Hyperbaric oxygen therapy (HBOT) and peridontal health

This study has tested the effects of hyperbaric oxygen in periodontal structures in agreement with the theories supported by literature research. Eight patients, from 30 to 50 years-of-age, were tested with pure oxygen inhalation, at the 2.5 ATA absolute pressure. Main approved tests of periodontal health were evaluated before and after HBOT’s cycles. The results in all patients treated with HBOT, have founded clear improvement of clinical and instrumental parameters.

Localization and modulation of NEDD8 protein in the human placenta

BACKGROUND

Neural precursor cell-expressed, developmentally down-regulated-8 (NEDD8) is a 76-amino-acid ubiquitin-like polypeptide. NEDD8 affects the signaling of various molecules but the major cellular target proteins are cullins. The neddylation process is correlated closely with apoptosis, cell-cycle regulation, embryogenesis and development.

AIM

The purpose of the present work was to investigate NEDD8 distribution and expression in the human placenta during gestation.

MATERIALS AND METHODS

A total of 30 samples, 15 chorionic villous samples from first trimester and 15 from full-term placentae, were used for the immunohistochemical analysis of NEDD8 expression. The gestation period ranged from 5 to 40 weeks.

RESULTS

NEDD8 was highly expressed in the cytotrophoblast of the first trimester of gestation, whereas in the third trimester, it was localized in the endothelial cells and stroma of placental villi.

CONCLUSION

Our results suggest that NEDD8 may play an important role in the control of proliferation and differentiation of human placenta throughout pregnancy.

Differentiation of human umbilical cord-derived mesenchymal stem cells, WJ-MSCs, into chondrogenic cells in the presence of pulsed electromagnetic fields

During cartilage regeneration, proliferation and differentiation of new chondrocytes are required and towards this goal, in humans electromagnetic stimulation has been used in order to increase the spontaneous regenerative capacity of bone and cartilage tissue. In vivo tissue engineering has pointed out that the absence of an abundant source of cells accelerating the healing process is a limiting factor in the ability to repair articular cartilage. Considering that the umbilical cord is a viable alternative source of mesenchymal stem cells (MSC), our study evaluated the possibility of a combined use of Wharton's jelly - mesenchymal stem cells (WJ-MSCs) and pulsed electromagnetic field (PMEF). The first effect observed was that compared with the untreated cells, when the WJ-MSCs were treated with PMEF, there was an increase in the division of cells and a rapid increase in cell density and the morphological and biochemical data showed that the treatment with PMEF reduced the time to obtain chondrocyte cell differentiation and deposition of extracellular matrix. Taken together these data indicate the capacity of PEMF to induce early differentiation of WJ-MSCs cells towards cartilaginous tissue.

Suppression of pre adipocyte differentiation and promotion of adipocyte death by anti-HIV drugs

In the present study, we investigated the ability of anti-HIV drugs to interfere with normal cell cycle progression and to induce oxidative stress by perturbing the redox environment. Our results provide evidence that anti-HIV drugs have a differential effect on adipocyte cell cycle and differentiation, being able to modify the response to oxidative stress through an increase of reactive oxygen species (ROS) that compromises the induction of phase-2 and antioxidant enzymes. In detail, saquinavir, efavirenz, and stavudine exert antiadipogenic influences on the model 3T3-L1 cell line, perturbing the oxidative response and inducing of apoptosis. When considered together, the effects of anti-HIV drugs on 3T3-L1 pre adipocytes are distinct but commonly antiadipogenic, thus suggesting another additional possible mechanism by which antiretroviral therapies could contribute to lipoatrophy.

