Exploring Microphone Technologies for Digital Auscultation Devices

The aim of this work is to present a preliminary study for the design of a digital auscultation system, i.e., a novel wearable device for patient chest auscultation and a digital stethoscope. The development and testing of the electronic stethoscope prototype is reported with an emphasis on the description and selection of sound transduction systems and analog electronic processing. The focus on various microphone technologies, such as micro-electro-mechanical systems (MEMSs), electret condensers, and piezoelectronic diaphragms, intends to emphasize the most suitable transducer for auscultation. In addition, we report on the design and development of a digital acquisition system for the human body for sound recording by using a modular device approach in order to fit the chosen analog and digital mics. Tests were performed on a designed phantom setup, and a qualitative comparison between the sounds recorded with the newly developed acquisition device and those recorded with two commercial digital stethoscopes is reported.

Aligned fibrous decellularized cell derived matrices for mesenchymal stem cell amplification

Biochemical and biophysical stimuli of stem cell niches finely regulate the self-renewal/differentiation equilibrium. Replicating this in vitro is technically challenging, making the control of stem cell functions difficult. Cell derived matrices capture certain aspect of niches that influence fate decisions. Here, aligned fibrous matrices synthesized by MC3T3 cells were produced and the role of matrix orientation and stiffness on the maintenance of stem cell characteristics and adipo- or osteo-genic differentiation of murine mesenchymal stem cells (mMSCs) was investigated. Decellularized matrices promoted mMSC proliferation. Fibrillar alignment and matrix stiffness work in concert in defining cell fate. Soft matrices preserve stemness, whereas stiff ones, in presence of biochemical supplements, promptly induce differentiation. Matrix alignment impacts the homogeneity of the cell population, that is, soft aligned matrices ameliorate the spontaneous adipogenic differentiation, whereas stiff aligned matrices reduce cross-differentiation. We infer that mechanical signaling is a dominant factor in mMSC fate decision and the matrix alignment contributes to produce a more homogeneous environment, which results in a uniform response of cells to biophysical environment. Matrix thus produced can be obtained in vitro in a facile and consistent manner and can be used for homogeneous stem cell amplification or for mechanotransduction-related studies.

On the influence of surface patterning on tissue self-assembly and mechanics

Extracellular matrix assembly and composition influence the biological and mechanical functions of tissues. Developing strategies to control the spatial arrangement of cells and matrix is of central importance for tissue engineering-related approaches relying on self-assembling and scaffoldless processes. Literature reports demonstrated that signals patterned on material surfaces are able to control cell positioning and matrix orientation. However, the mechanisms underlying the interactions between material signals and the structure of the de novo synthesized matrix are far from being thoroughly understood. In this work, we investigated the ordering effect provided by nanoscale topographic patterns on the assembly of tissue sheets grown in vitro. We stimulated MC3T3-E1 preosteoblasts to produce and assemble a collagen-rich matrix on substrates displaying patterns with long- or short-range order. Then, we investigated microstructural features and mechanical properties of the tissue in uniaxial tension. Our results demonstrate that patterned material surfaces are able to control the initial organization of cells in close contact to the surface; then cell-generated contractile forces profoundly remodel tissue structure towards mechanically stable spatial patterns. Such a remodelling effect acts both locally, as it affects cell and nuclear shape and globally, by affecting the gross mechanical response of the tissue. Such an aspect of dynamic interplay between cells and the surrounding matrix must be taken into account when designing material platform for the in vitro generation of tissue with specific microstructural assemblies.

Apparent diffusion coefficient obtained by magnetic resonance imaging as a prognostic marker in glioblastomas: correlation with MGMT promoter methylation status

OBJECTIVE

To evaluate whether apparent diffusion coefficient (ADC) values can predict the status of MGMT of glioblastoma multiforme (GBM) and correlate with overall survival (OS) and progression-free survival (PFS).

METHODS

This retrospective study included 47 patients with pathologically proven glioblastoma. All of them underwent MR DWI study before surgery (mean time 1 week) and the status of methylguanine-DNA-methyltransferase (MGMT) promoter methylation was searched for. Minimum apparent diffusion coefficient (ADC) values were evaluated. OS and PSF parameters were calculated, and Student's t-test, Kaplan-Meier curves, linear and Cox regression were performed.

RESULTS

Twenty-five patients showed positive methylation of the MGMT promoter. Patients showing MGMT promoter methylation had higher minimum ADC values, and they survived longer than those without MGMT promoter methylation. The median ADCmin value of 0.80 represents the cutoff value able to distinguish between methylated and un-methylated patients. Patients showing minimum ADC values higher than 0.80 survived longer than patients with minimum ADC values lower than 0.80. A linear correlation between minimum ADC values vs. the OS and PFS was observed.

CONCLUSIONS

Minimum ADC values in glioblastoma multiforme could be used as a preoperative parameter to estimate the status of MGMT promoter methylation and the survival of patients.

BTG2 loss and miR-21 upregulation contribute to prostate cell transformation by inducing luminal markers expression and epithelial-mesenchymal transition

Prostate cancer is one of the leading causes of cancer-related death in men. Despite significant advances in prostate cancer diagnosis and management, the molecular events involved in the transformation of normal prostate cells into cancer cells have not been fully understood. It is generally accepted that prostate cancer derives from the basal compartment while expressing luminal markers. We investigated whether downregulation of the basal protein B-cell translocation gene 2 (BTG2) is implicated in prostate cancer transformation and progression. Here we show that BTG2 loss can shift normal prostate basal cells towards luminal markers expression, a phenotype also accompanied by the appearance of epithelial-mesenchymal transition (EMT) traits. We also show that the overexpression of microRNA (miR)-21 suppresses BTG2 levels and promotes the acquisition of luminal markers and EMT in prostate cells. Furthermore, by using an innovative lentiviral vector able to compete with endogenous mRNA through the overexpression of the 3'-untranslated region of BTG2, we demonstrate that in prostate tumor cells, the levels of luminal and EMT markers can be reduced by derepression of BTG2 from microRNA-mediated control. Finally, we show that the loss of BTG2 expression confers to non-tumorigenic prostate cells ability to grow in an orthotopic murine model, thus demonstrating the central role of BTG2 downregulaton in prostate cancer biology.

Clinical applications of dynamic susceptibility contrast perfusion-weighted MR imaging in brain tumours

Magnetic resonance imaging (MRI) with a dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) sequence to study brain tumours provides information on the haemodynamic characteristics of the neoplastic tissue. Brain perfusion maps and calculation of perfusion parameters, such as relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) allow assessment of vascularity and angiogenesis within tumours of the central nervous system (CNS), thus providing additional information to conventional MRI sequences. Although DSC-PWI has long been used, its clinical use in the study of brain tumours in daily clinical practice is still to be defined. The aim of this review was to analyse the application of perfusion MRI in the study of brain tumours by summarising our personal experience and the main results reported in the literature.

Negative stress echo: Further prognostic stratification with assessment of pressure–volume relation

BACKGROUND

A maximal negative stress echo identifies a low risk for subsequent hard events subset. However, the potentially prognostically relevant information on global contractile reserve on the left ventricle is missed by standard regional wall motion assessment, and can be obtained by end-systolic pressure-volume relationship (PVR) evaluation.

AIM

To assess the relative prognostic value of PVR in patients with negative stress echo.

METHODS

We enrolled 99 consecutive patients (age=61+/-14 years; 81 males, LVEF 47+/-14%, WMSI=1.42+/-0.50) with negative exercise stress echo for standard wall motion criteria. To build the PVR, the force was determined at rest and peak stress as the ratio of the systolic pressure/end-systolic volume index. All patients were followed-up on medical therapy.

