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PubMed1989

Hematotoxicity and carcinogenicity of inhaled benzene.

CBA/Ca male mice have been exposed to benzene in air at 10, 25, 100, 300, 400, and 3000 ppm for variable intervals 6 hr/day, 5 days/week for up to 16 weeks. Two weeks of inhaling 10 ppm produced no hematologic effects; 25 ppm induced a significant lymphopenia. Inhalation of 100, 300, and 400 ppm produced dose-dependent decreases in blood lymphocytes, bone marrow cellularity, marrow content of spleen colony-forming units (CFU-S) and an increased fraction of CFU-S in DNA synthesis. Exposure of mice to 300 ppm for 2, 4, 8, and 16 weeks produced severe lymphopenia and decrease in marrow CFU-S. Recovery was rapid and complete after 2 and 4 weeks of exposure. After 8 and 16 weeks of exposure, recovery of lymphocytes was complete within 8 weeks. It took 16 weeks for the CFU-S to recover to that of the age-matched controls after 8 weeks of exposure and 25 weeks to recover to age-matched after 16 weeks of exposure. Inhalation of 3000 ppm for 8 days was less damaging than inhalation of 300 ppm for 80 days (same integral amount of benzene inhaled). The inhalation of 3000 ppm has not increased the incidence of leukemia or shortened its latency for development. Inhalation of 300 ppm 6 hr/day for 16 weeks significantly increases the incidence of myelogenous neoplasms in male CBA/Ca mice. Inhalation of 100 ppm for same interval does not influence incidence of myelogenous neoplasms but does increase incidence of solid neoplasms particularly in female CBA/Ca mice. Benzene is a potent carcinogen in CBA/Ca mice.

Administration, Inhalation↗

PubMed1996

Hydroquinone stimulates granulocyte-macrophage progenitor cells in vitro and in vivo.

To investigate whether hydroxylated metabolites of benzene may be responsible for the amplification of granulocyte-macrophage progenitor cells (GM-CFC) observed in mice that inhale benzene, groups of six C57BL6 mice were injected with hydroquinone (HQ) (75 mg/kg) or HQ (50 mg/kg) plus phenol (PHE) (50 mg/kg) twice daily for 11 days. Deviations in blood leukocyte and erythrocyte levels by up to one-third were noted in the treated groups; however, the peripheral blood differential counts were unchanged. Although no changes in bone marrow cellularity were observed in mice treated with HQ, cellularity was decreased by a factor of two in the mice that had received HQ plus PHE. The number of GM-CFC per femur was doubled in both treated groups. In vitro experiments using the murine multipotent hematopoietic progenitor cells FDCP mix also showed a duplication of GM-CFC formation in the presence of HQ at concentrations between 10(-6) M and 10(-10) M. When HQ and PHE were present at equimolar concentrations, significantly increased colony formation was still observed with 10(-12) M of metabolites. The effect was independent of the concentration of GM-colony-stimulating factor used. We suggest that HQ is a major mediator of the stimulatory effect of benzene on GM-CFC in mice. In addition, the in vitro data indicate that a direct effect of GM-CFC is involved.

Animals↗

PubMed2001

Pharmacokinetic interactions augment toxicities of sirolimus/cyclosporine combinations.

