A cytotoxicity study of silicon oxycarbide nanowires as cell scaffold for biomedical applications.

GOAL: Nanowires are promising biomaterials in multiple clinical applications. The goal of this study was to investigate the cytotoxicity of carbon-doped silica nanowires (SiOxCy NWs) on a fibroblastic cell line in vitro. MATERIALS AND METHODS: SiOxCy NWs were grown on Si substrates by CVD process. Murine L929 fibroblasts were cultured in complete DMEM and indirect and direct cytotoxicity tests were performed in agreement with ISO 19003-5, by quantitating cell viability at MTT and chemiluminescent assay. Cell cultures were investigated at Scanning Electron Microscope (SEM) and immunocytochemistry to observe their morphology and investigate cell-NWs interactions. Furthermore, hemocompatibility with Platelet-rich Plasma was assayed at SEM and by ELISA assay. RESULTS: SiOxCy NWs proved biocompatible and did not impair cell proliferation at contact assays. L929 were able to attach on NWs and proliferate. Most interestingly, L929 reorganised the NW scaffold by displacing the nanostructure and creating tunnels within the NW network. NWs moreover did not impair platelet activation and behaved similarly to flat SiO2. CONCLUSIONS: Our data show that SiOxCy NWs did not release cytotoxic species and acted as a viable and adaptable scaffold for fibroblastic cells, thus representing a promising platform for implantable devices.

Non-length-dependent small fibre neuropathy. Confocal microscopy study of the corneal innervation.

BACKGROUND: It has been recently observed that small fibre neuropathy (SFN) may present as distal symmetrical polyneuropathy and with atypical non-length-dependent pattern. OBJECTIVE: To describe a small series of patients with non-length-dependent SFN, investigating corneal innervation with corneal confocal microscopy (CCM). METHODS: Evaluation of the corneal nerve fibre density using CCM in six women with non-length-dependent SFN. The patients were characterised by sensory disturbance involving proximal regions of the limbs, face and trunks, and the diagnosis was confirmed by the findings of decreased intraepidermal nerve fibre density on skin biopsy. RESULTS: Six women, aged 35-64, had non-length-dependent SFN, related to Crohn disease, impaired glucose tolerance and Sjögren's syndrome, or idiopathic (three cases). In all patients, CCM demonstrated decreased corneal nerve fibre density (12.5-23.4/mm(2); normal, >30.6/mm(2)). CONCLUSION: Non-length-dependent SFN may represent an intriguing diagnostic problem because of its puzzling presentation and the need for special investigations for its confirmation. In this perspective, CCM may provide a useful, non-invasive tool to complement the diagnostic workup.

Porcine sclera as a model of human sclera for in vitro transport experiments: histology, SEM, and comparative permeability.

PURPOSE: To evaluate porcine sclera as a model of human sclera for in vitro studies of transscleral drug delivery of both low and high molecular weight compounds. METHODS: Human and porcine scleras were characterized for thickness and water content. The tissue surface was examined by scanning electron microscopy (SEM), and the histology was studied with hematoxylin-eosin staining. Comparative permeation experiments were performed using three model molecules, acetaminophen as the model compound for small molecules; a linear dextran with a molecular weight of 120 kDa as the model compound for high molecular weight drugs; and insulin, which was chosen as the model protein. Permeation parameters such as flux, lag time, and permeability coefficient were determined and compared. RESULTS: Human and porcine scleras have a similar histology and collagen bundle organization. The water content is approx 70% for both tissues while a statistically significant difference was found for the thickness, porcine sclera being approximately twofold thicker than human sclera. Differences in thickness produced differences in the permeability coefficient. In fact, human sclera was found to be two to threefold more permeable toward the three molecules studied than porcine sclera. CONCLUSIONS: The results obtained in the present paper prove that porcine sclera can be considered a good model for human sclera for in vitro permeation experiments of both low and high molecular weight compounds. In fact, if the different tissue thickness is taken into account, comparable permeability was demonstrated. This suggests a possible use of this model in the evaluation of the transscleral permeation of new biotech compounds, which currently represent the most innovative and efficient therapeutic options for the treatment of ocular diseases.

Molecular genetics of autosomal dominant retinitis pigmentosa (ADRP): a comprehensive study of 43 Italian families.

