Painful vaso-occlusive crisis as a prodromal phase of acute chest syndrome. Is only one chest X-ray enough? A case report.

The predominant pathophysiological feature of homozygous sickle cell anemia (SCA) is the vaso-occlusion. Vaso-occlusion can be associated with painful crises, which are the primary reason for those patients to seek medical care. Vaso-occlusion is responsible for the acute chest syndrome (ACS) with large morbidity and mortality or more rarely (and especially in adults) for priapism and acute neurological events (strokes). A 10-year-old boy with homozygous SCA was admitted to the Pediatric Emergencies with painful vaso-occlusive crisis and fever. Initially he had normal chest X-ray but, after 24-hour-hospitalization, he developed ACS with new chest X-ray findings. He was treated with broad spectrum antibiotics, blood transfusions and bronchodilators and after a six-day treatment, he was significantly improved. The patient was discharged 13 days later with no other therapy at home. The possibility of ACS development should be still considered, even when a known patient with SCA presents a painful vaso-occlusive crisis with an initial normal chest X-ray. Therefore, repeated clinical examination is required and possible changes in the clinical status could indicate the necessity of a new radiographic examination. In this way, early ACS could be recognized and the catastrophic consequences due to this syndrome could be avoided.

How accurate are diagnostic tools for Epstein-Barr virus (EBV) to establish causal association of an uncommon clinical condition with EBV?

UNLABELLED: Epstein-Barr virus (EBV) infection has been implicated as a possible cause of a wide range of clinical conditions in children and young adults. In uncommon clinical conditions, where clinical experience is missing, it is important to evaluate both the biological plausibility and the virological basis that substantiates their causal association with EBV. By reviewing the diagnostic procedures performed in the diagnosis of EBV infection in case reports concerning uncommon clinical conditions causally related to EBV infection in children and young adults, the aim of the present study was to discuss the limitations of the diagnostic procedure used to establish EBV diagnosis, which may cause false-positive results and compromise the reliability of such a diagnosis. We should be aware not only of the nuances of serological tests and virus detection tests for latent viruses such as EBV, but also of the risk of using them alone or in combination with molecular methods as the sole mean for establishing a causal relation between EBV infection and an uncommon clinical condition. Accurate laboratory tests for EBV detection, strict criteria for EBV infection diagnosis, and a cumulative clinical experience coupled with biological plausibility and experimental data are needed to avoid a possible coincidental association between several clinical manifestations, mainly uncommon clinical conditions, and EBV infection. KEYWORDS: Epstein-Barr virus; diagnostics; uncommon condition.

Unnecessary diagnostic investigations in benign acute childhood myositis: a case series report.

Benign acute childhood myositis (BACM) is a rare, acute, self-limiting muscle disorder, mainly affecting school-aged boys, with an excellent prognosis, requiring no therapeutic intervention. We report a series of seven previously healthy school-aged children with clinical and laboratory findings suggesting BACM where no specific diagnostic investigations were performed. All of the children were hospitalized without any specific therapeutic intervention and were discharged after two or three days free of symptoms, residual impairment or other complication. This report emphasizes that the correct diagnosis of BACM, by considering the characteristic clinical and laboratory findings of this syndrome and by recognizing more severe pathological conditions, which must be excluded from the diagnosis, can prevent unnecessary diagnostic investigations and reassure both parents and patients of the excellent prognosis.

Incrementally scalable optical interconnection network with a constant degree and constant diameter for parallel computing.

A new scalable interconnection topology called the spanning-bus connected hypercube (SBCH) that is suitable for massively parallel systems is proposed. The SBCH uses the hypercube topology as a basic building block and connects such building blocks by use of multidimensional spanning buses. In doing so, the SBCH combines positive features of both the hypercube (small diameter, high connectivity, symmetry, simple routing, and fault tolerance) and the spanning-bus hypercube (SBH) (constant node degree, scalability, and ease of physical implementation), while at the same time circumventing their disadvantages. The SBCH topology permits the efficient support of many communication patterns found in different classes of computation, such as bus-based, mesh-based, and tree-based problems, as well as hypercube-based problems. A very attractive feature of the SBCH network is its ability to support a large number of processors while maintaining a constant degree and a constant diameter. Other positive features include symmetry, incremental scalability, and fault tolerance. An optical implementation methodology is proposed for the SBCH. The implementation methodology combines the advantages of free-space optics with those of wavelength-division multiplexing techniques. An analysis of the feasibility of the proposed network is also presented.

Experimental demonstration of the optical multi-mesh hypercube: scaleable interconnection network for multiprocessors and multicomputers.

A prototype of a novel topology for scaleable optical interconnection networks called the optical multi-mesh hypercube (OMMH) is experimentally demonstrated to as high as a 150-Mbit/s data rate (2(7) - 1 nonreturn-to-zero pseudo-random data pattern) at a bit error rate of 10(-13)/link by the use of commercially available devices. OMMH is a scaleable network [Appl. Opt. 33, 7558 (1994); J. Lightwave Technol. 12, 704 (1994)] architecture that combines the positive features of the hypercube (small diameter, connectivity, symmetry, simple routing, and fault tolerance) and the mesh (constant node degree and size scaleability). The optical implementation method is divided into two levels: high-density local connections for the hypercube modules, and high-bit-rate, low-density, long connections for the mesh links connecting the hypercube modules. Free-space imaging systems utilizing vertical-cavity surface-emitting laser (VCSEL) arrays, lenslet arrays, space-invariant holographic techniques, and photodiode arrays are demonstrated for the local connections. Optobus fiber interconnects from Motorola are used for the long-distance connections. The OMMH was optimized to operate at the data rate of Motorola's Optobus (10-bit-wide, VCSEL-based bidirectional data interconnects at 150 Mbits/s). Difficulties encountered included the varying fan-out efficiencies of the different orders of the hologram, misalignment sensitivity of the free-space links, low power (1 mW) of the individual VCSEL's, and noise.