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At least 73 records · Page 4Linked to original sources
PubMed1983

Progenitor cell (CFUc) reconstitution after autologous stem cell transfusion in lethally irradiated dogs: decreased CFUc populations in blood and bone marrow correlate with the fraction mobilizable by dextran sulphate.

The present study in dogs concerns the functional potentials of the myeloid progenitor cell system during hemopoietic recovery after lethal total-body irradiation and autotransfusion of cryopreserved stem cells derived from peripheral blood and bone marrow. CFUc were assayed in peripheral blood and bone marrow before and at various intervals after grafting. In addition, the net increase of CFUc mobilizable from extravascular sites into the blood was determined after i.v. injection of 15 mg/kg body weight of dextran sulphate (DS). The data indicate a sustained deficiency of CFUc in otherwise hematologically normal recipients. The DS-response was subnormal even 225 days after transplantation, suggesting residual damage of the hemopoietic system is present for a prolonged period of time. A significant correlation was found between the actual blood CFUc concentration and the numbers of CFUc mobilizable by DS. Insight into progenitor cell kinetics and corresponding changes in the size of a mobilizable pool in extravascular sites may be helpful in estimating the marrow reserve of transplanted individuals suffering myelosuppressive effects of chemotherapy.

Animals↗
PubMed1996

[Impact of anesthetic technic (general anesthesia versus intradural anesthesia) on the immune status].

OBJECTIVE: To study changes in the immune system appearing after general and regional (intradural anesthesia). PATIENTS AND METHODS: Fifty patients scheduled for elective surgery to repair inguinal hernias were studied. The patients were randomly assigned to 2 groups: group A patients received general anesthesia and group B patients received intradural anesthesia. Blood was extracted 5 times to determine levels of lymphocytes, activated T cells and B lymphocytes, and T-suppressant activity: t0 (before surgery), t1 (1 h), t2 (4 h), t3 (24 h) y t4 (7 days). RESULTS: The patients in group A showed slight increases in T lymphocytes, activated T lymphocytes and B lymphocytes, whereas T-suppressant activity decreased significantly. All lymphoid population decreased in group B. Baseline levels had recovered in both groups by 7 days after surgery. CONCLUSION: Anesthetic procedures have an effect on immune responses but the impact is only temporary.

Adult↗
PubMed2004

Population effects of sarcoptic mange in Barbary sheep (Ammotragus lervia) from Sierra Espuña Regional Park, Spain.

The nonindigenous Barbary sheep population (Ammotragus lervia) of the Sierra Espuna Regional Park (Murcia, Spain) suffered an outbreak of sarcoptic mange between 1991 and 1995, which contributed to a population decrease of 86%. This study presents the results of two population surveys conducted in 1994 and 1999 based on the fixed point and itineraries method (FPI) and the excrement count (EC) method, as well as data from demographic estimates and clinical observations conducted by the Regional Administration of Murcia. Results of surveillance for mange are given between 1992 and 1995, because no animals were observed with sarcoptic mange in 1999. Prevalence of mange peaked in 1994 and then declined. During the regression phase of the epidemic, there was a higher infection rate in males (21.9%) than in females (16.6%) or young animals (5.1%). Males over 5 yr old were the worst affected age group, followed by subadults of both sexes. Few animals had generalized lesions of mange (7%), and most individuals (72%) had lesions of moderate severity. The most common locations of lesions were the neck, head, and back. The density of Barbary sheep in the Sierra Espuna Regional Park increased from introduction in 1972 until it peaked at 13 animals/km(2) in 1991, the year when the first case of sarcoptic mange was detected. After 2 yr of the mange epidemic, the average estimated density was 1.7 animals/km(2) in 1994, which increased to 5.0 animals/km(2) in 1999. The average group size also increased from 7.9 to 19.2 animals/group between 1994 and 1999. The sex ratio, expressed as the proportion of females in the total population observed, decreased from 0.61 in 1994 to 0.49 in 1999. The reproduction rate (kids per females per year) was essentially stable (0.59 in 1994 to 0.65 in 1999). Between 1994 and 1999 the population aged, with the number of young animals (<18 mo of age) decreasing from 45.3% to 36.6% from 1994 to 1999. In the same period, the proportion of males increased 21.4% to 32.6%. We believe sarcoptic mange acted as one of the regulating factors of population density after 1991 and that currently, although no sarcoptic mange lesions were observed in the 1999 survey, there is a demographic imbalance in sex ratio, age structure, and density.

Age Factors↗
PubMedDate not supplied

Comparison of the effects of low and high concentrations of group I metabotropic receptor agonists on field potentials in the hippocampal CA1 region in vitro.

