropic and inhomogeneous dielectric structures obtained as a direct extension of the scalar fast-Fourier-transform beam-propagation method. We solve Maxwell's equations in a generalized geometrical optics approximation, in which the reflected fields are neglected. This is a full-vectorial model because it accounts for the polarization effects that are due to both the anisotropy and the inhomogeneity of the medium.

Non linearly induced self waveguiding structure in dye doped nematic liquid crystals confined in capillaries

We report on experiments dealing with the propagation of a collimated laser beam in a dye doped nematic confined in a capillary of optical fiber size. The nematic is aligned in a such a way that the source beam is self focused. The behavior of the beam - focusing, multifocus regime, filamentation and undulation - already observed in larger cylindrical geometry and pure nematic is shown here to be reproduced in the dye doped medium, at much lower powers. Another feature is reported here: a stable regime looking like a waveguide appears in certain conditions, in which the beam to propagate in a narrow tube. This regime is simply modeled in terms of saturated reorientation of the nematic.

Subclinical hypothyroidism resulting from autoimmune thyroiditis in female patients with endogenous depression

Thyroid function and presence of thyroid autoantibodies were assessed in a group of 75 consecutive female patients with mood disturbances and in a group of 38 healthy women of similar age recruited as controls. Nine patients suffered from major (endogenous) depression and 66 from minor (neurotic) depression. The individual patients had normal values of circulating thyroid hormones. Nevertheless, endogenously depressed patients had total serum triiodothyronine (M +/- SE = 1.49 +/- 0.09 nmol/l) and both total (83.9 +/- 4.3 nmol/l) and free serum thyroxine (13.9 +/- 1.1 pmol/l) lower than in the group of minor depressed and in the group of controls (p < 0.01, in both comparison). The median value of serum thyrotropin was 5.22 mU/l in the major depressed patients versus 1.72 mU/l in the minor depressed and 1.69 mU/l in the controls. Thyroid function test results in the minor depressed group did not significantly differ from those in the controls. Five of the 9 endogenously depressed patients were subclinically hypothyroid, while none of the 66 patients with minor depressive disorder showed thyroid dysfunction. Antibodies against thyroglobulin and/or thyroid peroxidase were positive in all the 5 endogenously depressed women with subclinical hypothyroidism, revealing a symptomless autoimmune thyroiditis, which was also confirmed by ultrasonography in all cases and histopathologically demonstrated in one case. None of the endogenously depressed women without thyroid dysfunction and none of the 66 minor depressives were seropositive for thyroid autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)