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PubMed2004

[Research progress of adipose tissue-derived stromal cells].

OBJECTIVE: To review research progress of adipose tissue-derived stromal cells (ADSCs). METHODS: The recent articles on ADSCs were extensively reviewed, and the culture and differentiation ability of ADSCs were investigated. RESULTS: A population of stem cells could be isolated from adult adipose tissue, they were processed to obtain a fibroblast-like population of cells and could be maintained in vitro for extended periods with stable population doubling. The majority of the isolated cells were mesenchymal origin, with a few pericytes, endothelial cells and smooth muscle cells. ADSCs could be induced to differentiate into multiple mesenchymal cell types, including osteogenic, chondrogenic, myogenic and adipogenic cells, they could also differentiate into nerve cells. CONCLUSION: ADSCs can substitute mesenchymal stem cells and become an alternative stem cells source for tissue engineering.

Adipose Tissue↗
PubMed2006

[Biological characteristics of human umbilical cord-derived mesenchymal stem cells and their differentiation into neurocyte-like cells].

OBJECTIVE: To investigate the isolation and expansion of mesenchymal stem cells (MSCs) from human umbilical cord Wharton's jelly and their biological identities, and explore the possibility of inducing human umbilical cord-derived MSCs to differentiate into neurocyte-like cells. METHODS: The growth and proliferative abilities of human umbilical cord-derived MSCs were observed, and their immunophenotypes were determined by flow cytometry. Salvia miltiorrhiza and beta-sulfhydryl alcohol were adopted to induce the cells to differentiate. The differentiated and undifferentiated cells were identified with immunocytochemistry. The pleiotrophin and nestin genes were measured by RT-PCR. RESULTS: A population of human umbilical cord-derived MSCs were isolated from human umbilical Wharton's jelly; they were processed to obtain a fibroblast-like population of cells and could be maintained in vitro for extended periods with stable population doubling, and they were expanded as undifferentiated cells in culture for more than 10 passages, indicating their proliferative capacity. The human umbilical cord-derived MSCs were positive for CD(29), CD(44), CD(59), CD(105), but negative or weakly expressed the markers of hematopoietic cells such as CD(14), CD(33), CD(34), CD(28), CD(45) and CD(117). The important GVHD correlation markers were negative or weakly expressed, including CD(80) (B7-1), CD(86) (B7-2), CD(40) and CD(40L). Salvia miltiorrhiza beta-sulfhydryl alcohol could induce the MSCs to express nestin, a marker of neuronal precursor stem cells at early stage of differentiation. Later, they exhibited neural phenotypes, expressing beta-tubulin III and neurofilament (NF) and glial fibrillary acidic protein (GFAP). It was confirmed by RT-PCR that the MSCs could express pleiotrophin either before or after the induction of salvia miltiorrhiza, furthermore, after the induction the expression was markedly enhanced and the nestin gene was also expressed. CONCLUSION: The human MSCs could be isolated from human umbilical cord Wharton's jelly, and it was easy to propagate these MSCs. The negative GVHD correlated markers might result from the fact that MSCs had no HLA barrier, which may suggest potential clinical significance. The MSCs are capable of differentiating into neurocyte-like cells and they may represent an alternative stem cell source for CNS cells transplantation.

Antigens, CD↗
PubMed1997

Reversal of human allergic T helper 2 responses by engagement of signaling lymphocytic activation molecule.

Allergen-specific Th2 cells accumulate at high frequencies in the skin of patients with atopic dermatitis (AD), where they contribute to the induction and maintenance of the lesions that are characteristic for the disease. Attenuation of these lesions in response to successful therapy is associated with a reduction in IL-4-producing Th2 cells and the appearance of IFN-gamma-producing Th cells. In this study, we demonstrate that engagement of the signaling lymphocytic activation molecule (SLAM) by an agonistic mAb, during allergen-specific expansion of highly polarized Th2 cell populations derived from skin biopsies of AD patients, results in the generation of stable populations of IFN-gamma-producing cells. SLAM-mediated reversal of Th cell phenotype has important biologic consequences, because supernatants of these activated, allergen-specific Th cells fail to induce IgE synthesis by purified B cells costimulated by anti-CD40 mAbs. Thus, highly polarized, allergen-specific Th2 cell populations derived from the skin of AD patients can be reversed into Th cell populations that contain IFN-gamma-producing cells and that do not support IgE synthesis. These results define a new mechanism to promote Th0/Th1 differentiation and suggest a potential role for anti-SLAM mAbs in the treatment of Th2-mediated allergic diseases.

