Quantification of the layer dispersion degree in polymer layered silicate nanocomposites by transmission electron microscopy

As the performance of polymer layered silicate nanocomposites strongly depends on their interior layer dispersion, quantification of the layer dispersion degree is needed. In this work, a new methodology was developed to determine the dispersion parameter D_0.1, based on the measurement of the free-path spacing distance between the single clay sheets from the transmission electron microscopy (TEM) images. Several examples of exfoliated, intercalated, and immiscible composites were studied. It was found that the exfoliated composites had D_0.1 over 8%, while that of intercalated composites were between 4 and 8%. In the case of intercalation, a high frequency peak appeared at a short spacing distance in the histogram, which was a characteristic of the intercalation, distinct from the exfoliation. The main utility of this TEM methodology is for the quantification of exfoliated or intercalated samples with small number of layers with stacks. The dispersion parameter D_0.1 below 4% was suggested to classify as immiscible. A unique advantage of the TEM measurement is that the dispersion degree of different fillers can be counted individually.     

Reexpansion pulmonary edema

Reexpansion pulmonary edema is a rare complication attending the rapid reexpansion of a chronically collapsed lung, such as occurs after evacuation of a large amount of air or fluid from the pleural space. The condition usually appears unexpectedly and dramatically-immediately or within 1 h in 64% of patients and within 24 h in the remainder. The clinical manifestations are varied; they range from roentgenographic findings alone in asymptomatic patients to severe cardiorespiratory insufficiency. The radiographic evidence of reexpansion pulmonary edema is a unilateral alveolar filling pattern, seen within a few hours of reexpansion of the lung. The edema may progress for 24-48 h and persist for 4-5 days. Human data on the pathophysiology of reexpansion pulmonary edema derive from small series of patients, case reports, and reviews of the literature. On the other hand, a larger body of data exists on experimental reexpansion pulmonary edema in cats, monkeys, rabbits, sheep, and goats. This review examines the clinical and experimental evidence for reexpansion pulmonary edema. In addition, we detail the historical background, clinical setting, treatment, and outcome of reexpansion pulmonary edema.     

P2X3 is expressed by DRG neurons that terminate in inner lamina II

The P2X3 receptor subunit, a member of the P2X family of ATP-gated ion channels, is almost exclusively localized in sensory neurons. In the present study, we sought to gain insight into the role of P2X3 and P2X3-containing neurons in sensory transmission, using immunohistochemical approaches. In rat dorsal root ganglia (DRG), P2X3-immunoreactivity (-ir) was observed in small- and medium-sized neurons. Approximately 40% of DRG neuronal profiles in normal rats contained P2X3-ir. In rats that had received neonatal capsaicin treatment, the number of P2X3-positive neurons was decreased by approximately 70%. Analysis of the colocalization of P2X3-ir with cytochemical markers of DRG neurons indicated that approximately 94% of the P2X3-positive neuronal profiles were labelled by isolectin B4 from Bandeiraea simplicifolia, while only 3% contained substance P-ir, and 7% contained somatostatin-ir. In dorsal horn of rat spinal cord, P2X3-ir was observed in the inner portion of lamina II and was reduced subsequent to dorsal rhizotomy, as well as subsequent to neonatal capsaicin treatment. Finally, P2X3-ir accumulated proximal to the site of sciatic nerve ligation, and was seen in nerve fibres in skin and corneal epithelium. In summary, our results suggest that P2X3 is expressed by a functionally heterogeneous population of BSI-B4-binding sensory neurons, and is transported into both central and peripheral processes of these neurons.     

Pigmentation phenotypes of variant extension locus alleles result from point mutations that alter MSH receptor function

Coat colors in the chestnut horse, the yellow Labrador retriever, the red fox, and one type of yellow mouse are due to recessive alleles at the extension locus. Similarly, dominant alleles at this locus are often responsible for dark coat colors in mammals, such as the melanic form of the leopard, Panthera pardus. We show here that the murine extension locus encodes the melanocyte-stimulating hormone (MSH) receptor. In mice, the recessive yellow allele (e) results from a frameshift that produces a prematurely terminated, nonfunctioning receptor. The sombre (Eso and Eso-3J) and tobacco darkening (Etob) alleles, which both have dominant melanizing effects, results from point mutations that produce hyperactive MSH receptors. The Eso-3J receptor is constitutively activated, while the Etob receptor remains hormone responsive and produces a greater activation of its effector, adenylyl cyclase, than does the wild-type allele.     

