Actinium isotope cross sections for 226Ra(p,xn) reactions measured at low energies.

Cross sections for production of the medical isotope 225Ac by the 226Ra(p,2n) reaction have not previously been measured in fine steps over the relevant energy region, and no measurements are presently available in the literature for the actinium contaminant isotopes created by the adjacent 226Ra(p,n)226Ac and 226Ra(p,3n)224Ac reactions. We report thin-target cross-section measurements for production of 224Ac and 225Ac by protons of 15.1-16.8 MeV incident on radium. An upper limit for the 226Ac cross section is also reported.

A sphingosine-1-phosphate receptor 1 agonist inhibits tertiary lymphoid tissue reactivation and hypersensitivity in the lung.

Hypersensitivity pneumonitis is characterized by pulmonary accumulation of B-cell-rich tertiary lymphoid tissues (TLTs), which are alleged sites of amplification for antigen-specific responses. The sphingosine-1-phosphate receptor 1 (S1P1) regulates key mechanisms underlying lymphoid tissue biology and its chemical modulation causes lymphocyte retention in lymph nodes. Given the putative immunopathogenic impact of lymphocyte accumulation in TLTs, we investigated whether or not chemical modulation of S1P1 caused lymphocyte retention within TLTs in a model of hypersensitivity pneumonitis. Mice were exposed subchronically to Methanosphaera stadtmanae (MSS) in order to induce an hypersensitivity pneumonitis-like disease. MSS exposure induced B-cell-rich TLTs surrounded by S1P1-positive microvessels. Upon MSS rechallenge, the S1P1 agonist RP001 prevented the pulmonary increase of CXCL13, a chief regulator of B-cell recruitment in lymphoid tissues. This was associated with a complete inhibition of MSS rechallenge-induced TLT enlargement and with a 2.3-fold reduction of MSS-specific antibody titers in the lung. Interference with TLT reactivation was associated with a 77% reduction of neutrophil accumulation and with full inhibition of protein-rich leakage in the airways. Thus, an S1P1 agonist hinders TLT enlargement upon antigenic rechallenge and inhibits key pathognomonic features of experimental hypersensitivity pneumonitis.

An excision event that may depend on patchy homology for site specificity.

In mouse cells transformed by a mutant polyomavirus genome, recombination between integrated viral DNA and flanking cellular DNA resulted in the excision of two readily amplifiable chimeras, designated RmI and RmII. The crossing-over that generated RmII was unique in that it involved a simple cellular sequence in which the triplet 5'-CTG-3' was repeated many times. We show that the sequence across the junction resulting from excision was identical in several molecules of RmII, as if the cross-over generating this junction always involved exactly the same two sites on the viral and cellular DNA. We also show that the cellular site mapped where the replacement of a G by an A in one of many successive 5'-CTG-3' triplets generated a homology of five nucleotides (5'-CTACT-3') with the viral site. Oligonucleotides on both sides of these sites are probably involved in matching the two DNAs prior to recombination.

Possible association of the pro-melanin-concentrating hormone gene with a greater body mass index as a side effect of the antipsychotic olanzapine.

Following our report of a linkage at 12q24 with a phenotype of obesity under antipsychotics, we tested the pro-melanin-concentrating hormone (PMCH) candidate gene for a possible association in humans with the body mass index (BMI; kg/m2) in unrelated schizophrenic patients (SZ) receiving antipsychotics (N = 300) and in controls (CTL; N = 150). Subjects were classified in obese (OB) (BMI > or = 30 kg/m2), overweight (25 < or = BMI < 30 kg/m2), and normal weight (BMI < 25 kg/m2) groups. Single nucleotide polymorphisms (SNP) rs7973796 and rs11111201, located 5' at -4.5 kb and 3' at +1.8 kb, respectively, of PMCH were genotyped. Interaction effects of genotypes and antipsychotic treatment on BMI were tested in a covariance analysis with age and gender as covariates. Interaction effects on the prevalence of obesity were tested in a logistic regression analysis. For subjects under 50 years, the effect of the rs7973796 genotype on BMI differed between the SZ patients taking olanzapine and CTL group (interaction P = 0.025). Olanzapine-treated SZ patients carrying the ancestral homozygote genotype showed a higher BMI for rs7973796 (P = 0.016 with the LSMeans t-test) than the variant homozygotes. Accordingly, the ORs for obesity associated with rs7973796 genotypes differed in the SZ patients taking olanzapine compared to the CTL group (interaction P = 0.0094). The G allele was associated with an increase in the odds of obesity in SZ patients taking olanzapine. No association was observed for those over 50 years, or for rs11111201. These results suggest that the common allele of PMCH rs7973796 may be associated with a greater BMI in olanzapine-treated SZ patients.