Retinitis pigmentosa is the most common form of retinal degeneration and is heterogeneous both clinically and genetically. The autosomal dominant forms (ADRP) can be caused by mutations in 12 different genes. This report describes the first simultaneous mutation analysis of all the known ADRP genes in the same population, represented by 43 Italian families. This analysis allowed the identification of causative mutations in 12 of the families (28% of the total). Seven different mutations were identified, two of which are novel (458delC and 6901C-->T (P2301S), in the CRX and PRPF8 genes, respectively). Several novel polymorphisms leading to amino acid changes in the FSCN2, NRL, IMPDH1, and RP1 genes were also identified. Analysis of gene prevalences indicates that the relative involvement of the RHO and the RDS genes in the pathogenesis of ADRP is less in Italy than in US and UK populations. As causative mutations were not found in over 70% of the families analysed, this study suggests the presence of further novel genes or sequence elements involved in the pathogenesis of ADRP.

ETDRS-fast: implementing psychophysical adaptive methods to standardized visual acuity measurement with ETDRS charts.

PURPOSE: To measure visual acuity (VA) on Early Treatment Diabetic Retinopathy Study (ETDRS) charts with a modified faster procedure (ETDRS-Fast), based on adaptive psychophysics methods and to assess the method's validity and reproducibility. METHODS: Whereas the standard method for measuring VA with the ETDRS charts requires that the subject read all the letters beginning with the top row, in the ETDRS-Fast procedure, the subject is asked to read only one letter per row until a mistake is made. Then, following simple rules, the examiner finds a row from which the subject can begin reading all the letters downward, thus making the method identical with the standard method near threshold. VA determination was performed twice with both methods in 57 subjects in two separate sessions to assess validity and reproducibility. RESULTS: In both sessions the correlation between the two procedures was high (intraclass correlation coefficient 0.95), confirming the validity of the ETDRS-Fast procedure. Reproducibility was good for both procedures, with intraclass correlation coefficients of 0.94 for the standard and 0.96 for the ETDRS-Fast method. The ETDRS-Fast procedure allowed a significantly shorter test duration (-30%; P < 0.0001). CONCLUSIONS: Adaptive procedures allow accurate and fast determination of psychophysical thresholds by reducing the number of stimulus presentations when the subject is far from threshold. In the ETDRS-Fast method a few simple rules applied to optotype chart reading allow adaptation to each patient's level of VA. The ETDRS-Fast procedure significantly reduces test time and still yields results that are as accurate as those obtained with the standard method.

Retroillumination versus reflected-light images in the photographic assessment of posterior capsule opacification.

PURPOSE: To investigate the relative merit of retroillumination and of reflected light slit-lamp-derived photographs in the assessment of the opacification of the posterior lens capsule. METHODS: Retroillumination and slit-lamp-derived reflected-light photographs were taken on 23 consecutive eyes with posterior capsule opacification (PCO) in uncomplicated pseudophakia. Subjective grading was performed on both types of photographs to evaluate the extent and density of posterior capsular opacification. Best-corrected visual acuity (BCVA) before and after YAG laser capsulotomy was used to assess the impact of capsular opacification on visual function. RESULTS: After capsulotomy all patients attained a BCVA > or = 46 letters (> or =20/32) with a mean increase of 25 letters, indicating that PCO was the cause of visual impairment in these patients. The relative capacity of retroillumination and of reflected-light photographs to adequately capture the extent and the severity of posterior capsule opacification varied considerably. Reflected-light images, in addition to frequently producing higher severity scores for the opacity than retroillumination photographs, in 4 of 23 eyes (17.4%) proved to be the only technique able to document the presence of PCO. CONCLUSIONS: Our results indicate that, with respect to retroillumination images, reflected-light photography has an increased ability to adequately capture the presence and the severity of PCO and that the use of only retroillumination images may lead to its underestimation. This may be relevant to clinical studies aiming to evaluate incidence and progression of this condition.

Endoprosthesis implantation in the treatment of recurrent urethral stricture: a multicenter study. Sicilian-Calabrian Urology Society.

PURPOSE: This study was conducted by nine urology departments in southern Italy to assess the efficacy of and tolerance to treatment of recurrent urethral stricture using a permanent prosthesis. PATIENTS AND METHODS: Since 1992, 99 prostheses have been implanted to treat inflammatory and iatrogenic (seven departments) or all types (two departments) of urethral strictures. The Urolume Wallstent was used in 94 cases. Three centers implanted more than one prosthesis when this was indicated. Local anesthesia was used by six centers, spinal anesthesia by two, and local or general by one. At three centers, urethrotomy was performed immediately prior to implantation; two centers used dilation to 30F, and two centers performed urethrotomy 24 or 36 hours before implantation. The median follow-up is 29.1 months (range 3-53 months). RESULTS: The results were good in 52%, fair in 34%, and poor in 14% of patients. The maximum flow rate increased >75% in 82% of patients. All departments reported complete reepithelialization of the urethra by 6 months. The short-term complications (7-28 days) were perineal discomfort (86%) and dribbling (14%). The long-term complications were painful erection (44%), mucous hyperplasia (44%), recurring stricture (29%), and incontinence (14%). All departments performed resection for hyperplasia in many cases. CONCLUSION: Permanent urethral endoprostheses can produce excellent results in patients with recurrent urethral strictures.