Antigens, CD↗
PubMed1997

[Allometric signals of technogenic actions on the population].

The authors demonstrate possible use of allometric equations to describe age-matched oncologic morbidity and mortality in stable population. Deviations from the allometric model (allometric signals) could be traced to changed technogenic load on the population. Examples show relationships between rank parameters of the models and the technogenic load levels.

Age Distribution↗
PubMed1989

Migration and labour supply in New England.

The author links changes in regional employment with demographic changes in New England during the relative economic boom that occurred in the region during the 1980s. It is noted that during this period, "New England had a very slow rate of natural population growth. The relatively high rate of growth in jobs coupled with the relatively stable population has produced labour shortages in parts of the region. It is demonstrated that the labour supply has become dependent on migrants from other regions. If the economic expansion continues, the region must significantly increase its net migration gains. If immigration to the region remains sluggish, the revival will be short-lived." This is a revised version of a paper originally presented at the 1988 Annual Meeting of the Population Association of America (see Population Index, Vol. 54, No. 3, Fall 1988, p. 428).

Americas↗
PubMed1991

Tuberculosis in Saudi Arabia: epidemiology and incidence of Mycobacterium tuberculosis and other mycobacterial species.

The epidemiology of mycobacterial infections was studied in a wide cross-section of the Jeddah population over 2 years (1987-1989). Saudis, non-Saudis and patients from a stable population attending National Guard King Khalid Hospital (NGKKH) were compared. The ratio of Saudi to non-Saudi was 1:2 and males accounted for 65% of the total. The incidence was highest among young adults although the peak varied slightly between Saudi and non-Saudi patients. Extra-pulmonary tuberculosis was also preponderant among young adults, particularly females. Variants of Mycobacterium tuberculosis were investigated for the first time in Saudi Arabia. African and Asian variants were isolated from both Saudi and non-Saudi patients, the former being more numerous. Extra-pulmonary tuberculosis, particularly lymphadenopathy, accounted for a large proportion of mycobacterial infections, 59% at NGKKH. Mycobacterial species other than M. tuberculosis were fully identified and accounted for 9% of the isolates, Mycobacterium fortuitum and Mycobacterium chelonei being the two most prevalent.

Adolescent↗
PubMed2000

Prenatal diagnosis of congenital heart disease in the northern region of England: benefits of a training programme for obstetric ultrasonographers.

OBJECTIVE: To examine the results of fetal cardiac scanning and audit the changes in performance resulting from the introduction of a training programme for obstetric ultrasonographers. METHODS: Using the database of the Northern Regional Congenital Abnormality Survey (NORCAS), fetuses with complex or significant congenital heart disease (CCHD) diagnosed prenatally in 1994 were identified. A simple programme of centralised and local training was instituted in 1995 by the department of paediatric cardiology to teach obstetric ultrasonographers in district general hospital maternity departments to identify congenital heart malformations. The results of the training programme were assessed by comparing the 1994 identification rate of CCHD with the rates for 1996 and 1997. RESULTS: Birth rate fell during the study from 35,026 in 1994 to 32,874 in 1997. Registration of CCHD also fell, from 115 in 1994 to 87 in 1997. Prenatal recognition of CCHD rose from 17% in 1994 to 30% in 1995 and 36% in 1996. In 1997 it fell slightly to 26.9%. The total number of scans did not change much year on year, but the number of parents choosing termination increased significantly (from 22.7% to 57%). CONCLUSIONS: A simple training programme for obstetric ultrasonographers increased their ability to detect serious congenital heart disease at a routine 18-20 week anomaly scan. With a termination rate of more than 50%, the incidence of CCHD in the population fell from 3.3/1000 to 2.6/1000 live births. This audit, conducted within a stable population using ascertainment by a well established fetal malformation registry, suggests that prenatal diagnosis may have a significant effect on the incidence of complex or serious congenital cardiac malformations.