A hotspot for promoter-dependent recombination in polyomavirus DNA.

We have engineered polyomavirus (Py) DNA molecules carrying two large direct repeats within the late coding region, as well as a deletion encompassing the TATA box in the early promoter. Such constructs recombine less readily than a construct containing the same duplication of late sequences, but an intact early promoter. Furthermore, residual recombination in the molecules with a deletion occurs between homologous sites which differ from those used in the molecule without deletion. These findings are consistent with recombination being stimulated by transcription originating from the early promoter, rather than facilitated by the "openness" of viral chromatin undergoing transcription.

An amplified genome that may have resulted from recombination within bidirectionally replicating DNA.

Temperature shift-down of permissive mouse cells transformed by a temperature-sensitive (ts) polyomavirus (Py) genome has been shown to induce the accumulation of free copies of the viral DNA. We report here on an unusual product from such induction. The structure of this product is that expected from the occurrence of recombination between growing points in a bidirectionally replicating Py-mouse DNA molecule. This observation may be relevant to the mechanism of gene amplification in mammalian cells.

Mouse cells surviving polyoma virus infection generally retain the whole viral genome.

Permissive mouse 3T6 cells were exposed to polyoma virus--either wild-type or early mutant--at high multiplicities of infection. From colonies arising from surviving cells, so-called lines and clones were derived under conditions precluding superinfection. These lines and clones were examined for the presence of viral genetic information, using a variety of techniques. Two salient findings were made: most lines or clones analyzed had retained viral genetic material; generally, this material was nondefective, as evidenced by the production of virus and/or viral DNA molecules of genomic size. These findings indicate that mouse cells can survive for many generations while carrying a complete, infectious, and potentially cytocidal polyoma virus genome.

Anticholinesterase-responsive neuromuscular junction transmission defects in post-poliomyelitis fatigue.

Disabling generalized fatigue and muscle fatiguability are common features of post-poliomyelitis syndrome (PPS). In 17 fatigued PPS patients, we measured jitter on stimulation single-fiber electromyography (S-SFEMG) for at least 3.5 min before and after i.v. injection of 10 mg edrophonium. We observed reduction in jitter (defined as a significant difference in jitter means before and after edrophonium, unpaired t-test P < 0.05) in 7 patients, no change in 8, and a significant increase in 2 patients. Blinded to their edrophonium results, the 17 patients were treated with pyridostigmine 180 mg/day for 1 month, with a subjective improvement of fatigue in 9 patients, and with a significant reduction in mean Hare fatigue scores in the entire group of 17 patients (pre = 2.71, and post = 1.71; Wilcoxan signed rank sum test, P < 0.05). Edrophonium-induced reduction of jitter on S-SFEMG was significantly associated with pyridostigmine-induced subjective improvement of fatigue (Fisher's exact test, P < 0.04). A significant reduction in fatigue with pyridostigmine was observed only in the 7 patients who experienced a significant reduction in jitter with edrophonium (Wilcoxan signed rank sum test, P = 0.03). In addition, the 9 pyridostigmine responders experienced a significant reduction in jitter means pre- and post-edrophonium (100% vs. 88%, Bonferroni corrected, P < 0.01). We conclude that neuromuscular transmission as measured by jitter on S-SFEMG can improve with edrophonium in a proportion of PPS patients, and that generalized fatigue and muscle fatiguability in some patients with PPS may be due to anticholinesterase-responsive NMJ transmission defects.

Stimulation frequency-dependent neuromuscular junction transmission defects in patients with prior poliomyelitis.

Generalized fatigue and muscle fatiguability are major symptoms of post-poliomyelitis syndrome (PPS), and may be due to neuromuscular junction transmission defects, as suggested by increased jitter on single fiber electromyography (SFEMG). To determine the etiology of this defect, we studied jitter at low (1, 5 Hz) and high (10, 15, 20 Hz) frequency stimulation with stimulation SFEMG in 17 post-polio patients with muscle fatiguability, and in 9 normal controls. In 5 of 17 PPS patients and in 1 of 9 controls, jitter was significantly higher (unpaired t-test, P < 0.05) at high frequency stimulation (HFS). In the remaining PPS patients and controls there was no significant difference in jitter at high and low stimulation frequencies. PPS patients with increased jitter at HFS had a significantly longer time interval since acute polio (mean 48.5 years) than PPS patients without increased jitter at HFS (mean 40 years; P < 0.05), but were not distinguished by other historical or clinical criteria. We conclude that the neuromuscular junction defect in post-polio patients is similar to that observed in amyotrophic lateral sclerosis, and is probably due to ineffective conduction along immature nerve sprouts and exhaustion of acetylcholine stores. The appearance of an increase in jitter with HFS in post-polio patients may be dependent upon time after acute polio.

