bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural killer cell activity in a population of leukemia‐prone wild mice (mus musculus)
Authors: Scott Jonathan L. , Pal Bijay K. , Rasheed Suraiya , Gardner Murray B. 
Published: February 2007

AbstractNatural cell‐mediated cytotoxicity against YAC‐1 targets was measured in splenocytes from leukemiaprone wild mice trapped near Lake Casitas (LC) in southern California. Cytotoxicity was mediated by cells that were non‐adherent to nylon wool, non‐phagocytic and resistant to thy‐1.2 antiserum plus complement. Natural MuLV viremia in LC mice did not impair splenic cytotoxicity against YAC‐1 target cells. Cells infected with amphotropic and ecotropic MuLV of wild mouse origin were not appreciably lysed by LC splenic effectors. Although variable levels of cytotoxicity were detected against YAC‐1 by normal LC spleen cells, consistently low levels of cytotoxicity against allogenic LC lymphoma, sarcoma and carcinoma targets were found using the same splenocytes. These results indicate that LC mice possess splenocytes with the characteristics of natural killer (NK) cells as defined in inbred mice. The resistance of LC‐derived targets to lysis by LC NK cells suggests that NK cells may not be involved in natural tumor immunosurveillance or that the development of spontaneous tumors may involve escape from NK‐mediated effector mechanisms.
Staphylococcal protein a enhances natural killing activity against lymphoid tumor cell lines
Authors: Patel Pravin C. , Stefanescu‐Soare Irina , Menezes José 
Published: February 2007

AbstractProtein A (pA), was found to augment the natural killing (NK) activity of peripheral blood lymphocytes against Burkitt's lymphoma‐derived Raji and Daudi cells. This pA‐enhanced NK activity was determined using the 51Chromium release microcytotoxicity assay. It was found that the increased NK activitiy was dependent on the concentration of pA used. In addition, the pA‐enhanced NK activity was dependent on the time of incubation of pA with the effector and target cell mixture. Pretreatment of effectors for 16 h or more dramatically increased the NK activity against a wide range of tumor targets of different origin and possessing either B, T or null cell surface characteristics. The presence of the Epstein‐Barr virus (EBV)‐genome in the target cells did not influence the pA‐enhanced NK activity. Nylon‐wool column‐fractionated, non‐adherant lymphocytes (enriched in NK cells) showed an increased NK activity in the presence of pA than unfractionated lymphocytes. Pretreatment of certain targets with pA rendered them more sensitive to NK lysis. Interferon production was readily detected in supernatants from cultures of pA‐treated effectors or effector‐target mixtures, but not in supernatants from pA‐treated target cultures tested. Results of different physicochemical treatments indicate that the pA‐induced interferon is of γ type (type II). Thus, the data presented suggest that the pA‐induced enhancement of NK activity is most likely mediated by the pA‐induced interferon.
Distribution and molecular characterization of a cell‐surface and a cytoplasmic antigen detectable in human melanoma cells with monoclonal antibodies
Authors: Wilson Barry S. , Imai Kohzoh , Natali Pier G. , Ferrone Soldano 
Published: February 2007