RESULTS

Median follow-up was 21 months (interquartile range 12-26). Twenty-nine events have been observed: 6 deaths, 10 heart failure related hospitalization and 13 worsening NYHA class of >or=1 grade. Using Cox's proportional hazard model the best independent predictor of total events was SP/ESV index change (rest-stress) <1.5 mm Hg/ml/m(2) as determined by ROC analysis cut-off (RR=29, p=0.001, sensitivity=80%, specificity=93%). The overall survival and event-free survival was 34% in patients with change (rest-stress) SP/ESV index<1.5 mm Hg/ml/m(2) and 97% in whose with >1.5 mm Hg/ml/m(2).

CONCLUSIONS

In patients with negative stress echo, a preserved global contractility response can be easily identified through stress-induced variation in SP/ESV index, with powerful further risk stratification.

Dissection of NT3 functions in vivo by gene replacement strategy

The development of the peripheral nervous system is governed in part by a family of neurotrophic factors that signal through Trk tyrosine kinase receptors. Neurotrophin 3 (NT3) ablation in mice causes a more severe neuronal phenotype than deletion of its receptor TrkC, suggesting that NT3 acts also through other non-preferred Trk receptors. To study the role of low-affinity ligand receptor interactions in vivo, we have replaced the Nt3 gene with the gene for brain-derived neurotrophic factor (BDNF), a TrkB ligand. As in NT3 and TrkC null mice, the proprioception system of these mutants failed to assemble. However, sensory fiber projections in the embryonic spinal cord suggest chemotropic effects of BDNF in vivo. In the dorsal root ganglia, the developmental dynamic of neuron numbers demonstrates that NT3 is required for activation of TrkB during neurogenesis and that TrkA is required during target tissue innervation. In the inner ear, the ectopic BDNF rescued the severe neuronal deficits caused by NT3 absence, indicating that TrkB and TrkC activate equivalent pathways to promote survival of cochlear neurons. However, specific increased innervation densities suggest unique functions for BDNF and NT3 beyond promoting neuronal survival. This mouse model has allowed the dissection of specific spatiotemporal Trk receptor activation by NT3. Our analysis provides examples of how development can be orchestrated by complex high- and low-affinity interactions between ligand and receptor families.

Neurotrophin-3 modulates noradrenergic neuron function and opiate withdrawal

Somatic symptoms and aversion of opiate withdrawal, regulated by noradrenergic signaling, were attenuated in mice with a CNS-wide conditional ablation of neurotrophin-3. This occurred in conjunction with altered cAMP-mediated excitation and reduced upregulation of tyrosine hydroxylase in A6 (locus coeruleus) without loss of neurons. Transgene-derived NT-3 expressed by noradrenergic neurons of conditional mutants restored opiate withdrawal symptoms. Endogenous NT-3 expression, strikingly absent in noradrenergic neurons of postnatal and adult brain, is present in afferent sources of the dorsal medulla and is upregulated after chronic morphine exposure in noradrenergic projection areas of the ventral forebrain. NT-3 expressed by non-catecholaminergic neurons may modulate opiate withdrawal and noradrenergic signalling.

Spatial shaping of cochlear innervation by temporally regulated neurotrophin expression

Previous work suggested qualitatively different effects of neurotrophin 3 (NT-3) in cochlear innervation patterning in different null mutants. We now show that all NT-3 null mutants have a similar phenotype and lose all neurons in the basal turn of the cochlea. To understand these longitudinal deficits in neurotrophin mutants, we have compared the development of the deficit in the NT-3 mutant to the spatial-temporal expression patterns of brain-derived neurotrophic factor (BDNF) and NT-3, using lacZ reporters in each gene and with expression of the specific neurotrophin receptors, trkB and trkC. In the NT-3 mutant, almost normal numbers of spiral ganglion neurons form, but fiber outgrowth to the basal turn is eliminated by embryonic day (E) 13.5. Most neurons are lost between E13.5 and E15.5. During the period preceding apoptosis, NT-3 is expressed in supporting cells, whereas BDNF is expressed mainly in hair cells, which become postmitotic in an apical to basal temporal gradient. During the period of neuronal loss, BDNF is absent from the basal cochlea, accounting for the complete loss of basal turn neurons in the NT-3 mutant. The spatial gradients of neuronal loss in these two mutants appear attributable to spatial-temporal gradients of neurotrophin expression. Our immunocytochemical data show equal expression of their receptors, TrkB and TrkC, in spiral sensory neurons and thus do not relate to the basal turn loss. Mice in which NT-3 was replaced by BDNF show a qualitative normal pattern of innervation at E13.5. This suggests that the pattern of expression of neurotrophins rather than their receptors is essential for the spatial loss of spiral sensory neurons in NT-3 null mutants.

Mutations in Cdh23 cause nonsyndromic hearing loss in waltzer mice

Mutations at the waltzer (v) locus result in deafness and vestibular dysfunction due to degeneration of the neuroepithelium within the inner ear. Here, we use a positional cloning approach to show that waltzer encodes a novel cadherin (Cdh23), which is most closely related to the Drosophila Fat protein. A single nucleotide deletion in the v(J) allele and a single nucleotide insertion in the v allele are predicted to truncate each protein near the N-terminus and produce a functional null allele. In situ hybridization analysis showed that Cdh23 is expressed in the sensory hair cells of the inner ear, where it has been suggested to be a molecule critical for crosslinking of the stereocilia. In addition, Cdh23 is expressed in the urticulo-saccular foramen,the ductus reuniens, and Reissner's membrane, suggesting that Cdh23 may also be involved in maintaining the ionic composition of the endolymph. Finally, mutations in human CDH23 have recently been described for two loci, DFNB12 and USH1D, which cause nonsyndromic deafness, identifying waltzer as a mouse model for human hearing loss.

Can benchmarking be applied to radiation protection? And is it useful?

PURPOSE

Any program of protection from the ionizing radiations used for health care must ultimately lead to the total prevention of graduated effects and to the limitation of probabilistic effects to acceptable levels. The latter are the more dangerous because they may occur even at very low doses and involve the whole population including unexposed subjects; these effects may appear in the generations to come. The specific protection of the health of operators, patients, and the general population, depends on a series of physical-technical and bureaucratic-administrative factors. These must be known and applied based on precise reference standards, recommended or stated by law, as well as on appropriately regulated and controlled procedures. We chose to apply the benchmarking method to radiation protection in order to standardize and increase the efficacy of prevention and to plan, according to Deming's cycle, the continuous improvement of radiation protection performance.

METHOD

Benchmarking is a qualitative intercomparison method widely used in business economics to improve performance referring to best practice and the best in class. When applied in a department where all the partners belong (internal benchmarking), the method features a subdivision into different (sub)processes integrated according to the logic of problem-solving. These stages are: planning: 1) identifying benchmarking issues; 2) identifying the participants; 3) deciding the data collection method; 4) data collection; analysis: 5) measuring the gap; 6) planning future performance; integration: 7) reporting the results; 8) setting the functional goals; action: 9) developing and implementing plans; 10) checking results and resetting the target. The gross subdivision of resources into human and structural permits to check the gap between an actual and an ideal setting separately. Thus, the procedures will give information on the human factor which will be periodically checked in loco relative to all active and passive conducts, while standards will be used to assess the available spaces, facilities and equipment, as well as the relative regular activity. Specific physical-technical and bureaucratic-administrative indices will be needed in both cases.