Treatment of spasticity with tizanidine in multiple sclerosis.

Spasticity is a frequent and often disabling symptom in MS patients. Current drugs used as antispastic agents include Dantrolene Sodium, Baclofen and Diazepam. Tizanidine (5-chloro-4-(2imidazolin-2 yl amino)-2,1,3-benzothialdiazole) is a new antispasticity agent that has purported central action. A double blind placebo controlled trial was performed to study the efficacy of this drug in MS patients. Sixty-six patients entered an eight week therapeutic trial and fifty-nine completed the trial. Patients were assessed at 0, 2, 3 and 8 weeks of therapy for clinical effects. Electrophysiologic tests were performed at 0 and 8 weeks. A statistically significant benefit was noted in spastic muscle groups in the legs with concomitant significant reduction in hyperactive stretch reflexes and ankle clonus. Side effects most frequently cited included dry mouth and drowsiness. Two patients developed elevated liver function test that decreased with cessation of therapy. Other clinical details, side effects and electrophysiologic data will be presented. Tizanidine appears to reduce clinical spasticity and hyperreflexia in MS patients although no change in functional status was detected. Tizanidine may well serve as an alternate antispastic agent, alone or in combination with other agents.

Bubble propagation in a pipe filled with sand.

Granular flow with strong hydrodynamic interactions has been studied experimentally. Experiments have been carried out to study the movement of a single bubble in an inclined tube filled with glass beads and air. A maximum bubble velocity was found at an inclined angle straight theta(m). The density variations in the sand were measured by capacitance measurements, and a decompactification zone was observed just above the bubble when the inclination angle straight theta was larger than straight theta(m). The length of the decompactification front increased with increasing inclination angle and disappeared for angles smaller than straight theta(m). Both pressure and visualization experiments were carried out and compared with the density measurements.

The tapestry of care.

The analogy of a tapestry is used to explore artistic nursing activities. The warp is composed of acontextual knowledge and skills, available resources, and agency policies. The weft is the creative pattern of care. A sensitive awareness of the total context of the person being cared for enables the nurse to creatively use approaches and activities that match and balance the person's values, needs, and interests. An example of how the weft was developed for one client is described.

Electrophysiology and electrodiagnosis of the post-polio motor unit.

Post-poliomyelitis syndrome refers to new symptoms that may occur years after recovery from poliomyelitis. The most common of these symptoms are new weakness, fatigue, and pain. This article describes electrodiagnostic studies--conventional electromyography (EMG), single fiber electromyography (SFEMG), and macroelectromyography (macro-EMG)--that have provided information on the post-polio motor unit and on the possible etiology of some post-polio syndrome symptoms. Muscular fatigue, and indirectly, general fatigue, may be due to neuromuscular junction transmission defects in some post-polio individuals, as suggested by reduction of the compound motor action potentials on repetitive stimulation, and increased jitter and blocking on SFEMG. Progressive weakness and atrophy in post-polio syndrome is probably due to a distal degeneration of post-polio motor units with resultant irreversible muscle fiber denervation. Electrodiagnostic evidence of ongoing denervation includes fibrillation and fasciculation potentials on conventional EMG, increased jitter and blocking on SFEMG, and smaller macro-EMG amplitudes in newly weakened post-polio muscles. However, even though electrodiagnostic studies have provided insight into the possible causes of some post-polio syndrome symptoms, no specific electrodiagnostic test for the syndrome is currently available.

Learning caring behavior in an integrated manner.

We can see that by transferring caring behaviors from previous experiences, by imitation of role models, and by multiple experiential activities, learners form and utilize schemata of caring. By finding ways to stimulate learners to think about the feeling of caring and to imagine caring for others, caring becomes a psychophysiological or psychokinesthetic experience. A broad aim or high-level purpose, that is, to care, to have interest in and concern for others, or union and separation toward growth could serve as an inner context that would automatically evoke associated networks of learned, integrated caring actions. The caregiver would not usually be aware of each separate action. These broad aims would organize procedural knowledge, or "know how," in the motor areas of the brain. Let us return to Gardield's predicament. Can we help him walk again? Perhaps someone will call him in a friendly voice, someone whom he knows will give him a little chow and lots of stroking on his head. I suspect he would forget about his feet and just hurry over.

