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V Coppola

Publications and source records attributed to V Coppola.

At least 19 recordsLinked to original sources
PubMed2001

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.

Afferent Pathways↗
PubMed2001

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.

Alleles↗
PubMed2001

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.

Aging↗
PubMed2001

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.

Animals↗
PubMed2000

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)

Algorithms↗
PubMed1999

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.

Aggression↗
PubMed1999

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.

Alleles↗
PubMed1999

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.

Animals↗
PubMed1999

[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.

Costs and Cost Analysis↗
PubMed1999

[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.

Breast Neoplasms↗
PubMed1998

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.

Adult↗
PubMed1998

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.

3T3 Cells↗
PubMed1998

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.

Adult↗
PubMed1998

[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.

Adolescent↗
PubMed1998

[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.

Clinical Competence↗
PubMed1997

[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.

Adolescent↗
PubMed1997

[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.

Adult↗