We compared the effects of low and high concentrations of the selective group I metabotropic glutamate receptor (mGluR) agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) and the nonselective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD) on extracellularly recorded potentials which were evoked in the rat hippocampal CA1 region by stimulation of the Schaffer collateral/commissural pathway and on intracellularly recorded electrophysiological properties of CA1 neurons, in vitro. At low concentrations (2.5 and 5 microM) DHPG and (1S,3R)-ACPD increased while at high concentrations (20 and 50 microM) they decreased population spike amplitudes. Simultaneous recordings of population spikes in the CA1 cell layer and field excitatory postsynaptic potentials (fEPSPs) in stratum radiatum of the CA1 area revealed that the enhancement of the population spike amplitude is not associated with any change in the fEPSP slope, but the decrease in population spikes is accompanied with a decrease in the fEPSP slope, suggesting that at high concentrations both agents may attenuate excitatory synaptic transmission in CA1 cells. DHPG and (1S,3R)-ACPD had a number of direct excitatory effects on CA1 pyramidal cells like a concentration-dependent depolarization and an inhibition of the slow afterhyperpolarization, which in all probability underlay the increase in the amplitude of population spikes. At high concentrations, both mGluR agonists strongly depolarized CA1 cells indicating that depolarization block of cell discharges may underlay the reduction in the population spike amplitude. Furthermore, robust cell discharges induced by the strong depolarizations, activate several secondary processes which may significantly contribute to the action of high concentrations of DHPG and (1S,3R)-ACPD. Therefore, the effects of low and high concentrations of the studied mGluR agonists may involve different mechanisms, at low concentrations the effects can be directly related to the activation of postsynaptically localized group I mGluRs while at higher concentrations the contribution of indirect effects may predominate.

Animals↗
PubMed1984

Response of swine skin microvasculature to acute single exposures of X rays: quantification of endothelial changes.

An acute single X-ray exposure of 2300 R produces in swine skin a moist reaction (ulceration) that appears at 17 days, heals by 32 days, and may break down again between 42 and 70 days. Initial studies quantified the epidermal population density changes during this 70-day period. This study was designed to quantify the density changes occurring in the endothelial cell population of the dermal microvasculature. While the basal population decreases to a nadir of 10% control by 24 days, the endothelial population remains at control levels. Beyond 24 days, the endothelial cell density decreases abruptly to 50% as the epidermal cell density returns to control levels and overshoots by 20% at 32 days. Subsequently, both populations decrease to zero by 57 days. Endothelial cell loss parallels a similar decrease in vascular lumen density. These findings indicate that the initial moist reaction results from a radiation-induced loss of epidermal cells, while the second reaction results from the loss of dermal microvasculature.

Animals↗
PubMed1988

Probability of transition into cell cycle does not depend on growth factor concentration.

When quiescent cells in monolayer culture are stimulated to proliferate with growth factor, the entry into S-phase or mitosis appears to follow first-order kinetics, with a probability to enter the cell cycle that depends on growth factor concentration (Smith and Martin, 1973). Suboptimal growth factor concentrations also lead to a decreased fraction of the cell population that responds to the stimulation (Brooks et al., 1984). Using flow cytometry, we have re-investigated this dual effect of growth factor concentration on cultures of quiescent normal human skin fibroblasts, stimulated with submaximal concentrations of fetal calf serum, epidermal growth factor, and platelet-derived growth factor. The size of the responding population decreased with decreasing concentration of growth factor, but the time course of cell division within this responding population was identical for all growth factor concentrations. This is in conflict with previous concepts and indicates that the entry into the proliferative state is based on a decision mechanism that cannot be adequately described using transition probabilities determined by mitogen concentration.

Bisbenzimidazole↗
PubMed1987

Accommodative ability in younger-onset diabetes.

The relationships among accommodative ability, younger-onset diabetes, and other factors are examined in this report. The study population consists of younger-onset diabetic persons less than 45 years of age who participated in the Wisconsin Epidemiologic Study of Diabetic Retinopathy. In 656 of 859 such persons, near point of accommodation was measured twice for each eye using the best correction for distance visual acuity and a Prince rule. Mean amplitude of accommodation in the diabetic population decreased with age and was less than that of a nondiabetic group and of previously published reports. Other factors associated with decreased accommodation in the diabetic population in a multiple linear regression analysis include sex, with the female population being more susceptible; absence of myopia; a longer duration of diabetes; higher glycosylated hemoglobin level; higher blood glucose level; increasing severity of diabetic retinopathy; and higher systolic blood pressure.

Accommodation, Ocular↗
PubMed2003

Competitive and interactions affecting a fermentative spirochete in anaerobic chemostats.

Terminal restriction fragment length polymorphism and fluorescent in situ hybridization revealed that spirochete-related populations dominated two glucose-fed methanogenic bioreactor communities at dilution rates of 0.06, 0.13, and 0.17 day(-1). At dilution rates of 0.25 and 0.50 day(-1), spirochete-related populations decreased while Clostridium-related populations increased. Isolates representing both dominant populations were obtained (Treponema R8 and Clostridium S9) and competed against each other in continuous culture. Treponema R8 out-competed Clostridium S9 at all dilution rates applied (0.17 to 1.0 day(-1)) when sufficient pantothenate was supplied in the medium. Without sufficient pantothenate, the population size of Treponema R8 was limited to 40% of the total cells. Coculture of Treponema R8 with Methanobacterium bryantii increased the cell yield of Treponema R8 and relieved the pantothenate requirement. Triculture of Treponema R8, Clostridium S9, and M. bryantii in pantothenate-deficient medium allowed Treponema R8 to outcompete Clostridium S9 in continuous culture upto a dilution rate of 0.50 day(-1). These experiments demonstrate that cofactor and vitamin requirements can affect the competitive success of a microbial species.

