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Biomedical subjects

D E Harrison

Publications and source records attributed to D E Harrison.

At least 19 recordsLinked to original sources
PubMed1992

The same exhaustible multilineage precursor produces both myeloid and lymphoid cells as early as 3-4 weeks after marrow transplantation.

Hemopoietic precursors with the ability to differentiate into wide varieties of cell types are considered primitive, as are precursors with long-term repopulating ability. Here we study the populations of marrow precursors from which both myeloid and lymphoid lineages are descended shortly after transplantation. Surprisingly, few or none of these precursors show long-term repopulating ability. Equal portions of a mixture of marrow cells from C57BL/6J (B6) and congenic B6-Hbbd Gpi-1a mice are transplanted into a group of recipients. Three weeks later, highly significant correlations between percentages of B6 type T cells, B cells, granulocytes, and platelets in each recipient indicate that many lymphoid and myeloid cells are descended from common precursors. After 4-6 weeks, most correlations between lymphoid and myeloid cells improve, indicating that most or all differentiated cells are descended from common precursors. The more differentiated myeloid-specific precursors found in spleen colony-forming cell assays apparently fail to contribute significantly to the differentiated myeloid cell populations tested. By using the binomial model, in which variability of the data among the recipients is inversely related to the number of precursors in the mixture, donor precursor concentrations are estimated as approximately 21 per 10(5) marrow cells after 3 weeks, falling 3-fold to 6.6 per 10(5) after 4-6 weeks. This trend continues, with higher correlations, greater variabilities, and donor precursor concentrations of 1.9 per 10(5) marrow cells after 12-14 weeks and 1.4 per 10(5) after 24 weeks. Strong increases in variances between 3 and 12 weeks after transplantation suggest that most or all of the initially active multilineage precursors are exhausted during this time period. The fact that the ability of a hemopoietic stem cell to differentiate into widely disparate lineages is not associated with long-term repopulating ability requires a change in stem cell definitions, since primitive hemopoietic stem cells have traditionally been defined by both these abilities.

Animals↗
PubMed1992

Cellular determinants of age-related decrements in the T-cell mitogen response of B6CBAF1 mice.

Age-related changes in the cellular composition of the immune system that are associated with an impaired proliferative response to T-cell mitogens were identified for B6CBAF1 mice. The frequencies of precursors of Con A-induced IL-2-secreting cells (pHTL) and of Con A-induced cytotoxic cells (pCTL), determined by limiting dilution analysis, were lower for splenocytes from old mice, as were the proliferative responses to Con A and PHA, determined in conventional high cell density cultures for the same mice. The pHTL frequency correlated with the proliferative response to Con A (r2 = .94) and to PHA (r2 = .83) among old mice, but not among young; there were no correlations of pCTL frequency with proliferative responses. The reduced pHTL frequency in old mice resulted from: (a) an age-related doubling of the number of splenic B cells that diluted T cells, and (b) a 67% decline in the absolute number of Con A-reactive pHTL cells in the spleen that appeared despite the maintenance of normal numbers of total splenic CD4+ and CD8+ cells. Thus, both a decline in absolute pHTL numbers and an increase in the number of non-T cells in the spleen result in a diminished pHTL frequency that is closely linked to the impaired mitogen response observed for old B6CBAF1 mice.

Aging↗
PubMed1992

Polygenic influences on the length of oestrous cycles in inbred mice involve MHC alleles.