AbstractThe monoclonal antibodies 225.28S and 465.12 to human melanoma‐associated antigens have been tested with a large variety of surgically removed skin lesions and malignant tumors as well as with a panel of cultured cell lines in serological and immunochemical assays. The antibody 225.28S reacts with a plasma membrane antigen while the antibody 465.12 detects a cytoplasmic antigen. Both antibodies fail to react with melanocytes from normal skin as well as benign skin lesions but react with nevi, melanoma cells and some skin carcinomas. Analysis with surgically removed tumors and cultured human cell lines indicated that the plasma membrane antigen is restricted to skin lesions whereas the cytoplasmic antigen is synthesized by tumor cells of various histologcal origins. The plasma membrane antigen is composed of two glyco‐polypeptides of 280,000 and > 440,000 daltons, while the cytoplasmic antigen consists of 4 glycopolypeptides of 94,000, 75,000, 70,000 and 25,000 daltons. None of these components are bridged by disulfide bonds. The cytoplasmic antigen was readily detected in the spent culture medium of melanoma cell lines in the form of a major 94,000 dalton and a minor 72,000 dalton structure, while the plasma membrane antigen was detectable only after vastly increasing the sensitivity of the assay system.
Association of Epstein‐Barr virus with nasopharyngeal carcinoma in alaskan native patients: Serum antibodies and tissue EBNA and DNA
Authors: Lanier Anne P. , Bornkamm Georg W. , Henle Werner , Henle Gertrude , Bender Thomas R. , Talbot Marion L. , Dohan Peter H. 
Published: February 2007

AbstractBiopsy specimens from Alaskan Native patients with nasopharyngeal carcinoma (NPC) and from other patients seen on the otolaryngology service were tested for Epstein‐Barr virus‐specific DNA and nuclear antigen (EBNA). Serum samples from both groups were tested for various EBV‐related antibodies. EBV DNA and EBNA results were in agreement in 29 of 31 tissue specimens tested by the two methods. Ten of 11 biopsies containing NPC cells were positive for EBV DNA. Two NPC patients had biopsies that showed only atypical epithelium but were also positive for EBV DNA or EBNA. The other tissue specimens were negative except for biopsies from two patients: one with a parotid gland lymphoepithelial lesion; another with undifferentiated carcinoma of salivary gland origin.
In vivo inhibition of the development of myeloid leukemia by injection of macrophage‐and granulocyte‐inducing protein
Authors: Lotem Joseph , Sachs Leo 
Published: February 2007

AbstractIt is shown that injection of macrophage‐ and granulocyte‐inducing protein (MGI) can inhibit the development of myeloid leukemia in vivo and stimulate normal myelopoiesis. The MGI injected contained MGI‐1 activity that induces colony formation with normal myeloblasts, and MGI‐2 activity that induces differentiation of normal and MGI+D+ leukemic myeloblasts to mature macrophages or granulocytes. The MGI preparations injected did not contain interferon and it was shown that the results obtained were not due to minute amounts of contaminating lipopolysaccharide (LPS). Intraperitoneal injection of MGI stimulated myelopoisesis in normal adult mice. Markedly higher levels of serum MGI activity could be obtained by injecting MGI than by injecting LPS, a compound that stimulates the in vivo production of MGI. Injection of MGI into mice that had been inoculated intravenously with MGI+D+ or MGI+D− myeloid leukemic cells showed that, 3 weeks after the beginning of treatment, there was a 3‐ to 5‐fold decrease in the number of leukemic colony‐forming cells and an increase in mature granulocytes in the bone marrow, together with a 2‐ to 5‐fold decrease in the percentage of morphologically identified myeloid blast cells in the bone marrow and peripheral blood. The remaining leukemic colony‐forming cells in the MGI‐treated mice inoculated with MGI+D+ cells were not resistant to the induction of differentiation by MGI‐2. Injection of LPS to mice inoculated with LPS‐resistant MGI+D− leukemic cells also inhibited the development of leukemia, but this inhibition was less effective than with MGI and was presumably indirect. Injection of MGI reduced the tumor volume in mice subcutaneously inoculated with leukemic cells at least 50‐fold. The median survival time of MGI‐treated mice inoculated intravenously with MGI+D+ cells or subcutaneously with MGI+D− cells was increased by about 40%, and 50% of the MGI‐treated mice inoculated subcutaneously with MGI+D+ cells did not develop tumors. MGI also increased the anti‐tumor effect of cyclophosphamide. The leukemia‐inhibiting activity in the injected MGI preparations was associated with the peak of MGI activity separated on a hydroxylapatite column and was destroyed by treatment at the temperature which destroys MGI‐2 activity. This indicates that the inhibition of leukemia development was mediated by MGI‐2. It is suggested that improved schedules of MGI treatment, with or without compounds used in the cytotoxic types of therapy, should be able to give an even better inhibition of leukemia development and that these results should also be applicable to the therapy of human myeloid leukemia.
The formation and persistence of benzo(a)pyrene metabolite‐deoxyribonucleoside adducts in rat skin in vivo
Authors: Ashurst Stephen W. , Cohen Gerald M. 
Published: February 2007

