Effect of electric field on erythrocyte sedimentation rate. IV. Volume fraction dependence of human red cells in plasma

We measured the volume fraction dependence of erythrocyte sedimentation for human red cells in autologous plasma while the volume fraction, Hct, ranges from 0.220 to 0.650. A modified electrophoretic instrument was employed to investigate the electric effect of an upward DC field on erythrocyte sedimentation at a constant source supply of Vs = 60.0 +/- 0.5 V. The sedimentation curves all coincided well with the sigmoidal type equation, l = lmax/¿l + (t50/t)n¿, at Vs = 0, or 60.0 V. Here, lmax is the length of plasma level, l, when the time, t, tends to infinity; t50 is the elapsed time when the plasma level falls to lmax/2, and n is a constant (n > 0). A non-linear least-squares method was employed to fit experimental data. It was found that lmax decreased and t50 increased with the increase of Hct, while n ranged from 1.53 to 3.95. The volume fraction dependence of sedimentation velocity, Vmax, defined as the maximum slope of the sedimentation curve, fits well with an exponential-type curve, both at Vs = 60.0 V and at Vs = 0 V: Vmax = Vs (1-Hct)exp(-BHct), where Vs is the velocity at infinite dilution and B is a phenomenological parameter. In the range of Hct = 0.220-0.650, Vs and B are 326.1 mm/hr and 4.30, respectively, at Vs = 60.0 V, while they are 130.4 mm/hr and 2.46, respectively, at Vs = 0 V.

Natural selection and the origin of jingwei, a chimeric processed functional gene in Drosophila

The origin of new genes includes both the initial molecular events and subsequent population dynamics. A processed Drosophila alcohol dehydrogenase (Adh) gene, previously thought to be a pseudogene, provided an opportunity to examine the two phases of the origin of a new gene. The sequence of the processed Adh messenger RNA became part of a new functional gene by capturing several upstream exons and introns of an unrelated gene. This novel chimeric gene, jingwei, differs from its parent Adh gene in both its pattern of expression and rate of molecular evolution. Natural selection participated in the origin and subsequent evolution of this gene.

A calcium-binding protein in bile and gallstones

Calcium salts are often present in the center of all types of gallstones. Matrix proteins are known to be essential for biomineralization and may therefore also be important in the formation and growth of gallstones. Other researchers have described an anionic peptide fraction of a biliary lipoprotein complex in bile and a low-molecular weight acidic glycoprotein present in gallstones. Our goal was to determine whether such a protein was present in bile and whether this protein has any calcium-binding properties. We identified a pigment-associated, highly acidic protein that precipitates from bile on addition of CaCl2 0.5 mol/L. In addition, the protein is selectively concentrated in cholesterol and pigment stones. We have, therefore, confirmed the findings of these other researchers, and we have extended the study of this protein's interactions with calcium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrates a single band (molecular weight < or = 14 kD) that reacts positively with cationic stains. The protein was shown to inhibit the precipitation of CaCO3 from a supersaturated solution. The capacity to bind calcium was further confirmed by autoradiography with 45Ca++ and by a membrane adsorption-binding assay. Calcium-induced aggregation was demonstrated by equilibrium dialysis and by quasielastic light scattering studies. Protein measured by Lowry's assay method and amino acid analysis constitutes only 2% to 4% of the harvested material. We speculate that a substantial lipid component may also be present.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation of Caenorhabditis elegans mutants lacking alcohol dehydrogenase activity

Alcohol dehydrogenase (ADH) and the genes encoding this enzyme have been studied intensively in a broad range of organisms. Little, however, has been reported on ADH in the free-living nematode Caenorhabditis elegans. Extracts of wild-type C. elegans contain ADH activity and display a single band of activity on a native polyacrylamide gel. Reaction rate for alcohol oxidation is more rapid with higher molecular weight alcohols as substrate than with ethanol. Primary alcohols are preferred to secondary alcohols. C. elegans is sensitive to allyl alcohol, a compound that has been used to select for ADH-null mutants of several organisms. Allyl alcohol-resistant mutant strains were selected from ethylmethanesulfonate (EMS)-mutagenized nematode populations. ADH activity was measured in extracts from eight of these strains and was found to be low or nondetectable. These results form a basis for molecular and genetic characterization of ADH expression in C. elegans.

Evaluation of the stability of neuropsychological functioning after acute episodes of schizophrenia: one-year followup study

Few studies have evaluated the longitudinal stability of neuropsychological deficits in schizophrenia. In the present study, 39 inpatients with DSM-III-R schizophrenia were administered a comprehensive battery of neuropsychological tests after achieving sufficient clinical recovery to warrant discharge, and again 1 year after the first assessment during a nonacute period. Significant improvement in neuropsychological functioning from the first to the second assessment was observed on several tasks, including the following: Trails A and B, Digit Symbol, Judgment of Line Orientation, recognition memory on the Rey Auditory Verbal Learning Test, the Wisconsin Card Sort, and Finger Tapping. These improvements were unrelated to treatment history, and were similar in first episode and chronic cases. For many patients, the improvement in functioning brought test performance into line with normative scores from test standardization samples. These results indicate that considerable improvement in neuropsychological functioning can occur in schizophrenic patients over the months following an acute episode of illness, and that recovery of cognitive functioning can occur after substantial clinical recovery from an acute episode of illness has already been achieved.

