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T A Moore

Publications and source records attributed to T A Moore.

At least 55 records · Page 3Linked to original sources
PubMed1997

Laser-induced fluorescence studies of the biodistribution of carotenoporphyrins in mice.

The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated.

Animals↗
PubMed1996

Inhibition of gamma delta T cell development and early thymocyte maturation in IL-7 -/- mice.

While early thymic T cell precursor populations and their maturational sequence have been recently identified, the signals driving differentiation are unknown. While cytokines may play an integral role in T cell development, various mouse models rendered genetically deficient for specific cytokines do not display abnormalities in T cell development. Recently, we have generated IL-7 -/- mice and reported that IL-7 plays a unique and nonredundant role in lymphopoiesis. These mice displayed a 10- to 20-fold reduction in the total number of T and B cells. Here, we show that IL-7 -/- mice display a sharp reduction in both the frequency and absolute number of adult thymic gamma delta T cells while retaining normal frequencies of alpha beta T cells. This defect in gamma delta T cell production extends to peripheral organs as IL-7 -/- mice are essentially devoid of splenic and intestinal intraepithelial gamma delta T cells. This aberrant phenotype was traced back to impaired fetal gamma delta T cell maturation. In the absence of IL-7, differentiation of immature V gamma 3 low-CD24+ fetal T cells to mature V gamma 3 high CD24- cells is inhibited. In contrast, NK cell maturation appears to be only mildly affected in the absence of IL-7. To further clarify the role of IL-7 in thymic development, detailed analysis of CD3-4-8- thymic precursors was performed. A partial inhibition in the differentiation of CD44+25+ pro-T cells into CD44-25+ pre-T cells was observed. Unexpectedly, the lack of IL-7 resulted in decreased expression of CD117 (c-kit) on both CD4 low and pro-T cells, suggesting that IL-7 may influence the expression of other cytokine receptors involved in early hemopoietic development. Together, these data clarify the developmental abnormalities during T cell development due to the absence of IL-7.

Animals↗
PubMed1996

Murine natural killer cell differentiation: past, present, and future.

Natural killer cells are bone marrow-derived lymphocytes capable of lysing a variety of target cells without prior exposure. While the biological activities and function of mature NK cells have been extensively investigated, the differentiation of NK cells from primitive hematopoietic stem cells is poorly understood. Recently, we have reported on the identification of a highly enriched bone marrow population capable of repopulating recipient mice with mature NK cells. In this review, we will summarize our findings and those of others in an attempt to clarify the current status of murine natural killer cell differentiation.

Allergy and Immunology↗
PubMed1996

Diethylcarbamazine-induced reversal of early lymphatic dysfunction in a patient with bancroftian filariasis: assessment with use of lymphoscintigraphy.

Exposure of expatriates to the infective larvae of Wuchereria bancrofti can result in the early development of signs of lymphatic obstruction. The findings on the clinical presentation of expatriates are distinct from the chronic pathological findings seen among the native population and are similar to the findings in experimentally infected persons. We report the case of a Peace Corps volunteer who developed acute lymphatic dysfunction within 3 months of arriving in an area that was endemic for filariasis. The diagnosis was established clinically and by demonstrating the presence of antibodies to recombinant proteins specific for patients with lymphatic filariasis. Lymphatic flow was markedly abnormal when assessed with use of 99mTc-lymphoscintigraphy. Treatment with diethylcarbamazine reversed both the physical and lymphoscintigraphic abnormalities.

Adult↗
PubMed1995

T-cell lineage commitment and cytokine responses of thymic progenitors.

The earliest steps of intrathymic differentiation recently have been elucidated. It has been reported that both CD4lo (CD44+ CD25- c-kit+ CD3- CD4lo CD8-) and pro-T cells (CD44+ CD25+ c-kit+ CD3- CD4- CD8-, representing the next step in maturation) exhibit germline T-cell receptor beta and gamma loci, suggesting that neither population is exclusively committed to the T-cell lineage. Several groups have shown that CD4lo cells retain the capacity to generate multiple lymphoid lineages in vivo; however, the lineage commitment status of pro-T cells is unknown. To determine when T-cell lineage commitment occurs, we examined the ability of sorted CD4lo and pro-T cells to generate lymphoid lineage cells in vivo or in fetal thymic organ cultures (FTOCs). When intravenously injected into scid mice, CD4lo cells generated both T and B cells, whereas the progeny of pro-T cells contained T cells exclusively. Fetal thymic organ cultures repopulated with CD4lo cells contained both T and natural killer (NK) cells, whereas cultures repopulated with pro-T cells contained T cells almost exclusively. These observations strongly suggest that T-cell lineage commitment occurs during the transition of CD4lo to pro-T cells. Because it is likely that the thymic microenvironment plays a critical role in T-cell commitment, we compared the responses of CD4lo and pro-T cells to various cytokine combinations in vitro, as well as the ability of the cultured cells to repopulate organ cultures. Cytokine combinations that maintained T-cell repopulation potential for both CD4lo and pro-T cells were found. CD4lo cells proliferated best in response to the combination containing interleukin-1 (IL-1), IL-3, IL-6, IL-7, and stem cell factor (SCF). Unlike CD4lo cells, pro-T cells were much more dependent upon IL-7 for proliferation and FTOC repopulation. However, combinations of cytokines lacking IL-7 were found that maintained the T-cell repopulating potential of pro-T cells, suggesting that, whereas this cytokine is clearly very important for normal pro-T cell function, it is not an absolute necessity during early T-cell expansion and differentiation.