RESULTS AND DISCUSSION

Solving the operators' doubts and consequently decreasing the statistical errors and/or the cases of incorrect performance has resulted in improved rendered quality, which will be further increased after the planned replacement of substandard or unsafe equipment. Meanwhile, the early application of equipment quality controls has helped rationalize and markedly decrease maintenance costs, which results in possible technologic investment to improve emergency imaging. Greater attention to their protection has made patients feel an improvement in received quality and has increased empathy in general. Total quality, as compared with the best practice, has increased thanks to the positive stimulus from standardization, emulation and sharing, and not only to the controls performed. It is difficult to evaluate the management indices, especially the performance efficacy, that is the relationship between radiation protection and results, because the work is in progress and we still lack the actual data on the decrease in accidents at work or occupational diseases of the operators. Moreover, the epidemiological data on radiation-induced conditions will be difficult to collect and interpret, which will make the dynamics of lawsuits for unwarranted or excessive exposure a useful and more readily available piece of information. Finally, relative to economic results, we would like to stress that no additional costs have been necessary to implement safety and quality in a setting involving, directly or indirectly, thousands of people. (ABSTRACT TRUNCATED)

Brain-derived neurotrophic factor-deficient mice develop aggressiveness and hyperphagia in conjunction with brain serotonergic abnormalities

Brain-derived neurotrophic factor (BDNF) has trophic effects on serotonergic (5-HT) neurons in the central nervous system. However, the role of endogenous BDNF in the development and function of these neurons has not been established in vivo because of the early postnatal lethality of BDNF null mice. In the present study, we use heterozygous BDNF(+/-) mice that have a normal life span and show that these animals develop enhanced intermale aggressiveness and hyperphagia accompanied by significant weight gain in early adulthood; these behavioral abnormalities are known to correlate with 5-HT dysfunction. Forebrain 5-HT levels and fiber density in BDNF(+/-) mice are normal at an early age but undergo premature age-associated decrements. However, young adult BDNF(+/-) mice show a blunted c-fos induction by the specific serotonin releaser-uptake inhibitor dexfenfluramine and alterations in the expression of several 5-HT receptors in the cortex, hippocampus, and hypothalamus. The heightened aggressiveness can be ameliorated by the selective serotonin reuptake inhibitor fluoxetine. Our results indicate that endogenous BDNF is critical for the normal development and function of central 5-HT neurons and for the elaboration of behaviors that depend on these nerve cells. Therefore, BDNF(+/-) mice may provide a useful model to study human psychiatric disorders attributed to dysfunction of serotonergic neurons.

[Follow-up chest radiography in surgical breast cancer patients]

PURPOSE

We investigated to what extent the diagnostic findings of chest radiography can improve prognosis and treatment in surgical breast cancer patients. We also reviewed the literature and our personal findings to choose the optimal follow-up frequency to meet therapeutical and management needs, including radiation protection.

MATERIAL AND METHODS

We retrospectively reviewed 1556 chest radiographs of 195 surgical patients with M0 breast cancer performed January 1990 to December 1996. Patient's history and clinical data were accurately reviewed to investigate the relation between protocol type and results. The maximalist or intensive protocol featured 3 chest radiographs a year, even in the absence of any specific signs; the results were reviewed in terms of early diagnosis and prolongation of life.

RESULTS

Only 13% of the examinations had been performed following a specific clinical indication, while 87% had been performed for a generic referral. Recurrences were found in 0.6% only of the latter examinations, which means that radiography provided no diagnostic improvement or important change in treatment in as much as 99.4% of cases. In 1997 radiographic follow-up was made triannual instead of biannual as it used to be.

DISCUSSION AND CONCLUSIONS

In the absence of specific clinical indications, chest radiography can be performed in the two projections once a year. More aggressive protocols requiring more frequent examinations are not justified, as the patient's life expectancy is not increased. Yearly examinations permit to meet economic and management needs, with a better use of time, staff and materials. Moreover, the clinical-diagnostic yield is not affected by the skipping of unselected examinations. Finally, another pro is the technical thoroughness of the examination with orthogonal projections and the possibility to use ionizing radiations, which improves the management of clinical risks. Maximum radiologist-oncologist cooperation in clinical practice can improve both diagnostic efficiency and treatment efficacy, by reducing the population dose and rationalizing the use of human, instrumental, structural and financial resources.

Criteria for planning radiologic equipment replacement

INTRODUCTION

The correct procedure for acquiring new radiologic equipment includes technology assessment, the analysis of needs, equipment purchasing/renting, room setting, equipment installation, management, and planned replacement. Therefore we need a simple, independent and objective procedure to analyze the technical and economic need of replacing a piece of radiologic equipment. We report on a simple evaluation method permitting to judge radiologic equipment acceptability, as stated by the relevant Italian laws.

MATERIAL AND METHODS

Our system is adapted from similar business applications; it analyzes five main parameters, namely: support services (equipment age and working age, maintenance charges and the availability of spare parts), equipment function (life-supporting, diagnostic or treatment units; in an emergency department), the cost/benefit ratio, clinical efficacy and overall safety. If needed, another parameter can be added: accessibility by patients, involving such issues as time and ease of access to the examination/equipment and its location. The different criteria of radiologic equipment acceptability can be used to calculate the acceptability index (AI), as follows: AI = 0.4 (a + b + c + d) + 0.2 (e + f + g) + (h) where: (a) = unit's age, (b) = maintenance charges, (c) = non-use times, (d) = availability of spare parts, (e) = equipment function, (f) = operational analysis, (g) = diagnostic efficacy, (h) = safety. Each parameter is given a score according to the existing situation.

RESULTS

Four scenarios can result from the analysis: 1) the equipment needs not be replaced; 2) replacement is not urgent and another check is scheduled within 12 months; 3) replacement must be scheduled; 4) the equipment must be urgently replaced (within 12 months). In the latter case, the unit should be disconnected at once if safety measures are violated irremediable.

CONCLUSIONS

Our method is easy to use and a valid tool also for radioprotection purposes: the main difficulty is collaborating with the administrative offices in charge of equipment purchasing and maintenance. The facility's head radiologist can use the analysis to provide economic (and thus objective and indisputable) data about the need to replace, supplement, update, or repair pieces of diagnostic imaging equipment. Also, maintenance form and terms could be renegotiated and radioprotection improved. The Italian Society of Medical Radiology (SIRM) might suggest this method to the Italian Ministry of Health as the basis of the parliamentary bill on radiologic equipment replacement.

[Management of human resources, materials, and organization processes in radioprotection]

INTRODUCTION

The radiologist must learn to face daily management responsibilities and therefore he/she needs the relevant knowledge. Aside from the mechanisms of management accounting, which differ only slightly from similar analysis methods used in other centers, the managing radiologist (the person in charge) is directly responsible for planning, organizing, coordinating and controlling radiation protection, a major discipline characterizing diagnostic imaging. We will provide some practical management hints, keeping in mind that radiation protection must not be considered a simple (or annoying) technical task, but rather an extraordinary positive element for the radiologist's cultural differentiation and professional identity.

MATERIAL AND METHODS

The managing radiologist can use the theory and practice of management techniques successfully applied in business, customizing them to the ethics and economics of health care. Meeting the users' needs must obviously prevail on balancing the budget from both a logical and an accounting viewpoints, since non-profit organizations are involved. In radiological practice, distinguishing the management of human from structural resources (direct funding is not presently available) permits to use internal benchmarking for the former and controlled acquisition and planned replacement of technologies in the latter, obviously after evaluation of specific indicators and according to the relevant laws and technical guidelines.

