Ultra-small dye-doped silica nanoparticles via modified sol-gel technique.

In modern biosensing and imaging, fluorescence-based methods constitute the most diffused approach to achieve optimal detection of analytes, both in solution and on the single-particle level. Despite the huge progresses made in recent decades in the development of plasmonic biosensors and label-free sensing techniques, fluorescent molecules remain the most commonly used contrast agents to date for commercial imaging and detection methods. However, they exhibit low stability, can be difficult to functionalise, and often result in a low signal-to-noise ratio. Thus, embedding fluorescent probes into robust and bio-compatible materials, such as silica nanoparticles, can substantially enhance the detection limit and dramatically increase the sensitivity. In this work, ultra-small fluorescent silica nanoparticles (NPs) for optical biosensing applications were doped with a fluorescent dye, using simple water-based sol-gel approaches based on the classical Stöber procedure. By systematically modulating reaction parameters, controllable size tuning of particle diameters as low as 10 nm was achieved. Particles morphology and optical response were evaluated showing a possible single-molecule behaviour, without employing microemulsion methods to achieve similar results. Graphical abstractWe report a simple, cheap, reliable protocol for the synthesis and systematic tuning of ultra-small (< 10 nm) dye-doped luminescent silica nanoparticles.

Human NDE1 splicing and mammalian brain development.

Exploring genetic and molecular differences between humans and other close species may be the key to explain the uniqueness of our brain and the selective pressures under which it evolves. Recent discoveries unveiled the involvement of Nuclear distribution factor E-homolog 1 (NDE1) in human cerebral cortical neurogenesis and suggested a role in brain evolution; however the evolutionary changes involved have not been investigated. NDE1 has a different gene structure in human and mouse resulting in the production of diverse splicing isoforms. In particular, mouse uses the terminal exon 8 T, while Human uses terminal exon 9, which is absent in rodents. Through chimeric minigenes splicing assay we investigated the unique elements regulating NDE1 terminal exon choice. We found that selection of the terminal exon is regulated in a cell dependent manner and relies on gain/loss of splicing regulatory sequences across the exons. Our results show how evolutionary changes in cis as well as trans acting signals have played a fundamental role in determining NDE1 species specific splicing isoforms supporting the notion that alternative splicing plays a central role in human genome evolution, and possibly human cognitive predominance.

[Chronic spondylodiscitis. Clinical aspects and imaging features]. / La spondilodiscite cronica. Aspetti clinici e semeiologia delle immagini.

INTRODUCTION: The diagnosis of a chronic inflammatory process involving the vertebral body and disk is often very difficult because patient's history, subjective symptoms and physical findings are often unconclusive. Thus imaging techniques play a decisive role. Radiography, tomography, CT and MR have different capabilities and limitations and provide different findings in spondylodiscitis. MATERIAL AND METHODS: We observed 18 cases of spondylodiscitis in the last three years. The responsible microbe, a Staphylococcus aureus from extraosseous sites, was found in two cases at blood culture. Small cell inflammatory infiltration was confirmed with CT-guided biopsy in one case, while the other cases were diagnosed based on constant chronic back pain, feveret, moderate neutrophile leukocytosis or increased erythrosedimentation speed, plus changes in radiographic patterns following antibiotic therapy. RESULTS: Plain radiography and tomography are the techniques of choice to detect or suspect the lesion, which is then studied with CT or MRI. Clear-cut irregularities and erosions on opposing vertebral bodies, reactive bone sclerosis and reduced disk space were typical signs in our series; nine patients presented irregular cavitations(s), like bone caries, surrounded by reactive sclerosis in the body near the frontal vertebral plate. CONCLUSIONS: Together with the imaging patterns of all cases, we studied in detail three cases, relative to physical findings and diagnostic techniques. We also compared the changes in chronic spondylodiscitis with those in intraspongious herniation, intervertebral osteochondritis and severe degenerative arthritis. Bone erosions on the anterior cortical surface of the vertebral body were seen in 50% of our cases and may represent a specific sign of chronic spondylodiscitis if the finding is confirmed in further studies.

[Destructive arthrosis of the hip. Natural history, pathogenesis, and radiographic features]. / L'artrosi distruttiva dell'anca. Storia naturale, patogenesi e aspetti radiografici.