This study correlated the dynamic effects of sirolimus (rapamycin; RAPA) and cyclosporine (CsA) alone versus in combination to produce renal dysfunction, myelosuppression, or hyperlipidemia, with their corresponding blood and tissue concentrations. After salt-depleted rats were treated with RAPA (0.4 to 6.4 mg/kg per d) and/or CsA (2.5 to 20.0 mg/kg per d) for 14 d, the GFR, lipid levels, bone marrow cellularity, and CsA/RAPA concentrations in whole blood versus liver or renal tissues were measured, and the median effect model was used to discern the type of drug interactions. Compared with vehicle controls (1.98 +/- 0.34 ml/min), GFR values were reduced only by large doses of drug monotherapy, namely RAPA (3.2 mg/kg per d = 1.2 +/- 0.02 ml/min or 6.4 mg/kg per d = 1.3 +/- 0.2 ml/min; both P < 0.01) or CsA (10.0 mg/kg per d = 1.2 +/- 0.1 ml/min or 20.0 mg/kg per d = 0.8 +/- 0.4 ml/min; both P < 0.01). In contrast, hosts that were treated with smaller doses of CsA/RAPA combinations showed more pronounced effects in reduction of GFR values: 2.5/0.4 mg/kg per d, modestly (1.5 +/- 0.5 ml/min; P < 0.01); 5.0/0.8 mg/kg per d, moderately (0.23 +/- 0.01 ml/min; P < 0.001); and higher-dose groups, markedly. The exacerbation of renal dysfunction seemed to be due to a pharmacokinetic interaction of RAPA to greatly increase CsA concentrations in whole blood and, particularly, in kidney tissue. In contrast, the pharmacodynamic effects of CsA to potentiate two RAPA-mediated toxicities-myelosuppression and increased serum cholesterol/low-density lipoprotein cholesterol-occurred independently of pharmacokinetic interactions. RAPA aggravates CsA-induced renal dysfunction owing to a pharmacokinetic interaction, whereas CsA produces a pharmacodynamic effect that augments RAPA-induced myelosuppression and hyperlipidemia.

Animals↗

PubMed2005

Periodontal treatment in severe aplastic anemia.

BACKGROUND: Aplastic anemia (AA) is a rare hematologic disease characterized by hypo-cellular bone marrow. The clinical features include fatigue, increased bruising, and gingival bleeding caused by anemia, leukopenia, and thrombocytopenia. A patient with AA is at high risk for infection because of leukopenia. The risk of systemic infection is especially high in AA patients with severe local infections, including periodontitis. Accordingly, periodontal treatment should include antibiotic prophylaxis to reduce the risk of systemic infection. However, treatment of periodontitis in the AA patient is significantly complicated by the bleeding disorder. We present a case report of the successful periodontal treatment of an AA patient with spontaneous gingival bleeding. METHODS: The patient was closely monitored for platelet and neutrophil counts before every treatment. The patient's platelet count was always under 10,000/microl. Therefore, it was necessary to increase platelet counts to over 25,000/microl by transfusion, after which subgingival scaling with anesthesia was performed. When the neutrophil count was less than 2,000/microl, local minocycline chemotherapy was applied to the pockets. Periodontal infection was monitored by detection of bacterial DNA and measurement of serum immunoglobulin (Ig) G titer against periodontal bacteria. RESULTS: Following the physical and chemical treatment, the gingival appearance improved dramatically and the spontaneous gingival bleeding disappeared. Moreover, the IgG titer against periodontal bacteria decreased to normal range and specific periodontal pathogens were no longer detectable in the tested pockets. CONCLUSION: We believe that the treatment strategy in the present report provides new sight into treatment planning for severely medically compromised patients.

Adult↗

PubMedDate not supplied

Enhancement of hemopoietic recovery by indomethacin after sublethal whole-body gamma irradiation.

The effect of the non-steroid anti-inflammatory drug, indomethacin, a potent prostaglandin synthesis inhibitor, on the recovery of hemopoiesis was investigated in sublethally gamma irradiated mice. Treatment with indomethacin after irradiation was found to increase the granulocyte and lymphocyte counts in peripheral blood. Furthermore, an increased rate of the restitution of bone marrow cellularity and of the spleen weight was observed. Using the method of 125iodo-deoxyuridine uptake in the spleen, the ability of indomethacin to potentiate cell proliferation was demonstrated.

Animals↗

PubMed1980

Syndromes with increased red cell glutathione (GSH).