Animals↗
PubMed1995

Cytokine production and requirements during T-cell development.

Cytokines have been presumed to play an important role during T-cell development, but until recently formal proof has been missing. Most cytokine-knockout mice show apparently normal intrathymic T-cell development. The exception to this is IL-7, as both IL-7 and IL-7R alpha knockout mice show abnormally low thymic cellularity, making IL-7 the first cytokine shown to be necessary for normal intrathymic T-cell development.

Animals↗
PubMed1994

Imported malaria in the 1990s. A report of 59 cases from Houston, Tex.

OBJECTIVE: To determine the frequency, the clinical features, and the response to therapy of imported malaria that was diagnosed in the 1990s in a major North American city. METHOD: A retrospective case series from Houston, Tex, of 59 cases of imported malaria presenting between January 1990 and April 1993. RESULTS: Malaria was diagnosed in 59 patients, consisting of 12 cases among patients who had acquired the infection while they were living in endemic areas prior to immigration to the United States, 32 cases among US residents who were originally from endemic areas, and 15 cases among patients originally from North America or Europe. Only 12 patients had received malarial prophylaxis: eight with chloroquine, one with chloroquine and chloroguanide (proguanil), two with chloroquine and primaquine, and one with mefloquine taken intermittently. Eight presented with Plasmodium falciparum infection after receiving chloroquine, and one, after receiving chloroquine and chloroguanide. Two presented with malaria caused by Plasmodium vivax despite receiving chloroquine and primaquine as prophylaxis. In 25 cases, malaria was not considered as an initial diagnosis. Five patients presented with severe disease (three with severe hemolysis, two each with cerebral malaria and renal failure, and one with adult respiratory distress syndrome). Four of the five had initially received a misdiagnosis. Two patients died despite treatment with intravenous quinidine and exchange transfusions. Two patients with P vivax infection had multiple relapses despite courses of chloroquine and primaquine. Six patients were pregnant (including one with a fatal case), one congenital infection was identified. Six patients had not traveled outside of the United States in over 1 year. CONCLUSION: Imported malaria occurs frequently and usually results from the failure to use appropriate prophylaxis. Delayed diagnosis and misdiagnosis are common. Severe disease and fatal cases continue to be seen despite aggressive treatment. Drug resistance has continued to spread and now occurs with P vivax as well as P falciparum.

Adult↗
PubMed1994

Laser-induced fluorescence in malignant and normal tissue in mice injected with two different carotenoporphyrins.

Laser-induced fluorescence (LIF) was used to characterise the localisation of an intravenously administered trimethylated carotenoporphyrin [CP(Me)3] and a trimethoxylated carotenoporphyrin [CP(OMe)3] in an intramuscularly transplanted malignant tumour (MS-2 fibrosarcoma) and healthy muscle in female Balb/c mice, 3, 24, 48 and 96 h post injection. The fluorescence was induced with a dye laser pumped by a nitrogen laser, emitting light at 425 nm. The fluorescence spectra were recorded in the region 455-760 nm using a polychromator equipped with an image-intensified CCD camera. The tumour/peritumoral muscle ratio was about 5:1 for CP(Me)3 and about 6:1 for CP(OMe)3 in terms of the background-free fluorescence intensity, which peaked at about 655 nm. By including the endogenous tissue fluorescence, the contrast was further enhanced by a factor of approximately 2.

Animals↗
PubMed1994

Carotenoporphyrins as selective photodiagnostic agents for tumours.