Degenerative hip arthritis is caused by the joint failing to bear the normal walk load, because of changes in the anatomical components and of some factors leading to static or dynamic unbalance of the joint surfaces. Degenerative arthritis usually evolves slowly, but its evolution is rapid under certain circumstances and in elderly patients. In such cases destruction is severe and irregular erosions are observed in the femoral heads, which become small and move to the superior lateral edge of the acetabulum. Osteophytes and reactive osteosclerosis are uncommon. Severe pain, functional inability and lower limb shortening are quite constant findings. The patient is often immobilized in bed and risks his/her life. Since the pathogenesis of destructive arthritis is still debated and its clinical features are severe, the knowledge of the natural history and of the underlying factors appears to be very important. The only therapy is arthroprosthesis and prevention becomes, therefore, necessary. On the basis of radiographic findings, we selected three groups of elderly patients hospitalized from 1992 to 1995; of them, 178 had destructive arthritis. The control group consisted of 102 patients with degenerative arthritis and 188 with normal hip joints. The radiographic patterns were related to some clinical and laboratory findings, which are the suspected pathogenetic factors. Two main factors emerged, with high statistical development risk (p < 0.01): hypoxia from femoral head ischemia, due to atherosclerotic vasculopathy and associated anemia, and the articular biodynamic changes which, through minor repeated trauma, cause the lesions, with the appearance of stress fractures.

[Neurogenic senile vertebral spondylopathy]. / Spondilopatia vertebrale senile su base neurogenica.

Neurogenic spinal arthropathy is quite frequent a finding in elderly patients. Peripheral neuropathy underlies this complication. As a matter of fact, impaired proprioception and sensitivity, which are often associated with lesions of the motor nerves, prevent the joint or bone segment submitted to repeated traumas from perceiving alarm sensations, especially pain. Thus, bone lesions follow, which present as bone erosions, fractures, and even more severe bone destruction. At first, tabetic neuropathy was held responsible for this condition. Then, neurogenic arthropathy was observed in diabetes, syringomyelia, and sometimes trauma. However, in the elderly patient, other conditions can cause peripheral neuropathy, which accounts for the high incidence of this disorder. The radiologic findings of the lumbar spine of 23 of 4,922 patients examined in our department 1989 to 1991 were suggestive of neurogenic spinal arthropathy. Clinical, laboratory and electromyographic findings confirmed the presence of neuropathy. Besides the neurogenic lesions described in 7 diabetic patients, these lesions are reported for the first time in 4 cases of multiple myeloma, in a case of Waldenström's macroglobulinemia, in 2 cases of vincristine-treated lymphoma, and finally in an alcohol abuser. Analgesic abuse was observed in 2 patients. In the extant cases, the pathogenesis of neuropathy remained unknown, even though "elderly neuropathy" is known to exist and to be underlain by vascular or degenerative conditions.

[Aseptic osteonecrosis of the femoral head in cancer patients with neuropathies caused by vincristine and vinblastine]. / Osteonecrosi asettica della testa femorale in pazienti neoplastici con neuropatia da vincristina e vinblastina.

Aseptic osteonecrosis has been described in many and dissimilar pathologic conditions--most frequently as the aftermath of fractures or dislocations; in falciform anemia, obesity, alcoholism; in diseases requiring constant and heavy corticosteroid therapy, and also following renal transplantation. Many of these pathologies, especially alcoholism, diabetes, uremia, and collagen vascular diseases, have a common denominator: peripheral neuropathy, which is believed to be a pathogenetic factor supporting osteonecrosis. The authors analyze 3 cases of aseptic osteonecrosis of the femoral head in cancer patients treated with vincristine and/or vinblastine. Since in these subjects severe and persistent neuropathy preceded the onset of osteonecrosis, a possible relationship is postulated between the vincristine/vinblastine treatment and the onset of femoral head osteonecrosis, through the pathogenetic mechanism of peripheral neuropathy.

Perforations of the extraperitoneal rectum during barium enema.

Rectal injuries during barium enema are uncommon but not unusual complications. Radiologists and surgeons must be able to recognize them, as early diagnosis is essential for effective treatment. The Authors discuss various aspects of problems arising from rectal perforation, and report their experience on seven cases.

Osteonecrosis of the femoral head after renal transplantation. Pathogenetic considerations.

In 5 out of 16 renal transplantation patients, osteonecrosis of the femoral head developed in the presence (p less than 0.01) of significant uremic neuropathy; its possible pathogenetic role is discussed.

[Thickening of the bronchial wall in asthma and asthma-like bronchitis]. / L'ispessimento della parete bronchiale nell'asma e nella bronchite asmatiforme.