AbstractThe extent of reaction of benzo(a)pyrene with DNA and the formation of benzo(a)pyrene‐deoxyribonucleoside adducts in the skins of male Wistar rats were investigated. Following topical application of benzo(a)pyrene (200 nmoles), binding reached a maximum of 0,74 pmoles/mg DNA, 12 h after treatment, and remained high up to 48 h after treatment. Hydrolysis of the DNA and analysis of the deoxyribonucleoside adducts by HPLC revealed several products. The major adduct, C, (27‐40% of the total adducts), co‐chromatographed with deoxyribonucleoside adducts formed by reaction of (±)7β, 8α‐dihyroxy‐9α, 10α‐epoxy‐7,8,9,10‐tetrahydrobenzo(a)pyrene (anti BPDE) with DNA, whilst product B, (19–23% of the total adducts), also formed in significant amounts, co‐chromatographed with a further metabolite of 9‐hydroxybenzo(a)pyrene bound to an as yet undertermined base in the DNA. Smaller amounts of other deoxyribonucleoside adducts, D and I, were also observed and co‐chromatographed with marker compounds derived from reaction of anti BPDE with deoxyadenosine and (±)7β, 8α‐dihydroxy‐9β, 10β‐epoxy‐7,8,9,10‐tetrahydrobenzo(a)pyrene (Syn BPDE) with DNA respectively. There was no evidence for preferential removal of any of the four adducts (B, C, D and I) during the 48 h after treatment with benzo(a)pyrene. The relative resistance of rat skin, compared with mouse skin, to benzo(a)pyrene‐induced skin carcinogenesis may be due in part to a lower extent of binding of benzo(a)pyrene to DNA, and a smaller percentage of both methanol‐soluble hydrocarbon‐deoxyribonucleoside adducts and of adducts derived from the putative ultimate carcinogen, BPDE.
Development of resistance to vincristine in a childhood rhabdomyosarcoma growing in immune‐deprived mice
Authors: Houghton Janet A. , Houghton Peter J. , Brodeur Garrett M. , Green Alexander A. 
Published: February 2007

AbstractA cell line of childhood rhabdomyosarcoma (RD) has been grown as a xenograft in immune‐deprived mice. The tumor responded to vincristine (VCR), but not to vinblastine, doxorubicin or actinomycin D. The rate and frequency at which resistance developed from administration of VCR once weekly was investigated. Tumor growth could be inhibited for 6 weeks, after which time 11 of 16 xenografts grew progressively despite continued treatment. That this was a tumor‐acquired resistance was confirmed by growing both parent and “resistant” lines in the same host. Under these conditions VCR completely inhibited growth of the parent tumor, but not growth of the resistant line. Continued passage of the resistant line for 10 months in mice either treated with VCR (1.5 mg/kg/wk) or untreated, demonstrated that resistance to VCR was stable in the absence of selection pressure. In addition, the VCR‐resistant line acquired a stable change in karyotype with the addition of a number 9 chromosome and an additional, unknown marker.
EBV‐positive Burkitt's lymphoma from algeria, with a three‐way rearrangement involving chromosomes 2, 8 and 9
Authors: Philip T. , Lenoir G. M. , Fraisse J. , Philip I. , Bertoglio J. , Ladjaj S. , Bertrand S. , Brunat‐Mentigny M. 
Published: February 2007

