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The prevalence of SLE was determined in Dunedin, where there is a relatively stable population with ready access to hospital facilities. The overall prevalence of the disease was 1/6780 and its prevalence in women 1/4312.
This detailed study of a stable population compares the number and type of diagnostic radiology examinations, facilities, equipment, personnel and financial allocations for the years 1974 and 1979. The data have been obtained from $12.28 to $25.90. A computed tomography service began in 1977. The 1979 genetically significant radiation dose to the population is calculated to be 260 microgray. Continuing growth in computed tomography and diagnostic ultrasound with changing referrals for nuclear medicine are not yet ready for analysis.
We evaluated the effects over a ten-year period of a program for early detection and treatment of idiopathic scoliosis in a stable population of 1.5 million people. Seven hundred and twenty-five patients with a scoliosis of more than 20 degrees (as measured with Cobb's method) and who were twenty years old or younger were followed during this period. Although treatment principles remained essentially the same, the percentage of patients who required an operation each year decreased. The magnitude of the ten most severe curves detected each year decreased from an average of 64 degrees to 44 degrees. Efforts to detect scoliosis early have resulted in a threefold increase in the number of patients treated for scoliosis.
In this and previous studies we have shown that during the course of B cell isotype differentiation occurring in the CH12.LX B cell line, small numbers of cells appear that bear both membrane (m)IgM and membrane IgA. We have cloned relatively stable populations of such dual-bearing cells and have performed studies to determine their molecular status. In the study of one such subclone (CH12.LX.7.10), we show by primer extension that both mu and alpha mRNA contain identical VHDJH gene segments. In complementary studies of another such subclone (CH12.LX.7.13), we show using DNA restriction fragment analysis, that the C mu gene segment, but not the C alpha gene segment, is associated with the JH gene segment. Additionally, Northern blot analysis of productive message of this clone shows that both mu and alpha mRNA cohybridize to the same VH region-specific probe. Taken together, these data suggest that CH12.LX mIgM/mIgA dual-bearing cells occur in the absence of C mu gene segment deletion and that the mu and alpha mRNA transcripts are derived using an alternative mechanism such as transplicing or alternative splicing of a long RNA transcript. On the assumption that these clones are representative of mIgM/mIgA dual-bearing cells appearing during CH12.LX IgM to IgA isotype differentiation, these data support the idea that B cells simultaneously produce mu and alpha mRNA transcripts during one stage of IgA isotype switching.
The relationship between passive tension applied to aortic rings and the resulting increase in tissue length was nearly linear over the range of 1 to 15 g. However, even with increasing tissue length, within the range of 1 to 10 g passive tension, the total active force generated upon stimulation was not significantly changed. These observations emphasize the great flexibility of the mechanism(s) underlying the contractile response of vascular smooth muscle with regard to changes in tissue preload and length. Neither the blockade of microtubule polymerization by colchicine nor the blockade of actin polymerization by cytochalasin B significantly changed the slope of the tissue length-preload curve, indicating no effect on the tissues' capacity to stretch at a given preload. With stimulation of the tissue at different levels of stretch, colchicine caused an increase in the initial fast component of active tension development, but partially blocked the secondary slow rise in tension. Cytochalasin B dramatically reduced the total contractile response at each preload studied, and this effect was confined almost exclusively to the secondary slow increase in tension. When tissues were cooled to cause complete dissolution of the microtubule network and then warmed in the presence of colchicine to prevent repolymerization of both the active and stable populations of microtubules, there was also a significant reduction in the slow component of contraction with no effect on the fast response. The partial blockade of synthesis of the microtubule-associated motor protein kinesin by application of an antisense oligonucleotide to aortae in situ or to aortic rings in tissue culture significantly reduced the contractile response to potassium depolarization. The results suggest that the microtubules and the actin filaments of the cytoskeleton play an active role in slow force development as opposed to a solely passive role based on the effect of the static, structural properties of these filaments on mechanical resistance. We propose that a tension-bearing element of the actin-containing cytoskeleton undergoes remodeling to adjust tension within the system. The microtubules could act either through the directed movement of the molecules involved in the transduction process or through the direct action of kinesin-mediated intracytoskeletal interactions in force development that involve a remodeling of the tension-bearing elements of the cytoskeleton.
