The hemoglobins of Artemia salina. IV. A model for genetic control of hemoglobin 1, hemoglobin 2, and hemoglobin X

Two loci account for all genetic variation resulting in difference in electrophoretic mobility in three hemoglobins (Hb1, Hb2, and HbX) in the hemolymph of the brine shrimp. Four alpha alleles and nine beta alleles have been studied. In shrimps of all genotypes and in electrophoresis in media with varying degrees of molecular sieving, Hb2 is approximately equidistant from Hb1 and HbX. A shrimp heterozygous at both loci has a three-banded Hb1, a four-banded Hb2, and a three-banded BbX. We conclude that Hb2 contains n alpha-polypeptides and n beta-polypeptides. Hb1 contains 2n alpha-polypeptides. HbX contains 2n beta-polypeptides. During electrophoresis, the three native hemoglobins undergo reversible dissociation to n subunits. Subunits with the same charge reassemble to migrate as molecules of the same size as the native molecules. Although there is no evidence for an additional polypeptide in the three hemoglobins, we cannot exclude such a possibility. If it exists, it is under three constraints: (1) it must be present in equal amounts in each of the three hemoglobins; (2) it must have the same molecular weight as the alpha- and beta-polypeptides; and (3) it must be free of genetic variation (detectable by electrophoresis).     

Simulation of electromagnetically induced hyperthermia: a finite element gridding method

A finite element gridding method for simulating electromagnetically (EM) induced hyperthermia is presented. The method uses patient CT data as its primary input, with critical structures manually outlined (on a graphics workstation) for explicit demarcation. The paper outlines the various stages involved in mesh creation, including procedures for conforming the finite element representation of critical structures to their smooth boundaries, modelling of heating equipment, and modelling of the outer boundaries. The procedure for generating the finite element model is illustrated for an example treatment. Additionally, the results of computing the SAR in six patients are compared to measured values. The comparison reveals agreement between the model prediction and actual treatment within the limits of measurement error.     

Uracil as a Potentially Useful Indicator of Spoilage in Egg Products

The relationship between sensory acceptability of egg products and their uracil content was investigated. Pasteurized liquid whole egg, albumen, and yolk were allowed to deteriorate for 5-8 days at temperatures not exceeding 22°C. Periodically a panel of USDA inspectors evaluated the products'odors and samples were frozen for analysis. Uracil and uridine were determined by high performance liquid chromatography. Uridine contents decreased and uracil contents increased as the products deteriorated. Spoilage odors were detected only in products containing ≥1.7 μ, g/g uracil. Analysis for uracil is potentially useful for objectively detecting egg decomposition.     

The elevation of plasma DNA in patients with systemic lupus erythematosus is attributable to increased DNA release and defective DNA binding of mononuclear cells

BACKGROUND: Although immunoprecipitable DNA has been found in a subgroup of patients with systemic lupus erythematosus (SLE) exhibiting systemic vasculitis and/or central nervous system involvement, the mechanism for elevated plasma DNA in these patients is poorly understood. METHODS: The plasma DNA concentrations and reactivity of serum and lymphocytes to six species of double-stranded DNA from calf thymus, human placenta, Escherichia coli, Micrococcus lysodeikticus, Clostridium perfringens and poly (dG.dC). poly (dG.dC) were measured in twenty-seven patients with active SLE. To understand the mechanism of increased plasma DNA in SLE, the DNA binding and release of the mononuclear cells were examined. RESULTS: Compared with the controls, the incidence of the presence of plasma DNA was markedly increased in SLE (59.3% in SLE vs. 7.4% in controls) as detected by counterimmunoelectrophoresis. Except for DNA from Clostridium perfringens, the reactivity of lupus sera to various DNA samples was significantly higher than that of the controls. The reactivity of lymphocytes to 6 species of DNA (as defined by 3H-thymidine incorporation of the cells) was also higher in SLE patients. In DNA binding and releasing experiments, patients with SLE were found to have decreased 3H-DNA binding activity (0.169 +/- 0.018 micrograms/2 x 10(6) cells in SLE vs. 0.283 +/- 0.02 micrograms/2 x 10(6) cells in controls, p = 0.001) but to have increased spontaneous release of DNA (1,465 +/- 412 cpm in SLE vs. 630 +/- 179 cpm in controls, p = 0.0173) in mononuclear cells. CONCLUSIONS: The results suggest that some subsets of lymphocytes can be sensitized by different DNA samples in vivo to increase endogenous DNA release from mononuclear cells, which in addition to decreased DNA clearance as has been previously reported, may be responsible for the elevation of plasma DNA in patients with SLE.     