AbstractBurkitt's lymphoma was diagnosed in a male Algerian child presenting with abdominal and jaw tumours. Viral studies revealed that this non‐endemic case was associated with the Epstein‐Barr virus. Cytogenetic examination of tumour cells showed a complex three‐way rearrangement involving chromosomes 2, 8 and 9. Our report indicates that, in Burkitt's lymphoma, not only simple but also complex translocations involving chromosome 8 may arise. This finding in a North African case emphasizes the need for more detailed study of the clinical, virological and cytogenetic features of Burkitt's lymphoma throughout the world.
A note on the role of dietary retinol and carotene in human gastro‐intestinal cancer
Authors: Modan B. , Cuckle H. , Lubin F. 
Published: February 2007

AbstractDietary data relating to 406 patients with gastrointestinal cancers (cases) and 812 controls have been analysed to test the hypotheses that dietary vitamin A (retinol) and its precursor, carotene, may be protective agents in human carcinogenesis. There was no deficit among cases in the intake of retinol‐containing food items whereas several of the main carotene‐containing fruits and vegetables were eaten less often among cases than among controls. However, when total daily intake was estimated, there was no protective effect of carotene, perhaps implying that some other constituent of the fruits and vegetables is protective.
Combined effects of natural resistance and chemotherapy against a murine lymphoma in lethally‐irradiated mice
Authors: Iorio Anna M. , Neri Mariella , Enrico Paola , Goldin Abraham , Bonmassar Enzo 
Published: February 2007

AbstractLymphoma EL‐4 of B6 origin was inoculated into lethally‐irradiated syngeneic B6 or resistant BD2F1 hybrid recipients. Marked impairment of lymphoma cell proliferation (i.e. hybrid resistance, HR) occurred in the spleen but not in the liver or lung of BD2F1 hosts. Treatment with DTIC at the optimal dose of 80 mg/kg i.p. produced inhibitory effects in spleen, liver and lung of young BD2F, mice, that were much greater than those observed in syngeneic B6 hosts. Increased anti‐lymphoma effects for HR and DTIC chemotherapy were not detectable in the liver or lung of old BD2F1 mice or in the spleen, liver or lung of young hybrid recipients depressed for HR by pretreatment with cyclophosphamide. This is the first report on combined antileukemic effects of the host's anti‐tumor natural resistance and chemotherapy.
Steroids inhibit tumor promoting agent induced Epstein‐Barr virus early antigens in raji cells
Authors: Sundar Syam K. , Ablashi Dharam V. , Armstrong Gary R. , Zipkin Mitchell , Faggioni Alberto , Levine Paul H. 
Published: February 2007

AbstractFour steroids and one protease inhibitor were evaluated for their effects on 12‐O‐tetradecanoyl phorbol 13‐acetate (TPA)‐induced and Epstein‐Barr virus‐induced early antigens (EBV‐EA) in Raji cells. Continuous treatment with dexamethasone, prednisolone, hydrocortisone and cortisone inhibited TPA‐induced EBV‐EA to varying degrees, but the protease inhibitor N‐α‐p‐tosyl L‐lysine chloromethyl ketone‐HCI (TLCK) had no significant effect. None of the agents tested inhibited EBV‐induced EA. In addition, the effect of the steroids was reversible since the removal of these agents resulted in recovery of the percentage of EBV‐EA‐positive cells in TPA‐treated cultures. These results were in agreement with the in vivo experiments of other investigators, who demonstrated inhibition of tumor promotion with steroids. Since TLCK failed to inhibit TPA‐induced EA, it is unlikely that induction of EA by TPA is the result of production of proteases.
A geographical study of antibodies to membrane antigens of HSV‐2‐infected cells and HSV‐2‐specific antibodies in patients with cervical cancer
Authors: Mendis Lalitha N. , Best Jennifer M. , Senarath Lorraine , Chiphangwi J. , Vestergaard B. F. , Banatvala J. E. 
Published: February 2007