Genetic influences on female reproductive cycles were analysed in histocompatibility-congenic strains of mice. Oestrous cycles of young, virgin mice of inbred-congenic strains, hybrid crosses (F1), and parental-hybrid backcrosses (F2) were monitored for 3 months. Oestrous cycles were categorized by length (inter-oestrous interval): 4, 5, 6, or 7-14 days. Mice with the following H-2 haplotypes had a greater proportion of 5-day oestrous cycles: H-2b, H-2r, H-2h2, H-2h4, and H-2i5. In contrast, the H-2k and H-2d haplotypes had mostly 4-day oestrous cycles. Influences of H-2 haplotype were seen on two genetic backgrounds, C57BL/10Sn and C3H. Non-H-2 alleles were also implied by different patterns of cycles between strains with the same H-2b haplotype: C57BL/10Sn with predominantly 5-day cycles vs. C57BL/6J with a mix of 4- and 5-day cycles. The genetic basis for strain differences was investigation in F1 hybrids and their backcrosses. F1 hybrids of an H-2b (C57BL/10Sn; 5-day cycles) and an H-2k (B10.BR; 4-day cycles) strain had mostly 5-day cycles, indicating dominance of an H-2b allele(s). However, F1 hybrids from the reciprocal B6 x B10 cross (both H-2b) also display a preponderance of 5-day cycles, indicating dominance of a non-H-2 autosomal allele from the C57BL/10Sn strain. Among F2 mice, a '4-day' phenotype segregated with homozygosity for the k haplotype (P < 0.05, chi 2). These findings demonstrate the influence of genetic differences at the major histocompatibility complex on oestrous cycles.

Alleles↗
PubMed1991

Most primitive hematopoietic stem cells are stimulated to cycle rapidly after treatment with 5-fluorouracil.

To test whether primitive hematopoietic stem cells (PHSC) cycle rapidly during recovery from an initial 5-fluorouracil (5-FU) treatment, two doses of 5-FU were administered 1, 3, 5 or 8 days apart. Cells from treated marrow donors were mixed with untreated competitor marrow that would produce genetically distinguishable erythrocytes and lymphocytes, using hemoglobin (Hb) and glucosephosphate isomerase (GPI) transplantation markers. These cell mixtures were injected into lethally irradiated hosts. Functional abilities of donor marrow populations were assessed after 3, 6, and 12 months as percentages of donor type Hb and GPI in the host's circulating erythrocytes and lymphocytes, respectively. Bone marrow from mice treated with two doses of 5-FU 3 to 5 days apart was severely affected, producing circulating erythroid and lymphoid cells an average of only 25% of normal for doses 3 days apart, and 14% of normal for doses 5 days apart. Two doses of 5-FU administered 1 day or 8 days apart had much smaller effects, producing circulating cells 75% or 58% of normal. Thus, most PHSC are stimulated to proliferate rapidly 3 to 5 days after treatment with 5-FU, but far fewer PHSC proliferate as early as 1 day, or as late as 8 days, after the 5-FU treatment.

Animals↗
PubMed1991

Lymphoid and erythroid repopulation in B6 W-anemic mice: a new unirradiated recipient.

The W-anemic family of mouse mutants is an important model for studying repopulation in unirradiated recipients. This is the first study of blood lymphoid cell repopulation in adult W-anemic mutants given high doses of marrow cells, and it shows a wide difference in repopulation rates of circulating lymphoid and erythroid cells. This study also offers an improved model for marrow transplantation, using W alleles that are spontaneous mutations on the widely used inbred strain C57BL/6J (B6). Unirradiated B6-W41J/W41J or -W41J/W39J recipients of 2 x 10(6) B6 marrow cells are completely repopulated with donor erythrocytes after 3 months, whereas complete repopulation of lymphocytes requires a year. Surprisingly, the eventual degree of repopulation is independent of the severity of the mutation. The new mutants are not as anemic as the commonly used WBB6F1-W/Wv anemic mutants, they have a much higher ability to form macroscopic spleen colonies (spleen colony-forming units, CFU-S), and B6-W41J/W41J mice are fertile. Nevertheless, lymphoid and erythroid repopulation occur to a similar extent in B6-W41J/W41J or -W41J/W39J and in WBB6F1-W/Wv anemic mutants. Repopulation is more rapid in the latter, but host cells may be damaged by B6 reactions against the WB parent. Avoiding graft-versus-host reactions, hybrid resistance, and similar complications are important advantages in using donors and unirradiated recipients all on the B6 mouse genetic background. Additionally, congenic B6 mice provide a variety of genetic markers, allowing myeloid and lymphoid repopulation to be readily quantitated.