RESULTS AND DISCUSSION

Managing human resources means safeguarding the patient, the operator and the population, which can be achieved or improved using benchmarking in a diagnostic imaging department. The references for best practice will be set per tabulas based on the relevant laws and (inter)national guidelines. The physical-technical and bureaucratic-administrative factors involved will be considered as process indices to evaluate the gap from normal standards. Among the different elements involved in managing structural resources, the appropriate acquisition of a piece of radiological equipment is important from both a radiation protection and an economic viewpoints. In the acquisition process, the first and the last steps (technology assessment and planned replacement, respectively) are specifically important for the radiologist and play a major role in global management. In both cases the radiologist must be able to lay out autonomous and objective working projects, also using evaluation algorithms.

Frequency of a mutated CCR-5 allele (delta32) among Italian healthy donors and individuals at risk of parenteral HIV infection

The aim of this study was to assess the frequency of a truncated allele of the CCR-5 gene (delta32) in Italy, and address its possible role in parenteral HIV transmission, as well as its influence in HIV-associated disease progression. In 371 unrelated seronegative healthy blood donors the delta32 allele frequency was 0.047; this figure was significantly different from those reported in northern America and northern Europe populations. However, delta32 allele frequency in healthy individuals did not differ significantly from that found in 54 seronegative drug users (0.065), 98 seronegative hemophiliacs (0.051), and 81 seropositive hemophiliacs (0.049). Although in seropositive hemophiliacs the wt/delta32 heterozygous genotype was associated with a trend to a slower decline in CD4+ cell counts, its presence did not seem to influence disease progression, as comparable delta32 allele frequency frequencies were found among progressing (0.042) and nonprogressing (0.111) patients. These data do not seem to support a protective role of the delta32 allele in preventing HIV infection through the parenteral route, or in influencing the natural history of the disease in this particular risk category, although the delta32 heterozygous state was associated with lower plasma viremia levels. On the other hand, the finding of non-syncytium-inducing HIV strains in the majority of delta32 heterozygous seropositive patients suggests that its presence could not be a major factor in driving a switch toward more cytopathic, T-tropic HIV strains through selective pressure in coreceptor usage.

Evidence for a role of truncated trkC receptor isoforms in mouse development

The trkC locus encodes several receptors for neurotrophin-3, including the well studied full-length tyrosine kinase isoform, in addition to receptor isoforms lacking the kinase active domain. TrkC receptors are widely expressed throughout mouse development in many different organs. To investigate the function of truncated receptors in vivo and to identify cell types that are biologically responsive to this gene product, we have overexpressed a physiological truncated trkC isoform in the mouse. Mice overexpressing this receptor develop to term but die in the first postnatal days. High levels of transgene expression result in severe developmental defects in the peripheral nervous system and in the heart. The severity of neuronal losses observed in these animals suggests that truncated receptors may act by sequestering neurotrophin, thus, closely relating this mouse model to the neurotrophin-3-deficient one. Lower levels of exogenous truncated receptor in transgenic mice result in a more modest phenotype and, in some neuronal populations, do not cause neural deficits. Taken together, these data suggest that truncated trkC receptor isoforms may have modulatory functions in development.

[Assessment of microvascularization around the plaques in Peyronie's disease with Doppler color ultrasonography, power Doppler and ultrasonography contrast media]

INTRODUCTION

The origin of Peyronie's disease remains obscure although the first report of this condition dates back to 1743. The disease prevalence in 388.6 in 100,000 population and little physiopathologic information is available. Repeated microtrauma to the tunica albuginea appears to favor the onset of inflammatory phenomena which result in fibrosis and calcification. The disease activity produces a microvascularization around the fibrocalcific plaques. We studied the evolution of the inflammatory process in Peyronie's disease relative to clinical symptoms, in order to optimize treatment follow-up.

MATERIAL AND METHODS

We examined 20 patients with Peyronie's disease aged 34 to 56 years using a GE Sonora Logic 500 MD US scanner with linear probes of 7.5 and 13 MHz. The microvascularization around the plaques was studied with color and power Doppler investigations before contrast agent administration and with combined color and power Doppler after contrast agent administration. We injected Levovist (300 mg/mL) and 10 micrograms prostglandin E1 (PGE1). Examinations were repeated after 2-4 months in the patients with evidence of microvascularization around the plaques.

RESULTS

US demonstrated fibrocalcific plaques in all the patients. The microvascularization around the plaques was seen with color Doppler in 3 cases (15%), with power Doppler in 5 cases (25%) and with contrast-enhanced color and power Doppler in 7 cases (35%). At 2-4 months' follow-up, we observed slight plaque enlargement and worsened symptoms in 5 of 7 patients (71%) with evidence of some microvascularization around the plaque.

CONCLUSIONS

The plaque presence allows to define the condition and the microvascularization provides information on its evolution. The disease activity can be distinguished into 3 stages which can be related to the painful symptoms. US exhibits a better cost/benefit ratio than contrast-enhanced MRI.

Small bowel enteroclysis in surgically treated obesity

PURPOSE

To define the indications, technical limitations and diagnostic yeld of small bowel transbuccal enema in the follow-up of surgical jejunoileal shunting in patients with complicated severe essential obesity.

MATERIAL AND METHODS

Three patients were submitted to surgical diversion: two of them underwent an intestinal bypass after Payne-De Wind (isoperistaltic end-to-side jejunoileostomy) and the other after Scott (end-to-end jejunoileostomy). The latter refers to intestinal recanalization and antiperistaltic lower end-to-side gastroenteric restoration.

RESULTS

Radiologic studies are the only means to depict the surgical small bowel. Radiographic follow-up needs barium sulfate administration and therefore cannot be performed any sooner than 30 days postoperatively. In the last three years the classic transbuccal enema has been performed with a Rollandi tube (with a terminal opening and a balloon). Both the anastomosis and the blind loop are difficult to demonstrate.

CONCLUSIONS

Jejunoileal bypass can be used to treat severe obsity uncontrollable otherwise, to reduce food absorption. Different severe complications may result and small bowel studies may permit to show late local complications. Small bowel enema is also indispensable in bypass reversal. There are no alternatives to this radiologic examination which is however very difficult to perform, because of the changes made by previous operation(s), and to interpret because the anastomosis, the sutured loop and wall changes are often poorly demonstrated.

Differential effect on TCR:CD3 stimulation of a 90-kD glycoprotein (gp90/Mac-2BP), a member of the scavenger receptor cysteine-rich domain protein family

We studied the effects of a 90-kD glycoprotein (gp90/Mac-2BP) belonging to the scavenger receptor family, present in normal serum and at increased levels in inflammatory disease and cancer patients, on some T cell function parameters. Whereas the lymphocyte proliferative response to non-specific mitogens such as phytohaemagglutinin (PHA) and concanavalin A (Con A), but not pokeweed mitogen (PWM), was strongly reduced, probably due to the lectin-binding properties of gp90/Mac-2BP, the response to T cell receptor (TCR) agonists such as superantigens and allogeneic cells was potentiated. When lymphocytes were stimulated with different anti-TCR:CD3 MoAbs, both in soluble and solid-phase form, gp90/Mac-2BP was able to down-regulate the proliferative response to anti-CD3 MoAb, whereas the response to anti-TCR alphabeta MoAb was enhanced. A similar differential effect was observed when a MoAb against CD5 (another member of the scavenger receptor superfamily) was added to anti-CD3 or anti-TCR-stimulated cells; anti-CD5 MoAb strongly down-modulated the CD3-mediated response, whereas its presence in culture was associated with potentiation of the response to TCR alphabeta agonists. gp90/Mac-2BP was able per se to up-regulate Ca2+ levels in freshly isolated lymphocytes; moreover, its presence in culture was associated with increased Ca2+ mobilization following stimulation with anti-TCR alphabeta, but not anti-CD3 MoAb. These data indicate that gp90/Mac-2BP could be able to influence some immune responses, possibly through multiple homologous interactions with other members of the scavenger receptor family; moreover, our findings suggest that signalling through the different components of the TCR:CD3 complex may follow distinct activation pathways into the cells.

