Legionnaire's disease: a current update.

Legionnaire's disease was first identified and described in January 1977. Even today, it is often regarded as an unusual or exotic disease, when in fact it is a very common form of community and nosocomial acquired pneumonia. The major roles of the acute care nurse, including patient health education; psychosocial needs of the patient; and strategies for disease prevention and control, are discussed.     

RF refocused echoes of J-coupled spin systems: effects on RARE-based spectroscopic imaging.

A numerical simulation tool was developed to calculate the echo amplitudes of J-coupled resonances within a series of radiofrequency (RF) refocused echoes. The signal modulation due to J-coupling in rapid acquisition with relaxation enhancement (RARE) is suppressed only when the inverse of the pulse interval (tau) is large compared to both the chemical shift (CS) difference (Deltadelta) of the coupled spins and the coupling constant. In contrast, the echo amplitudes in ultrafast low-flip-angle RARE (U-FLARE) oscillate around a quasi-steady-state value that is greater than zero (neglecting relaxation and diffusion) even when Deltadelta > 1/tau. The flip-angle distribution over the measured slice caused by the use of Gaussian-shape slice-selective refocusing pulses further reduces the echo oscillations. When the pulse interval falls short of the fast pulse rate regime, spectroscopic U-FLARE provides an improved spatial impulse response in the phase-encoding (PE) direction compared to spectroscopic RARE.     

Retention of water and potassium by erythrocytes prevents calcium-induced membrane rigidity.

Modest increases in intracellular calcium concentrations, in association with ATP depletion, cause the appearance of pathologic changes in erthrocyte shape and deformability. The loss of erythrocyte ATP and simultaneous increase in cellular calcium have previously been considered the sole requisites for the appearance of erythrocyte membrane rigidity. We report that red cells suspended in high-potassium buffers may be simultaneously loaded with calcium (through exposure to the divalent cation ionophore A23187) and depleted of ATP without incurring drastic changes in shape or in membrane stiffness. Incubation of erythrocytes under these conditions effectively blocks both water and potassium loss normally caused by calcium accumulation. However, the high external potassium has no influence on either the ionophore-induced accumulation of calcium or on the the concomitant hydrolysis of cellular ATP. These results suggest the involvement of at least one further parameter, ie, changes in cell water and cation content, in the development of calcium-induced erythrocyte rigidity.     

Expression of ORF-69 of turnip yellow mosaic virus is necessary for viral spread in plants.

Turnip yellow mosaic virus (TYMV) RNA has two extensively overlapping open reading frames (ORFs) encoding noncapsid proteins. The longest of these, ORF-206, is essential for RNA replication. We have investigated the expression and role of ORF-69 (encoding a protein with a MW of 69K) using specific antiserum and mutant genomic RNAs designed to interrupt ORF-69 expression. TYC69 antiserum immunoprecipitated a protein with an apparent MW of 75K (p69) from in vitro translations of TYMV RNA. Mutant RNAs with stop codons inserted at nucleotides 139, 178, and 178/224 in ORF-69 expressed ORF-69 at very low levels in vitro. These mutants replicated to wild-type levels in turnip or Chinese cabbage protoplasts, but were not recovered from any leaves of inoculated plants. These results suggest that ORF-69 products are dispensible for replication, but are required for viral spread. Revertant and pseudorevertant viruses with uninterrupted ORF-69 were recovered from plants showing delayed onset of symptoms after inoculation with two of the above mutants, indicating the importance of ORF-69 expression in establishing a systemic infection in plants. ORF-69 expression could be detected using Western blots in extracts from young, symptomatic leaves of infected plants. A single band with an apparent MW of 75-80K was detected in leaves infected with cDNA-derived viral RNAs, while a doublet was detected after infection with type strain viral RNA, suggesting the presence of two ORF-69 alleles or differential post-translational modification.     

Distal rectus femoris surgery in children with cerebral palsy: results of a Delphi consensus project

