Allergen-driven limiting dilution analysis of human IL-4 and IFN-gamma production in allergic rhinitis and clinically tolerant individuals

Difficulties in detecting human IL-4 synthesis in antigen-driven primary culture have led to widespread reliance on less physiologic approaches to T cell activation. Although there is general agreement of a Th2-like bias, the precise defects in cytokine responsiveness remain controversial. Analysis of cytokine protein production by fresh, unselected cell populations in response to cognate, antigen-driven stimulation remains an important goal. Here, limiting dilution analysis (LDA) was used to evaluate antigen-stimulated cytokine gene expression by fresh peripheral blood mononuclear cells (PBMC). PBMC from 19 grass pollen sensitive, allergic rhinitis subjects and normal, non-atopic controls were evaluated 1 month after natural reimmunization (the peak of the local grass pollen season). Surprisingly, highly atopic subjects and clinically non-allergic individuals exhibited virtually equivalent antigen-specific, CD4-dependent cytokine production in response to short-term culture with these common environmental antigens. As anticipated, pronounced increases in Th2-like activity were evident in the circulating immune repertoire of grass pollen sensitive individuals, leading to a median ratio of antigen-stimulated IFN-gamma:IL-4 frequencies of 117:1 among normal subjects versus 4:1 among those with allergic rhinitis (Mann-Whitney U-test, P = 0. 00067). This Th2-like bias reflected both a lower frequency of IFN-gamma-producing cells and a markedly increased frequency of IL-4-producing cells in the circulating grass-pollen specific repertoire of atopic donors. The observation that every atopic and normal subject produced IFN-gamma (+/-IL-4) following antigen re-stimulation argues that the decision as to whether allergy or (clinical) tolerance results, hinges not on a genetically determined capacity of whether allergen-reactive T cells can be stimulated in any given individual by chronic exposure to ubiquitous environmental antigens, but on the nature of the cytokine response that comes to dominate that individual's response.     

Crank inertial load has little effect on steady-state pedaling coordination

Inertial load can affect the control of a dynamic system whenever parts of the system are accelerated or decelerated. During steady-state pedaling, because within-cycle variations in crank angular acceleration still exist, the amount of crank inertia present (which varies widely with road-riding gear ratio) may affect the within-cycle coordination of muscles. However, the effect of inertial load on steady-state pedaling coordination is almost always assumed to be negligible, since the net mechanical energy per cycle developed by muscles only depends on the constant cadence and workload. This study test the hypothesis that under steady-state conditions, the net joint torques produced by muscles at the hip, knee, and ankle are unaffected by crank inertial load. To perform the investigation, we constructed a pedaling apparatus which could emulate the low inertial load of a standard ergometer or the high inertial load of a road bicycle in high gear. Crank angle and bilateral pedal force and angle data were collected from ten subjects instructed to pedal steadily (i.e., constant speed across cycles) and smoothly (i.e., constant speed within a cycle) against both inertias at a constant workload. Virtually no statistically significant changes were found in the net hip and knee muscle joint torques calculated from an inverse dynamics analysis. Though the net ankle muscle joint torque, as well as the one- and two-legged crank torque, showed statistically significant increases at the higher inertia, the changes were small. In contrast, large statistically significant reductions were found in crank kinematic variability both within a cycle and between cycles (i.e., cadence), primarily because a larger inertial load means a slower crank dynamic response. Nonetheless, the reduction in cadence variability was somewhat attenuated by a large statistically significant increase in one-legged crank torque variability. We suggest, therefore, that muscle coordination during steady-state pedaling is largely unaffected, though less well regulated, when crank inertial load is increased.     

Effect of lysogeny on transfection and transfection enhancement in Bacillus subtilis

Strains of Bacillus subtilis 168 lysogenic for bacteriophage phi105 transfer with deoxyribonucleic acid (DNA) isolated from bacteriophage SPO2 at a higher efficiency than non-lysogenic strains. This enhancement of transfection was not the result of recombination between bacteriophages SPO2 and phi105. Superinfection marker rescue increased transfection with DNA from bacteriophage phi105 occurred simultaneously with the addition of the transfecting DNA. Again, this enhancement of transfection was not the result of recombination but rather a protection of the transfecting DNA by the superinfecting bacteriophage. The ability of the superinfecting bacteriophage to protect the transfecting DNA from inactivation was maximal when the bacteria were just becoming competent. Bacteriophage phi1 cannot replicate after the transfection of competent bacteria lacking a functional DNA replication system, whereas bacteriophage phi1 was able to replicate after infection of competent bacteria grown under comparable conditions. These observations support the hypothesis that GAPase and an inducible repair system play an important role in the development of competence.     

The fall in household size and the rise of the primary individual in the United States

The long-term fall in household size in the United States is discussed within the framework of the aging of the population, continuing as the effects of fertility and mortality decline accumulate. Using distributions of households by size from U.S. census data 1790-1970 and a components of change analysis on primary individuals for 1950-1974, household changes are related to demographic change for the periods 1790-1900, 1900-1950, and 1950-1974. Fertility and mortality declines have unambiguous impact on household size until the increases in primary individuals begin. But these, too, have a theoretically interesting, if indirect relationship to population structure.     