AbstractSera were obtained from patients with squamous carcinoma of the cervix from Great Britain (29), Sri Lanka (32), Malawi (27) and Sudan (27), and from controls from all countries except Sudan. Controls were matched for ethnic origin, age and social class. Sera were tested by indirect immunofluorescence (IF) for IgG and IgA antibodies to membrane antigens (MA) and IgA antibodies to VCA of HSV‐2 infected cells. Compared with controls, IgA antibodies to MA (IgA anti‐MA) were detected more frequently and at higher titres in all groups of patients. However, there was no significant difference in prevalence of these antibodies at titres ≥1:4 between Malawian patients and controls, although a significantly higher proportion of patients had IgA anti‐MA titres of ≥1:16. In contrast, IgA anti‐VCA did not distinguish patients from controls. More than 90% of both patients and controls from all countries had IgG antibodies to MA (IgA anti‐MA). Malawian patients had a significantly higher geometric mean titre (GMT) of IgG anti‐MA than controls and both patients and controls and significantly higher GMTs than their counterparts from other countries. The variation between herpes IgG anti‐MA titres in subjects from different countries did not reflect differences in serum immunoglobulin levels and similar variations in titre were not seen in rubella and measles HAI titres. Among the patients there was a geographical variation in the prevalence of HSV‐2 specific antibodies detected by ELISA, which varied from 52% among British and Sudanese patients to 73% among Malawian patients. Even when adjustment was made for possible false negative results, there were between 10 and 31% patients without HSV‐2‐specific antibodies, although only 2 of 103 (1.9%) patients had neither HSV‐1 nor HSV‐2 antibodies. The association of HSV‐2 with cervical carcinoma appeared to vary with age.
Morphological and microbiological signs of endogenous C‐virus in human oocytes
Authors: Larsson E. , Nilsson B. Ove , Sundström P. , Widéhn Sibylle 
Published: February 2007

AbstractHuman oocytes in different stages of maturation were obtained by follicular aspiration from women given Clomovid and Gonadex. Particles similar to type‐C virus were observed in three out of 16 oocytes. The particles were irregularly distributed along the oocyte membrane. They were seen both in a state of budding and lying free in the perivitelline space. Reverse transcriptase activity was detected in three out of nine samples of follicular fluid obtained from women other than those donating the oocytes. The supernatants from bat lung cells and dog thymus cells cultivated with oocytes or follicular fluids were tested for reverse transcriptase. An increased activity was observed only transiently in one case. It is assumed that these findings indicate the expression of endogenous retroviruses in human oocytes.
Retrovirus p30‐related antigen in human syncytiotrophoblasts and IgG antibodies in cord‐blood sera
Authors: Suni Jukka , Wahlström Torsten , Vaheri Antti 
Published: February 2007

AbstractSensitive immunological techniques were used to detect retrovirus markers in human pregnancy. A total of 1,540 human cord‐blood sera were tested for retrovirus‐reactive IgG antibodies using solid‐phase enzyme immunoassay and purified RD114 virus as antigen. Of these, 118 (7.7%) sera were positive. Blocking assays with specific animal anti‐p30 sera, use of control antigen, and electrophoretic protein experiments combined with immunological detection indicated that the human antibodies reacted specifically with the p30 protein. The occurrence of antibodies in cord‐blood serum had a highly significant correlation to complications during pregnancy and also correlated to the number of previous abortions and stillbirths. When goat anti‐RD114 p30 serum was used in the peroxidase‐anti‐peroxidase tissue staining procedure, p30‐related antigen was detected in sections of all placental specimens (early and term pregnancies, blighted ova, hydatidiform moles, destructive moles and choriocarcinomas). However, in each case only syncytiotrophoblastic cells were positive. These findings, supplemented with different types of blocking tests, lead us to conclude that retrovirus p30‐related antigen is selectively expressed in the highly differentiated syncytiotrophoblasts, which in the normal placenta are directly exposed to maternal blood. It is suggested that retrovirus‐reactive antibodies may represent an autoimmune‐like immune response to the p30‐related syncytiotrophoblast antigen escaping during cellular damage.
Synergistic action of two polyamine antimetabolites leads to a rapid therapeutic response in childhood leukemia
Authors: Siimes M. , Seppänen P. , Alhonen‐Hongisto L. , Jänne J. 
Published: February 2007