[The relationships between the specialist in radiology, the competent physician, the licensed physician and the qualified expert]

PURPOSE

To define the juridical figures of the medical specialist (in radiodiagnostics, radiotherapy, nuclear medicine), of the qualified doctor, of the physician authorized to radioprotection controls, and of the qualified expert. To analyze the role of these professionals and their working integration in the light of the regulations in force. To review the regulations referrable to nonspecialist physicians in the activities with ionizing radiation risks. To stress how patient radioprotection remains one of the major concerns of the radiologist, not only with the precautions he/she must take directly but also with the radioprotection policy he/she must promote in the different application fields and with the other specialists.

DISCUSSION

Only the specialist (in radiodiagnostics, radiotherapy, nuclear medicine) can practice the specific relevant profession. The physicians working in public institutions in radiodiagnostics, radiotherapy, or nuclear medicine departments without the relative specialization will have to acquire it by 2007, the deadline of a specific moratorium (not indemnity) measure. Also the other medical specialists and nonspecialists using ionizing radiations for complementary activities to clinics are responsible for the radioprotection measures they take; particularly, nonspecialists will be allowed to work only if they get the relative specialization diploma. The medical specialist can interact with the authorized physician at three different levels: as the object of the regulation, he/she being exposed for professional reasons; as the promoter of the radioprotection of patients and the general population; as the person in charge and thus the direct responsible, together with the head of department and the management for the application of the regulations. Thence the need of effective consulting and collaboration between the two professionals. The same should apply also in full for the qualified expert, who is responsible for the physical control of radioprotection.

CONCLUSIONS

The medical specialists is both the subject and the object of radioprotection regulations. For optimal collaboration with the other two professionals and to make the needed protection effective for patients and the population (as well as for the involved workers), he/she must be qualified enough and have sufficient technical-professional training, as well as a radioprotection-oriented attitude. In this respect the Italian Society of Medical Radiology (Società Italiana di Radiologia Medica: SIRM) plays a fundamental role.

[Normal value of the tracheal bifurcation angle and correlation with left atrial volume]

PURPOSE

We evaluated the mean value and the variability range of the tracheal bifurcation angle by patient gender, age, height, weight, build, body area and max transverse diameter of the chest under normal conditions. We also evaluated tracheal bifurcation angle changes in orthostatism and recumbency, as well as in the different respiratory phases. Finally, we investigated the statistical correlation between the tracheal bifurcation angle value and the left atrial volume, to eventually derive either value from the other.

MATERIAL AND METHODS

We reviewed 700 high-voltage radiographs of the chest performed in 500 patients with normal echocardiographic findings from 1986 to 1990. To analyze the relationships with the left atrium, 100 patients with echocardiographically enlarged atrium were submitted to high-voltage radiography. The tracheal bifurcation angle was measured directly.

RESULTS

Mediastinal radiographs nearly always depict the trachea and extraparenchymal bronchi adequately. The tracheal bifurcation angle should be measured continuing and joining the upper and lower parabronchial contours. A 4-degree deviation is accepted between the upper or interbronchial and lower or carinal angles since the angles formed by parallel segments have the same value. Under normal conditions the absolute mean value of the tracheal bifurcation angle was 79.7 degrees and the range 37-105 degrees.

DISCUSSION AND CONCLUSIONS

In normal patients the mean value of the tracheal bifurcation angle: is independent of age and gender; depends on build; is related to the max transverse diameter of the chest and to body area; exhibits no major radiographic changes in orthostatism versus recumbency; exhibits no major radiographic changes in expiration versus inspiration; is correlated with left atrial volume, but the value is not statistically significant.

Lymphoproliferative disease in human peripheral blood mononuclear cell-injected SCID mice. IV. Differential activation of human Th1 and Th2 lymphocytes and influence of the atopic status on lymphoma development

Intraperitoneal transfer of PBMC from EBV+ donors into SCID mice leads to high human Ig levels in mouse serum and B cell lymphoproliferative disease. As these events depend on the activation of coinjected human T cells, we addressed the behavior of the Th1 and Th2 subsets in this model. Production of IFN-gamma, but not of Th2 cytokines such as IL-4, was detected in culture supernatants of PBMC stimulated in vitro with mouse splenocytes. Moreover, anti-CD3 stimulation of the human cells recovered from mice brought about IFN-gamma, but not IL-4, synthesis; on the other hand, PCR and in situ hybridization analysis of ex vivo-recovered cells disclosed the presence of mRNA for both cytokines following in vitro restimulation, thus suggesting posttranscriptional regulation of IL-4 gene expression. When SCID mice were inoculated with PBMC from atopic donors, whose Th1/Th2 profile displays an imbalance toward Th2 cells, tumor development rates were lower, and tumor latency was higher, compared with those in mice injected with PBMC from normal donors. Isotypic analysis of human Ig in mouse serum showed the exclusive presence of IFN-gamma-driven IgG subclasses; in addition, human IgE were low or undetectable in most cases. These findings indicate that following transfer into SCID mice, human Th1 lymphocytes undergo preferential activation, whereas Th2 function is down-regulated. Th1 lymphocytes probably are a major component in promoting EBV+ B cell expansion and tumor development; the individual Th1/Th2 profile could in part account for the as yet unexplained donor variability in tumor generation in this experimental model.

[Computed tomography in injuries to the respiratory system in children. The correlation with adults]

INTRODUCTION

Diagnostic imaging in emergency rooms may be inadequate and delayed, which makes chest traumas in children more severe and difficult to treat. We carried out a retrospective study on adults and children who had survived major chest traumas involving the respiratory tract to assess the differences between the two age groups and the role of emergency CT.

MATERIAL AND METHODS

Our series consisted of fourteen children admitted to the emergency department for various accidents. Home accidents prevailed (9/14 = 64.3%). On admission, chest radiography was performed in most cases (11/14 = 78.6%); CT was carried out in 21.4% (3/14 patients).

RESULTS

Trauma involved more organs in pediatric patients (11/14 = 78.6%) and lung involvement was always associated with other types of injury, namely contusion (14/14 = 100%), pneumothorax (11/14 = 78.6%), hemothorax (10/14 = 71.4%), tear (4/14 = 28.6%). CT corrected or integrated the radiographic findings of contusion focus in 67% (8/14) and that of pneumothorax in 63.6%; both patterns cannot be demonstrated otherwise.

DISCUSSION

Mixed and multiple posterior parenchymal injuries with no rib fractures prevail in young subjects because their bones and ligaments are more elastic, which may lead to trauma underestimation. Tracheobronchial ruptures and pneumomediastinum are much more severe in children than in adults. Chest plain film is often the only diagnostic tool used, despite its major technical and interpretative limitations, also because skull and abdomen are the most investigated regions. Executive limitations are stronger in childhood, increasing the margin of error and the risk of delayed treatment. CT is as cost-effective as radiography and shows even the injuries missed or poorly depicted on conventional images; CT also gives accurate information on damage severity and nature.

CONCLUSIONS

Traumatic injuries are more severe in pediatric patients due to their build and to biomechanical, clinical and management factors. Spiral CT should be considered the examination of choice to be performed in the emergency department equipped also for pediatric re-animation.