Abortion, Therapeutic↗
PubMed1999

Looking into the demography of an iron age population in the western Mediterranean. I. Mortality.

In this paper, we attempt to reconstruct the mortality pattern of the population buried in S'Illot des Porros (Majorca), an Iron Age necropolis in the western Mediterranean, by means of paleodemographic analysis. The skeletal sample consists of 285 individuals, 93 subadults (under 20 years old) and 192 adults. The aim of this study is twofold: first, to identify and to evaluate the structural anomalies of the skeletal sample, and second, to obtain a possible and realistic description of the biological dynamics of this population, with special reference to its mortality pattern. The study uses current demographic methodology and several demographic models (for comparison). An abridged life table was built to estimate the mortality parameters. To evaluate the likelihood of the estimated data, an indirect analysis, which consisted of a comparison of our results with different population models (Weiss [1973] American Antiquity 38; Coale and Demeny [1996] Regional Model Life Tables and Stable Populations. Princeton: Princeton University Press; Ledermann [1969] Nouvelles tables-types de mortalité. Paris: Presses Universitaires de France), was carried out. An important bias was identified in the case of children, mostly affecting infants but also children between the ages of 1 and 5. This was interpreted as a census error due to taphonomic reasons and to an excluding differential funeral rite. A life expectancy at birth of approximately 28 years was estimated from the observed data. When this bias was removed, the estimated life expectancy at birth dropped to 23 years. The use of the Brass logit system allowed us to sketch a possible mortality profile for this population: low life expectancy, high infant mortality and hard life conditions, which were the cause of the low levels of survivorship in old ages. Am J Phys Anthropol 110:285-301, 1999.

Adolescent↗
PubMed1976

Colonization of the intestinal tract of conventional mice with Candida albicans and treatment with antifungal agents.

Conventional mice inoculated with Candida albicans per os were unable to maintain this organism in the intestinal tract as judged by decreasing numbers of yeast recoverable from feces. After inoculation with 10(7) cells/mouse, fecal counts ranged from 10(5) cells per g of feces to 5 x 10(3) cells per g of feces during a 12-day experimental period. Addition of various antibiotics to the drinking water did not result in any improvement in maintenance or stability of the gut population. A combination of X irradiation and administration of tobramycin or gentamicin, however, resulted in a stable population of C. albicans in the intestinal tract, with cell counts in the feces remaining constant at a level of about 10(6)/g of feces for a period of 10 to 15 days. The usefulness of this model in assessing the effect of experimental drugs on C. albicans infections of the gut was demonstrated by the fact that treatment with a new antifungal antibiotic (A9145), amphotericin B, 5-fluorocytosine, or nystatin resulted in a reduction in the fecal counts of C. albicans from experimentally infected animals.

Animals↗
PubMed2006

[The in vitro study of the human adipose tissue-derived stromal cells differentiating into the neuron-like cells].

