Mild ring 17 syndrome shares common phenotypic features irrespective of the chromosomal breakpoints location.

Ring 17 syndrome is a rare disorder with clinical features influenced by the presence or deletion of the Miller-Dieker critical region (MDCR). Presence of the MDCR is associated with a mild phenotype, including growth delay (GD), mental retardation (MR), seizures, cafè au lait skin (CALS) spots and minor facial dysmorphisms. Previous studies have been mainly focused on this locus providing poor information about the role of other genes located on the p- and q-arms. Here, we used bacterial artificial chromosome (BAC)/P1 artificial chromosome (PAC) and fosmid clones as fluorescence in situ hybridization (FISH) probes to perform a cyto-molecular analysis of a ring 17 case and found that the breakpoints were close to the telomeric ends. METRNL is the sole gene located on the q-arm terminal end, whereas two open reading frames and the RPH3AL gene are located on the terminal p-arm. To detect possibly unrevealed small deletions involving the transcription units, we used subcloned FISH probes obtained by long-range polymerase chain reaction (PCR), which showed that the investigated regions were preserved. Comparing our findings with other reports, it emerges that different breakpoints, involving (or not) large genomic deletions, present overlapping clinical aspects. In conclusion, our data suggest that a mechanism based on gene expression control besides haploinsufficiency should be considered to explain the common phenotypic features found in the mild ring 17 syndrome.

Holographic grating formation in photopolymers.

We introduce a model describing real-time grating formation in holographic photopolymers, under the assumption that the diffusion of free monomers is much faster than the grating formation. This model, which combines polymerization kinetics with results from coupled-wave theory, indicates that the grating formation time depends sublinearly on the average holographic recording intensity, and the beam intensity ratio controls the grating index modulation at saturation. We validate the model by comparing its predictions with the results of experiments in which DuPont HRF-150X001 photopolymer was used.

Health survey of workers occupationally exposed to cobalt.

The results are presented for a health control program using 236 male workers exposed to a cobalt inhalation risk. The study group consisted of grinders, producers of diamond tools, workers in metallurgical and mechanical industries (where Widia tools are processed and sharpened), and finally formerly exposed workers. All subjects received a clinical examination, the European Community for Coal and Steel questionnaire on respiratory complaints, a chest X-ray, pulmonary function test, electrocardiogram and determination of urinary cobalt; in 91 subjects, the metacholine bronchial provocation test was performed. Three cases of interstitial lung disease were identified. There were no cases with a significant alteration of ventilatory function while 20 cases (16 exposed and four formerly exposed workers) showed a reduced carbon monoxide transfer coefficient (TL,CO,sb/Va).

Cobalt exposure evaluation in dental prostheses production.

Dental laboratory technicians may be exposed to a number of toxic materials including metal alloys that have been identified as potential health hazards. Particularly, alloys, such as vitallium, wisil, duralium and vironite which in dentistry are used in the production of crowns, bridges and dental prostheses. The most common constituents of these prostheses are cobalt (45-70%), chromium (25-30%), molybdenum, silica, nickle, tantalum and other metals in different amounts. The objectives of this paper are to describe the technology related to the production of dental prostheses, evaluating the most hazardous working jobs and reporting results concerning the monitoring of cobalt and chromium in the urine of 31 people employed in five laboratories of Bergamo, Italy, where workplace air monitoring has also been undertaken.

Occupational dermatitis from isothiazolinones in the nylon production.

Kathon is a biocide consisting of a mixture of two isothiazolinone derivatives (5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one) in an approximate ratio of 3:1, respectively, and with MgCl2 and Mg(NO3)2 present as stabilizers. The isothiazolinones are marketed under several brand names, and the concentration of the active ingredient varies according to their intended application. At a concentration of 3-15 ppm it shows activity against a wide spectrum of fungi, gram-positive and gram-negative bacteria. Contact allergy to it has been caused by cosmetics and also by products used in the pottery and various other industries. Recently we had the opportunity to observe 6 cases of occupational allergic contact dermatitis from an isothiazolinone mixture named Grotan TK 2 in a large textile industry producing nylon. An oil emulsion containing isothiazolinones is used in the spinning phase of the work cycle to prevent bacterial contamination that would damage yarn quality; furthermore, it helps to decrease the electrostatic charge that is produced by high speed at which the yarn moves and also to decrease the breakage possibility.

Single-step copying process for multiplexed volume holograms.

A technique for copying the index or absorption modulation of a multiplexed volume holographic element into a second volume holographic medium is presented. The technique utilizes a set of coherent but mutually incoherent optical sources and can perform the copy process in a single exposure step. The concept is demonstrated experimentally for the case of three angularly multiplexed holographic gratings in dichromated gelatin.

Metyrapone modulation of tyrosine aminotransferase induction by dexamethasone in cultured hepatocytes.

Metyrapone, an inhibitor of cytochrome P-450-dependent monooxygenases, enhanced the induction of tyrosine aminotransferase by dexamethasone in primary cultures of hepatocytes, while it had no effect on the basal level of the enzyme activity in the absence of the hormone. The amplification of the hormonal induction of tyrosine aminotransferase activity was strictly correlated with the concentration and with the inhibitory action of the compound on cytochrome P-450. The phenomenon occurred even at the maximally effective concentrations of dexamethasone, thus showing that metyrapone is a 'Glucocorticoid Potency Amplifier'. The dexamethasone activity amplification by metyrapone could be the consequence of a modulation of the glucocorticoid biotransformations due to the cytochrome P-450 inhibitor.

[Allergic contact dermatitis and oculorhinitis due to tulips]. / Dermatite allergica da contatto ed oculorinite da tulipano.

A case of occupational allergic contact dermatitis with conjunctivitis and rhinitis due to tulips bulbs is described. The patient, aged 23, was employed in a florist storehouse. The dermatitis, affecting his hands, face, armpits, knees, elbows and ears, was accompanied by a rhinoconjunctivitis. Patch tests made with a tulip thin slice outcome positive results. The appearance, the way of arising and the results of the patch tests suggest the existence of an immediate type immunologic reaction (type I or IgE-dependent hypersensibility).

Statistical distribution of frequency fluctuations in semiconductor lasers.

We present experimental results showing a departure from the usually assumed Gaussian statistics of the fluctuations of the instantaneous emission frequency in single-mode semiconductor lasers operating under the influence of an external optical feedback. The amount of this departure is studied and analyzed under various operating conditions.

Direct measurement of the nonlinear phase shift between the orthogonally polarized states of a single-mode fiber.

We measure the phase shift induced by the optical Kerr effect between the two orthogonally polarized states of a birefringent single-mode fiber. The associated noise, which can arise whenever amplitude fluctuations of the source are present, is discussed.

Measurements of the injection-locking influence on the frequency noise spectrum of single-mode semiconductor lasers.

The power spectral density of the instantaneous oscillation frequency of single-mode semiconductor lasers under the influence of an external optical driving signal is directly measured for the first time to our knowledge. The experimental results show how the frequency noise of the slave is influenced by the value of the injected power and by the difference between the emission frequencies of the master and slave optical cavities and how it is correlated to the noise properties of both the master and the free-running slave.

Influence of semiconductor-laser phase noise on coherent optical communication systems.

Several authors have recently investigated phase noise in semiconductor lasers and the related problems that arise when such lasers are employed in coherent optical communication systems. We report accurate measurements of high-frequency phase noise in single-mode injection lasers that show the presence of a peak in the phase-noise spectrum at the same frequency as that of the amplitude-noise peak. This peculiar phenomenon must be taken into account when one studies the characteristics of coherent optical communication systems.