GSH, the most abundant erythrocyte thiol, is synthesized from its constituent amino acids by two ATP-dependent enzymes present in the mature red cell. Its unusual gamma-glutamyl linkage precludes degradation by any known red cell peptidase. The erythrocyte lacks a complete "gamma-glutamyl cycle" as described by Meister. GSH has important enzymatic and non-enzymatic roles in oxidoreduction reactions. As the specific co-factor of glutathione peroxidase, it participates in the reduction of harmful organoperoxides. Oxidized glutathione is reconverted to GSH via NADPH-dependent, glutathione reductase. NADPH in the red cell is generated solely by the two dehydrogenases of the pentosephosphate shunt. Increased GSH concentrations are normally present in neonatal erythrocytes. For reasons not clear, they are an epiphenomenon in inherited pyrimidine 5'-nucleotidase deficiency. Many syndromes of heterogeneous etiology having in common dyserythropoietic anemia and ineffective erythropoiesis despite a cellular bone marrow also exhibit abnormally high concentrations of red cell GSH as one component of a constellation of metabolic abnormalities. In a single patient with the Lesch-Nyhan syndrome studied by us, erythrocyte GSH was increased. A kindred with dominantly transmitted (or possibly x-chromosome linked) hereditary hemolytic anemia in which the only thus far detected abnormality is increased red cell GSH has also been documented. The fundamental molecular lesion in this syndrome is unknown.

Anemia, Hemolytic↗

PubMed1992

The modulatory hematopoietic activities of leukemia inhibitory factor.

Leukemia inhibitory factor (LIF) is a multi-potential cytokine which has been implicated in the hematopoietic regulatory machinery. For example, we have found that LIF is constitutively expressed in marrow stroma. Other investigators have reported that LIF affects remodeling of bone, and that, in concert with other growth factors, it stimulates hematopoietic stem cell proliferation. Moreover, in vivo animal trials reveal that, at high doses, administration of LIF induces myelosclerosis whereas, at lower doses, megakaryocytosis and thrombocytosis with reduced bone marrow cellularity and marrow lymphopenia are observed. Therefore, the role of LIF in the pathogenesis of myeloproliferative disorders such as myelofibrosis and sclerosis merits investigation. Further, its megakaryocytic stimulatory properties suggest that LIF may be exploitable in the clinic to enhance platelet production.

Animals↗

PubMed1994

Low-dose ara-C in myelodysplastic syndromes (MDS) and acute leukemia following MDS: proposal for a predictive model.

Patients with myelodysplastic syndromes (MDS) comprise an extremely heterogeneous group. There is a need for decision models both for predicting the natural course of the disease and the outcomes of different treatment alternatives. In 102 consecutive patients with MDS or acute myelogenous leukemia (AML) following MDS, pre-treatment variables were studied in relation to the response to treatment with low-dose ara-C. Thirty patients (29%) responded with either a complete remission or a significant rise in the hemoglobin level. For the remaining 71%, the treatment was ineffective and in some cases hazardous. The factors associated with a poor response to treatment could be divided into two groups: one included low platelet counts and the presence of chromosomal aberrations, both signs of progressive MDS with a short survival, and the other comprised morphological findings, indicating ineffective hemopoiesis. Patients with platelet counts > 150 x 10(9)/l had a response rate of 55%, compared to 24% in patients with subnormal platelet counts. Logistic regression identified low bone marrow cellularity, absence of ring sideroblasts and < 2 chromosomal aberrations as predictors of a favourable response in patients with platelet counts < 150 x 10(9)/l. These factors and the platelet count were combined in a predictive model which divided patients into three groups with different probabilities of response: one favourable (38% of the patients), with a response rate of > 50%; a second, intermediate group (33% of the patients), with a response rate of 24%; and a third, unfavourable group (29% of the patients) with only 3% responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1995

Low-dose cytosine arabinoside in patients with acute myeloid leukemia not eligible for standard chemotherapy.