Structural organization of the human gamma-glutamyl hydrolase gene.

Gamma-glutamyl hydrolase (GH) plays an important role in the metabolism of folic acid and the pharmacology of antifolates such as methotrexate. We have previously cloned and characterized the human GH cDNA. In this report, the complete organization and structure of the human GH gene was determined. The human GH gene spans 24 kb in the human genome, with nine exons sized from 51 to 371 bp. All of exon-intron splice junctions follow the GT-AG rule. The sequence upstream of exon 1 consists of a promoter-like, GC-rich region and a number of putative cis active elements including Sp1, AP1, and MZF1 sites. A TATA sequence in the 5' region of human GH gene was not observed, similar to housekeeping genes known to be tissue-specific and differentially expressed. S1 nuclease protection analysis with human liver, prostate, brain, and mammary gland revealed a major transcription start point at nucleotide -125 relative to the ATG start codon and several minor transcription start points. Analysis of GH cDNA isolated from human liver indicated a nucleotide change, T-->C, in the leader sequence of GH, which suggested a polymorphism. Studies of cDNA from different human tissue sources provided evidence that there is a single spliced cDNA species in human.

Dominant negative mutations in the alpha-factor receptor, a G protein-coupled receptor encoded by the STE2 gene of the yeast Saccharomyces cerevisiae.

The alpha-mating pheromone receptor encoded by the STE2 gene of the yeast Saccharomyces cerevisiae is a G protein-coupled receptor (GPCR) that is homologous to the large family of GPCRs that mediate multiple types of signal transduction in mammals. We have screened libraries of mutant receptors to identify dominant negative alleles that are capable of interfering with the function of a co-expressed normal receptor. Two dominant negative alleles have been recovered in this manner. In addition, we find that previously isolated loss-of-function mutations in the alpha-factor receptor exhibit dominant negative effects. Detection of the dominant effects requires high-level expression of the mutant receptors but does not require a high ratio of mutant to normal receptors. Cellular levels of the normal receptors are not affected by co-expression of the dominant negative alleles. Expression of the mutant receptors does not interfere with constitutive signaling in a strain that lacks the G protein alpha subunit encoded by GPA1, indicating that interference with signaling occurs at the level of the receptor or the interacting G protein. Expression of increased levels of G protein subunits partially reverses the dominant negative effects. The dominant negative behavior of the mutant receptors is diminished by deletion of the SST2 gene, which encodes an RGS (Regulator of G protein Signaling) protein involved in desensitization of pheromone signaling. The most likely explanation for the dominant negative effects of the mutations appears to be the existence of an interaction between unactivated receptors and the trimeric G protein that titrates the G protein away from the normal receptors or renders the G protein insensitive to receptor activation. This interaction appears to be mediated by the SST2 gene product.

The study of visual evoked potentials in patients with thyroid-associated ophthalmopathy identifies asymptomatic optic nerve involvement.

In the present study we have recorded visual evoked cortical potentials (VECP) in 88 patients affected by autoimmune thyroid disease and thyroid-associated ophthalmopathy (TAO) without clinical signs of optic neuropathy. At the time of ophthalmological examination, 37 of these patients were hyperthyroid, 41 were euthyroid, and 8 were hypothyroid; 2 were not assessed. Twenty-nine normal subjects served as controls. We performed pattern reversal visual stimulation and recorded the amplitude and latency of the cortical electric response at 100 ms (P100 wave). There were no differences in the mean P100 amplitude of TAO patients and normal subjects. The mean P100 latency in patients was 105.6 +/- 0.5 ms, significantly higher than that in normal subjects (102.0 +/- 0.5 ms; P < 0.00003). Latency in euthyroid patients did not differ from that in either hypo- or hyperthyroid patients. The VECP test was positive (latency, > or = 110.0 ms) in 21 (23.8%) TAO patients. In patients with proptosis greater than 21 mm, latency was 106.7 +/- 0.7 ms, significantly higher than that in patients with normal Hertel measurements (104.3 +/- 0.6 ms; P < 0.01). Latency was not increased in patients with acute inflammatory signs compared to those with inactive eye disease and in patients with altered extrinsic motility. In patients with an abnormal visual field study, the mean latency was 110.3 +/- 1.5 ms, significantly higher than that in patients with a normal visual field (104.7 +/- 0.4; by t test, P < 0.000003). In conclusion, we observed a prolongation of the latency of the evoked cortical response in patients with TAO without subjective visual complaints and without optic nerve compression. We believe that the study of VECP in TAO is complementary to the study of the visual field in identifying early optic nerve dysfunction in the absence of decreased visual acuity.

