Out of hospital point of care ultrasound: current use models and future directions.

INTRODUCTION: Ultrasound has evolved from a modality that was once exclusively reserved to certain specialities of its current state, in which its portability and durability lend to its broadly increasing applications. OBJECTIVES: This review describes portable ultrasound in the hospital setting and its comparison to gold standard imaging modalities. Also, this review summarizes current literature describing portable ultrasound use in prehospital, austere and remote environments, highlighting successes and barriers to use in these environments. DISCUSSION: Prehospital ultrasound has the ability to increase diagnostic ability and allow for therapeutic intervention in the field. In austere environments, ultrasound may be the only available imaging modality and thus can guide diagnosis, therapeutics and determine which patients may need emergent transfer to a healthcare facility. The most cutting edge applications of portable ultrasound employ telemedicine to obtain and transmit ultrasound images. This technology and ability to transmit images via satellite and cellular transmission can allow for even novice users to obtain interpretable images in austere environments. Portable ultrasound uses have steadily grown and will continue to do so with the introduction of more portable and durable technologies. As applications continue to grow, certain technologic considerations and future directions are explored.

Surface plasmon resonance imaging measurements of DNA and RNA hybridization adsorption onto DNA microarrays.

Surface plasmon resonance (SPR) imaging is a surface-sensitive spectroscopic technique for measuring interactions between unlabeled biological molecules with arrays of surface-bound species. In this paper, SPR imaging is used to quantitatively detect the hybridization adsorption of short (18-base) unlabeled DNA oligonucleotides at low concentration, as well as, for the first time, the hybridization adsorption of unlabeled RNA oligonucleotides and larger 16S ribosomal RNA (rRNA) isolated from the microbe Escherichia coli onto a DNA array. For the hybridization adsorption of both DNA and RNA oligonucleotides, a detection limit of 10 nM is reported; for large (1,500-base) 16S rRNA molecules, concentrations as low as 2 nM are detected. The covalent attachment of thiol-DNA probes to the gold surface leads to high surface probe density (10(12) molecules/cm2) and excellent probe stability that enables more than 25 cycles of hybridization and denaturing without loss in signal or specificity. Fresnel calculations are used to show that changes in percent reflectivity as measured by SPR imaging are linear with respect to surface coverage of adsorbed DNA oligonucleotides. Data from SPR imaging is used to construct a quantitative adsorption isotherm of the hybridization adsorption on a surface. DNA and RNA 18-mer oligonucleotide hybridization adsorption is found to follow a Langmuir isotherm with an adsorption coefficient of 1.8 x 10(7) M(-1).

Surface plasmon resonance imaging measurements of ultrathin organic films.

The surface-sensitive optical technique of surface plasmon resonance (SPR) imaging is used to characterize ultrathin organic and biopolymer films at metal interfaces in a spatially resolved manner. Because of its high surface sensitivity and its ability to measure in real time the interaction of unlabeled biological molecules with arrays of surface-bound species, SPR imaging has the potential to become a powerful tool in biomolecular investigations. Recently, SPR imaging has been successfully implemented in the characterization of supported lipid bilayer films, the monitoring of antibody-antigen interactions at surfaces, and the study of DNA hybridization adsorption. The following is included in this review: (a) an introduction to the principles of surface plasmon resonance, (b) the details of SPR imaging instrumental design, (c) a short discussion concerning resolution, sensitivity, and quantitation in SPR imaging, (d) the details of DNA array fabrication on chemically modified gold surfaces, and (e) two examples that demonstrate the application of the SPR imaging technique to the study of protein-DNA interactions.

Epstein-Barr virus-negative post-transplant lymphoproliferative disorders: a distinct entity?

Post-transplant lymphoproliferative disorders (PTLDs) are usually but not invariably associated with Epstein-Barr virus (EBV). The reported incidence, however, of EBV-negative PTLDs varies widely, and it is uncertain whether they should be considered analogous to EBV-positive PTLDs and whether they have any distinctive features. Therefore, the EBV status of 133 PTLDs from 80 patients was determined using EBV-encoded small ribonucleic acid (EBER) in situ hybridization stains with or without Southern blot EBV terminal repeat analysis. The morphologic, immunophenotypic, genotypic, and clinical features of the EBV-negative PTLDs were reviewed, and selected features were compared with EBV-positive cases. Twenty-one percent of patients had at least one EBV-negative PTLD (14% of biopsies). The initial EBV-negative PTLDs occurred a median of 50 months post-transplantation compared with 10 months for EBV-positive cases. Although only 2% of PTLDs from before 1991 were EBV negative, 23% of subsequent PTLDs were EBV negative (p <0.001). Of the EBV-negative PTLDs, 67% were of monomorphic type (M-PTLD) compared with 42% of EBV-positive cases (p <0.05). The other EBV-negative PTLDs were of infectious mononucleosis-like, plasma cell-rich (n = 2), small B-cell lymphoid neoplasm, large granular lymphocyte disorder (n = 4) and polymorphic (P) types. B-cell clonality was established in 14 specimens and T-cell clonality was established in three (two patients). None of the remaining specimens were studied with Southern blot analysis and some had no ancillary studies. Rearrangement of c-MYC was identified in two M-PTLDs with small noncleaved-like features, and rearrangement of BCL-2 was found in one large noncleaved-like M-PTLD. Ten patients were alive at 3 to 63 months (only three patients received chemotherapy). Seven patients, all with M-PTLDs, are dead at 0.3 to 6 months. Therefore, EBV-negative PTLDs have distinct features, but some do respond to decreased immunosuppression, similar to EBV-positive cases, suggesting that EBV positivity should not be an absolute criterion for the diagnosis of a PTLD.