[Pancreatic fractures: the role of CT and the indications for endoscopic retrograde pancreatography]

PURPOSE

To assess the role and the diagnostic yield of CT and of endoscopic retrograde cholangiopancreatography (ERCP) in the study of emergency pancreatic injuries from blunt abdominal trauma.

MATERIAL AND METHODS

January, 1992, to December, 1996, eleven subjects with pancreatic trauma were operated on. The patients were 8 men and 3 women (mean age: 28.4 years, range: 15-47 years) with pancreatic traumas of different severity but all with gland fracture and severe ductal injuries. Direct radiography was performed in all cases in different projections: CT with 1 cm slice thickness and feed was also performed. A contrast agent was administered orally in 8/11 patients and i.v. in 11/11. ERCP was performed in supine recumbency within 12 hours of trauma; a hypotonic agent was administered i.v. in 5 cases. The examination was successful in 10 patients. Wirsung duct studies were extended to the biliary tract in 6 cases.

RESULTS

Pancreatic traumas were never isolated and usually associated with other abdominal injuries in the liver, spleen, small intestine, kidneys (by frequency) and with injuries in other body regions--the chest in 8/9 cases, limbs in 7/9, the spine in 4/9 and the skull-brain in 3/9 cases. Pancreatic fractures were mostly cervical and 3 of them were bifocal. The radiologic findings of pneumoperitoneum (4 cases), sentinel loop (3), paralytic ileum (11), air-fluid levels (9) were always aspecific. CT had 66.7% sensitivity, with over-all accuracy of pancreatic involvement by trauma in 5/11 cases and specific findings of fracture in 1/11 cases. CT showed associated parenchymal injuries in both the abdomen and other sites. ERCP diagnostic accuracy and sensitivity topped 100% in the demonstration of ductal injuries.

DISCUSSION

Pancreatic traumas are usually a rather uncommon event. They are classified as major and minor according to the extent and severity of ductal involvement. Injury site corresponds to the direction of impact force, but the neck is the preferential site for fractures because it is compressed within the spine and extended. Clinical findings are usually aspecific and questionable and diagnostic imaging, especially CT, plays therefore a major role in treatment planning. However, CT provides mainly indirect signs and fails to depict ductal rupture. Despite its difficult technical execution in emergency, ERCP shows ductal injuries with extreme accuracy and specificity, which finding is indispensable for treatment planning.

CONCLUSIONS

Both CT and ERCP are necessary tools to diagnose pancreatic fractures: the former because it provides indispensable panoramic findings and the latter because it is the only method showing ductal involvement. Therefore, both techniques should be used for accurate surgical planning, which is a crucial step for the prognosis of these injuries. Cost-effectiveness and safe execution are well balanced.

Single-lead VDD pacing. A case of cross-talk

The haemodynamic and electrophysiological benefits of dual chamber pacing are well recognized at the cost of a more complex and expensive implant. In selected groups of patients VDD-mode dual chamber pacing offers the advantages of dual chamber pacing with the use of a single catheter and is nowadays gaining increasing popularity. The following report describes an uncommon and potentially harmful pacemaker malfunction secondary to the dislodgement of the catheter.

[Cystic dilatation of the seminal vesicles: which diagnostic approach?]

PURPOSE

We investigated the frequency, clinical features, diagnostic course and therapy of congenital and acquired seminal vesicle cysts.

MATERIAL AND METHODS

Seven vesicular cysts were found in adult subjects in 1995-1996. All diagnoses were made with suprapubic and transrectal US, CT and MRI. Vesiculo-deferentography was never used for diagnosis. Patient age and symptoms, cyst site, structure and dysembryogenetic associations were considered for diagnosis.

RESULTS

All the patients were adult and all but one fertile. Age ranges were IV (43%), III and V (28.5%) decades. The cyst was congenital in 5 patients, associated with other dysplasias in 60% of them, and acquired in 2 patients. 57% of patients had urogenital symptoms and 2 patients (28.5%) had no clinical signs. US was performed for fertility tests in one patient. The left gland was always and exclusively involved; its size ranged 3.2 to 5.8 cm and its shape was characteristic only in 2 acquired cysts.

DISCUSSION

Both abdominal and rectal US examinations were always performed and always reliably showed cyst site, origin, size and components. CT confirmed local findings and was also used to study the abdomen assessing renal presence and function. MRI permitted the best anatomical study with the multiplanar demonstration of the relationships between small pelvis structures.

CONCLUSIONS

Congenital cysts and acquired distension of the seminal vesicles are uncommon findings also because they are difficult to diagnose. Diagnostic imaging reliably differentiates vesicular cysts from other cystic collections in that region, providing enough information to distinguish acquired from congenital forms, the former curable with drug treatment and the latter requiring more invasive therapy. Relative to site prevalence (100% in the left gland), we do not know if this was an aleatory finding or it indicated an actual congenital predisposition. US yields the indispensable diagnostic findings, but MRI should be always performed to ensure diagnosis, to study the abdomen and to plan possible surgery.

[Doppler color ultrasonography with contrast media in the study of eye and orbit neoplasms]

We investigated the diagnostic efficacy of the i.v. administration of a sonography (US) contrast agent to study eye and orbit tumors at different stages. We administered Levovist (Schering), an air microbubble stabilized by fatty acid, which is specific for angiographic indications. Baseline color Doppler US was performed on 24 selected patients and tumor vascularization patterns were classified into three classes. Color Doppler signal enhancement was assessed after contrast agent administration and the signal-to-noise ratio (SNR) was improved in 70% of cases, which helped identify vascular patterns and improved flowmetric accuracy. The Doppler effect was also improved and vascular signal was always enhanced. The SNR was improved also by the postcontrast detection of small vessels missed on baseline scans. Doppler signal enhancement was proportional to precontrast vascularization and depended on tumor size, with poor results in lesions < 5 mm. In contrast, vascular signal spots with increased postcontrast echogenicity sometimes caused excessive noise affecting the results. No correlation was found between signal enhancement and lesion histotype or between signal and lesion site. Treated lesions exhibited poorer contrast agent enhancement. The examination technique must be accurate and the various parameters set optimally, especially the velocity scale, gain and filtration; the unit must feature adequate recording capabilities (mm/s). To conclude, we believe that the routine use of i.v. US contrast agents will play a major role in improving diagnostic imaging in oculistics also thanks to the lack of untoward reactions and to the ease of contrast agent preparation.

[Clinico-radiologic considerations on "stress fractures" of the leg]

Stress fractures are ubiquitary and most often caused by the subject's activities. In the past they occurred mostly in recruits, but today they are frequent in sportsmen. Stress fractures most frequently occur in the lower limbs, especially in the distal leg. We reviewed 32 injuries observed January, 1993, to June, 1995, and found that 25% of them had been misdiagnosed as stress fractures: in the cases where the diagnosis was correct, fatigue fractures (32%) were less frequent than insufficiency fractures (68%) and occurred in young subjects (mean age: 24 years), usually sportsmen (2/3 of cases). Insufficiency fractures may occur in people aged 8 to 81 years (mean: 61 years) and in subjects with metabolic disorders (45.5%). Considering the injury biomechanics and the patient history and symptoms, these lesions appear a rather uncommon event, whose radiologic diagnosis must be confirmed by clinical findings, since radiology mostly (81.6% of cases) showed only the repair process, rather than the fracture itself. The radiologic patterns were classified into three groups: the fracture margin was not shown in 70% of cases (group I), where however intraperiosteal reaction and/or soft tissue effusion were found; bone fracture was shown in 3 cases (group II) and fracture sequels in 4 (group III), where bone thickening (3 cases) or abnormal consolidation (1 case) was found. There are several synonyms of "stress fracture" and confusion is increased because stress lines and other not necessarily abnormal signs such as Park or Harris lines, reinforcement or calcification lines, are often grouped together with stress fractures. Only accurate clinical examination and laboratory findings permit to distinguish fatigue from insufficiency stress fractures and the latter are also very difficult to differentiate from pathologic fractures. The differentiation of fatigue from insufficiency fractures, originally made by English speaking authors, may be confusing because the definition "pathologic fractures" should be reserved only to focal injuries while in the past it included also insufficiency fractures. Thus, only (bone) fatigue injuries in patients exercising intensely and constantly should be considered stress fractures. Conventional radiography is an indispensable tool and MRI is used in selected cases where the former method is negative and in the patients needing early mobility to go back to work. If radiographic findings are questionable for metastases, nuclear medicine is the method of choice and CT and/or MRI may be indicated as second-line diagnostic imaging tools.

