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Enhancement of ascorbate cytotoxicity by chelation with ferrous ions through prolonged duration of the action.

Fe(II)-L-ascorbic acid complex (FeAsc) exhibited a greater cytotoxicity [50% inhibitory dose (IC50), 24-32 microM] to human carcinoma A 549 or rat SV40-transformed W3Y cells than ascorbic acid (Asc) (IC50, 460-660 microM); a simple mixture of Fe(II) and Asc, or Fe(II) alone was also less cytotoxic. Malignant cells from a variety of tissues of different species were also susceptible to FeAsc. FeAsc exhibited a longer half-life (66-82 hours) during cell contact than that of Asc (2.5-3.1 hours). Thus chelated Fe(II) but not unbound Fe (II) was responsible for the enhanced cytotoxicity of FeAsc, which was attributed primarily to its prolonged duration of action.

Animals↗

PubMed1987

[Histologic varieties of adeno-squamous cancer of the endometrium].

Adenosquamous carcinoma of the endometrium combines glandular and squamous cell tumour structures. It is advisable to distinguish well- and poorly differentiated variants of adenosquamous carcinoma (ASC). Well-differentiated ASC is characterized by the intraglandular growth of squamous cell structures in the form of pseudopapillae and has a favourable prognosis (5-year survival rate is 88%). Squamous cell structures of poorly differentiated ASC involve the myometrium in line with the glandular component and this variant has an unfavourable prognosis (5-year survival rate in 45%).

Adenocarcinoma↗

PubMed1985

Adherent stem cells: frequency in mouse marrow and terminal clone sizes in long-term culture.

Adherent stem cells (ASC) are hematopoietic stem cells of the mouse bone marrow that are equivalent to CFU-S in pluripotency (they produce CFU-S) and proliferative ability (they go through up to 25 doublings). They can be assayed in vitro by a limiting dilution overlay technique in which stromal bone marrow long-term cultures serve as underlayers. In this article we estimate the occurrence rates of ASC in fresh and adherent bone marrow cells and report the distribution of population doublings estimated for 152 ASC clones.

Animals↗

PubMed1982

[Role of atypical sex cells in the histogenesis of germinative testicular tumors].

Histochemical and electron microscopic study of 23 germinative tumors of the testicle and organ tissue beyond the tumor was carried out. In 78% of the observations, normal seminiferous tubules were found to contain a special kind of cell elements, atypical sex cells (ASC), not observed in health. Ultrastructural and histochemical features of undifferentiated cells comprising seminoma and embryonal cancer were found to be similar to those of ASC and gonocytes of human embryo. The results suggest that ASC are the stem tumor cells for human germinative neoplasia which are characterized by single cytohistogenesis.

Cell Differentiation↗

PubMed1981

Kinetics of antigen-sensitive cells in the lymphoid organs of rats during allotransplantation reaction.

The kinetics of antigen-sensitive cells in the peripheral blood, spleens, regional lymph nodes, and thymuses of rats was investigated at different time intervals after immunization with allogeneic lymph node cells or after immunization with allogeneic skin or tumour grafts. The lytic effect of the immunizing antigen in vitro was estimated by the percentage of surviving cells after 24 h incubation with the specific antigen prepared from the lymph nodes of graft donors. The percentage of active lymphocytes in individual lymphoid organs of rats immunized with allogenic lymphocyte suspensions was determined by the nucleolar test. Regional lymph node enlargement was evaluated by determining lymph node relative weights and enlargement indices. An immunologically specific enlargement of the regional lymph nodes, increased numbers of ASC and increased percentage of active lymphocytes were seen as early as 24 h after immunization with allogeneic lymph node cells. At this time, the number of ASC in the peripheral blood was reduced and the percentage of active lymphocytes was low. After immunization with allogeneic skin and tumour grafts, ASC were detected first in the peripheral blood, then in the regional lymph nodes as late as 8 days after immunization, and after 10 days in the spleens.

Animals↗

PubMed1980

The transport of neutral amino acids in cultured human fibroblasts.