The covalent binding of a carotene moiety to one phenyl ring and meso-tetraphenyl-substituted porphyrins (see Figure 1) efficiently quenches the photosensitising activity of the porphyrin while a relatively large yield of fluorescence emission around 650 nm is retained. Pharmacokinetic studies performed with two carotenoporphyrins (CPs) and the corresponding porphyrins (Ps) in Balb/c mice bearing an MS-2 fibrosarcoma show that the two Ps give a high selectivity of tumour localisation (tumour/peritumoral tissue ratios of dye concentration ranging between c. 30 and 90 at 24 h after injection of 4.2-8.4 mumol kg-1 in a Cremophor emulsion) and photosensitive tumour necrosis upon red light irradiation. For the same injected doses, the two CPs show no tumour-photosensitising activity even though they localise in the tumour in concentrations of the order of 10-40 micrograms g-1 at 24 h with tumour/peritumoral ratios larger than 10. Thus, the fluorescence emitted by these CPs in the tumour can be used for photodiagnostic purposes with no risk of skin photosensitisation. However, this approach is presently limited by the large accumulation and prolonged retention of the CPs in the liver and spleen.

Animals↗
PubMed1994

Expression of CZ-1: a CD45RB epitope on progenitors of natural killer and other haematopoietic cells.

CZ-1 is a novel sialic acid-dependent epitope of the murine CD45RB molecule which is expressed on cells that proliferate when cultured in IL-2. Because IL-2 appears to be important in the differentiation of NK cells, the authors examined the expression of CZ-1 on immature NK-lineage cells within the bone marrow. All mature NK1.1+ cells as well as their NK1.1- IL-2 responsive precursors were CZ-1+. Furthermore, IL-2 unresponsive transplantable NK progenitor cells expressed CZ-1 also. To examine expression of CZ-1 on other immature lymphoid progenitor cells, CZ-1+ and CZ-1- marrow cells were transplanted into lightly irradiated scid mice. Transfer of CZ-1+ cells resulted in rapid and sustained generation of thymocytes and splenic B cells, whereas CZ-1- cells caused delayed repopulation. This suggested that the slowly repopulating pluripotent stem cells lacked CZ-1. Therefore, expression of CZ-1 on Ly6+ Lin- c-kit+ cells, highly enriched for pluripotent stem cells, was examined. This population appeared to be homogeneously CZ-1dull. Thus, it appears that expression of CZ-1 is developmentally regulated, with differentiation associated with increased expression. Since CZ-1 is expressed on a protein tyrosine phosphatase, it is likely that this molecule regulates differentiation of NK and other lymphoid cells.

Animals↗
PubMed1993

The photophysics of monomeric bacteriochlorophylls c and d and their derivatives: properties of the triplet state and singlet oxygen photogeneration and quenching.

Measurements of pigment triplet-triplet absorption, pigment phosphorescence and photosensitized singlet oxygen luminescence were carried out on solutions containing monomeric bacteriochlorophylls (Bchl) c and d, isolated from green photosynthetic bacteria, and their magnesium-free and farnesyl-free analogs. The energies of the pigment triplet states fell in the range 1.29-1.34 eV. The triplet lifetimes in aerobic solutions were 200-250 ns; they increased to 280 +/- 70 microseconds after nitrogen purging in liquid solutions and to 0.7-2.1 ms in a solid matrix at ambient or liquid nitrogen temperatures. Rate constants for quenching of the pigment triplet state by oxygen were (2.0-2.5) x 10(9) M-1 s-1, which is close to 1/9 of the rate constant for diffusion-controlled reactions. This quenching was accompanied by singlet oxygen formation. The quantum yields for the triplet state formation and singlet oxygen production were 55-75% in air-saturated solutions. Singlet oxygen quenching by ground-state pigment molecules was observed. Quenching was the most efficient for magnesium-containing pigments, kq = (0.31-1.2) x 10(9) M-1 s-1. It is caused mainly by a physical process of singlet oxygen (1O2) deactivation. Thus, Bchl c and d and their derivatives, as well as chlorophyll and Bchl a, combine a high efficiency of singlet oxygen production with the ability to protect photochemical and photobiological systems against damage by singlet oxygen.

Bacteria↗
PubMed1991

Inhibition of murine natural killer cell differentiation by dehydroepiandrosterone.

Dehydroepiandrosterone (DHEA) is a naturally occurring steroid. We have previously shown that dietary DHEA (0.45% wt/wt) inhibits murine lymphopoiesis but not myelopoiesis. To assess the effect of DHEA on stages of natural killer (NK) cell differentiation, lethally irradiated mice fed DHEA or not were infused with 10(6) or 20 x 10(6) syngeneic bone marrow cells (BMC) as a source of transplantable NK cell progenitors. The differentiation of progenitor cells to lytic NK cells was assessed by the ability to clear radiolabeled YAC-1 tumor cells from the lungs. DHEA-fed recipients of 10(6) or 20 x 10(6) BMC failed to generate NK activity. Because NK progenitor cells are believed to differentiate into interleukin-2 (IL-2)-responsive precursor cells before maturation, BMC from recipient mice were cultured with IL-2 and the generation of NK cells was assessed. DHEA feeding prevented the generation of IL-2-responsive precursor cells in recipients of 10(6) BMC, but this inhibition was overcome in recipients of 20 x 10(6) BMC. To evaluate the capacity of stem cells to generate NK progenitor cells in DHEA-fed mice, the ability of marrow cells from primary recipients to generate NK activity in irradiated secondary recipients was determined. The production of NK progenitors was inhibited 20-fold. Thus, DHEA appears to inhibit the generation of NK progenitors from more primitive stem cells, the differentiation of progenitors into IL-2-responsive precursors cells and the maturation of IL-2-responsive precursor cells into mature NK cells.