Antimicrobial resistance pattern of methicillin-resistant Staphylococcus aureus in the food industry

There is increasing concern about the impact on public health of methicillin-resistant Staphylococcus aureus (MRSA) associated with animal food products. MRSA remains a serious problem because of the high incidence and multidrug resistance of the strains, even for strains isolated from foods, food environments and food handlers. The objectives of this study are: (i) to evaluate the susceptibility of S. aureus strains isolated from food, food handlers and food-processing environments to 14 antibiotics currently used in veterinary and human therapy; (ii) to assess the presence of the mecA gene. A total of 1007 samples were collected from food, food handlers, and environments and were analyzed for the presence of S. aureus. S. aureus was present in 165 of the 1007 samples. A total of 157 isolates were methicillin-susceptible S. aureus (MSSA) and 8 isolates were MRSA. In particular, out of 8 MRSA strains detected, 4 strains harboured the mecA gene. All MRSA strains were resistant to at least one of the tested antibiotics and 6 strains demonstrated multi-resistance. Considering the high level of resistances in S. aureus and the isolation of MRSA strains, the surveillance of antimicrobial resistance and the spreading of this pathogen is of crucial importance in the food production chain. These data are useful in improving background data on antimicrobial resistance of S. aureus isolated from food, processing environments and food handlers, supporting the prudent use of antibiotics and the development of international control programs.

Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism

Gemcitabine (GEM, 2′,2′-difluorodeoxycytidine) is currently used in advanced pancreatic adenocarcinoma, with a response rate of < 20%. The purpose of our work was to improve GEM activity by addition of cannabinoids. Here, we show that GEM induces both cannabinoid receptor-1 (CB1) and cannabinoid receptor-2 (CB2) receptors by an NF-κB-dependent mechanism and that its association with cannabinoids synergistically inhibits pancreatic adenocarcinoma cell growth and increases reactive oxygen species (ROS) induced by single treatments. The antiproliferative synergism is prevented by the radical scavenger N-acetyl--cysteine and by the specific NF-κB inhibitor BAY 11-7085, demonstrating that the induction of ROS by GEM/cannabinoids and of NF-κB by GEM is required for this effect. In addition, we report that neither apoptotic nor cytostatic mechanisms are responsible for the synergistic cell growth inhibition, which is strictly associated with the enhancement of endoplasmic reticulum stress and autophagic cell death. Noteworthy, the antiproliferative synergism is stronger in GEM-resistant pancreatic cancer cell lines compared with GEM-sensitive pancreatic cancer cell lines. The combined treatment strongly inhibits growth of human pancreatic tumor cells xenografted in nude mice without apparent toxic effects. These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells.

Intracellular zinc increase inhibits p53(-/-) pancreatic adenocarcinoma cell growth by ROS/AIF-mediated apoptosis

We show that treatment with non-toxic doses of zinc in association to the ionophore compound pyrrolidine dithiocarbamate (PDTC) inhibits p53(-/-) pancreatic cancer cell growth much more efficiently than gemcitabine, the gold standard chemotherapeutic agent for pancreatic cancer. Both the metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine and the radical scavenger N-acetyl-l-cysteine are able to recover cell growth inhibition by Zn/PDTC, demonstrating that this effect depends on the increased levels of intracellular zinc and of reactive oxygen species (ROS). Zn/PDTC treatment induces a strong apoptotic cell death that is associated to ROS-dependent nuclear translocation of the mitochondrial factor AIF, but not to the regulation of apoptotic genes and caspase activation. Primary fibroblasts are more resistant than pancreatic cancer cells to Zn/PDTC treatment and exhibit a lower basal and Zn/PDTC-induced enhancement of intracellular zinc. We show that Zn/PDTC induces p53 proteasomal degradation and that the proteasome inhibitor MG132 further increases fibroblast growth inhibition by Zn/PDTC, suggesting that p53 degradation plays an important role in fibroblast resistance to Zn/PDTC.