Analysis of Epstein-Barr virus (EBV) type and variant in spontaneous lymphoblastoid cells and Hu-SCID mouse tumours

Epstein-Barr virus (EBV) type and strain variations were examined using both lymphoblastoid cell lines (LCLs), spontaneously derived in vitro from peripheral blood mononuclear cells (PBMC) of 15 HIV-1-seropositive individuals; and SCID mouse tumours induced by inoculation of PBMC from 11 healthy human donors (Hu-SCID tumours). Polymerase chain reaction (PCR) analysis disclosed that all but one of the 26 EBV + samples harboured EBV nuclear antigen (EBNA) 2 and 3C type A virus. On the other hand, single strand conformation polymorphism (SSCP) analysis using Epstein-Barr encoded RNA (EBER) specific primers detected an AG876-like (type B) band pattern in 21 of the 26 EBV + samples. Three Hu-SCID tumours scored as B95.8-like (type A), and two showed neither a type A nor a type B SSCP migration pattern. Sequence analysis of the amplified EBER fragments confirmed the PCR-SSCP findings; moreover, additional mutations were present not only in the two EBV + samples with anomalous SSCP pattern, but also in two other samples with a standard SSCP profile. Thus, EBER analysis did not correlate with EBNA typing, and appeared to be unsuitable for EBV type assessment. Latent membrane protein (LMP) analysis disclosed, on the whole, sever size variants: as expected, the differences were due to the variable numbers of a 33-bp repeat in the amplified fragment, as assessed by direct sequencing. The broader variability detected by LMP analysis should prove more useful than typing for assessing the presence of single and/or mixed variants resulting from EBV reactivation and/or reinfection.

The hu-PBL-SCID mouse in human lymphocyte function and lymphomagenesis studies: achievements and caveats

The chance isolation of a mouse strain mutant that shows a complete deficiency in both the humoral and cellular immunity compartments has opened new perspectives in numerous fields of medicine and biology, including oncology, hematology and immunology. However, the original concept that the severe combined immunodeficiency mouse might behave as a 'living vessel', and allow experimental approaches that are precluded in man by technical and ethical constraints, has not fully withstood the test of time. At present, despite the body of important results achieved in the past few years, the use of this model in some areas is somewhat deregulated; no standard protocols are available, and some critical variables that could affect experimental results are not always under control. In this article, we have focused on the use of the SCID mouse reconstituted with human mature lymphoid cells in immunological studies, and tried to enucleate, in the array of existing experimental work, some basic concepts that might favor more judicious and appropriate approaches to the use of this important experimental model.

A CD3+CD8+ T cell population lacking CD5 antigen expression is expanded in peripheral blood of human immunodeficiency virus-infected patients

In this study we analyzed the behavior of a CD3+ T cell subpopulation lacking CD5 antigen expression in PBMC from HIV-1-infected patients. CD3+CD5- lymphocytes were greatly increased in peripheral blood of HIV-1+ patients, accounting for 20.6 +/- 9.9% of the total CD3+ cells, compared to seronegative individuals (5.5 +/- 3.2%). In both seropositive patients and controls, CD3+CD5- cells belonged to the CD8+ compartment; they were nonactivated, TCR alpha/beta+, naive lymphocytes, and in seronegative individuals preferentially expressed NK cell-associated markers, such as CD11b, CD16, CD56, and CD57. The phenotypic profile of this subset was slightly different in seropositive patients; while TCR expression and CD45RA/RO profile were comparable, CD11b and CD16 expression was lower compared to control figures, while CD56 expression was not changed, and CD57 expression was enhanced. Functional analysis of enriched CD3+CD8+CD5- cells showed an impaired ability to proliferate in response to mitogenic and antigenic stimuli; despite their NK-like phenotype, CD3+CD8+CD5- cells did not exert any NK cytotoxic activity, and only a lectin-dependent cytotoxic potential could be evidenced in this population. These results describe a novel alteration in the lymphocytes phenotypic profile during HIV-1 infection, involving a "transitional" population, which shares some properties of the T and of the NK cell lineage.

Dominance of a single Epstein-Barr virus strain in SCID-mouse tumors induced by injection of peripheral blood mononuclear cells from healthy human donors

Severe Combined Immune Deficiency mouse tumors, induced by inoculating peripheral blood mononuclear cells from 11 healthy human donors (hu-PBMC-SCID tumors), were used to analyse Epstein-Barr virus (EBV) type and strain variations. PCR analysis of EBNA 2- and EBNA 3C-specific sequences showed that EBV type A was present in SCID-mouse tumors induced by PBMC from all donors but one, while, using amplimers for a highly polymorphic region within the latent membrane protein (LMP) coding sequence, 5 different strains could be detected among the samples examined. The same LMP fragment was present in different tumors arising in the same animal, as well as in different mice injected with PBMC from any donor. Compared to B95.8 and AG876 prototype viruses, sequence analysis of LMP variants disclosed a higher homology to the latter, with 33 bp additional repetitions and a few point mutations in specific sites. This study confirms and extends previous data on the presence of a single EBV type and strain in the peripheral blood of most normal healthy subjects using the SCID-mouse system.

Lymphoproliferative disease in human peripheral-blood-mononuclear-cell- injected scid mice. II. Role of host and donor factors in tumor generation

Intraperitoneal injection of lymphoid cells from EBV+ donors into SCID mice might provide a useful tool for studying the pathways of B-cell lymphomagenesis in man. Since previous studies showed that donor T cells greatly favor B-cell proliferation and tumor generation in this model, we addressed the host and donor factors involved in limiting or promoting lymphoma development. The number of EBV-infected B-cell precursors was crucial, since purified B lymphocytes, which alone were unable to generate tumors, underwent expansion and established tumor masses when the animals were inoculated with an EBV-containing supernatant. Host factors were critical in limiting tumor development; in vivo NK-cell removal allowed purified B cells to expand and proceed to tumors in the absence of T lymphocytes, whereas potentiation of mouse NK-cell activity prevented tumor generation in PBMC- and LCL-injected animals. The T-cell-derived factors that favor lymphomagenesis could not be identified; IL-2, IL-4, IL-6, and soluble CD23 were not able to promote B-cell expansion, and treatment of PBMC-injected mice with the relevant anti-cytokine anti-sera did not counteract lymphoma development. These experiments also showed that IL-6 plays a minor role, if any, in B-cell lymphoproliferation in this model. Our data indicate that reconstitution of SCID mice with PBMC from EBV+ donors may constitute a useful model for determining the events involved in lymphomagenesis in humans, provided that strict control of all the experimental variables is guaranteed.