Confusion points and constant-luminance planes for trichromats, protanopes and deuteranopes.

The confusion points of dichromats are derived from the constant-luminance planes of trichromats, protanopes and deuteranopes experimentally defined by heterochromatic-flicker photometry: (1) the zero-luminance planes of the observers considered in this experiment intersect almost exactly in a line that crosses the plane of the chromaticity diagram in the tritanopic-confusion point and confirm that the short-wavelength sensitive cones can be considered to have no contribution to luminance; (2) protanopic- and deuteranopic-confusion points are taken as being defined by the intersection of the tangent line to the long-wavelength region of the spectrum locus and the zero-luminance plane for protanopes and deuteranopes, respectively.

Intrasplenic posttraumatic pseudoaneurysm: echo color doppler diagnosis.

Nonsurgical conservative treatment of blunt splenic trauma has gained widespread consensus in the last few years. It has been demonstrated that 60% of patients with blunt abdominal trauma with spleen lesion achieve the best therapy by using conservative therapy. Despite the accuracy of ultrasonography (US) and computed tomography in detecting and grading the spleen lesions, the evolution of the lesion is often unexpected. In 15 to 30% of patients, a two-stage splenic rupture may be expected within 2 weeks. Delayed complications, such as splenic abscesses and pseudoaneurysms of the splenic artery and its branches, have been observed. To prevent complications, a short follow-up has been scheduled for these patients by using US and US color Doppler. The authors propose routine echo Doppler evaluation for all patients affected by intraparenchymal hematoma after blunt abdominal trauma.

Color discrimination along the cardinal chromatic axes with VECPs as an index of function of the parvocellular pathway. Correspondence of intersubject and axis variations to psychophysics.

Chromatic information is carried only by the parvocellular pathway, giving the neurophysiologist the opportunity for eliciting specific responses. Further subdivision of the parvo chromatic system in two opponent chromatic mechanisms is potentially of great interest, given that the anatomical correlate seems to reside in subclasses of parvo ganglion cells that show differences both in size and in susceptibility to disease. We separately recorded responses arising from each chromatic opponent mechanism using visual stimuli chosen to belong to one of the "cardinal" chromatic axes. A calibrated color monitor, driven by a high resolution (14 bits/gun) computer board, was used for visualization of 1 c/deg isoluminant color gratings, sinusoidally modulated in time at 4 Hz. VECPs were recorded at several color contrasts along both cardinal axes, allowing extrapolation of contrast thresholds. Psychophysical thresholds were derived in the same stimulus conditions for comparison and found to correlate very well with the electrophysiologically derived values, both as intersubject and axis differences. The S-(L+M) opponent mechanism consistently yielded higher thresholds, smaller amplitude, and higher phase lag than the L-M mechanism. This finding was largely explained by the perceptual non-uniformity of the CIE chromaticity diagram. Correcting the VECP data for the perceptual differences yielded comparable responses, supporting the view that the two mechanisms are similarly represented in the cortex. In conclusion, recording of cortical responses to color contrast stimuli belonging to the cardinal chromatic axes seems a reliable procedure and may prove to be useful in performing clinical evaluations that refine the assessment of the physiology of the visual system.

Visual evoked cortical potentials and psychophysical determination of color contrast thresholds along different chromatic axes.

Color vision can be assessed by examining the color contrast threshold along various color axes. We investigated the possibility of determining these thresholds objectively by means of visual evoked cortical potentials. A color-calibrated flicker-free (112-Hz) monitor and a 14-bit-per-gun board allowed visualization of colors with specified xyY CIE 1931 coordinates. Horizontal grating, 1 c/deg were sinusoidally alternated at 8 Hz for both visual evoked cortical potential recordings and psychophysical determinations. Two healthy emmetropic 35 year-old subjects performed color brightness matching along each color axis, before any recording and reduction in color contrast. For each color axis, extrapolation to zero voltage of the visual evoked cortical potential amplitude versus log color contrast response allowed determination of the color contrast threshold. The visual evoked cortical potential-derived threshold changed considerably with the color axis, with evident intersubject differences. These differences were similar to those observed in the psychophysically determined thresholds. Visual evoked cortical potential responses to suitable chromatic stimuli allow determination of color contrast thresholds that correspond well to those determined psychophysically. Hence, with the visual evoked cortical potential, accurate objective assessment of color vision is feasible and may be useful in both research and clinical settings.