Zinc depletion efficiently inhibits pancreatic cancer cell growth by increasing the ratio of antiproliferative/proliferative genes

We investigated the ability of the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) to reduce pancreatic cancer cell viability. TPEN was much more efficient to inhibit pancreatic adenocarcinoma cell growth than a panel of anti-cancer drugs, including 5-fluorouracil, irinotecan, cisplatin, edelfosine, trichostatin A, mitomycin C, and gemcitabine, the gold standard chemotherapeutic agent for pancreatic cancer. Moreover, TPEN showed a dose- and time-dependent anti-proliferative effect significantly higher on pancreatic cancer cells than on normal primary fibroblasts. This effect may be explained by a significantly higher zinc depletion by TPEN in pancreatic cancer cells as compared to fibroblasts. Cell viability reduction by TPEN was associated to both G1-phase cell cycle arrest and apoptosis, and to the increased ratio of the expression level of cyclin-Cdk inhibitor versus cyclin genes and apoptotic versus anti-apoptotic genes. Finally, we show that apoptotic cell death induced by TPEN involved mitochondrial injury and caspase 3 and caspase 8 activation. In this study, we suggest that zinc depletion may be an efficient strategy in the treatment of pancreatic cancer because of its reduced antiproliferative effect on normal cells.

Inducible nitric oxide synthase expression elicited in the mouse brain by inflammatory mediators circulating in the cerebrospinal fluid

Expression of inducible nitric oxide synthase (iNOS) protein was studied in the brain after intracerebroventricular injections of interferon (IFN)-gamma, and IFN-gamma combined with lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-alpha, compared to ovalbumin as control. Wild-type mice and mice with targeted deletion of the IFN-gamma receptor gene were used. Findings based on iNOS immunoreactivity were evaluated at 1, 2, 4 and 7 days post-injection, using also quantitative image analysis and double labeling with glial cell markers. IFN-gamma administration induced iNOS immmunostaining in activated microglia and macrophages in the parenchyma surrounding the ventricular system, several cortical fields and fiber tracts. IFN-gamma-elicited iNOS immunoreactivity was down-regulated after 1 day. The number of iNOS-immunopositive cells was significantly enhanced by co-administration of LPS or TNF-alpha; IFN-gamma+TNF-alpha injections also resulted in longer persistence of iNOS immunoreactivity. No immunopositive cells were seen in the brain of IFN-gamma receptor knockout mice after IFN-gamma administration; very few immunostained macrophages were detected in these cases, mostly around the injection needle track, after co-administration of LPS or TNF-alpha. Western blot analysis confirmed a marked iNOS induction in the brain of wild-type mice 24 h after IFN-gamma+LPS injections. The findings show that inflammatory mediators circulating in the cerebrospinal fluid induce in vivo iNOS in the brain with topographical selectivity and temporal regulation. The data also demonstrate that the signaling cascade activated by IFN-gamma binding to its receptor is critical for iNOS induction, and the synergistic action of LPS and TNF-alpha as iNOS inducers in brain cells is largely mediated by the receptor-regulated action of IFN-gamma.

[Clinical and sperm follow-up after subinguinal varicocelectomy]

In order to evaluate the sperm output and the adverse-side-effects after subinguinal varicoceloctomy, a follow-up study of 16 months was performed on 196 selected patients (aged from 22 to 43 years) affected by left varicocele (VR). In the pre-treatment, both Doppler ultrasonography and didymo-epididymal ultrasonography allowed to distinguish two homogeneous patient groups: group A (no. = 136), including patients affected by VR alone and, group B (n. = 60), including patients with VR combined to coincidental didymo-epididymal morphological abnormalities, DEMA). These DEMA lesions (testis size < 12 ml, epididymides abnormalities: increased head- > or = 12 mm- and/or tail- > or = 6 mm-diameter, multiple microcysts, large idrocele) were omolaterally to VR in 30/60 (50%), eterolaterally in 19/60 (31.7%) or bilaterally in 11/60 (18.3%). During sperm follow-up, group A patients showed both a significant temporal change (p < 0.01 ANOVA) of all sperm parameters studied (sperm density, total sperm count, motility and morphology) from month 8 onward and sperm values significantly higher than found in group B patients. On the contrary, the sperm parameters of group B patients did not change significantly during the follow-up observations. As far as the varicocelectomy-mediated clinical symptoms, some patients complained early and transiently (on 1-2-4 weeks following varicocelectomy) the following symptoms: didymal pain (1.5%), didymo-epididymal pain (4.1%) and parasthesiaes on the anterior-medial side of the left thigh (4.1%) or scrotal (3.1%); only four patients (2%) complained permanent paresthesiaes on the anterior-medial side of the left thigh. Furthermore, the clinical follow-up also revealed a low rate of complications: persistent VR (3.6%), hydrocele (1.5%), intrascrotal venous ecstasies (6.1%), epididymitis (0.5%). Some morpho-structural abnormalities at US scans were transient (1-2 weeks): scrotal oedema (6.1%), orchitis (2%), orchi-epididymitis (1%). Subinguinal varicocelectomy performed on large population demonstrated a significant improvement of the sperm output from month 8th onward in patients with VR alone, while sperm parameters did not show any significant change in patients with VR plus coincidental DEMA. This surgical technique also demonstrated safety since both low rates of symptoms and (transient) complications were registered.