The results of treatment with low dose cytosine arabinoside (LDARA-C) in 131 AML patients ineligible for standard regimens were analyzed retrospectively. Eighty-seven were previously untreated, 25 were refractory to conventional chemotherapy and 19 were relapsed patients. The median age was 66 years (15-84). An antecedent hematological disorder (AHD) was documented in half of the patients. Overall, 22 (17%) achieved complete remission, 14 (11%) partial remission, 77 (59%) had resistant leukemia and 18 died during induction. Median disease free survival was 57 weeks and median survival, for the 87 previously untreated patients, was 22.5 weeks. The prognostic value of initial parameters was analyzed for response. Bone marrow cellularity was the only significant factor. We observed 33% vs 81% (p < 0.01) of responses in patients with normo-hypercellular and hypocellular marrow, respectively. Accordingly, there was a trend to more responses in patients with leukocyte counts of less than 10 x 10(9)/L. M4-M5 FAB subtypes were frequently resistant to LDARA-C, resulting in a lower response rate compared to M0-M2 (18% vs 32%). Other parameters, including age, sex, hemoglobin, platelet count, AHD and fever at diagnosis, had no prognostic value. Our findings suggest that LDARA-C may be an effective treatment for some patients who are not eligible for first line conventional chemotherapy. However, this schedule is not advised in patients with monocytic leukemia or those with an hypercellular marrow.

Acute Disease↗

PubMed1997

Excessive proliferation matched by excessive apoptosis in myelodysplastic syndromes: the cause-effect relationship.

The paradox of pancytopenia despite cellular bone marrows (BM) was investigated in 120 patients with myelodysplastic syndromes (MDS). Detailed cell cycle kinetics were examined following in vivo infusions of iodo--and/or bromodeoxyuridine (IUdR/BrdU), while the incidence of apoptosis was measured by in situ end labeling (ISEL) of fragmented DNA. Results showed that MDS are highly proliferative disorders with an equally high incidence of apoptotic intramedullary cell death accounting for the paradox of cellularity/cytopenia. By double-labeling BM biopsy sections for ISEL/BrdU we found the peculiar situation of "signal antonymy" where S-phase cells were frequently apoptotic, a phenomenon so far only seen in MDS biopsies. The cause-effect relationship of this excessive proliferation/apoptosis is discussed at length.

Apoptosis↗

PubMedDate not supplied

Randomized study of dose or schedule modification of granulocyte colony-stimulating factor in platinum-based chemotherapy for elderly patients with lung cancer.

It is generally believed that elderly patients are less able to tolerate aggressive cancer chemotherapy than their younger counterparts. Bone marrow cellularity diminishes with age and elderly patients may have decreased tolerance to myelosuppressive agents. Between November 1995 and October 1999, 68 chemotherapy-naive elderly (70 or more years old) patients with histologically or cytologically proven lung cancer who were to receive platinum-based chemotherapy were enrolled in this study. All patients had adequate cardiac, hematological, liver and renal function to receive chemotherapy. Patients were randomized into 3 groups. Patients in groups 1 and 2 received 2 microg/kg and 4 microg/kg granulocyte colony-stimulating factor (G-CSF, lenograstim), respectively, when grade 3 leukopenia (<2,000/microl) or neutropenia (<1,000/microl) appeared after chemotherapy. Patients in group 3 received 2 microg/kg G-CSF when grade 2 leukopenia (<3,000/microl) or neutropenia (<1,500/microl) appeared after chemotherapy. G-CSF was stopped in all groups when the leukocyte count increased to over 10,000/microl or the neutrophil count exceeded 5,000/microl. Full blood cell counts were examined 3 times a week after chemotherapy. All patients received platinum-based chemotherapy. Eighteen, 16 and 22 patients (78%, 73% and 96%) in groups 1, 2 and 3, respectively, received G-CSF when leukopenia or neutropenia appeared. The durations of G-CSF treatment required by groups 1 and 3 (5.7+/-3.6 and 6.6+/-3.2 days, respectively) did not differ significantly, but the duration of treatment required by group 2 (3.7+/-2.8 days) was significantly shorter than that of group 1 (p=0.048). The duration of grade 4 neutropenia in group 2 (0.7+/-1.1 days) was marginally shorter than that in group 1 (1.6+/-2.1 days, p=0.076). The neutrophil nadir of group 2 (949+/-757/microl) was marginally higher than that of group 1 (592+/-438/microl, p=0.058). No patients in group 2 experienced grade 4 neutropenia for 4 days or more or a neutrophil nadir less than 100/microl a significant difference from group 1, where 22% and 17% of patients experienced these events (p=0.02 and p=0.04, respectively). Similarly, no infections requiring antibiotics after chemotherapy occurred in patients in group 2, a significant difference from group 1 (26%, p=0.01). The rates of neutropenia and infection in groups 1 and 3 did not differ significantly. The peak plasma concentration of G-CSF in group 2 was significantly higher than in group 1 (p=0.0018), but did not differ significantly between groups 1 and 3. Doubling the dose of G-CSF could help to decrease neutropenia and prevent infection after chemotherapy in elderly patients with lung cancer.