Amplified rhinovirus colds in atopic subjects

Evidence suggests that atopic individuals may be predisposed to more severe rhinoviral colds coupled to a worsening of existing airway disease than those with asthma. The role of atopy and IgE levels, as well as their relationship to clinical disease expression have not been defined. We hypothesized that an allergic diathesis modulates rhinoviral colds and have initiated studies of normal, atopic and asthmatic subjects employing experimental rhinoviral infection, with measurements of symptom scores, viral shedding and cultures, albumin in nasal washes and serological responses. Twenty-two subjects (11 normal, 5 atopic, 6 atopic and asthmatic) participated and were inoculated with human rhinovirus serotype 16 (HRV 16). Measurements of neutralizing antibody and viral culture were performed at screening, pre-inoculation, during the cold and at 8-10 weeks convalescence. Daily symptoms were noted, nasal washes done, IgE measured and atopy was diagnosed by skin tests. Seventeen volunteers developed clinical colds as assessed by symptom scores, virus shedding was demonstrated (with positive culture) in all subjects and a fourfold or higher seroconversion occurred in 11/22. Neutralizing HRV antibody developed unexpectedly in 10 subjects between screening and inoculation and the presence of absence of this pre-inoculation antibody determined subsequent severity of colds in normal but not in atopic subjects. Atopic antibody positive individuals developed severe clinical colds that were independent of preinoculation antibody in contrast to normal subjects who developed mild colds in the presence of a neutralizing antibody (P = 0.01). Both atopic and normal antibody negative subjects developed severe colds.(ABSTRACT TRUNCATED AT 250 WORDS)     

Appearance of oxidized cellulose (Surgicel) on postoperative CT scans: similarity to postoperative abscess

OBJECTIVE: Oxidized regenerated cellulose (Surgicel), a sterile knitted fabric that causes thrombus formation because of its physical properties, is frequently used for intraoperative hemostasis. Unlike traditional surgical sponges, it is bioabsorbable and can be left in the surgical bed. On CT scans, the appearance of the retained oxidized cellulose can mimic that of an abscess. The purpose of this study was to describe the appearance of oxidized regenerated cellulose on postoperative CT scans so that an erroneous diagnosis of an abscess can be avoided. MATERIALS AND METHODS: We reviewed the CT examinations of five postoperative patients in whom oxidized regenerated cellulose had been used for surgical hemostasis. Operative reports and surgeons confirmed the use of oxidized cellulose. Four CT scans were abdominal examinations, and one was a head examination. RESULTS: In four cases, CT scans showed focal, linear collections of gas within masses with mixed attenuation in or near the operative site. No air-fluid levels were present. In three patients, cultures of specimens obtained by aspiration were negative for pyogenic organisms. CONCLUSION: Retained oxidized cellulose can mimic an abscess on CT scans. Focal collections of air centrally located within a mass should alert the radiologist that oxidized cellulose may have been placed in the operative site, and an appropriate history should be sought.     

Spatio-temporal vernier acuity

The study of space-time vernier (STV) provides information on the spatio-temporal structure of the visual system in the same way that the classical spatio-spatial vernier (SSV) provides information on its spatial structure. The transposition of a SSV task into a STV one yields the following experimental format: an object (in the present case a Gaussian Blob) drifts with a constant velocity, V, disappears at x0, t0 and reappears after a variable duration delta t at a position x1 +/- delta x with x1 the correct position (given a constant V) and delta x the minimum (positive and negative) spatial offset discriminable from x0, i.e. the STV threshold. Observer's task is to specify whether the reappearance position is ahead of, or behind x1. The STV functions of delta t measured for 1, 5 and 10 deg/s reference velocities are linear with non-zero spatial and temporal intercepts at the origin. We refer to these x and t intercepts as dynamic dmin and tmin. Dynamic dmin is the smallest instantaneous displacement (infinite velocity) discriminable from a continuous drift, V. Dynamic tmin is the shortest 'motion stop' discriminable from the same continuous drift, V. To our knowledge these quantities have not yet been assessed. Estimated dynamic dmin increases with V. whereas tmin is more or less V independent suggesting that the motion sensors presumably involved in the STV task have peak spatial frequencies inversely proportional with V and a temporal frequency characteristic independent of V (at least within the studied range). The observed STV linearity with the spatio-temporal separation implies that the STV task is equivalent to a velocity discrimination. Two additional observations yield support to this conclusion. (i) The slopes of these functions yield velocities very similar to those discriminable from the reference V in a standard V-discrimination experiment. (ii) The predicted STV performances based on a decomposition of the task into two velocity discrimination tasks run as independent experiments are reasonably accurate.     

Effects of SR 141716A after acute or chronic cannabinoid administration in dogs

This study was undertaken to investigate the effects induced by the systemic administration of RB 101 [N-[(R,S)-2-benzyl-3[(S)(2-amino-4-methylthio)butyl dithio]-1-oxoprpyl]-L-phenylalanine benzyl ester], a mixed inhibitor of the enkephalin catabolism able to cross the blood-brain barrier, in antinociception produced by adrenal medullary tissue transplanted in the rat spinal subarachnoid space. For this purpose, the antinociceptive responses induced by intravenous (i.v.) administration of RB 101 were evaluated in the tail-flick in rats transplanted 28 and 56 days before the test. Systemic administration of RB 101 induced antinociceptive effects in sham-operated rats, as previously reported. RB 101 also enhanced significantly the antinociception produced by the autotransplant 28 and 56 days after surgery. The antinociceptive responses of RB 101 in both sham-operated and autotransplanted rats were blocked by naloxone, but were not modified by the noradrenergic antagonist, phentolamine, suggesting a selective involvement of opioid mechanisms. The present results indicate that the inhibitors of enkephalin catabolism enhance the antinociception induced by adrenal medullary transplants.