The transport of neutral amino acids and their interactions for uptake have been studied in skin-derived-diploid human fibroblasts cultured at confluency. Properly timed preincubations in a medium defined in composition and requirements have been adopted to control size of internal amino acid pools and regulatory interferences affecting amino acid transport. L-Proline, L-alanine, and L-leucine were used as natural amino acid substrates. Amino acid uptake and exchange with preaccumulated molecules have been measured under conditions approaching initial entry rates in the absence and in the presence of Na+ and of transport-specific model substrates. Cultured human fibroblasts were found to contain three neutral amino acid transport systems: A, ASC, and L. L-Proline was taken up preferentially by System A. System ASC appeared to mediate the largest fraction of L-Leucine entered the cells mainly by the Na+-independent System L. Preaccumulation of the cells with Site A-reactive amino acids caused trans-inhibition of the activity of System A. The activity of System L was strongly trans-stimulated in cells preloaded with Site L-reactive amino acids. The inward transport of L-alanine was trans-inhibited by internal Site A-reactive amino acids and trans-stimulated by preaccumulated L-alanine exchanging with the external amino acid through the operation of System ASC.

Alanine↗

PubMed1980

Characteristics of an amino acid transport system in rat liver for glutamine, asparagine, histidine, and closely related analogs.

In the rat hepatocyte, whether freshly separated or in primary culture, we do not find L-glutamine entry by Systems A and ASC as seen in cells previously studied. Instead the mediated entry of glutamine appears to occur exclusively by a Na+-dependent system ("N") apparently specific to amino acid amides and L-histidine; however, a portion of asparagine uptake occurs by System A. The simplest evidence for the separateness of the added system is the failure of model substrates for System A (e.g. N-methylalanine) to inhibit glutamine uptake significantly, and the failure of glutamine to inhibit the uptake of L-cysteine, model substrate for System ASC, at least in this cell. As is the case for cysteine, glutamine inhibits transport by System A (although not competitively), even though showing no transport by that system. Our finding confirms an earlier inference that glutamine uptake by this cell may follow a route not taken by alanine or serine, and explains the apparently erroneous companion inference that glutamine also shares a route with these two amino acids. Its uptake has now been characterized to show a series of differences from Systems A and ASC. Especially significant in view of the importance of glutamine metabolism are an insensitivity of the new system to stimulation by either insulin or glucagon, and its distinct enhancement (not as large as that for System A) on starvation of the cells with respect to amino acids. Hence, a second system has been found to show adaptive regulation.

Amino Acids↗

PubMed1995

Phenotypic characterization of circulating antibody-secreting cells after mucosal and systemic immunizations in humans.

We have developed a simple approach for immunophenotyping of functional lymphoid cell subpopulations. Using this approach we have partly characterized circulating antigen-specific ASC after systemic versus mucosal immunization with respect to maturational and activation stages, and to their anatomic commitment(s). Comparative analyses of mucosally versus systemically activated circulating ASC reveal differences with respect not only to utilization of homing receptor molecules but also to certain activation markers, and especially cell surface MHC class II molecules. We have now extended these studies to several other markers including early and late B-cell maturation markers, and we are currently examining whether differential expression of HLA-DQ molecules on the majority of mucosally activated blood ASC may explain the relative inability of these cells to present soluble antigens to class II-restricted T-cells.

Administration, Oral↗

PubMed1994

Levels of hepatocyte growth factor in synovial fluid and serum of patients with rheumatoid arthritis and release of hepatocyte growth factor by rheumatoid synovial fluid cells.

OBJECTIVE: To determine the levels of hepatocyte growth factor (HGF) in synovial fluids (SF) and sera from patients with rheumatoid arthritis (RA); to examine how these correlate with several disease variables in patients with RA and with levels of interleukin-6 (IL-6) in SF of these patients; and to examine whether HGF is released from adherent synovial cells (ASC) and synovial fluid cells (SF cells). METHODS: An enzyme linked immunosorbent assay was used to measure levels of HGF and IL-6. SF samples were obtained from 22 patients with RA, 12 with osteoarthritis (OA), and one with septic arthritis. Serum samples were collected from 40 patients with RA. HGF levels in culture supernatants from ASC and SF cells were measured. RESULTS: The mean values of HGF in SF were 1.21 ng/ml for patients with RA, 0.19 ng/ml for those with OA and 0.18 ng/ml for the one with septic arthritis. HGF levels in SF of patients with RA were significantly higher than of those with OA (p < 0.01). The levels for patients with RA correlated with the serum C-reactive protein concentrations (r = 0.626, p < 0.01) and IL-6 levels in SF (r = 0.476, p < 0.05). The mean value of HGF in sera from patients with RA was 0.28 ng/ml. HGF levels in SF were higher than those in sera drawn simultaneously from the same patients with RA. In vitro, release of HGF from rheumatoid ASC was not detected. However, SF cells from patients with RA released HGF spontaneously. CONCLUSION: Our observations suggest that HGF in SF of patients with RA is produced by SF cells and is related to disease activity of RA, and thus that HGF may play a role in RA.