Androgen receptor dependent and independent activities of testosterone on hepatic microsomal drug metabolism

Administration of testosterone for 6 days to intact female and castrate male BALB/cJ mice stimulated hepatic microsomal ethylmorphine N-demethylase activity and cytochrome P-450 content by 50-75%. Testosterone also stimulated hepatic microsomal NADPH-oxidase activity, but to a lesser degree. To probe the mechanism of this effect of androgens, two antiandrogens (cyproterone acetate and flutamide) were employed. Since cyproterone acetate was a potent stimulator of hepatic microsomal ethylmorphine N-demethylase activity and cytochrome P-450 content, no antiandrogenic activity of this steroid could be detected. By contrast, flutamide alone had little effect on either ethylmorphine N-demethylase activity or cytochrome P-450 content. However, this drug effectively blocked the stimulatory effects of testosterone on ethylmorphine N-demethylase activity and cytochrome P-450 content but not on NADPH-oxidase activity. This effect was not species specific, since flutamide also prevented androgen stimulation of ethylmorphine metabolism in adult castrate and prepubertal male Fisher rats. The testosterone-induced increase of hepatic weight and microsomal protein content was not affected by the administration of flutamide. The observations are consistent with the hypothesis that androgens have two distinct effects on the liver. First, testosterone may act as a general, nonspecific stimulant of liver weight and microsomal protein content which is independent of the androgen receptor. Secondly, testosterone action in the liver may be expressed via an androgen-specific or androgen receptor-dependent mechanism which controls, in part, the cytochrome P-450-dependent demethylase system.     

Midtrimester amniocentesis and culture of aminiotic fluid cells

On the basis of the large, well-controlled, prospective study from the NICHD, it can be stated that midtrimester ammniocentesis is safe if properly performed. The details of performance, with emphasis on possible pitfalls, are presented in an effort to encourage more practicing obstetricians to begin performing the procedure in cooperation with their area genetics laboratories (11). Emphasis is also placed on performing this procedure in a manner most likely to produce success. This success is measured not only in obtaining the fluid, but more importantly in gaining useful information from the analysis of the fluid. Although the aspects of diagnosing and preventing genetic disease have been emphasized, perhaps the greatest value of midtrimester amniocentesis is the reassurance afforded the more than 95% of couples when the fluid analysis is normal (19). The consumer demand for amniocentesis is rapidly increasing. Although the medicolegal implications of the techniques are not fully understood at present, it is clear that failure on the part of a clinician to offer indicated diagnostic amniocentesis may make the clinician vulnerable to litigation if the pregnancy outcome is abnormal. The demand for amniocentesis and laboratory analysis of the fluid will soon overtax existing facilities. Until such time as new and expanded facilities are available, discretion must be used in offering the procedures. Governmental action may soon be forthcoming to provide facilities designed to make midtrimester diagnostic amniocentesis available to all for whom it is indicated.     

Naloxone in the parturient and her infant

Eighteen women in labor received analgesia with moderately large total doses of meperidien. Various doses of naloxone (8, 12, 18, 27, 40, or 60mug/kg of body weight) were given intravenously to the mothers before delivery in an attempt to find the dose that would prevent neonatal narcotic depression. Maternal and neonatal blood gas values, Apgar scores, and postnatal neurobehavioral examinations were used to assess the effects. Infants born of mothers who had received neither meperidine, promethazine, nor naloxone served as controls. After the naloxone injection, the mothers showed an improvement in consciousness and blood gas values. When the study infants, as a group, were compared with control infants, there was very little difference in blood gas values or neurobehavioral examination. Infants in the groups receiving naloxone in doses of 18, 27, and 40mug/kg compared most favorably with the control infants, indicating that naloxone may be effective in preventing neonatal narcotic depression.     

Complete primary structure of the major component myoglobin of California gray whale (Eschrichtius gibbosus)

The complete primary structure of the major component myoglobin from the California gray whale, Eschrichtius gibbosus, was determined by specific cleavage of the protein to obtain large peptides for degradation by the automatic sequenator. Cleavage at the two methionine residues of the apomyoglobin with cyanogen bromide and at the three arginine residues of the methyl acetimidated protein with trypsin resulted in three and four easily separable peptides, respectively, which when sequenced accounted for 85% of the primary structure. The remainder of the covalent structure was obtained by further digestion of the central cyanogen bromide peptide with trypsin and S. aureus strain V8 protease. This protein differs from that of the sperm whale, Physeter catodon, at 12 positions, from that of the common porpoise, Phocoena phocoena, and the Black Sea dolphin, Delphinus delphis, at 14 positions, and from that of the Amazon River dolphin, Inia geoffrensis, at 7 positions. All substitutions observed in this sequence fit easily into the tertiary structure of sperm whale myoglobin.