OBJECTIVE: To investigate the possibility of the adipose tissue derived stromal cells (ADSCs) to differentiate into the neuron-like cells and to explore a new cell source for the transplantation related to the central nervous system. METHODS: Adipose was digested by collagenase, cultured in the fetal bovine serum containing a medium. Trypse was used to digest the cells and the cell passage was performed. The 3rd to the 9th passage ADSCs were used to make an induction. Isobutyl-methylxanthine, indomethacin, insulin, and dexamethasone were used to induce the ADSCs to differentiate into the neuronlike cells and adipocytes. Sudan black B and immunocytochemistry were used to identify the cells. RESULTS: A population of the ADSCs could be isolated from the adult human adipose tissue, they were processed to obtain a fibroblast-like population of the cells and could be maintained in vitro for an extended period with the stable population doubling, and they were expanded as the undifferentiated cells in culture for more than 20 passages, which indicated their proliferative capacity. They expressed vimentin and nestin, and characteristics of the neuron precursor stem cells at an early stage of differentiation. And the majority of the ADSCs also expressed the neuron-specific enolase and beta III-tubulin, characteristics of the neurons. Isobutyl-methylxanthine, indomethacin, insulin, and dexamethasone induced 40%-50% of ADSCs to differentiate into adipocytes and 0. 1%-0.2% of ADSCs into neuron-like cells. The neuron-like cells had a complicated morphology of the neurons, and they exhibited a neuron phenotype, expressed nestin, vimentin, neuron-specific enolase and beta III-tubulin, but some neuron-like cells also expressed the smooth muscle actin (SMA), and the characteristics of the smooth muscle cells; however, the neurons from the central nervous system were never reported to express this kind of protein. Therefore, the neuron-like cells from the ADSCs could be regarded as functional neurons. CONCLUSION: Our results support the hypothesis that the adult adipose tissue contains the stem cells capable of differentiating into the neuron-like cells, and they can overcome their mesenchymal commitment, which represents an alternative autologous stem cell source for transplantation related to the central nervous system.

Adipose Tissue↗
PubMed2000

Do subplate neurons comprise a transient population of cells in developing neocortex of rats?

Studies were undertaken to determine whether neurons of the subplate layer represent a transient or stable population of cells in developing neocortex of rat. The first set of studies sought to determine the fraction of subplate neurons that is lost during early postnatal development. The optical dissector method was used to analyze fluorescently stained material in animals the age of postnatal day 0 (P0) to P40. These results demonstrate a reduction of slightly less than half of the total number of subplate neurons from P0 to P40. Counts of labeled cells in littermates at varied ages after [(3)H]thymidine or BRDU treatment on gestational day 14 (G14 - birthdate of occipital subplate neurons) or G18 (birthdate of layers III-IV neurons) demonstrate loss of approximately 50% of neurons in the subplate layer between P0 and P40, somewhat greater than the loss of neurons from cortical layers III-IV. The second set of studies investigated whether subplate neurons display cellular atrophy during postnatal development. Analysis of subplate neurons injected intracellularly with Lucifer yellow in fixed slice preparations indicates no reduction in soma size, number of dendrites, or extent of dendritic fields of subplate neurons taken from animals age P0 to P60. The third set of studies investigated whether functional markers of subplate neurons are reduced during postnatal development. Analysis of tissue stained histochemically for cytochrome oxidase or acetylcholinesterase, or stained immunocytochemically for GABA, somatostatin, or neuropeptide Y, demonstrate a remarkable loss of expression of staining patterns from late gestational ages to P20. These data demonstrate that, although subplate neurons seem not to be a transient population of cells in the usual sense of being eliminated by cell death or structural atrophy, the loss of histochemical and immunocytochemical markers indicates that they may be a functionally transient population of cells.

Acetylcholinesterase↗
PubMed2003

Isotope variations in white-tailed kites from various habitats in California: possible limitations in assessing prey utilization and population dynamics.

White-tailed kite (Elanus leucurus) populations in the 1930s were close to extirpation in the United States. But by the 1940s, an upward trend towards recovery was apparent and continued to their current stable population levels. These dramatic fluctuations in kite numbers may have been related to changes in rodent prey populations due to the conversion of native habitats to agriculture. To address this question, we evaluated the use of stable isotope analysis in determining if a shift in diet could be isotopically differentiated in current and historic kite populations. We first compared delta13C, delta15N, and delta34S values from present-day kite flight feathers and prey fur samples from four locations in California. The total ranges of isotope values for kite and their rodent prey were similar within each site. Carbon isotope values ranged from -27.1 to -22.2 per thousand in Arcata, -26.1 to -16.9 per thousand in Davis, -27.0 to -15.0 per thousand in Cosumnes, and -28.2 to -11.6 per thousand in Santa Barbara. Nitrogen isotope values ranged from 3.2 to 15.7 per thousand in Arcata, 2.8 to 12.7 per thousand in Davis, 4.0 to 15.7 per thousand in Cosumnes, and 1.7 to 20.0 per thousand in Santa Barbara. Sulfur isotope values ranged from -7.8 to 12.4 per thousand in Arcata, -1.1 to 9.2 per thousand in Davis, 0.7 to 10.9 per thousand in Cosumnes, and -8.6 to 15.6 per thousand in Santa Barbara. Carbon, nitrogen, and sulfur isotope values at each site reflect typical trophic enrichments due to physiological processes. At each site, delta13C and delta15N values reflected the influence of a predominantly C3 or a mixed C3/C4 plant community. Sulfur isotope values reflect the influence of predominant marine or terrestrial sulfur sources at each site. However, variability in isotope values may limit the usefulness of such analyses for addressing prey utilization and population dynamics.