Cytosolic free calcium concentration in the mitogenic stimulation of T lymphocytes by anti-CD3 monoclonal antibodies

The effects of anti-CD3 monoclonal antibodies on cytosolic free Ca2+ concentration, [Ca2+]i, were investigated in freshly isolated lymphocytes, T cell lines, T clones and the leukemic T cell line Jurkat with three different methodologies, i.e. classical cuvette experiments, cytofluorimetry and videoimaging. With any technique, concentrations of anti-CD3 antibodies optimal for stimulation of DNA synthesis were completely ineffective at inducing early increases of [Ca2+]i in freshly isolated lymphocytes. At supraoptimal mitogenic concentrations: (i) anti-CD3 mAb induced negligible increases of [Ca2+]i when tested in suspensions of freshly isolated lymphocytes, but the response increased progressively during in vitro culturing with IL2; (ii) most, but not all, T clones, when tested in suspension, were responsive to these concentrations of anti-CD3 antibodies in terms of [Ca2+]i; (iii) using the videoimaging technique at the single cell level, it was demonstrated that the anti-CD3 antibodies induced large increases of [Ca2+]i in lymphocytes only under conditions which allowed adherence of the antibodies (and of the cells) to the glass surface. In all T cell types investigated, the [Ca2+]i increases were most often composed by multiple, asynchronous oscillations. The buffering of [Ca2+]i increases, obtained by loading the cells with membrane permeant esters of Quin-2 and Fura-2, inhibited anti-CD3 mAb induced DNA synthesis, but this appeared entirely attributable to a toxic side effect of the ester hydrolysis. The relevance of these data is discussed in terms of their methodological and functional implications for the understanding of the role of Ca2+ in mitogenic stimulation of T cells.

Alpha-interferon induces depletion of intracellular iron content and upregulation of functional transferrin receptors on human epidermoid cancer KB cells

We have demonstrated that interferon-alpha (IFN alpha) upregulates the epidermal growth factor receptor (EGF-R) on human epidermoid carcinoma cells. Here we report that IFN alpha induces growth inhibition and upregulation of transferrin receptor (TRF-R) on epidermoid cancer KB cells. IFN alpha does not alter TRF-R affinity for its ligand and induces a two-fold increase of TRF binding sites. IFN alpha does not modify receptor internalization and cycling. Intracellular iron levels are known to regulate TRF-R expression: we have, therefore, evaluated whether changes in the iron content could be determined by IFN alpha. Iron levels are transiently increased after addition of fresh growth medium in untreated controls but not in KB cells exposed for 48 h to IFN alpha. Iron depletion is however completely reversed 24 h later when maximal TRF-R upregulation occurs in IFN alpha-treated cells. We suggest that IFN alpha-induced iron depletion elicits a homeostatic cellular response through upregulation of TRF-R.

Properties of tumors arising in SCID mice injected with PBMC from EBV-positive donors

Groups of SCID mice were injected with different PBMC sub-populations, and established LCL cells. In about 80% of PBMC-injected animals, tumors developed in association with high levels of human Ig in mouse serum and detectable IL-6 levels. The tumors showed a histopathologic pattern reminiscent of large cell immunoblastic non-Hodgkin's lymphoma; in situ hybridization invariably evidenced EBV sequences in a minority of cells. Genotypic analysis of tumors arising in PBMC-injected mice showed the presence of different oligoclonal B cell populations in different tumor sites. Southern blot analysis disclosed the presence of both linear (replicating) and episomal (latent) EBV DNA forms; sequential analysis of LCL cells serially passaged into animals revealed the progressive selection of clonal cells with only the latent episomal form. Attempts to dissect the events underlying tumor development revealed that the presence of T cells within the injected population was essential for tumor generation; however, the putative T cell-derived factors involved are unclear, and IL-6 seems to play a minor role.

Phorbol 12-myristate 13-acetate induces resistance of human melanoma cells to natural-killer- and lymphokine-activated-killer-mediated cytotoxicity

Human melanoma cells are sensitive to the lytic activity of natural killer (NK) and lymphokine-activated killer (LAK) cells in vitro. The events resulting in tumour cell killing by lymphocytic effectors have not been completely clarified, and the same target cell determinants regulating responsiveness to immune cytolysis have not yet been identified. Indeed, changes in the differentiative status of leukemia cells as well as in the expression of major histocompatibility complex (MHC) antigens have been described to modulate sensitivity to cytotoxic effectors; moreover surface expression of adhesion factors or extracellular matrix proteins by the cancer cells can promote the activation of the cytolytic effectors and has been described to correlate with tumour cell sensitivity to cytolytic cells. We reasoned that treatment with differentiation inducers could modulate melanoma cell sensitivity to NK and LAK cells. The present study demonstrates that human melanoma GLL-19 cells, when treated with the phorbol diester phorbol 12-myristate 13-acetate (PMA) in vitro, undergo growth inhibition and neuron-like differentiation. Moreover, PMA treatment induces an evident inhibition of GLL-19 cell sensitivity to NK- and LAK-mediated cytotoxicity. GLL-19 cells express constitutively MHC class I antigens. PMA treatment, however, does not modify the expression of MHC class I and class II DR antigens in human melanoma GLL-19 cells. We have finally evaluated the effects of PMA on the expression at the cell surface of adhesion factors such as ICAM-1, and extracellular matrix proteins such as collagen IV, laminin and fibronectin; we have also studied the expression of the integrin vitronectin receptor, a membrane receptor for adhesive proteins. While adhesion factors and extracellular matrix proteins appear to play an important role in the interaction between immune effector and tumour target, it can be supposed that the modulation of such membrane-associated proteins or glycoproteins induces NK and LAK resistance in cancer cells. We indeed found that PMA treatment induced in GLL-19 a marked reduction of membrane expression of collagen IV and ICAM-1; moreover PMA reduced the cell membrane expression of the integrin vitronectin receptor. On the other hand, membrane expression of fibronectin and laminin was not affected by PMA. These data indicate that the acquisition of a NK- and LAK-resistant phenotype by GLL-19 cells occurs together with cell differentiation, down-regulation of membrane expression of collagen IV, ICAM-1 and vitronectin receptor, but in the absence of changes in MHC antigens.

[Cardiovascular adaptation during cycloergometric exercise test in insulin-dependent diabetics with or without autonomic cardiopathy]

Sixty patients with type I diabetes mellitus underwent an ergometric stress test (EST) to evaluate the relationship between cardiac autonomic neuropathy (CAN) and hemodynamic changes during EST. All patients were divided into 2 groups: in the Group A were included 26 patients (mean age 43 +/- 9 years) with impairment of 2 or more autonomic tests according to Ewing (patients with CAN) and in the Group B were included 34 patients (mean age 38 +/- 13 years) without CAN. The EST was symptom-limited and performed with load increases of 25 W every 3 min. No positive EST were observed in both groups. Heart rate (HR) at rest and systolic blood pressure (SBP) at maximum common workload were significantly higher in Group A than in Group B. Moreover, a significant linear correlation was found between a CAN score and SBP x HR product at rest and at maximal workload. These findings are correlated with increased sympathetic activity due to a parasympathetic impairment. The data show the relationship between hemodynamic changes during EST and the Ewing test used in the diagnosis of CAN.

[Dynamic test in the echographic evaluation of the common bile duct]

Common bile duct (CBD) diameter was measured with ultrasonography in 396 patients (131 had previous cholecystectomy) before and 40 minutes after the ingestion of a fatty meal. CBD diameter reduced in 177 cases, remained unchanged in 175, increased in 44. The increasing of CBD diameter always means obstructive choledochal pathology, caused by stones or other pathologic conditions. Caliber reduction or other pathologic conditions. Caliber reduction is physiologic. When CBD remains unchanged, in 10% of the cases there are stones in the duct.