Anemia↗
PubMed1990

Effects of transplantation on the primitive immunohematopoietic stem cell.

Transplantation has strong deleterious effects on the primitive immunohematopoietic stem cells (PSC) from which circulating lymphocytes and erythrocytes are descended. We studied these effects over 300-400 d, testing whether PSC numbers, repopulating abilities, or both, were reduced. Equivalent PSC numbers were estimated in recipients of mixtures of genetically different cells, using the binomial model with covariance. Percentages of lymphocyte and erythrocyte types were closely correlated, as were percentages of either type sampled at intervals of several months. This suggests that the same PSC produced lymphoid and myeloid cells, and that most circulating cells were descended from the same PSC over hundreds of days. Equivalent PSC concentrations were approximately 1/10(5) fresh marrow cells, and were about twofold lower using previously transplanted marrow. However, such marrow repopulated only one-seventh to one-eighth as well as fresh marrow. Apparently, transplantation not only reduces PSC concentrations, but also reduces the repopulating ability per PSC. This may result from excessive stimuli to differentiate that overbalance the stimuli for PSC to replenish themselves.

Analysis of Variance↗
PubMed1990

5-Fluorouracil spares hemopoietic stem cells responsible for long-term repopulation.

The long-term immunohemopoietic reconstituting ability of bone marrow, treated with a single administration of 5-fluorouracil (5-FU), was measured to determine whether 5-FU caused any deleterious effect upon primitive stem cells (PSCs). Cells from 5-FU-treated marrow donors were mixed in four different proportions of total marrow contents with untreated competitor marrow containing genetically distinguishable hemoglobin (Hb) and glucosephosphate isomerase (GPI) transplantation markers. These cell mixtures were introduced into lethally irradiated hosts. The functional ability of the donor cell population was assessed by measuring the percentage of donor type Hb and GPI found in the host's circulating erythrocytes and lymphocytes, respectively. Bone marrow from mice treated with 5-FU 1, 5, and 8 days prior to transplantation produced circulating lymphoid and erythroid cells as well as equal fractions of untreated fresh marrow when surveyed approximately 90 days after transplantation. Normal reconstitutive ability was thus maintained despite a tenfold reduction in marrow cell numbers when donor mice had been treated with 5-FU 5 days prior to transplantation. Donor marrow treated with 5-FU 15 days prior to transplantation had slightly decreased repopulating ability in one of two experiments. A second round of repopulation was stimulated subsequent to the initial 90-day screening by giving hosts a sublethal (500 rad) dose of irradiation. After 3-4 months, Hb and GPI parameters were the same as preirradiation values. Thus, the radioresistance of 5-FU treated PSCs remains comparable to that of fresh marrow, and their relative repopulating ability was not comprised by the additional stress of sublethal irradiation. After both rounds of repopulation the myeloid and lymphoid pathways were repopulated equally well by PSCs surviving 5-FU treatment. Repopulation of both pathways to the same extent suggests a common precursor as the proliferative agent. These results indicate that the PSCs were unaffected after a single treatment with 5-FU, although they were concentrated tenfold.

Animals↗
PubMed1989

Numbers and functions of transplantable primitive immunohematopoietic stem cells. Effects of age.