Diode-pumped Cr:LiSrAlF(6) laser

A Cr:LiSrAlF(6) laser is diode pumped with both commercial 10-mW visible laser diodes and a higher-power 100-mW cw, 265-mW pulsed diode. Polarization combination of pump diodes to reach threshold is demonstrated with two low-power lasers. Pumping with the high-power diode produced powers of 19.9 mW cw and 78 mW pulsed. Details of the Cr:LiSrAlF(6) crystal growth and high-power diode architecture are presented, along with optical characterization data for the laser resonator. Passive losses in the crystal are less than 0.1% cm(-1).

Single-dose trospectomycin for chlamydial urethritis in men

Trospectomycin is an aminocyclitol analog of spectinomycin with significant in vitro activity against Chlamydia trachomatis. A single 1-g intramuscular dose was administered to 10 men with symptomatic, culture-positive chlamydial urethritis. Trospectomycin was well tolerated but failed to eradicate chlamydial infection, as determined by cultures obtained approximately 1 week after treatment.

Codon usage divergence of homologous vertebrate genes and codon usage clock

This paper is concerned with the divergence of synonymous codon usage and its bias in three homologous genes within vertebrate species. Genetic distances among species are described in terms of synonymous codon usage divergence and the correlation is found between the genetic distances and taxonomic distances among species under study. A codon usage clock is reported in alpha-globin and beta-globin. A method is developed to define the synonymous codon preference bias and it is observed that the bias changes considerably among species.

Effect of electric field on erythrocyte sedimentation rate. II. Dependence on electric current

We measured the electric current dependence of sedimentation curves of swine erythrocytes in a saline solution at the volume fraction of erythrocytes H = 0.091 and 0.220. The sedimentation curve fitted well to the exponential type equation l = a[1-exp(-bt)] at the upward initial electric current I0 = 0.50 mA, 1.01 mA and 1.50 mA, where l is the length of the medium layer at time t, and a and b are phenomenological parameters. The initial slope v0 of sedimentation curve was enhanced from 0.68 mm/hr at I0 = 0 mA to 2.85 mm/hr, 3.87 mm/hr and 5.50 mm/hr at I0 = 0.50 mA, 1.01 mA and 1.50 mA, respectively, for H = 0.220. We also made sedimentation measurements of erythrocytes in their own plasma at H = 0.220 and 0.316. Sedimentation curves coincided with the sigmoidal type equation l = l infinity/[1 + (t50/t)beta] at I0 = 0 mA and 0.50 mA, where l infinity is l at t----infinity, t50 is the time when the plasma level falls to l infinity/2 and beta is a constant. The maximum slope vmax of sedimentation curve increased from 13.29 mm/hr at I0 = 0 mA to 18.65 mm/hr at I0 = 0.50 mA for H = 0.220.

The impact of a resident dog on an institution for the elderly: effects on perceptions and social interactions

A longitudinal case study was made of a sub-unit of a nursing home to examine the perceptions and social interactions of patients and staff after introduction of a resident dog. A behavioral mapping procedure was used to determine staff and patient interactions 6 weeks before and 6 weeks and 22 weeks after the dog's arrival. Interviews were also conducted with patients and staff. Six weeks after the dog's arrival, a significant increase in frequency of interactive behaviors was seen for both staff and patients. By 22 weeks, behaviors for patients had reverted to base-line levels, while remaining high for staff.

Source of methyl groups in brain and nerve tissue in the rat

Previous studies that demonstrated that mouse brain accumulated significantly more radioactivity from subcutaneously administered 5-methyltetrahydrofolate labelled in the methyl group compared to the label in the folate moiety are open to two interpretations. The methyl group could have been transferred to another compound (probably methionine) prior to its transport into the brain. Alternatively, if plasma 5-methyltetrahydrofolate per se is significantly involved in the provision of methyl groups to brain and nerve tissue it would be expected that the folate moiety would be returned to the plasma to complete the cycle and thus would appear not to have been taken up. In this article, using competition experiments that exploit the differences in the mechanism of transport of methionine and 5-methyltetrahydrofolate into brain and nerve, evidence is presented that in the rat the methyl group of 5-methyltetrahydrofolate is transported after its conversion to methionine.

Interpretation of pulmonary artery wedge pressure and pullback blood gas determinations during positive end-expiratory pressure ventilation and after exclusion of the bronchial circulation in the dog

Left atrial pressure (LAP) and pulmonary artery wedge pressure (PWP) were measured at different heights during graded increases in positive end-expiratory pressure (PEEP). Six healthy anesthetized dogs were placed in lateral decubitus positions with a balloon-tipped pulmonary artery catheter inserted in each lung. PWP in the gravitationally superior lung overestimated LAP at 15 and at 20 cm H2O PEEP (p less than 0.05). PWP in the dependent lung was virtually identical to LAP at all degrees of PEEP. Wedge blood could be aspirated through the distal lumen of the pulmonary artery catheters during balloon inflation at all degrees of PEEP except for 3 attempts. PCO2 in wedge blood in both the nondependent and dependent lungs at all degrees of PEEP was consistently lower than PCO2 in arterial blood (p less than 0.05). Wedge blood was arterialized, i.e., oxygen saturation greater than 95%, in all but 4 specimens. Surgical elimination of the bronchial artery supply to the lung in 3 dogs did not affect PWP or blood gas measurements. We conclude that in this animal model: (1) the tip of a pulmonary artery catheter must be below the level of the left atrium, Zone III location, to accurately reflect LAP at high degrees of PEEP; (2) arterialization of wedge blood samples does not guarantee that PWP reflects LAP; (3) bronchial artery blood supply does not affect PWP or wedge blood gas measurements, even at high degrees of PEEP.