Aged↗

PubMed2004

Megadose CD34+ hemopoietic stem cell transplantation for patients with high risk acute myeloid leukemia who have no HLA matched donor--a pilot study of a full haplotype mismatch transplantation.

BACKGROUND: Haploidentical transplantation has become a popular modality of treatment for acute myeloid leukemia (AML) patients lacking donors with matching HLA. We attempted to assess the success rate and ramifications of full haplotype mismatch transplantation. METHODS: Four patients received stem cell transplantation from their full haplotype mismatched family donors. The conditioning regimen included total-body irradiation, intravenous busulfan, antithymocyte globulin, and fludarabine. Megadose CD34+ stem cell transplants were performed, in a dosage range between 10.9 x 10(6)/kg and 20.6 x10(6)/kg. Neither GvHD prophylaxis nor post-transplant G-CSF were administered. We monitored patients' bone marrow cellularity and peripheral blood chimerism using real-time PCR. RESULTS: All patients evidenced stable engraftment. The most frequent side effect was severe mucositis, but all patients recovered successfully, without early death. No patients exhibited acute GvHD. Two refractory patients relapsed soon after transplantation. The other 2 patients have remained in good clinical condition, with a follow-up duration of 1-4 months. CONCLUSION: Using a newly-developed conditioning regimen, we were able to circumvent GvHD and graft failure, which are the main limitations associated with full haplotype mismatch transplantation. According to our analysis of the relevant literature, it appears that this is the first report of such a conditioning regimen.

Adolescent↗

PubMed1983

Junin virus infection of Callithrix jacchus: pathologic features.

Infection of Callithrix jacchus, a New World primate, with the prototype strain of Junin virus produced a severe disease. The animals developed multifocal hemorrhages and characteristic microscopic lesions such as meningoencephalitis, interstitial pneumonia, lymphocytic depletion of lymphatic tissue, hepatocytic necrosis, and a variable decrease in bone marrow cellularity. High virus concentrations correlated with lesions, and with the presence of viral antigenic determinants as revealed by immunofluorescent methods. With the exception of central nervous system damage, the morphological features and immunohistochemical and viral findings were similar to those recorded in human Argentine hemorrhagic fever.

Animals↗

PubMed1976

Histological studies on early changes of the hamster gingival epithelium by N-nitrosomethylurea.

The effect of repeated intragastric administration of N-nitrosomethylurea on the molar gingival epithelium of the hamster was investigated both higtologically and histoautoradiographically. Thickening and downward proliferation of the gingival epithelium were evident from the second month of the treatment, in the attachment epithelium and interdental epithelium. Subsequently, the apical part of the crevicular epithelium, epithelium of the oral aspect of the gingiva, and the marginal crevicular epithelium thickened. About three months after the beginning of the administration, thickening, hyperkeratosis, and downward proliferation of the gingival epithelium were widespreas and proliferated epithelial cell nests were parakeratotic, often assuming a structure of keratotic cyst, which invaded the periodontium, accompanied with compressive resorption of the alveolar bone and involvement of bone marrows. Cellular atypia appeared three months after the first treatment, occasionally suggesting early malignancy. Epithelial proliferation was generally not accompanied with any distinct inflammatory change. In the autoradiographic analysis, it was clearly noticed that labeled cells had increased in each epithelial zone before the histological changes became evident- The results of the present experiment were discussed in reference to the pathogenesis of gingival carcinoma.

Animals↗

PubMed2001

[Regeneration of the immune system after bone marrow transplantation].