Base Sequence↗
PubMed2003

Estimating tsetse population parameters: application of a mathematical model with density-dependence.

A density-dependent model is used to describe the dynamics of an open population of tsetse flies (Diptera: Glossinidae). Immigration (or emigration) takes place when the total population is below (or above) a biologically determined threshold value. The population is also subjected to birth and death rates, as well as to the risk of being trapped (continuously or intermittently). During trapping the population decreases toward a 'low' equilibrium population and when trapping ceases the population starts recovering and increases toward a 'high' equilibrium. The model is fitted using data collected on trapped flies in four experiments. The first one was conducted with 'intermittent trapping' (i.e. several trapping-recovery cycles) on Glossina fuscipes fuscipes Newstead in the Central African Republic (Bangui area). In the other experiments, trapping data on Glossina palpalis palpalis (Robineau-Desvoidy) was collected in 'aggregate' form over several days at a time. Two of these were in Congo-Brazzaville (Bouenza area) and one in the Ivory Coast (Vavoua focus). Estimates are derived for the low and high equilibrium values as well as the trapping rate. The estimated effect of sustained trapping is to reduce the population to low equilibrium values that are 85-87% lower than the levels without trapping. The effects of the natural intrinsic growth and of the migration flows cannot be estimated separately because in the model they are mathematically indistinguishable.

Animal Migration↗
PubMedDate not supplied

Correctness of racial coding of American Indians and Alaska Natives on the Washington State death certificate.

Underestimation of death rates for specific races can obscure health problems and impair the ability of public programs to prevent premature death and disability. For accurate race-specific death rates, the racial classification of both the population at risk and the decreased population must be accurately ascertained. However, studies suggest that the American Indian (AI) and Alaska Native (AN) races may be not be accurately recorded on the death certificate. We performed a computerized linkage between the Indian Health Service (IHS) patient registry and the 1985-1990 computerized Washington State death certificate data. The deceased was correctly identified as AI or AN on the death certificate for 1,088 (87.2%) of 1,248 matched deaths. The majority (93%) of deceased persons identified on the death certificate as not AI or AN were listed as white. The percentage of American Indian ancestry was strongly associated with correct racial classification on the death certificate (P < .001). Birth in Washington State, membership in a large Washington State tribe, and death from an alcohol condition independently added to the likelihood of correct AI or AN racial classification. Persons who died from cancer were significantly less likely to be correctly coded as AI or AN on the death certificate.

Alaska↗
PubMed1989

[Recent trends and prognosis of pulmonary diseases in Japan].

To determine trends of death rates for patients with chronic pulmonary diseases the author compiled the numbers of deaths per 100,000 Japanese population per annum based on the annual reports of the Japan Vital Statistics for the past 43 years. Death rates for the newborn population as well as for the younger population decreased while those for the aged population remained unchanged. Increasing numbers of deaths from lung cancer and decreasing numbers of death from pulmonary tuberculosis were noted. The death rate from the chronic obstructive lung diseases was maintained while the death rate for diffuse fibrotic lung diseases tended to be elevated. Baseline reference values for respiratory physiology parameters, established by the Special Commission for Respiration Physiology of the Japan Society of Chest Diseases, were presented by single linear regression equations represented in terms of age covering the subject's whole age span, including the aged population. The author carried out further analyses based on the data collected in a multi-center cross-sectional survey and concerning, some parameters found consistent differences the linear regression equation calculated for the aged population from those for the younger population. A longitudinal survey conducted by follow-up observations at Keio University Hospital to determine the annual decline of parameters on respiration physiology was designed to cover healthy subjects as well as subjects with chronic pulmonary diseases. Annual declines in vital capacity, forced vital capacity, forced expiratory volume in one second, arterial oxygen tension and arterial carbon dioxide tension showed linear changes throughout the entire age span. Some parameters, such as flow max at 25% vital capacity or alveolar-arterial oxygen tension difference (AaDO2), demonstrated statistically consistent differences in annual decline between younger and older age populations. The annual decline of parameters in patients with chronic pulmonary diseases demonstrated consistently larger values compared with those for healthy subjects. In a study on the pathophysiology and prognosis of patients with respiratory failure with/or without cor pulmonale extension of the survival period for the patients with cor pulmonale was demonstrated.

Adolescent↗
PubMedDate not supplied

[Children of immigration: effects of their presence on the demographic situation in selected employment countries].

The author examines the impact of migrant workers in Europe on such demographic developments as declining fertility, population decrease, and demographic aging. Official government and U.N. data are used to contrast age distributions of migrant and native populations in selected receiving countries in Europe. "In his analysis of the impact of second-generation migrants on demographic development in the principal European employment countries, the author shows that in all of these countries the foreign population improves the age distribution of the population as a whole by way of reinforcing the weight of the younger age groups in relation to the older groups. The ageing of the national populations...is thus countered by the presence of second-generation migrants." (summary in ENG)

Age Distribution↗