Cell-specific differences in the regulation of IL-6 expression by PMA

We have studied the regulation of IL-6 expression in human blood monocytes and lymphocytes. LPS and IFN-gamma induced IL-6 gene expression with a similar qualitative profile in both cell types. Treatment of monocytes and lymphocytes with PMA resulted, instead, in different effects: monocytes accumulated IL-6 and its message, while lymphocytes were inhibited either in the absence or the presence of LPS and IFN-gamma. These results suggest that the signal transduction pathways triggered by LPS and IFN-gamma are similar in both cell types, while PMA may activate a tissue-specific pathway which leads to opposite responses.

[A facilitated technique for donor hepatectomy: experimental study in the pig]

A facilitated technique of porcine donor hepatectomy is reported underlying the possibility to make an easy procedure without in situ portal perfusion, so other abdominal organs supplied by superior mesenteric system can be harvested at the same time. The viability of those grafts procured without in situ portal perfusion has been compared with an other group of livers harvested with in situ aortic and portal flushing. The evaluation of the histology and early graft function two hours after riperfusion has shown no differences between both groups.

Lithostathine messenger RNA expression in different types of chronic pancreatitis

Lithostathine may play a physiological role in preventing the precipitation of excess calcium in the pancreatic juice. The hypothesis has been advanced that in chronic calcifying pancreatitis the abnormal biosynthesis of lithostathine might be the original defect to which genetic proneness to the disease may be ascribed. The aim of the present work was to study lithostathine messenger RNA expression in the pancreas of patients with different types of pancreatitis. Lithostathine and chymotrypsinogen mRNA were determined in surgical specimens obtained from the pancreases of the following subjects: (a) 13 patients with chronic alcoholic pancreatitis (84.6% calcified); (b) 4 patients with chronic hereditary pancreatitis (all calcified); (c) 6 patients with chronic obstructive pancreatitis (4 calcified); and (d) 27 subjects suffering from pancreatic cancer. Significantly lower concentrations of both mRNAs were found in the pancreases of chronic pancreatitis patients than in non-cancerous tissue from pancreatic cancer subjects. However, about 70% of the pancreatic cancer subjects showed lithostathine and chymotrypsinogen mRNA levels comparable to those of chronic pancreatitis patients. These results indicate that the decrease in the level of mRNA is not specific to lithostathine and it is unrelated to the presence of pancreatic stones.

Cross-linked trimers of bovine ribonuclease A: activity on double-stranded RNA and antitumor action

Trimers of bovine pancreatic RNase A were obtained by cross-linking native RNase A with dimethyl suberimidate. They degrade double-stranded RNA more efficiently than dimers and monomers of RNase A, and display significant cytotoxic and/or cytostatic actions against C4-I cells (a human cell line derived from squamous carcinoma of the uterus cervix). On the same cell line cross-linked dimers of RNase A appear to be ineffective.