Adult↗

PubMed1994

Hepatic Na(+)-independent amino acid transport in endotoxemic rats: evidence for selective stimulation of arginine transport.

The effects of endotoxin on the activities of the major Na(+)-independent amino acid transporters in rat liver (Systems n, asc, L, bo,+, and y+) were studied using using hepatic plasma membrane vesicles (HPMVs). Rats were treated with a single dose of Escherichia coli endotoxin (E. coli lipopolysaccharide 0127:B8 (LPS), 7.5, 15, or 30 mg/kg BW) and HPMVs were prepared by Percoll density gradient centrifugation at various timepoints after LPS administration. Vesicle purity and integrity was established by assay of enzyme markers and identical equilibrium uptakes. The activities of the Na(+)-independent amino acid transport systems y+ and bo,+ (arginine), asc (alanine and cysteine), L (leucine), and n (glutamine) were evaluated by measuring the uptake of radiolabeled amino acids using a rapid mixing/filtration technique. Amino acid uptake by HPMVs consisted of saturable and nonsaturable components. Prior treatment with endotoxin did not alter the activities of Systems n, asc, or L but resulted in a time- and dose-dependent stimulation of saturable arginine transport. Arginine transport increased within 2 h of LPS administration and exhibited a return towards basal levels by 24 h. Nonsaturable uptake (diffusion) in HPMVs was unaltered by LPS treatment. Kinetic analysis of arginine transport demonstrated the presence of both a high affinity and a low affinity carrier. Treatment with LPS resulted in a 73% increase in the Vmax of the high affinity carrier (System y+) and a 25% increase in the Vmax of the low affinity transporter (System bo,+). The data indicate selective stimulation of Na(+)-independent arginine transport in the liver during endotoxemia which may serve to support important arginine-dependent pathways during sepsis.

Analysis of Variance↗

PubMed1995

Anti-liver cytosolic antigen type 1 (LC1) antibodies in childhood autoimmune liver disease.

Antibodies to liver cytosol antigen type 1 (anti-LC1), which recognize a 60-kd peptide contained in the liver cytosolic fraction, have been reported to define a subset of autoimmune hepatitis (AIH) either negative for other autoantibodies or positive for anti-liver kidney microsomal antibody type 1 (LKM-1) and to be best detected in immunodiffusion. To analyze the prevalence of anti-LC1 in childhood liver disease, we have tested the sera of 95 patients using immunoblot, indirect immunofluorescence, and immunodiffusion. Fifteen children had smooth muscle antibody (SMA) and/or anti-nuclear antibody (ANA)-positive AIH, 13 had anti-LKM-1-positive AIH, 14 had autoimmune sclerosing cholangitis (ASC) (all SMA and/or ANA positive), and 53 had non-autoimmune liver disease (10 had alpha 1-anti-trypsin deficiency [alpha 1-ATD], 11 had Wilson's disease [WD], 14 had Alagille's syndrome, and 18 had chronic hepatitis B virus [HBV] infection). Twenty healthy children were studied as controls. Anti-LC1 positivity in immunodiffusion and strong reactivity in immunoblot were found in 4 LKM-1- and 2 SMA/ANA-positive patients with AIH and in 1 patient with ASC, but in none of the patients with other liver diseases nor in controls. A weak 60-kd band was detected by immunoblot in 6 more patients with AIH (2 were LKM-1- and 4 were SMA/ANA-positive) and 6 patients with ASC, all anti-LC1-negative by immunofluorescence and immunodiffusion. No distinct clinical features characterized the anti-LC1-positive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

[Psychedelic experiences at the onset of productive episodes of endogenous psychoses].

Hallucinogenic drugs (psychedelics, e.g. Psilocybin, Mescaline, LSD) induce in humans qualitatively altered states of consciousness (ASC), which can be used as experimental models for endogenous psychosis. However, some researchers claim that these ASCs are not appropriate models for schizophrenia. We report two clinical cases of acute endogenous psychoses demonstrating striking similarities to psychedelic experiences. We consider the psychedelic-induced ASC to be an appropriate model for the beginning acute endogenous psychotic episode, but not for the schizophrenic disease as a nosological entity.

Adult↗

PubMed1977

Neutral amino acid transport. Characterization of the A and L systems in isolated rat hepatocytes.