Animals↗
PubMed2002

The evolution of self-fertilization in density-regulated populations.

The evolution of selfing in hermaphrodites has been studied to reveal the demographic conditions that lead to intermediate selfing rates. Using a demographic model based on Ricker-type density regulation, we assume first that, independent of population density, inbred individuals survive less well than outbred individuals and second, that inbred and outbred individuals differ in their competitive abilities in density-regulated populations. The evolution of selfing, driven by inbreeding depression and the cost of outcrossing, is then analysed for three fundamentally different demographic scenarios: stable population densities, deterministically varying population densities (resulting from cyclical or chaotic population dynamics) and stochastic fluctuations of carrying capacities (resulting from environmental noise). We show that even under stable demographic conditions evolutionary outcomes are not confined to either complete selfing or full outcrossing. Instead, intermediate selfing rates arise under a wide range of conditions, depending on the nature of competitive interactions between inbred and outbred individuals. We also explore the evolution of selfing under deterministic and stochastic density fluctuations to demonstrate that such environmental conditions can evolutionarily stabilize intermediate selfing rates. This is the first study, to our knowledge, to consider in detail the effect of density regulation on the evolution of selfing rates.

Adaptation, Physiological↗
PubMed2003

Population structure and variation in red snapper (Lutjanus campechanus) from the Gulf of Mexico and Atlantic coast of Florida as determined from mitochondrial DNA control region sequence.

The mitochondrial DNA control regions of red snapper (Lutjanus campechanus) from the Gulf of Mexico (n = 140) and Atlantic coast of Florida (n = 35) were sequenced to generate a prestocking genetic baseline for planned stock enhancement. Intrasample haplotype and nucleotide diversities ranged from 0.94 to 1.00 and 1.8% to 2.5%, respectively. All population analyses were consistent with the hypothesis that red snapper constitute a single, panmictic population over the sampled range. A ubiquitous, predominant haplotype, shared by 23% of the specimens, appeared to be evolutionarily recent, in contrast to previous findings based on restriction fragment length polymorphism data. Tajima's D values were suggestive of a recent bottleneck. Mismatch distributions from Gulf samples were smooth and unimodal, characteristic of recent population expansion. However, the Atlantic sample exhibited a comparatively broader, possibly multimodal distribution, suggestive of a more stable population history. Additional control-region data may clarify potentially disparate demographic histories of Gulf and Atlantic snapper.

Animals↗
PubMed1999

Cerebral palsy in Malta 1981 to 1990.

Of 55200 Maltese children born in the Mediterranean islands of Malta and Gozo in the birth years 1981 to 1990 inclusive, 134 fitted the case definition of cerebral palsy (CP). Children were allocated to prenatal, perinatal, and postnatal groups according to strict criteria and to various CP syndromes using the Swedish classification. The study was undertaken between 1994 and 1996 and the period prevalence rate was calculated. The control group comprised 134 children who were matched for sex and born immediately before or after the index subjects in the same hospital. Data related to risk factors were extracted from medical records and collected by interview with parents/carers. Unadjusted odds ratios (OR) with 95% confidence intervals for a range of risk factors were calculated. For risk factors with a relatively high prevalence in the population, such as prematurity and low birthweight, ORs were calculated from case-control data. For low-prevalence risk factors, such as breech presentation and multiple pregnancy, ORs were calculated against the whole population data for the 10-year birth cohort. The prevalence rate of CP in the geographically defined, stable population of the Maltese islands was similar to that in the UK and higher than that for Sweden, but the rates for different types of CP were markedly different from most developed countries, with a higher rate of spastic tetraplegias. Risk factors were as expected and similar to those reported from other developed countries. The study shows a strong social gradient with a higher than expected proportion of CP in children of unskilled manual workers.