AbstractSequential administration of α‐difluoromethyl ornithine and methylglyoxal bis(guanylhydrazone), two differently acting inhibitors of the biosynthesis of natural polyamines, produced a rapid and distinct therapeutic response in four children with advanced lymphoblastic and in one with myeloblastic leukemia. The synergism between the action of the two compounds was based upon a unique drug interaction; a preceding treatment with difluoromethyl ornithine greatly increased the uptake of subsequently administered methylglyoxal bis‐(guanylhydrazone) as verified by the actual determinations of the latter drug in the circulating leukemia cells. The side‐effects associated with the combined drug regimen were either absent or mild.
Binding of 125I‐labelled human αinterferon to human lymphoid cells
Authors: Mogensen Knud Erik , Bandu Marie‐Thérèse , Vignaux Franloise , Aguet Michel , Gresser Ion 
Published: February 2007

AbstractTo investigate the binding of interferon to human lymphoid cells, we purified human α interferon and radio‐labelled it with iodine −125. Binding at 4°C could be saturated and was inhibited by unlabelled interferon; it was specific for cells of human origin. Dissociation constants for the complex of interferon and receptor site were of the order 10−9–10−11 M. All human cells tested showed such binding. Occupation of these high‐affinity sites, at 37°C, was compared with the inhibition of cellular growth due to interferon. The most sensitive cell line (Daudi) gave a complete biological response with only a fraction of its sites occupied. Evidence of two sites was found for a line (P3HRI) showing intermediate sensitivity. A relatively insensitive line (Raji) showed no response when all its high‐affinity sites were occupied.
Natural antibodies carrying a cross‐reactive idiotype enhance tumor growth in the rat
Authors: Natori T. , Takahashi S. , Nakagawa H. , Aizawa M. , Itaya T. 
Published: February 2007

AbstractA population of Fab fragments was identified in the papain‐solubilized fraction of membranes of a rat chemically‐induced sarcoma, KMT 17. The Fab fragments were partially purified by gel filtration and column electrophoresis. A rabbit antiserum against the partially purified Fab fragments was raised and shown to be specific for Fab fragments by immunoelectrophoresis. Furthermore, four lines of evidence indicated that the KMT 17 Fab fragments carry a cross‐reactive idiotype: (1) the antiserum could bind only with a restricted population of normal Fab fragments having a pl of 6.3; (2) an unrelated antibody (WKA anti‐SRBC) showed a weak cross‐reactivity (less than 6%); (3) syngeneic antisera against the KMT 17 could bind with the 1251‐KMT 17 Fab preparation that was purified by an immunoabsorbent column with the rabbit anti‐KMT 17 Fab antiserum (anti‐idiotype antibody); (4) the rabbit anti‐KMT 17 Fab antiserum could bind with neither heavy nor light chains of WKA IgG. The natural antibody carrying the idiotype was found in normal serum and in various organs as well, especially in the lung of the conventional rats. In addition, the fractions containing Fab fragments (Frll) were shown to enhance tumor growth when injected into syngeneic animals, whereas Fab‐free fractions that were separated from the Fab fragments by column electrophoresis showed no enhancing activity. These results strongly suggested that a population of Fab fragments carrying a cross‐reactive idiotype was responsible for the enhancement of tumor growth. Mechanisms for the biological function of natural anti‐tumor antibodies carrying a cross‐reactive idiotype are discussed.