[Role of hyperbaric oxygen in the treatment of necrotizing infections of the soft tissues]

The Authors report their experience in the treatment of soft tissue necrotizing infections. The correct "timing" of the association of surgery, antibiotics and hyperbaric oxygen therapy is stressed. The good clinical results obtained in the patients examined confirm the usefulness of an early treatment modulated according to the needs of each single patient.

Protein synthesis inhibitors cycloheximide and anisomycin induce interleukin-6 gene expression and activate transcription factor NF-kappaB

In two human cell lines, MDA-MB-231 and HeLa, the inducible expression of the interleukin-6 (IL-6) gene by two protein synthesis inhibitors, cycloheximide and anisomycin, was compared with the induction by the most potent physiological inducer of IL-6 described to date, interleukin-1beta (IL-1beta). In cycloheximide or anisomycin treated cells, the accumulation of the IL-6 message and the activation of transcription factors required for IL-6 gene expression occurs at an extent similar to that obtained with IL-1beta. Furthermore, IL-6 mRNA accumulation stimulated by cycloheximide or anisomycin is almost completely inhibited in the presence of actinomycin D, indicating that this effect occurs mainly through the activation of the transcriptional machinery. These data indicate that transcriptional induction of the IL-6 gene by inhibitors of protein synthesis is triggered by the same nuclear signals as other inducers.

Nuclear factor kappa B (NF-kappa B), nuclear factor interleukin-6 (NFIL-6 or C/EBP beta) and nuclear factor interleukin-6 beta (NFIL6-beta or C/EBP delta) are not sufficient to activate the endogenous interleukin-6 gene in the human breast carcinoma cell line MCF-7. Comparative analysis with MDA-MB-231 cells, an interleukin-6-expressing human breast carcinoma cell line

A comparative study of the molecular mechanism of interleukin-6 (IL-6) gene induction on two breast-carcinoma-derived cell lines has been performed. MDA-MB-231 cells produce constitutive detectable levels of both secreted IL-6 and mRNA which, as expected, are dramatically enhanced following induction by either IL-1 beta or tumor necrosis factor-alpha (TNF-alpha). The levels of both secreted IL-6 and IL-6 mRNA are significantly higher in response to IL-1 beta in spite of the fact that stimulation by TNF-alpha alone enhances the half life of IL-6 mRNA. The protein synthesis inhibitor cycloheximide is also a fairly strong inducer of IL-6 in these cells. In contrast, MCF-7 cells fail to produce detectable IL-6 protein or mRNA, even after stimulation with proper inducers. Analysis of transcription factors NF-kappa B, NFIL6 and NFIL6 beta, which have been described to be sufficient to activate the IL-6 gene in other cell systems, shows a similar pattern of expression in both MCF-7 and MDA-MB-231 cells. Furthermore, transfection of a recombinant plasmid carrying the IL-6 promoter linked to a luciferase reporter gene shows that both cell lines are able to drive IL-1 beta or TNF-alpha activation of this construction in a very similar manner. Finally, when MCF-7 cells were treated with IL-1 beta or TNF-alpha in the presence of cycloheximide, transcription of IL-6 mRNA from the endogenous IL-6 gene was observed. These data suggest that a mechanism of IL-6 gene repression is active in MCF-7 cells.

Sequences related to the ox pancreatic ribonuclease coding region in the genomic DNA of mammalian species

Mammalian pancreatic ribonucleases form a family of homologous proteins that has been extensively investigated. The primary structures of these enzymes were used to derive phylogenetic trees. These analyses indicate that the presence of three strictly homologous enzymes in the bovine species (the pancreatic, seminal, and cerebral ribonucleases) is due to gene duplication events which occurred during the evolution of ancestral ruminants. In this paper we present evidence that confirms this finding and that suggests an overall structural conservation of the putative ribonuclease genes in ruminant species. We could also demonstrate that the sequences related to ox ribonuclease coding regions present in genomic DNA of the giraffe species are the orthologues of the bovine genes encoding the three ribonucleases mentioned above.