Hepatocytes isolated from adult rat liver by enzymatic dispersion were used to investigate amino acid transport. Steady state and influx experiments were carried out with alpha-amino[1-14C]isobutyric acid and [1-14C]cycloleucine in the presence and absence of sodium under various experimental conditions. Hepatocytes concentrated alpha-aminoisobutyric acid to a 3-fold higher degree than cycloleucine. At low external alpha-aminoisobutyric acid levels (2 to 5 mM), about 25% and 75% of entry were accounted for by nonsaturable and saturable processes, respectively. The nonsaturable component was sodium-independent, and had the properties of passive diffusion. The saturable transport was dependent on external sodium; the rate of transport reached its maximal value with sodium greater than or equal to 75 mM. Sodium increased the apparent Vmax of transport without changing the apparent Km. This component was largely dependent on energy supplies and was strongly reduced at pH less than or equal to 6.5. The value for activation energy (Ea approximately equal to 15 kcal/mol, calculated from the Arrhenius plot) favors a mediated active transport. The Na+-dependent influx of alpha-aminoisobutyric acid was competitively inhibited by N-methyl-alpha-aminoisobutyric acid (Ki approximately equal to 9.3 mM) and alanine (Ki approximately equal to 2 mM) to the extent of 70% and 100%, respectively. The N-methyl-alpha-aminoisobutyric acid-sensitive part of alpha-aminoisobutyric acid influx represents transport through the "A" system, whereas the N-methyl-alpha-aminoisobutyric acid-insensitive part of transport is believed to occur through the "ASC" system. No evidence was obtained to suggest that alpha-aminoisobutyric acid is transported by the "L" system. Cycloleucine transport was a composite phenomenon involving at least two saturable processes, one of which was sodium-dependent and inhibited by alpha-aminoisobutyric acid, and probably represents entry through the A and ASC systems. The sodium-independent component was completely and competitively inhibited by 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (Ki approximately equal to 2 mM). This component exhibited accelerative exchange-diffusion and was pH-insensitive, properties which suggest a facilitated diffusion process. However, the weak inhibition exerted by oligomycin and cyanide along with the concentrative effect observed indicated that uphill transport was also operative. These data are in good agreement with those reported for the L system. We conclude that, as in Ehrlich ascites tumor cells and in embryonic heart cells, the A, ASC, and L systems are operative in isolated hepatocytes for the transport of amino acids.

Amino Acids↗

PubMed1993

Cloning and expression of a novel Na(+)-dependent neutral amino acid transporter structurally related to mammalian Na+/glutamate cotransporters.

A cDNA has been isolated from human hippocampus that appears to encode a novel Na(+)-dependent, Cl(-)-independent, neutral amino acid transporter. The putative protein, designated SATT, is 529 amino acids long and exhibits significant amino acid sequence identity (39-44%) with mammalian L-glutamate transporters. Expression of SATT cDNA in HeLa cells induced stereospecific uptake of L-serine, L-alanine, and L-threonine that was not inhibited by excess (3 mM) 2-(methylamino)-isobutyric acid, a specific substrate for the System A amino acid transporter. SATT expression in HeLa cells did not induce the transport of radiolabeled L-cysteine, L-glutamate, or related dicarboxylates. Northern blot hybridization revealed high levels of SATT mRNA in human skeletal muscle, pancreas, and brain, intermediate levels in heart, and low levels in liver, placenta, lung, and kidney. SATT transport characteristics are similar to the Na(+)-dependent neutral amino acid transport activity designated System ASC, but important differences are noted. These include: 1) SATT's apparent low expression in ASC-containing tissues such as liver or placenta; 2) the lack of mutual inhibition between serine and cysteine; and 3) the lack of trans-stimulation. SATT may represent one of multiple activities that exhibit System ASC-like transport characteristics in diverse tissues and cell lines.

Amino Acid Sequence↗

PubMed1995

Hexachlorobenzene treatment increases the number of splenic B-1-like cells and serum autoantibody levels in the rat.