Adolescent↗
PubMedDate not supplied

Chlorinated hydrocarbon contamination in osprey eggs and nestlings from the Canadian Great Lakes basin, 1991-1995.

Populations of osprey (Pandion haliaetus) in the Great Lakes basin declined dramatically during the 1950s-1970s due largely to adverse effects of persistent chlorinated hydrocarbons, ingested in their fish prey, on eggshell thickness and adult survival. Nevertheless, these contaminants were not measured in osprey tissues during the decades of decline on the Canadian Great Lakes. Between 1991 and 1995, we monitored recovering osprey populations on the Great Lakes, including Georgian Bay and the St. Marys River area on Lake Huron and the St. Lawrence Islands National Park, as well as at two inland sites within the basin. Current OC levels, even from the most contaminated lakes, were typically lower than those associated with reproductive effects. DDE levels in fresh eggs averaged 1.2-2.9 microg/g, well below the 4.2 microg/g level associated with significant eggshell thinning and shell breakage. Nevertheless, a proportion of eggs from all study areas did exceed this level. PCB levels in eggs seldom exceeded 5 microg/g except in one lake of high breeding density in the Kawartha Lakes inland study area, where the mean sum PCB level was 7.1 microg/g and the maximum concentration measured was 26.5 microg/g. On average, mean reproductive output (0.78-2.75 young per occupied nest) of breeding populations in Great Lakes basin study areas exceeded the threshold of 0.8 young thought necessary to maintain stable populations. We concluded that, although eggs and especially nestling plasma, are useful in reflecting local contaminant levels, ospreys are relatively insensitive, at least at the population level, to health effects of current levels of chlorinated hydrocarbons on the Canadian Great Lakes.

Animals↗
PubMedDate not supplied

Use of serum biochemistry to evaluate nutritional status and health of incubating common eiders (Somateria mollissima) in Finland.

During 1997-1999, we collected serum samples from 156 common eider (Somateria mollissima) females incubating eggs in the Finnish archipelago of the Baltic Sea. We used serum chemistry profiles to evaluate metabolic changes in eiders during incubation and to compare the health and nutritional status of birds nesting at a breeding area where the eider population has declined by over 50% during the past decade, with birds nesting at two areas with stable populations. Several changes in serum chemistries were observed during incubation, including (1) decreases in serum glucose, total protein, albumin, beta-globulin, and gamma-globulin concentrations and (2) increases in serum uric acid, creatine kinase, and beta-hydroxybutyrate concentrations. However, these changes were not consistent throughout the 3-yr period, suggesting differences among years in the rate of carbohydrate, lipid, and protein utilization during incubation. The mean serum concentrations of free fatty acids, glycerol, and albumin were lowest and the serum alpha- and gamma-globulin levels were highest in the area where the eider population has declined, suggesting a role for nutrition and diseases in the population dynamics of Baltic eiders.

3-Hydroxybutyric Acid↗
PubMed1989

Population history of Nauru: a cautionary tale.

"Available records relating to Nauruan population attributes are critically evaluated to develop a reconstructed population history of this native Micronesian people. Historical evidence consists of documentation of the effects of diseases and modern warfare and more recent behavioral changes traceable to altered economic conditions. Unpredictable and dramatic fluctuations in population characteristics throughout the historic period are revealed, precluding the use of standard population models. Even structural similarities at widely separated time periods are shown to be insufficient evidence of stable population conditions, a cautionary finding for paleodemographers, archaeologists, and others working throughout the Pacific."

Behavior↗