After haematopoietic stem cell transplantation, reconstitution of bone marrow consists of two distinct phenomena, numerical recovery of bone marrow cellular elements on the one hand and functional recovery of cellular interactions on the other. Immune reactivity during the first month postgrafting is extremely low. Cytotoxic and phagocytic functions usually recover by day 100, while more specialized and cooperative functions of T and B cells remain impaired up to one year or more postgrafting. Regeneration of total CD4+ T cell number in adult (and especially in elderly) transplant recipients is severely limited and occurs largely by peripheral expansion of mature CD4+ T cells. While restoration of total CD8+ T cell number is commonly seen in adults, potentially important alterations in the subset composition of CD8+ populations remain. Contracted T cell repertoires for CD4+ and CD8+ T cells are consistently found in adults after T cell regeneration. This suggests that thymic function is frequently limiting in adults and that thymic-independent pathways are insufficient for restoring host immunocompetence. Although there are similarities in immune reconstitution after alllo- and autologous haematopoietic stem cell transplantations, allogeneic transplantation involves graft versus host disease and the use of immunosuppressive therapy to control it, both of which further interfere in the early developmental stages of immune reconstitution.

Animals↗

PubMed1976

Oxymetholone treatment in aregenerative anaemia. II. Remission and survival--a prospective study.

This is a prospective multi-center study in which patients with aregenerative anaemia were treated with a standardized high dosage regime of an anabolic steroid (oxymetholone, Anasteron). 53 patients were included and divided into two groups according to bone marrow cellularity. Furthermore the hypocellular group was subdivided in order to make comparison with earlier studies possible. In the hypocellular group, the frequency of remission was 56% and the 2-year-survival from the onset of symptoms was 75%. This is longer than in some earlier studies, perhaps because of possible differences in etiology and/or because of the effect of systematic high dosage, long term androgen therapy. Patient selection was minimized and was not considered to be of major importance. Patients with hypercellular marrows, on the other hand, responded poorly to androgens. In this group 63% died of acute leukaemia, which confirms earlier suggestions that this form of aregenerative anaemia, frequently is of a preleukaemic nature.

Adolescent↗

PubMed2004

[Extramembranous glomerulonephritis and myelodysplastic syndrome].

Membranous glomerulonephritis (MGN) is the main cause of nephrotic syndrome in adults and is usually idiopathic. We report a case of nephrotic MGN associated with a myelodysplastic syndrome (MDS) in a 43 year old man. The initial treatment consisted of oral corticosteroids (1 mg/kg/day). Within 3 months proteinuria decreased from 22.4 g/day to 3.96 g/day and the blood cell count was normalized. Renal biopsy disclosed type I MGN. Ponticelli's protocol was started with a favorable effect: negative proteinuria, normal blood cell count and normal bone marrow cellularity. The association between MGN and MDS is quite rate. The possible links between the two conditions are reviewed.

Adrenal Cortex Hormones↗

PubMed2004

[Effective treatment with rituximab in a patient with refractory idiopathic thrombocytopenic purpura].

A 75-year-old woman had an episode of sudden nasal and oral bleeding. After that, petechiae appeared on her entire body. She received a platelet transfusion, and was referred to our hospital. On admission, the platelet count was as low as 1.2 X 10(4)/microl, and the PAIgG level was slightly elevated. Bone marrow cellularity was low, with a normal count of megakaryocytes. Anti-glycoprotein IIb/IIIa antibody-secreting B cells in the peripheral blood and platelet-associated anti-glycoprotein IIb/ IIIa antibodies were significantly high, and the patient was diagnosed as having idiopathic thrombocytopenic purpura (ITP). She failed to respond to corticosteroids, splenectomy and other therapies, so we administered rituximab, anti-CD20 monoclonal antibody, 375 mg/m2 weekly for four weeks. After the second infusion of rituximab, the platelet count began to increase. The platelet count continued to rise until a peak count (15.0 x 10(4)/microl) observed after 2 weeks from the fourth infusion, and the response was maintained for 8 more weeks. The levels of anti-glycoprotein IIb/IIIa antibody-secreting B cells and platelet-associated anti-glycoprotein IIb/IIIa antibodies decreased after the administration of rituximab. Rituximab was effective in this case of refractory ITP.

Aged↗