Animals↗
PubMed1991

Analysis of rat brain microdialysate by gas chromatography-high-resolution selected-ion monitoring mass spectrometry.

Gas chromatography-high-resolution selected-ion monitoring mass spectrometry was used to analyze catecholamine metabolites in rat brain microdialysate. Dialysate samples were collected in vials containing stable isotope analogues of homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG) and 5-hydroxyindoleacetic acid (5HIAA) and analyzed as their trimethylsilyl derivatives. The metabolite levels were monitored at 20-min intervals throughout the time course of the experiment, beginning immediately after surgery and implantation of the dialysis probe and ending 4 h after amphetamine treatment. The levels of HVA were observed to decrease after amphetamine treatment, while those of MHPG and 5HIAA did not change significantly.

Amphetamine↗
PubMed1990

Analysis of the primary signals required for activation of the mitogenic pathway in murine thymocytes from protein phosphorylation patterns.

It has been proposed that phorbol esters and the Ca2+ ionophore A23187 are effective comitogens for some species of lymphocytes because together they mimic the normal secondary signals for cell activation by mitogens that cause phosphatidylinositol 4,5-bisphosphate (PtdInsP2) breakdown (e.g., anti-TCR and anti-Thy-1 antibodies and Con A). To test whether activation of protein kinase C and an increase in [Ca2+]i account for the activation of the mitogenic pathway in murine thymocytes by the mitogens that cause PtdInsP2 breakdown, the two-dimensional phosphorylation patterns generated by the three classes of mitogens (protein kinase C activator, Ca2+ ionophore, and activator of PtdInsP2 breakdown) and by activators of cAMP-dependent kinases have been compared. From the phosphorylation patterns, by which each mitogen could be distinguished reproducibly, it was concluded that: 1) The phosphorylation patterns generated by the mitogens that activate PtdInsP2 breakdown are only slightly affected by the removal of extracellular Ca2+ under conditions that abolish the normal rise in [Ca2+]i and do not therefore depend on the activation of Ca2(+)-dependent protein kinases. In contrast, the phosphorylation pattern generated by A23187 is totally dependent on extracellular Ca2+. 2) Neither A23187 nor the mitogens that activate PtdInsP2 breakdown nor activators of cAMP-dependent kinases caused significant activation of protein kinase C assayed by phosphorylation of the diagnostic proteins 80b and 78a. Consistent with this conclusion, only the phorbol esters or oleoyl acyl glycerol caused translocation of protein kinase C activity from the cytosolic to the membrane fraction. 3) Neither A23187 nor the mitogens that cause PtdInsP2 breakdown activated cAMP-dependent kinases. Taken together the data imply that the mitogens that cause PtdInsP2 breakdown must generate an additional, independent primary mitogenic signal. It is suggested that this signal may be the activation of tyrosine kinases (e.g., p56lck) via the TCR and working hypotheses for effective combinations of primary mitogenic signals that will activate DNA synthesis are developed.

Animals↗
PubMed1990

The use of laboratory microcomputers to hold NMR data bases.

Computer-based data bases are essential tools for NMR spectroscopists working with complex mixtures such as tissue extracts. Algorithms are described which are easily implemented on a small laboratory microcomputer and which can be used to make, edit, and query personalized laboratory data files. The data are stored in a series of small files accessed by pointers to overcome inherent redundancy in the information. Performance times are tabulated for a BBC Model B microcomputer working in the BASIC language and using 5.25-in. floppy discs as virtual memory.

Algorithms↗
PubMed1990

Photophysical properties of 2-nitro-5,10,15,20-tetra-p-tolylporphyrins.

Tetraarylporphyrins substituted with nitro groups at beta-pyrrolic positions are potential candidates for electron-accepting pigments in model systems for photosynthesis. The photophysics of 2-nitro-5,10,15,20-tetra-p-tolylporphyrin and its zinc analog have been studied in order to evaluate this potential. The ground state absorption spectrum, the triplet-triplet absorption spectrum, the fluorescence emission spectrum, and associated photophysical parameters have been determined. The molecules have short singlet lifetimes and anomalous temperature- and solvent-dependent emission spectra which are consistent with the formation of an intramolecular charge transfer state of the type P+.-NO2-. in which the nitro group is twisted about its bond to the porphyrin, relative to the ground state conformation.

Molecular Structure↗