Inducible permissive cells transformed by a temperature-sensitive polyoma virus: superinfection does not allow excision of the resident viral genome.

After exposure of mouse embryo cells to the early temperature-sensitive mutant tsP155 of polyoma virus (Py), a transformed cell line (Cyp line) that can be readily induced to synthesize Py by transfer to 33 degrees C was isolated at 39 degrees C (7). Virus production and synthesis of free viral DNA occurring after temperature shiftdown or superinfection with wild-type Py or both were studied in several clonal isolates of the Cyp cell line. Measurements of virus yields indicated that, although some could be induced more effectively than others, all cell clones behaved as highly permissive when subjected to superinfection. We analyzed the origin of free viral DNA accumulating in the superinfected cultures, taking advantage of (i) the unique physical properties of the low-molecular-weight DNA which, in the case of one of the Cyp clones, accumulates during temperature shiftdown, and (ii) the differences between resident and superinfecting viral genomes in their susceptibilities towards restriction endonucleases. At 33 degrees C, both viral genomes were found to accumulate in all clones studied whereas in the case of the clones with lower inducibility, the replication of the resident genome appeared to be enhanced by superinfection. At 39 degrees C, however, accumulation of the superinfecting genome was not accompanied by that of the resident genome, unless it had already been initiated before superinfection. These findings demonstrate that, when routinely cultivated at 39 degrees C, Cyp cells contain few viral DNA molecules readily available for autonomous replication and that, upon transfer to 33 degrees C, therefore, excision must first take place before the resident genome can accumulate as free viral DNA. Our findings also suggest that, unlike the P155 gene product provided by the resident viral genome upon induction, the allelic gene product supplied by the superinfecting genome may be less effective in triggering excision than in promoting replication.

p53-mediated DNA renaturation can mimic strand exchange.

The process of strand exchange is considered to be the hallmark of DNA recombination. Proteins known to carry out such exchange are believed to operate via one or the other of two mechanisms. RecA-like proteins promote the formation of a three-stranded or triplex synaptic intermediate in which strand exchange occurs, whereas other proteins would allow the coordinated exonucleolytic degradation of one strand in the duplex DNA and its replacement by an invading strand of similar sequence and polarity. In view of properties ascribed to it, we have attempted to determine whether p53 belongs to one or the other of these groups of proteins. The in vitro assay used relies on a double-stranded (ds) oligonucleotide (oligo 1+2) and a single-stranded (ss) oligonucleotide (oligo 3), part of which is complementary to oligo 1. The data collected suggest that, under the conditions of the assay, oligo 1+2 undergoes partial denaturation; p53 then catalyzes renaturation of oligo 1 with oligo 3, rather than true strand exchange. Since p53 is not known for being able to 'melt' DNA, it would seem unlikely that this protein would effect strand exchange in vivo without assistance from another, denaturing, protein.

Preferred crossover sites on polyomavirus DNA.

RmI is a hybrid replicon consisting of polyomavirus (Py) and mouse sequences that yields unit-length polyomavirus DNA via recombination between two directly repeated viral sequences of 182 base pairs (S repeats). To define the contribution of the S repeats in this intramolecular recombination, we derived from RmI a series of replicons containing the original S repeats as well as additional direct viral repeats which were 1 to 2 kilobases in length (L repeats). After mouse 3T6 cells were transfected with these constructs, recombination products that displayed the physical properties of homologous recombinants were detected. The structures of these recombinants indicated that whereas repeat length influences the likelihood of recombination, crossover occurs preferentially near the S repeats, provided that one of them is proximal to the viral origin of replication. This finding suggests that recombination near the S repeats depends on a process initiated near the viral origin of replication.

Alternative homologous and nonhomologous products arising from intramolecular recombination.

RmI, a chimeric DNA molecule containing polyomavirus (Py) and mouse sequences, generates unit-length Py DNA via intramolecular recombination between two directly repeated viral sequences of 182 base pairs (S repeats). To analyze the contribution of the S repeats in this process, we produced mutants of RmI carrying deletions in either one or both S repeats and tested them for their ability to recombine in mouse 3T6 cells. Mutant DNAs were found to yield unit-length Py DNA as long as they carried a minimal internal homology of 40 to 50 base pairs. Unlike RmI itself, however, the mutants also gave rise to nonhomologous recombination products. These results suggest that when the generation of homologous products is hampered by a limiting homology, nonhomologous products may arise instead of homologous ones. Therefore, the initial step(s) in the mechanisms yielding the two kinds of products could be identical.