This report introduces a new method in immunology, a use of the binomial formula with covariance to estimate numbers and proliferative patterns of the most primitive lymphoid precursors. We studied the primitive stem cells (PSC) from which most circulating lymphocytes and erythrocytes were descended during 300 to 400 days in recipients of genetically distinguishable marrow mixtures in competitive repopulation. Equivalent PSC concentrations (Eq. PSC Conc. or Conc.) were estimated, with the notion of common PSCs contributing equally in lymphoid and myeloid compartments. Similar estimation was done for common PSCs from which lymphocytes (and erythrocytes) drawn at successive sampling times about 100 days apart were descended. The percentages of lymphocyte and erythrocyte types, P1 and Pe, measured in each recipient were closely correlated, especially after 6 months and later. Close correlations were also found in cells sampled at successive one hundred day intervals, especially after the first. Apparently a few PSCs or their direct descendents produced most of the blood lymphocytes and E, and this production continued for many months. Concentrations of these PSCs (Equivalent PSC concentrations) were about one per 10(5) marrow cells from young donors. This is much lower than previous estimates, probably because our methods focus only on the most interesting precursors, those from which most of the circulating cells were descended. Equivalent PSC concentrations were about two-fold higher in old donors; old marrow produced correspondingly higher P1 and Pe values, but these declined with time. There were also small increases with time in the P1 and Pe values with young donors. To explain the temporal trends, we suggest that excess concentrations of precursors less primitive than PSC are present in old marrow, and their contribution to the differentiated cell population gradually declines. Possibly such precursors, as well as true PSC, proliferate in old donors to compensate for deficiencies that develop with age.

Aging↗
PubMed1988

Biomarkers of aging: tissue markers. Future research needs, strategies, directions and priorities.

Objective tests that allow early detection of deleterious changes with age are necessary to develop treatments enhancing the health span--the length of healthy life. Here we report tests of eight biological systems that can be performed in mice with no harm to the subjects. Male and female B6, CBA and F1 mice were used. While most test results correlated with chronological age in most genotypes, none predicted subsequent longevities in more than two genotypes. Surprisingly, the open field activity test that most consistently predicted longevities, did not correlate with chronological age. Six tests predicted beneficial effects of food restriction in F1 males, but only one correctly predicted the deleterious effects of the same food restriction regimen in B6 males. These results suggest that different biological systems age at different rates, that rates are affected by genotype and that an anti-aging treatment beneficial in one genotype may be harmful in another.

Aging↗
PubMed1988

Number and continuous proliferative pattern of transplanted primitive immunohematopoietic stem cells.

We estimated numbers of transplantable primitive stem cells (PSCs) and found evidence that the same PSC continuously produced circulating erythrocytes and lymphocytes. These estimations used the binomial formula on data from recipients of identical portions of marrow mixtures containing two distinguishable cell types. Analysis of variance was used to compare repeated tests within each recipient. Values of pi s or pi c, probabilities that two independently sampled cells were descended from the same PSC, were also estimated, as this does not require the unverified condition that all PSCs contribute equally to the differentiated cell population. Several months after transplantation, erythrocytes were descended from only a single PSC per 1-2 X 10(5) marrow cells injected, several times rarer than previously reported. Percentages of erythrocyte and lymphocyte types in each recipient were closely correlated, with r values ranging from 0.86 to 0.94, in groups receiving 2-8 X 10(5) marrow cells; apparently the same precursors repopulated both myeloid and lymphoid lines in each recipient, as expected of true PSCs. Our data did not fit the clonal succession model, which predicts sequential activation of new PSCs and deactivation of old. Between 76 and 154 days, differentiated erythrocyte precursors were probably exhausted, with no evidence for new precursor activation or for further change between 154 and 250 days. The percentage of newly produced erythrocytes (reticulocytes) of each donor type varied little when individual recipients were followed between 165 and 295 days after transplantation, and variances within recipients were similar at marrow doses from 8 to 200 X 10(5) cells, further contradicting models of sequential activation and deactivation of PSC clones. Thus, transplanted PSCs were continually active during much of the recipient's lifespan.

Analysis of Variance↗
PubMed1988

Aging and glucose homeostasis in C57BL/6J male mice.