In the present study, the role of B-1 cells in hexachlorobenzene (HCB)-induced autoimmune aberrations in the Wistar rat was investigated. To that end, male and female rats were exposed to a semi-synthetic diet containing 0 or 1000 mg HCB/kg food for 3 weeks. After dissection, serum was prepared form coagulated blood to determine (auto)antibody levels, and spleens and lymph nodes were isolated and weighed. Cell suspensions were prepared, counted and analysed for B- and T-cell subsets by flow cytometry. Quantification of antibody-secreting cells (ASC) in spleen cell suspensions was done with an ELISPOT assay. Previous findings that HCB treatment induced an increase of relative lymph node and spleen weights and serum (auto)antibody levels were confirmed, while it appeared that numbers of some lymph nodal, and of the splenic large cell populations, were elevated as well. HCB treatment did not change subsets of lymph nodal T and B cells, but elevated the absolute numbers of large splenic CD4+ T cells by about 70%, IgMdull/IgDbright B cells by about 60%, and IgMbright/IgDdull B cells by about 200% cells of control numbers, and the absolute numbers of splenic IgM and IgG (auto) ASC by 300-400% of the control numbers. As splenic IgMbright/IgDdull numbers and ASC numbers correlated with statistical significance, the results indicate that HCB treatment selectively activates rat splenic B-1 cells, which may underlie the elevation of serum autoantibody levels.

Animals↗

PubMed1995

Exercise training generates ascorbate free radical in rat heart.

Exercise generates free radicals and can cause damage to the tissues. This investigation shows the formation of ascorbate radicals during exercise training (ET) which reduce the toxicity of free radicals. Male Fischer-344 rats (n = 8) (77 weeks old) were given exercise training (ET) on a treadmill with a low intensity of exercise that gradually increased from the first to the ninth week resulting in an average increase in respiratory exchange ratio, oxygen consumption rate and heat production. The sedentary control (SC) rats (n = 8) were not exercised and maintained under the same conditions. The heart tissues from different SC and ET rats were analyzed for ascorbate free radical (Asc.-) using electron paramagnetic resonance (EPR). The heart tissue from the ET and not from the SC rat showed the presence of Asc.-. This Asc.- was characterized by an EPR spectrum which showed doublet with a hyperfine coupling constant of 1.89 Gauss (0.189 mT). The benefit of exercise could be attributed to the formation of ascorbate radical in the heart muscle of the old rat. Exercise training can provide protection to the heart tissue against oxidative damage via ascorbate ion and vitamin E.

Animals↗

PubMed1996

[A clinicopathological study of adenosquamous carcinoma of the lung].

We studied, clinicopathologically, 34 cases of adenosquamous carcinoma (ASC) treated in our institution over the last 30 years. Its incidence was 2.3% of all primary lung cancers. Following findings were characteristics to this type of lung cancer, male dominant, old age, heavy smoker, comparatively large diameter, peripheral location, and normal level of tumor makers. The 5-year survival rates were 35.0% for ASC, 38.1% for squamous cell carcinoma (SCC), and 50.2% for adenocarcinoma (AC). The component of SCC was predominant or equal to that of AC in 27 (79.4%) ASC cases. The degree of cell differentiation was moderate and both SCC and AC components showed the same degree of cell differentiation in most cases. Lymph node metastasis was seen in 15 (48.4%) cases.

Aged↗

PubMed1997

Aetiology and outcome of non-traumatic altered states of consciousness in north western Ethiopia.

Awareness of the relative prevalence of diseases causing altered states of consciousness (ASC) in a particular geographic locality could greatly facilitate the approach to patient management. This prospective study has, therefore, evaluated 202 patients with ASC admitted to the medical wards of GCMS teaching hospital in a two year period, between January 1994 and December 1995. ASC was defined as a clinical state manifested by conditions ranging from confusion and disorientation in person, place and time to stupor and deep coma. History, physical examination, limited laboratory tests and course of the patient in the hospital were used to identify the aetiology. There were 122 (60.4%) males and 80 (39.6%) females with male to female ratio of 3:2. Most of the patients, 122 (60.4%), belong to the age group below 40 years and the median age was 33 years (range = 15.84). The median duration of hospital stay was six days (range = 1-90). The commonest cause was infections, 111 (55%) followed by metabolic disorders, 45 (22.3%), structural lesions, 30 (14.9%) and poisoning, seven (3.5%). The aetiology was not identified in nine (4.5%) of the patients. Cerebral malaria was the commonest infectious cause followed by chronic meningitis and/or encephalitis. In hospital mortality rate was 60.4%. Unknown diagnosis, structural neurologic and metabolic causes were associated with increased mortality rate, with p values of 0.002, 0.009 and 0.015, respectively. The same was true for presence of HIV infection, P = 0.02. Since infectious causes are the commonest causes in our series, of which most are treatable with a relatively favourable outcome, critical evaluation for infections and early intervention is recommended. In addition, diagnostic facilities, especially for structural central nervous system lesions has to be improved because successful treatment and prognosis depends on the identification of a specific aetiology.

Adolescent↗