This study aimed at analysing the temporal aspects of foot-pad dermatitis in Swedish broilers. The information on disease prevalence and severity was based on a 2-year foot-health surveillance programme where information on producer, breed, feed manufacturer, region, abattoir, date of slaughter and several other variables was recorded. The seasonal effects were evaluated using classical multiplicative decomposition time series analysis. This study shows that there has been a significantly consistent decrease in the prevalence of severe foot-pad lesions during the first 2 years of the programme. Looking at the development over time we found a trend-cycle component of 10.4% and a seasonal component of 48.7% resulting in a total adjusted R-square value of 58.5% for the total foot-pad score. This means that almost 60% of the variation in flock foot-pad score can be explained by the variable 'time', and that this variation was mainly related to seasonal effects but also to a general decreasing trend over the study period. However, substantial differences in temporal patterns among slaughterhouses, feed suppliers and regions were found. The time series analysis approach was found to be useful for this type of investigation when evaluating the effects of an intervention programme, and it can also be applied for projecting the future development of disease status in a stable population.
The phenotypic and functional characteristics of Ag-specific memory CD4+ lymphocytes are poorly defined. To examine the properties and cytokine responsiveness of these cells, we have developed an adoptive transfer system using in vitro-activated T cells expressing the DO.11 transgenic TCR specific for OVA(323-339)+ I-Ad. In vitro-activated DO.11 CD4+ cells exhibit comparable survival patterns at 1, 6, and 10 wk after adoptive transfer, indicating that a stable population of memory cells has been generated. In the absence of Ag, previously activated T cells survive longer than their naive counterparts in vivo, rapidly revert to a partially naive phenotype, and maintain their effector cytokine profile. The DO.11 CD4+ memory cells are capable of proliferating in response to IL-2 and IL-4, while naive DO.11 CD4+ cells exhibit no such proliferative responses.
The comparability between an analysis of variance that employs untransformed proportions and one that employs two common arcsine transforms is assessed by using preweaning mouse litter survival data from a toxicological experiment that involves stable laboratory populations. The importance of controlling for litter order, litter size and birth cohort is demonstrated. An adaptation of a nonparametric method suggested by Mantel (1963, Journal of the American Statistical Association 58, 690-700) is proposed as an alternative procedure. Although the results indicate that the nonparametric method is modestly less powerful than the parametric approach, its use is recommended when the assumptions underlying the analysis of variance are questionable. A method for plotting the temporal pattern of the effect of continuous exposure to the toxicant (DDT) on preweaning survival is also presented.
Cylindrical traps made from Alsynite fiberglass were placed in 4 habitats in a confined cattle feedlot environment from 2 May to 30 October 1996 to evaluate abundance, sex ratio, physiological age structure, and blood-fed status of trapped adult stable flies, Stomoxys calcitrans (L.). Significantly more stable flies were caught on the trap located between host cattle and trees. The abundance of stable flies decreased geometrically with increasing distance from the host cattle in the open area. The spatial distribution of adult flies in cattle feedlot habitats became less heterogeneous as the population density increased. Male stable flies clearly dominated the total collection (66.7:33.3, male:female). A higher proportion (38.9%) of female stable flies was found on the trap close to a major immature developing area (manure pile). Most of the trapped flies (64.8%) showed a positive blood-fed status, but only 331 (8.8%) of 3,767 flies had recently fed. A majority (72.6%) of the attracted females was at the early nulliparous stage. Trap positioning did not have any significant influence on specific physiological age groups of the captured flies.
In order to simulate the outcome of the P-M status of Eurasian populations of Drosophila melanogaster, the evolution of experimental mixed-strains was monitored for up to 50 generations. The results were compared with the evolution in natura of European populations sampled in 1981-83 and 1986-87 over a similar period of time. Different combinations of P and M' strains, Q and M' strains, M' and M' strains and M and M' strains were set up at 25 degrees C and duplicated at 13 degrees C night-21 degrees C day. The possibility of a change towards a P type only appeared with the introduction of the strong P strain Harwich into Eurasian strains. Strains with strength similar to that of Harwich are not currently found in wild populations. With the introduction of weak P and Q strains of the strength presently observed in western Europe, experimental populations evolved slowly towards a Q state or a weak M' state. M'-M' mixed populations resulted in strong M' strains, as was the case for M-M' populations. In these cases. P sequences were not eliminated. In wild populations both genetic and molecular analyses showed no significant differences, over a five year period, for GD sterility potentials, for total P copy number or for distribution of the full-sized and KP elements. Changes in Eurasian populations are probably taking place at a very low rate and may even have stopped, leading to a quasi-stable differentiation over the continent. During the different steps of progressive invasion of P transposable elements, several deleted elements developed and natural selection may have acted on them. The possibility of the selection of different types of regulatory mechanisms according to the presence of different kinds of derivative elements, leading to a world-wide differentiation between P-Q and M' strains is discussed.