CD5 negative diffuse mantle cell lymphoma with splenomegaly and bone marrow involvement.

We report the case of a 78-year-old man in whom routine physical examination revealed cervical adenopathy and splenomegaly. Peripheral blood showed a normal white blood cell count with an absolute lymphocytosis, which included a population with slightly indented nuclei. Lymph node biopsy showed morphology compatible with mantle cell lymphoma. Bone marrow biopsy showed replacement by a lymphoid proliferation composed of lymphocytes with features similar to those found in the peripheral blood. Immunophenotypic analysis of both peripheral blood and lymph node showed positivity for CD19, CD20 and CD22, with lambda light chain restriction. Tests for CD5 and CD10 were negative. Cytogenetic analysis and polymerase chain reaction studies confirmed the presence of t(11,14) supporting a diagnosis of mantle cell lymphoma. This unusual case of CD5-negative mantle cell lymphoma exemplifies the importance of combined molecular, cytogenetic, and morphologic evaluation when confronted with a lymphoma having an atypical phenotype.

Clonal and morphological variation in a posttransplant lymphoproliferative disorder: evolution from clonal T-cell to clonal B-cell predominance.

The majority of posttransplant lymphoproliferative disorders (PTLD) are Epstein-Barr virus (EBV)-associated and of B-cell origin. A much smaller proportion of PTLD are of T-cell origin. We report the clinical, morphological, immunophenotypic, and genotypic results of a unique PTLD, initially diagnosed as immune mediated thrombocytopenia (ITP), which at presentation was predominantly an anaplastic appearing EBV-associated T-cell PTLD and, after reduction in immunosuppression and the administration of antiviral agents, predominantly an EBV-associated plasma cell rich B-cell PTLD. Subsequent chemotherapy resulted in a complete remission. This case has both practical and biological implications. It highlights how PTLD may be misdiagnosed as other entities, how biclonal cases can have different morphological appearances and include both B- and T-cell clones, how PTLD can evolve over time possibly related to immune reconstitution, and why PTLD should be rebiopsied when the disease does not respond to decreased immunosuppression or recurs.

Two-wavelength operation of the nonlinear fiber loop mirror.

We describe the two-wavelength operation of the nonlinear fiber loop mirror. In this mode of operation a high-power signal at one wavelength switches a low-power signal at another wavelength. This device is investigated both theoretically and experimentally. The experimental results show that the nonlinear loop mirror performs as an optical modulator that consists of all-fiber components.

Improved mode locking of an F-center laser with a nonlinear nonsoliton external cavity.

We demonstrate that solitons are not essential for the operation of the soliton laser. The external cavity employed contains an optical fiber with negative group-delay dispersion and therefore does not support bright solitons. Thus the improved mode locking cannot be attributed to the injection of an N = 2 soliton.

All-fiber pulse compression at 1.32 microm.

We have constructed a pulse compressor using two different optical fibers. By adjusting the waveguide dispersion it has been possible to produce fibers with positive and negative dispersion at 1.32 microm. We have demonstrated the compression of 130-psec pulses down to our photodiode limit of 70 psec. This is supported by our calculations, which give a theoretical pulse width of 50 psec. This is the first reported demonstration of both an all-fiber pulse compressor and optical pulse compression at 1.32 microm.

Pathology and Development of the Grasshopper Inclusion Body Virus in Melanoplus sanguinipes.

Grasshoppers, Melanoplus sanguinipes (F.), infected with the grasshopper inclusion body virus (GIBV) showed a general torpor, took longer to develop, and had abnormally high rates of mortality. Infection was found only in the fat body, and developing viruses and inclusion bodies were observed in the nuclei and cytoplasm of infected cells. Although the size of the inclusion bodies in cells varied at different stages of infection, the inclusion bodies appeared to grow during the infection. Electron microscopic investigations of viral replication showed that at about 8 days after inoculation presumptive viral particles had developed as buds or protrusions from precursor granular masses; thereafter, these particles underwent internal differentiation and were incorporated into developing inclusion bodies. The GIBV was similar to insect viruses in the genus Vagoiavirus Weiser and to pox viruses, particularly vaccinia.