Protein-DNA interactions in the 5'-flanking region of the bovine pancreatic ribonuclease gene

In the 5'-flanking region of the bovine pancreatic ribonuclease gene a sequence has been identified which specifically binds one or more factors present in nuclear protein extracts prepared from bovine pancreas. The binding site, as delineated by footprinting analysis, is located in a region extending from positions -113 to -146 relative to the transcription initiation site of the ribonuclease gene. This region contains consensus sequences for known control transcriptional elements. The observed pattern of protein-DNA interactions is likely to be pancreas-specific as it could not be detected with nuclear extracts prepared from HeLa or bovine aorta endothelium cells.

[A controlled clinical experiment "within subjects" with heparan sulfate in intermittent claudication]

An experimental clinical trial was carried out using heparan sulphate in order to assess its antithrombophilic, profibrinolytic and possibly hemorheological characteristics. Twenty patients with stage 2 obliterating arteriopathy of the lower limbs were enrolled in the study. Patients were fully informed regarding the experimental protocol: a controlled, crossover and double-blind study. The population sample included 20 subjects, male and female, mean age 60.9 years who received heparan sulphate at a dose of 200 mg/die (one 100 mg tablet twice a day): treatment continued for 120 days (60 days of treatment with heparan sulphate and 60 days with placebo). The results obtained were in favour of medical therapy which was significantly more effective than placebo in relation to a number of parameters: compared to basal values, walking parameters were improved, recovery times were more rapid and gait was longer. Significant changes in hemocoagulative and hemorheological parameters were also observed (euglobulin lysis time, fibrin degradation products, erythrocytic filtration, hematic viscosity) and their positive trend may account for peripheral hematic perfusion, as shown by photoplethysmographic tests, velocimetric tests and the modification of the Windsor index. Therapeutic efficacy and the good tolerance (one case of gastralgia, two of pyrosis) as well as broad safety margins offered by the drug justify the use of heparan sulphate in all clinical conditions characterized by thrombophilia and local ischemia, above all those which require long-term treatment.

Orbital expansion in plagiocephaly

In moderate to severe plagiocephaly, the transverse diameter of the orbit on the affected side is consistently decreased. In these cases, the supraorbital rim has been expanded by the required amount and bone grafted. This makes for greater orbital symmetry and ease in obtaining the correct supraorbital convexity. Ten patients have been handled in this way with satisfactory postoperative results.

Use of external reservoirs in tissue expansion

The use of tissue expanders having external reservoirs is presented. Twenty-four patients had 36 tissue expanders placed in the scalp, face, neck, upper limbs, chest, and lower limbs. All patients, apart from one, were taken to completion. This patient had erosion of the skin over expander and was only partially completed after removal of the expander. Apart from one instance of deflation at the end of the expansion where the skin could still be used, there were no other complications, in particular, no infections. The advantages of this technique are reduced operating time, ease of injection into the reservoir, lack of pain for the patient, early detection of reservoir or filling tube junction leakage, and lack of complications associated with the reservoir. This procedure is not recommended on at least theoretical grounds for breast expansion, where a permanent implant is to be inserted.

Different sensitivities of granulocyte-macrophage and erythroid progenitor cells of normal human bone marrow to S-phase-specific agents

The extraordinary sensitivity of early erythroid progenitor cells (BFU-e) of normal human bone marrow to tritiated thymidine ([3H]TdR) was studied. While exposure of bone-marrow cells to [3H]TdR for 1 hr resulted in the death of only 40% of the granulocyte-macrophage progenitor cells (CFU-c), 90% of BFU-e were killed. Experiments in which normal bone-marrow cells were mixed with bone-marrow cells which had been exposed to [3H]TdR demonstrated that the excessive killing of BFU-e by [3H]TdR reflected carry-over of the [3H]TdR by the exposed cells. A carry-over effect was not observed for CFU-c, suggesting the presence of a fundamental difference in the metabolism of TdR between CFU-c and BFU-e. There was a suggestion of a carry-over effect regarding two other S-phase-specific agents, hydroxyurea and 1-beta-D-arabinofuranosylcytosine.