The aminothiol WR-1065 protects T lymphocytes from ionizing radiation-induced deletions of the HPRT gene

Aminothiols, such as WR-2721 and its active free thiol, WR-1065, reduce mutations from ionizing radiation in exponentially growing cells. In this study, human noncycling G0 T lymphocytes were exposed in vitro to gamma-irradiation in the presence or absence of WR-1065. The five treatment groups were: (a) control; (b) treatment with 4 mM WR-1065; (c) treatment with 3 Gy of gamma-radiation, from a 137Cs source; and (d) and (e) treatment with WR-1065 30 min prior to or 3 h after 3 Gy of gamma-irradiaiton, respectively. A total of 224 cloned HPRT mutants representing 179 independent mutations were analyzed for genetic alterations using multiplex PCR. Ionizing radiation alone significantly increased the percentage of mutations with gross structural alterations compared to controls (P = 0.02). Although the frequency of such large structural mutations was not different from control cells treated with WR-1065 alone, this aminothiol significantly reduced their frequency among irradiated mutants (P = 0.01) when the radioprotector was present during the irradiation. Addition of WR-1065 3 h postirradiation also greatly reduced the percentage of gross structural alterations; however, due to small numbers, this was not statistically significant. This is the first demonstration that the antimutagenicity of WR-1065 in human cells specifically protects against these kinds of large-scale DNA alterations induced by ionizing radiation. WR-1065 and similar aminothiol compounds may afford protection against radiation-induced mutations through polyamine-like processes, e.g., stabilization of chromatin structure, inhibition of cell proliferation, and influences on DNA repair systems.     

Collection of peripheral blood progenitor cells after the administration of cyclophosphamide, etoposide, and granulocyte-colony-stimulating factor: an analysis of 497 patients

BACKGROUND: There is great interpatient variability in the number of peripheral blood stem cells collected, as measured by CD34+ cell content, after the administration of chemotherapy and a growth factor. The ability to predict patients who fail to yield adequate quantities of CD34+ cells would be of value. However, very few reports include large numbers of patients treated in an identical fashion. STUDY DESIGN AND METHODS: Between 1991 and 1995, 497 consecutive patients with a variety of malignant diseases received cyclophosphamide (4 g/m2), etoposide (600 mg/m2), and granulocyte-colony-stimulating factor (6 micrograms/kg/day) for mobilization and collection of a target dose > or = 2.5 x 10(8) CD34+ cells per kg. Multivariate analyses were performed to determine the factors associated with failure to achieve this target harvest. RESULTS: A median of 14.71 x 10(6) CD34+ cells per kg (range, 0.08-137.55) was harvested with a median of 2 (range, 1-11) apheresis procedures. Ninety-one percent of patients yielded > or = 2.5 x 10(5) CD34+ cells per kg. Patients with Stage II-III breast cancer, who had pretreatment platelet counts > or = 150 x 10(9) per L and patients who underwent < or = 1 prior chemotherapy regimen had improved CD34+ cell yields. However, most patients with adverse risk factors yielded > or = 2.5 x 10(6) CD34+ cells per kg. CONCLUSION: A regimen of cyclophosphamide, etoposide, and granulocyte-colony-stimulating factor led to the successful collection of adequate numbers of CD34+ cells in most patients without excessive toxicity. These observations confirm previous reports that intense prior therapy adversely affects the quantity of CD34+ cells harvested. Pretreatment and posttreatment variables did not predict with any certainty the small fraction of patients who fail to yield > or = 2.5 x 10(6) CD34+ cells per kg via multiple apheresis procedures.     

Neurotoxicity following the ingestion of a Chinese medicinal plant, Alocasia macrorrhiza

1. A case of poisoning due to the raw root tuber of a Chinese medicinal plant, Alocasia macrorrhiza is presented. 2. The patient developed neurological (severe pain and numbness in the perioral area and throat) and gastrointestinal (nausea, vomiting, abdominal pain) symptoms immediately after eating the root tuber. 3. A macrorrhiza has properties and morphology very similar to another medical plant. A. odora. The root tuber of the latter is known to contain a neurotoxin sapotoxin.     

Lipid and lipoprotein distributions in children by ethnic group, gender, and geographic location--preliminary findings of the Child and Adolescent Trial for Cardiovascular Health (CATCH)

Male and female isometric strength curves for elbow fixation, shoulder flexion, and wrist supination-pronation are obtained during systematic variation in arm configuration. The shape of a given moment-angle curve is found to be a function of the orientations of joints kinematically coupled to the primary joint. It is also found that female elbow strength curves are shifted toward flexion with respect to male elbow-strength curves, suggesting that the in situ rest length of upper-limb muscles relative to joint angle may be longer for males than for females. Experimental results were contrasted with simulation results obtained using a three-dimensional musculoskeletal model which estimates the relationships between initial joint orientations, muscle tension-length behavior, and joint moments. In most of the cases, simulation results complimented experimental data and provided insights into likely in situ muscle rest lengths and moments arms, especially for the multiarticular biceps brachii muscle. Where inconsistencies exist between simulated and experimental data, subtle biomechanical complexities within the forearm and the shoulder girdle complex are identified that require future investigation.