Emotional reactions to music by gender, age, and expertise.

Fragments of classical music were submitted to 80 subjects, 40 children 9 to 10 years old and 40 adults 19 to 29 years old who were divided into eight groups of ten, to induce feelings of happiness, sadness, anger, and fear. The task required linking each piece of music to one emotion, identifying at the same time the intensity of the emotional response on a scale of 1 to 3. The goal was to study how gender, age, and exposure or expertise related to emotional perceptions of music. Analysis showed (a) experts in music and nonexperts ascribed similar emotions to pieces of music, (b) there was no difference in emotional response to music by gender, although women linked to music stronger emotions of anger than girls, (c) children perceived greater feeling of happiness in music and less feeling of anger than adults, and (d) emotions of anger and fear in music were often confused with one another.

The role of ultrasonography in blunt abdominal trauma: results in 250 consecutive cases.

The accuracy of ultrasonography (US) in detecting abdominal lesions and free fluid collections in patients with blunt abdominal trauma was evaluated in 250 patients. Particular attention was paid to the role of associated US-guided paracentesis in doubtful cases and in those referred for nonsurgical therapy. The overall sensitivity of US in detecting free fluid collection was 98% (51 of 52 cases) with a specificity of 99% and a positive predictive value of 100%. The overall sensitivity was 93% in spleen injuries, 80% in liver injuries, and 100% in kidney lesions with a positive predictive value of 93%, 100%, and 100%, and a specificity of 99%, 100%, and 100%, respectively. Three stable patients underwent celiotomy on the basis of the results of US-guided paracentesis. The versatility, sensitivity and, repeatability of US, along with its feasibility at bedside and the possibility of performing a guided paracentesis represent the main characteristics that make US the first diagnostic approach to patients with blunt abdominal trauma.

Changes in glucose level affect rod function more than cone function in the isolated, perfused cat eye.

The glucose concentration (gl) in mammalian serum incorporates a normal range of variation of several millimoles. We studied the effects of such variations on light-evoked electrical signals in the in vitro arterially perfused cat eye, avoiding extraocular regulatory mechanisms that might confound data interpretation. Changes in gl from the nominal control value of 5 mmol/l were maintained for 5-40 min. Stimuli of near rod threshold intensity were presented in full dark adaptation, and stimuli of higher intensity were presented in the presence of a white background for cone responses. We recorded the dc-electroretinogram (ERG), the scotopic threshold response (STR), the optic nerve response (ONR), and the transretinal slow P-III and transepithelial retinal pigment epithelium c-wave from the subretinal space. The ocular standing potential changed by up to +/- 2 mV in parallel with an increase and decrease in gl, independent of the adaptation condition. Our results show that the rod-ERG, STR, and rod-driven optic nerve response (ONR) have a marked sensitivity to small changes in gl (+/- 1 to 3 mmol/l). The field potentials increased and decreased in parallel with changes in gl. The cone ERG and cone ONR, in contrast, failed to respond consistently to increases in gl and revealed decreases in amplitudes only with an extreme decrease in gl. Decrease in gl, down to 2 mmol/l and less, is known to induce drastic behavioral and electrophysiologic phenomena in the central nervous system. Our results imply that the "normal" glucose level, at least in the cat, could be marginal for rod-mediated retinal function. The results also suggest a marked difference in metabolic mechanisms for cone versus rod photoreceptors.

[The prevention of postoperative deep venous thrombosis with heparan sulfate per os. A controlled clinical study vs. heparin calcium]. / Prevenzione della trombosi venosa profonda postoperatoria con eparansolfato per os. Studio clinico controllato vs eparina calcica.

The paper reports the results of a randomised study carried out on a pool of 100 patients undergoing surgery in order to assess the efficacy and tolerability of orally administered heparan sulfate versus heparin calcium in the prevention of postoperative deep-vein thrombosis. Despite the limits of oral administration, heparan sulfate is indicated in the pharmacological prevention of postoperative deep-vein thrombosis.