Immunofluorescent staining method for use with monoclonal antibodies

This note describes an immunofluorescent staining method for cells in the S-phase which have been allowed to take up bromodeoxyuridine into their DNA in place of thymine. The technique involves the use of fluorescinated monoclonal antibodies against bromodeoxyuridine and allows rapid and accurate estimation of cells in the S-phase, the technique does not require interpretation by skilled technicians.

In vitro busulfan sensitivity of granulocyte-macrophage and erythroid progenitor cells in patients with chronic myelogenous leukemia

As part of an attempt to develop and test potential in vitro measures of busulfan sensitivity of patients with chronic myelogenous leukemia (CML) in chronic phase, we compared the busulfan sensitivity of granulocyte-macrophage (CFU-C) and early erythroid progenitor cells (BFU-E) in the bone marrow (BM) and peripheral blood (PB) specimens obtained from ten normal individuals and from 13 patients with CML. CFU-C in the normal BM and in both the BM and PB of CML patients showed comparable degrees of sensitivity to busulfan. BFU-E, regardless of source, showed similar degrees of sensitivity to busulfan, except that normal PB BFU-E were less sensitive than were PB BFU-E of CML patients. CFU-C were more resistant to busulfan than BFU-E. The sensitivity of BM CFU-C and BFU-E of CML patients reflected that of PB CFU-C and BFU-E, respectively, and the sensitivity of BM and PB CFU-C of CML patients reflected that of BM and PB BFU-E, respectively. When the CML patients were ranked according to sensitivity to busulfan, the order of sensitivity of BM CFU-C and BFU-E paralleled that of PB CFU-C and BFU-E, respectively, and the order of sensitivity of BM and PB CFU-C paralleled that of BM and PB BFU-E, respectively. These results suggest that any of the four progenitor cells, BM CFU-C, BM BFU-E, PB CFU-C, and PB BFU-E, can be used to investigate the relative busulfan sensitivity of the hemopoietic progenitor cells of different CML patients.

Effects of S-phase-specific agents on granulocyte-macrophage and erythroid progenitor cells obtained from normal individuals and from patients with chronic myelogenous leukemia

The effects of three S-phase-specific agents, [3H]thymidine, hydroxyurea, and 1-beta-D-arabinofuranosylcytosine, on granulocyte-macrophage colony-forming units (CFU-C) and erythroid progenitor cells (erythroid burst-forming units) (BFU-E) from the bone marrow or peripheral blood obtained from 23 normal individuals and 12 patients with chronic myelogenous leukemia were investigated. CFU-C, regardless of their source, showed comparable degrees of sensitivity to each of the S-phase-specific agents, with perhaps a slightly greater level of sensitivity to [3H]thymidine. In contrast, the sensitivities of chronic myelogenous leukemia and normal marrow BFU-E to the 3 agents were quite different, with essentially all BFU-E being killed by [3H]thymidine, 50 to 70% being killed by 1-beta-D-arabinofuranosylcytosine, and only 15 to 20% being killed by hydroxyurea. BFU-E present in normal peripheral blood were insensitive to [3H]thymidine or hydroxyurea but were sensitive to 1-beta-D-arabinofuranosylcytosine. These studies demonstrated similarities between the CFU-C and BFU-E of CML patients and the CFU-C and BFU-E present in normal bone marrow. On the other hand, the sensitivities of normal peripheral blood progenitor cells to "S-phase-specific" agents differed from that of CML progenitor cells or the progenitor cells present in normal bone marrow. Additionally, these studies have demonstrated the limitations inherent in suicide techniques as methods for estimating the cell cycle characteristics of clonogenic cells.