Age-dependent changes in glucose homeostasis were assessed in specific pathogen-free C57BL/6J male mice. Increased islet size and pancreatic insulin content in old (21-25-month-old) mice were associated with lower nonfasting plasma glucose levels and improved clearance of either an oral or an i.p. administered glucose load in comparison with young, mature (4-5-month-old) males. The almost twofold increase in islet size correlated with a twofold increase of glucose-stimulated insulin secretion from perifused islets from 25-month-old males compared with 5-month-old males. These aging male mice did not become obese, and there were no fibrotic changes associated with the hyperplastic islets observed in the old males. Thus, the findings that glucose tolerance did not deteriorate with age, coupled with the lack of evidence for impaired beta cell responsiveness to glucose in old males, suggest that deterioration in glucose homeostasis is not an inevitable consequence of aging in the mouse.

Aging↗
PubMed1988

Properties of single potassium channels modulated by glucose in rat pancreatic beta-cells.

1. The patch clamp method has been used to examine the effect of glucose on single K+ channel currents recorded from cell-attached patches on dissociated rat pancreatic beta-cells. Patch pipettes contained a 140 mM-K+ solution. 2. In glucose-free solution three types of K+ channels were observed. Two of these, having conductances of around 50 pS (G-channel) and 20 pS when the external K+ concentration, [K+]0, was 140 mM, were active at the resting potential of the cell. The G-channel was observed in more patches and showed higher activity; it therefore appears to contribute the major fraction of the resting K+ permeability of the beta-cell. At membrane potentials positive to about +20 mV a third type of K+ channel, having a mean conductance of 120 pS, was activated. The open probability of this channel was strongly voltage dependent and increased with depolarization. 3. The reversal potential of the G-channel current was shifted 59 mV by a 10-fold change in external K+ (Na+ substitution) indicating the channel is highly K+ selective. The single-channel conductance varied with [K+]o as predicted from the Goldman-Hodgkin-Katz equation; at physiological [K+]o (5 mM-K+) an inward conductance of around 10 pS is predicted. The amplitude of the single-channel current showed a tendency to saturate with increasing [K+]o. 4. Single G-channel currents show burst kinetics indicating at least two closed states. The open and closed (gap) times within the bursts were distributed exponentially with time constants of 2.5 ms (tau o) and 0.5 ms (tau c1) respectively at the resting potential of the cell. There was little change in tau c1 over the voltage range -40 to 60 mV (pipette potential) but tau o increased slightly with membrane depolarization. 5. The addition of glucose to the bath solution produced a reversible, dose-dependent decrease in G-channel activity. This decrease results principally from a reduction in the frequency and duration of the bursts of openings with increasing glucose. In addition, the mean open time decreases. The short gaps during the bursts were little affected by glucose. 6. At glucose concentrations of .10 mM and above the decrease in G-channel activity is accompanied by an increase in the input resistance of the cell and by the initiation of action potentials. 7. It is concluded that glucose metabolism results in a reduction of G-channel open probability and thereby produces depolarization of the beta-cell.

Action Potentials↗
PubMed1988

The decrease in long-term marrow repopulating capacity seen after transplantation is not the result of irradiation-induced stromal injury.

Marrow cells from nonirradiated F1-W/Wv mice repopulated slightly less well than cells from lethally irradiated recipients. Therefore, avoiding irradiation of recipients did not improve the relative repopulating ability of their marrow cells. In other experiments, F1-W/Wv mice were transplanted by parabiosis with marrow of WBB6F1-+/+ (F1-+/+) mice, avoiding cellular handling and irradiation. Marrow cells transplanted to F1-W/Wv mice by this procedure demonstrated slightly better repopulating ability than did marrow cells transplanted by injection. However, they performed no better than those transplanted by parabiosis to irradiated F1-+/+ recipients. Significant impairment of stromal function after irradiation was not indicated. Apparently, stem cell damage caused by transplantation may have greater importance in causing loss of stem cell replicative potential than effects of irradiation-induced stromal injury.

Animals↗
PubMed1988

Effects of transplantation and age on immunohemopoietic cell growth in the splenic microenvironment.