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Data about the epidemiology of primary intracranial tumours (PIT) are still heterogeneous depending on different methodological approach in collecting data. In Valle d' Aosta, north west side of Italy, we have carried out a prospective consecutive population based study to calculate the incidence of PIT in the last decade (1992-1999) and to compare these rates with the previous period (1986-1991), data reported in a previous paper. The mean annual PIT incidence rate (ri) per 100,000 inhabitants was 25.48. The mean annual incidence rates in the two period of comparison were adjusted to the 1991 Italian population by the direct method. The standardised ratio was 26.43 in the previous period and 23.24 in the second decade. There is no statistically significant difference. The mean annual PIT incidence rates by tumour types were meningiomas 13.27/100,000 (men 9.77; women 16.7), neuroepithelial group 9.3 (men 10.62; women 8.1), adenomas 1.26, neurinomas 0.7. Mean annual incidence rates by tumour class were also stable. The stable incidence rate in the two periods and the similar incidence in England (21.04/100,000 person year), strengthen the evidence for a stable incidence rate of PIT in the last decade. These three papers used similar methodology. The homogeneous methodology allows comparison and further evaluation.
BACKGROUND: Renal transplant recipients were noted to appear cushingoid while on low doses of steroid as part of a triple therapy immunosuppression of cyclosporin A (CsA), prednisolone, and azathioprine. METHODS: The study group comprised adult renal transplant recipients with stable graft function who had received their renal allograft a minimum of 1 year previously (43 studies undertaken in 22 men and 20 women) with median daily prednisone dose of 7 mg (range 3-10). The control group was healthy nontransplant subjects [median dose 10 mg (10-30)]. Prednisolone bioavailability was measured using a limited 6-hour area under the curve (AUC), with prednisolone measured using specific HPLC assay. RESULTS: The median prednisolone AUC/mg dose for all transplant recipients was significantly greater than the control group by approximately 50% (316 nmol x h/L/mg prednisolone versus 218). AUC was significantly higher in female recipients (median 415 versus 297 for men) and in recipients receiving cyclosporin (348 versus 285). The highest AUC was in women on estrogen supplements who were receiving cyclosporin (median 595). A significantly higher proportion of patients on triple therapy had steroid side effects compared with those on steroid and azathioprine (17/27 versus 4/15), more women than men had side effects (14/16 versus 7/22), and the AUC/mg prednisone was greater in those with side effects than without (median 377 versus 288 nmol x h/L/mg). DISCUSSION: The results are consistent with the hypothesis that CsA increases the bioavailability of prednisolone, most likely through inhibition of P-glycoprotein. The increased exposure to steroid increased the side-effect profile of steroids in the majority of patients. Because the major contributor to AUC is the maximum postdose concentration, it may be possible to use single-point monitoring (2 hours postdose) for routine clinical studies.
Genetic models of sexual selection are concerned with a dynamic process in which female preference and male trait values coevolve. We present a rigorous method for characterizing evolutionary endpoints of this process in phenotypic terms. In our phenotypic characterization the mate-choice strategy of female population members determines how attractive females should find each male, and a population is evolutionarily stable if population members are actually behaving in this way. This provides a justification of phenotypic explanations of sexual selection and the insights into sexual selection that they provide. Furthermore, the phenotypic approach also has enormous advantages over a genetic approach when computing evolutionarily stable mate-choice strategies, especially when strategies are allowed to be complex time-dependent preference rules. For simplicity and clarity our analysis deals with haploid mate-choice genetics and a male trait that is inherited phenotypically, for example by vertical cultural transmission. The method is, however, easily extendible to other cases. An example illustrates that the sexy son phenomenon can occur when there is phenotypic inheritance of the male trait.
Although convergence to stability is typically a complex and irregular process, the Kullback distance provides a measure that moves consistently to 0 as a population becomes stable. The roots of the Kullback distance are in information theory, but it is a meaningful demographic quantity. It reflects a population's log momentum, or the amount of growth built into a population's nonstable age distribution. The rate at which the Kullback distance moves toward 0 is neither constant nor monotonic. At any point in time, however, it decreases by the covariance between a population's age-specific growth rates and its log momentum. Although the present findings are couched in terms of movement toward stability, they are generally applicable because they relate to the behavior of any population at any instant. It is a fundamental principle of population dynamics that a population is always moving toward the stable population implied by its prevailing fertility and mortality rates, and that the extent of its movement is determined by the covariance between its age-specific growth and its log momentum.
Numerical methods are presented for a general age-structured population model with demographic rates depending on age and the total population size. The accuracy of these methods is established by solving problems for which alternate solution techniques are available and are used for comparison. The methods reliably solve test problems with a variety of dynamic behavior. Simulations of a blowfly population exhibit cyclic fluctuations, whereas a simulated squirrel population reaches a stable age distribution and stable equilibrium population size. Life-history attributes are easily studied from the computed solutions, and are discussed for these examples. Recovery of a stressed population back to equilibrium is examined by computing the transition in age structure, and the transient behavior of other properties of the population such as the per capita growth rate, the average age, and the generation length.