Small ring-shaped images, related to 2nd or 3rd bronchial walls are seen in prahilar lung region in 80% of chest Xray films, when a bronchus in seen "end on". This bronchial wall thickening (greater than 0.3 mm) is present in numerous lung diseases such as silicosis, bronchiectasis and pulmonary edema. In order to evaluate the significance of such bronchial wall thickening in chronic obstructive bronchitis and bronchial asthma, 78 patients suffering from these diseases have been studied correlating bronchial wall-thickening with the major clinical and bio-humoral indices of broncho obstruction a significant correlation was found between bronchial wall thickening and Tiffeneau index (p less than 0.05), the PaO2 (p less than 0.01), and the E.S.R., expressed as Katz index (p less than 0.001). No correlation was observed between bronchial wall thickening and positivity to allergological tests. It follows that the bronchial wall thickening is an expression of mucous membrane edema and/or endobronchial mucous or purulent hypersecretion. This aspect, though not usefull in the differential diagnosis between chronic obstructive bronchitis and paroxysmal bronchial asthma due to topical inhalants, is indicative of an acute phase in the inflammation process in such patients.

Lesions of the spine in heroin addicts.

The authors present 6 cases of spinal lesions in heroin addicts--3 infective, 3 traumatic. The striking feature about all these cases is the comparative absence of spinal symptoms. This underlines the importance of accurate and early diagnosis in these subjects.

Neuropathic arthropathy (Charcot's joint) in dialysis patients.

To the author's knowledge, uraemic neuropathy has not been previously reported as a cause of Charcot's joint. In this paper they present three cases in which the association between clinical and radiographic patterns suggest the diagnosis of neuropathic arthropathy. The features of uraemic neuropathy are stressed and the role of secondary hyperparathyroidism in the development of this type of arthropathy is discussed. The extremely severe hyperparathyroidism reported here, may cause tendon and ligament disease, especially at the site of their bone insertion. Uraemic tendon and ligament failures weaken joints and produce further instability, which may be a precipitating factor of uraemic Charcot's joint in patients undergoing chronic haemodialysis.

Osteoporosis and decline of gonadal function in the elderly male.

The bone mineral content was evaluated in 30 male subjects aged between 60 and 90 years using the relief of the percent cortical area (PCA) at the level of the second phalanx of the left-hand index finger, by Garn's method. This was to evaluate the rate of bone loss with increasing age. Testosterone, androstenedione, estrone, 17 beta-estradiol plasma levels were determined in all subjects by the RIA method. 60% of our patients showed increased bone resorption (PCA less than 55%); in these subjects testosterone and androstenedione plasma levels were significantly lower than in subjects not affected by osteoporosis. A positive linear correlation is evident between PCA and testosterone, androstenedione and estrone plasma levels. Thus, like in women, decline of gonadic function determines an increased bone resorption in men too.

Tendon disease and adjacent bone erosion in dialysis patients.

Six out of 169 patients on maintenance haemodialysis showed spontaneous tendon rupture. In all six, bone erosion had previously been observed at the site of tendon insertion. In a further 13 patients whose tendons had never ruptured, marked bone erosions at the sites of tendon insertions were also observed. Both groups of patients, with tendon rupture and with bone erosion only, showed significantly greater blood alkaline phosphatase and parathyroid hormone levels than all the others. Moreover, osseous radiological findings of hyperparathyroidism were more marked in all these 19 patients than in the others. Bone erosion at the site of tendon insertion may be a true and specific sign of tendon disease in patients with uraemia. Our series shows that it bears a close relationship to hyperparathyroidism, and suggests that tendon disease is a specific sign of severe secondary hyperparathyroidism in patients with uraemia.

[Intracortical tunnels: an early sign of hyperparathyroidism in chronic uremia under periodic hemodialysis]. / I tunnel intra-corticali: precoce segno di iperparatiroidismo nell'uremico cronico in emodialisi periodica.

The authors studied the hand bones in 83 uremic patients undergoing periodic hemodialytic treatment, with microfocus and magnification, valuing particularly the debated findings of cortical striation (tunnelling). In 33 cases the radiological signs have been compared with the values of plasma parathyroid hormone and a significant relationship was found between the hyperparathyroidism and the development of cortical striation. The intracortical tunnels are proposed as an important sign for the early diagnosis of renal osteodystrophy.

[Usefulness of arthrography of the knee in assessing the unfavorable outcome from a meniscectomy intervention]. / Utilità dell'artrografia del ginocchio nella valutazione degli esiti sfavorevoli dell'intervento di meniscectomia.

Knee arthrography was performed in 22 patients suffering from persistent articular symptoms after meniscectomy. In 3 cases a surgically proved tear of the opposite meniscus was assessed. In 4 cases no meniscal tear was found, but 3 out of these patients had a significant anatomic lesion. In 15 cases meniscectomy was found to be incomplete, and a residual posterior horn of the medial meniscus was observed, normal in shape in 7 cases, torn or detached in 8. It is suggested that the persistence of the posterior horn of the medial meniscus after meniscectomy may cause the persistent symptoms; the value of knee arthrography before surgery is emphasized.