Intact spleens from young adult and aged mice were transplanted into young recipients to compare effects of age and effects of spleen transplantation on hemopoietic and immune functions. Hemopoietic functions of histocompatible spleen transplants were assessed by partial cures of genetically anemic WBB6F1-Sl/Sld recipients, and immune functions were measured as numbers of anti-SRBC PFC(sheep red blood cell plaque-forming cells) and responses to the mitogen PHA (phytohemagglutinin). Spleens from WCB6F1 and WBB6F1 donors at least 28 months old partially corrected anemias in 10 of 28 Sl/Sld recipients, whereas spleens from 5- to 10-month-old donors performed significantly better, partially correcting anemias in 22 of 31 Sl/Sld recipients. B6D2F1 spleens were transplanted from either old or young donors in B6D2F1 recipients to test their ability to support immune-responsive cells. These spleen grafts were much smaller than recipient spleens and contained few anti-SRBC PFC. In contrast WCB6F1-+/+ spleens transplanted in Sl/Sld recipients were much larger, weighing more than the intact spleens of the recipients. Nevertheless when these spleens were from young donors, they contained only about 10% as many anti-SRBC PFC and PHA-responsive cells as did recipient spleens, whereas old donor spleens contained even fewer. Use of splenectomized Sl/Sld recipients did not alter these results. Apparently the effect of transplantation was much more important than age in reducing the spleens' abilities to support immune-responsive cells.

Aging↗
PubMed1987

A semiquantitative measure of immune responses against erythropoietic stem cell antigens.

A semiquantitative assay was developed and used to measure the effects of immune responses against 16 independent non-H-2 antigenic loci on erythropoietic stem cells. The assay compares repopulation in genetically anemic WBB6F1-W/Wv recipients that have normal immune responses, and in lethally irradiated WBB6F1 +/+ mice whose immune responses are suppressed by the irradiation. The differences in repopulating ability between these two types of recipients measure how immune responses affect erythropoietic stem cells. Stem cell repopulating abilities for the cells with antigens specified by the Thy-1, H-1, H-24, Ly-1, H-37, and H-17 loci were affected slightly, if at all. Repopulating abilities were moderately reduced by responses against antigens specified by H-15, 16, Ea-2, and Ly-2, 3 loci, and against the differences between the B6 and B10 genotypes, although marrow of these types cured W/Wv recipients. A surprising result occurred for the antigen specified by the H-8 locus, in which immune responses strongly reduced repopulating abilities, although this type of marrow cell cured W/Wv recipients. A comparison of these results with skin graft survival times suggests that the antigens specified by the H-17 and H-24 loci are strongly immunogenic on skin but not on marrow stem cells, while those specified by the H-12 and H-8 loci are strongly immunogenic on marrow stem cells but not on skin.

Anemia↗
PubMed1987

Genetic differences in effects of food restriction on aging in mice.

Lifelong food restriction to two-thirds of normal ad libitum consumption extended mean and maximum life spans more than 200 d in male B6CBAF1 hybrid mice, already a long-lived genotype. The following biological systems were improved by food restriction, with values for older mice being similar to those previously found for younger individuals: tight wire clinging, a measure of neuromuscular performance; open field movement, a measure of voluntary activity; tail tendon denaturation rate, a measure of collagen solubility; urine concentrating ability, a measure of renal function, and hair regrowth rate, a measure of the frequency of hair follicle cycling. However, wound healing was slower in food-restricted mice than in ad libitum-fed controls. The same food restriction treatment had entirely different effects on longevities of a different genotype, male B6 (C57BL/6J) mice, reducing mean and maximum life spans 265 and 27 d, respectively. This surprising deleterious effect was not predicted by tests of tight wire clinging, open field movement and tail tendon denaturation, but was predicted by hair regrowth rates, as these were lower in restricted B6 mice than in fed controls. In genetically obese (ob/ob) B6 mice, food restriction extended mean and maximum longevities 327 and 440 d, yet no biological systems tested performed better than those of food-restricted normal (+/+) mice whose life spans were reduced. Thus the food restriction regimen that increased longevities for individuals of two genotypes decreased them for individuals of a third genotype tested in the same set of experiments.

Aging↗