PurposeThe purpose of this study was for an international panel of experts to establish consensus indications for distal rectus femoris surgery in children with cerebral palsy (CP) using a modified Delphi method.MethodsThe panel used a five-level Likert scale to record agreement or disagreement with 33 statements regarding distal rectus femoris surgery. The panel responded to statements regarding general characteristics, clinical indications, computerized gait data, intraoperative techniques and outcome measures. Consensus was defined as at least 80% of responses being in the highest or lowest two of the five Likert ratings, and general agreement as 60% to 79% falling into the highest or lowest two ratings. There was no agreement if neither threshold was reached.ResultsConsensus or general agreement was reached for 17 of 33 statements (52%). There was general consensus that distal rectus femoris surgery is better for stiff knee gait than is proximal rectus femoris release. There was no consensus about whether the results of distal rectus femoris release were comparable to those following distal rectus femoris transfer. Gross Motor Function Classification System (GMFCS) level was an important factor for the panel, with the best outcomes expected in children functioning at GMFCS levels I and II. The panel also reached consensus that they do distal rectus femoris surgery less frequently than earlier in their careers, in large part reflecting the narrowing of indications for this surgery over the last decade.ConclusionThis study can help paediatric orthopaedic surgeons optimize decision-making for, and outcomes of, distal rectus femoris surgery in children with CP.Level of evidenceV     

Bihemispheric Collateralization of the Cortical and Subcortical Afferents to the Rat's Visual Cortex

A fluorescent dye (usually fast blue or rhodamine tagged latex microspheres) was injected into cortical area 17 (or area 17 and the lateral part of area 18b) of adult and juvenile (15 - 22 day old) Sprague-Dawley albino rats. Another fluorescent dye (usually diamidino yellow) was injected into cortical areas 17, 18a and 18b of the opposite hemisphere. The injections involved only the cortical grey matter. After postinjection survival of 2 - 14 days the distribution of retrogradely labelled mesencephalic and prosencephalic cells was analysed. Both small and large injections labelled retrogradely a substantial number of cells in specific and nonspecific dorsal thalamic nuclei (lateral geniculate, lateral posterior, ventromedial, several intralaminar nuclei and nucleus Reuniens) as well as a small number of cells in the preoptic area of the hypothalamus and the mesencephalic ventral tagmental area (VTA). While labelled thalamic cells contained only the dye injected into the ipsilateral cortex, a small proportion of hypothalamic and VTA cells was labelled with the dye injected into the contralateral cortex. Virtually none of the cells in these areas were double labelled with both dyes. Both small and large injections labelled cells in the ipsilateral telencephalic magnocellular nuclei of the basal forebrain and the caudal claustrum. A substantial minority of labelled cells in these structures was labelled by the dye injected into the contralateral cortex. Furthermore, a small proportion (about 1%) of claustral cells projecting to the ipsilateral cortex were double labelled with both dyes. In several cortical areas ipsilateral to the injected area 17, associational neurons were intermingled with commissural neurons projecting to the contralateral visual cortex. A substantial proportion of associational neurons projecting to ipsilateral area 17 also projected to the contralateral visual cortex (associational-commissural neurons). Thus, in visual area 18a, the associational-commissural neurons were located in all laminae, with the exception of lamina 1 and the bottom of lamina 6, and constituted about 30% of the neurons projecting to ipsilateral area 17. In paralimbic association area 35/13, associational-commissural neurons were located in lamina 5 and constituted about 20% of neurons projecting to ipsilateral area 17. In the limbic area 29d, the associational-commissural neurons were located in laminae 4, 5 and the upper part of lamina 6 and constituted about 10% of the associational-commissural neurons projecting to ipsilateral area 17. In oculomotor area 8, double-labelled neurons were located in lamina 5 and constituted about 10% of the neurons projecting to ipsilateral area 17. Thus, it appears that the axons of mesencephalic and diencephalic neurons projecting to the visual cortex do not send collaterals into both hemispheres. The bihemispheric projection to the rat's visual cortex originates almost exclusively in the retinotopically organized cortical area 18a and in integrative cortical areas 35/13, 29d and 8.     

Rabbit immunoglobulin kappa genes: structure of a germline b4 allotype J-C locus and evidence for several b4-related sequences in the rabbit genome.

To investigate the genetic mechanism by which certain rabbits can express immunoglobulins unexpected on the basis of their pedigree (i.e., "latent" allotypes), we have begun a study of the rabbit immunoglobulin kappa gene locus. Here we report the structure of a germline genomic clone that encodes the b4 allotype of rabbit kappa immunoglobulin and corresponds to the kappa gene expressed by the rabbit-mouse hybridoma 12F2. The nucleotide sequences of the joining (J) and constant (C) regions reveal structures generally similar to the homologous mouse and human loci, although only one of the five J-like sequences of this rabbit gene is apparently expressed. Southern blotting analysis of DNA from several rabbit allotypic strains by using probes derived from the cloned b4 gene demonstrates that, in contrast to mouse and human, rabbits possess multiple kappa-related sequences. Rabbits of the nominal b4, b5, b6, and b9 allotypes each contain at least two b4-related sequences that are associated with their own J regions and that are highly homologous to the cloned b4 gene in both coding and flanking regions.