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S Wolff

Publications and source records attributed to S Wolff.

At least 127 records · Page 7Linked to original sources
PubMed1984

Effect of 5-bromodeoxyuridine substitution on sister chromatid exchange induction by chemicals.

The fluorescence-plus-Giemsa (FPG) technique for analysis of sister chromatid exchange (SCE) is widely used as an assay for mutagenic carcinogens. There is very little information, however, on whether incorporation of the bromodeoxyuridine (BrdU) necessary for visualization of SCEs affects the sensitivity of the SCE test system to different chemical agents. We have investigated the effect of BrdU incorporation on SCE induction by labeling cells with BrdU for either the first cell cycle or the first and second cell cycles. The cells were then treated with bleomycin, which produces DNA strand breakage; proflavine, which intercalates into DNA; mitomycin C, which produces monoadducts and DNA crosslinks; or aphidicolin, which inhibits DNA polymerase alpha. Chemicals were added before BrdU exposure or during the first, second, or both cell cycles. Only mitomycin C, which induces long-lived lesions, elevated the SCE frequency when cells were treated before BrdU labeling. When bleomycin, proflavine, or mitomycin C was present concurrently with BrdU, the frequency of SCEs was increased independently of the BrdU labeling protocol. Aphidicolin, on the other hand, induced more SCEs when present for the second cell cycle, when DNA replicates on a template DNA strand containing BrdU. We also examined the induction of SCEs in the first cell cycle (twins) and in the second cell cycle (singles) after continuous treatment of cells with BrdU and the test chemicals. Only aphidicolin increased SCE frequency in the second cell cycle. These results indicate that aphidicolin, but not bleomycin, proflavine, or mitomycin C, affects BrdU-substituted DNA and unsubstituted DNA differently. This type of interaction should be taken into consideration when the SCE test is used as an assay system.

Animals↗
PubMed1984

Cultured human lymphocytes proliferate faster in medium lacking fetal calf serum and antibiotics.

When human whole blood was cultured in medium containing neither fetal calf serum nor antibiotics, more peripheral lymphocytes initiated DNA synthesis at about 24 h of culture than did lymphocytes in blood cultured in complete medium. Furthermore, the cells proliferated faster, so that by 48 h in culture approximately 20% of the metaphase cells in medium lacking fetal calf serum and antibiotics were in their second division. Such rapid cell proliferation can affect quantitative studies of chromosome aberrations, which should be observed in their first mitosis in culture, before cell death can cause a diminution in aberration yields. The rapid appearance of second-division metaphases should also be advantageous for the measurement of sister-chromatid exchanges (SCEs), which require two cell divisions for their observation. In contrast to cultures with complete medium, cells grown without fetal calf serum and antibiotics had fewer SCEs in second-division cells that divided later in the culture period.

Adult↗
PubMed1984

The significance of fibrinogen derivatives in plasma in human renal failure.

The concentrations in plasma of fibrinogen derivatives fibrinopeptide A (FPA), beta 15-42 antigen and fragment E (FgE) antigen have been determined in patients with renal failure and compared to the concentrations of the platelet release products, beta-thromboglobulin (beta TG) and platelet factor 4 (PF4). In 'partial renal failure' (51Cr-EDTA clearance rate 4-60 ml/min) FPA, beta 15-42 antigen, FgE antigen and beta TG levels were significantly raised above a normal laboratory control group. These levels were further raised in a group of patients whose disease required regular maintenance haemodialysis (51Cr-EDTA clearance rate less than 4 ml/min). PF4 levels were not significantly raised in either group. A statistical analysis of all patient results revealed that FPA, beta 15-42 antigen and FgE antigen levels all correlated with beta TG levels but not with PF4 levels. It is known that beta TG is catabolized by the kidney but PF4 is not and that elevated beta TG levels in renal failure are caused by impaired elimination rather than increased production. These results suggest that the plasma levels of these three fibrinogen derivatives are elevated in renal disease at least in part by decreased elimination rather than by increased thrombin and plasmin activities alone.

Adolescent↗
PubMed1984

Induction of sister chromatid exchange by 3-aminobenzamide is independent of bromodeoxyuridine.

The poly(ADP-ribose) polymerase inhibitor, 3-aminobenzamide (3AB), significantly increases sister chromatid exchange (SCE) frequency without causing apparent damage to cellular DNA. A previous study has suggested that the increase of SCEs by 3AB results from DNA replication on a template strand containing bromodeoxyuridine (BrdU), which is used to visualize SCEs. Therefore, to study the importance of BrdU incorporation on the induction of SCEs by 3AB, we analyzed exchanges induced during the first round of replication (twin SCEs) and those induced during the second (single SCEs). 3AB increased the formation of SCEs in both replication cycles, but significantly more exchanges were induced in the second cycle, when BrdU was present in the template DNA. These data are consistent with the suggestion that the presence of BrdU in the template strand of DNA plays an important role in SCE induction by 3AB. However, we also studied 3AB-induced SCEs by autoradiography of cells cultured with 3H-thymidine (3H-dT) instead of BrdU. A significant increase in SCE frequency was also observed in cells from these cultures. Furthermore, the analysis of twin and single SCEs showed that with 3H-dT too, there was a greater increase in SCEs in the second cycle than in the first. Thus, SCE induction by 3AB in the second cycle is not dependent on the presence of BrdU in template DNA. Incubation of cells with deoxycytidine was found to have no effect on the frequency of SCEs induced by 3AB, suggesting that an imbalance in the deoxycytidine precursor pool did not account for the effect.

Animals↗
PubMed1984

A consensual validation of schizoid personality in childhood and adult life.

Life histories and interview descriptions of 23 young men diagnosed as offizoid in middle childhood and adult life and of 20 control subjects not given this diagnosis were presented for diagnostic rating to two independent general psychiatrists. Agreement about the presence or absence of schizoid personality was good. It is concluded that, in the case of boys, the syndrome of schizoid personality in childhood (Asperger's syndrome) corresponds to or is subsumed by the more general clinical picture psychiatrists have of schizoid personality in adult life, and that our original use of this diagnostic label for the youngsters we described was not idiosyncratic.

Adult↗
PubMed1983

Effects of 3-aminobenzamide on DNA synthesis and cell cycle progression in Chinese hamster ovary cells.

3-Aminobenzamide (3AB), an inhibitor of poly(ADP-ribose) polymerase, is a potent inducer of sister chromatid exchanges (SCEs). Because of the possible relation between SCEs and DNA synthesis, the effects of 3AB on DNA synthesis and cell cycle progression in Chinese hamster ovary (CHO) cells were examined. Unlike all other SCE-inducing agents whose effects on DNA synthesis have been studied, short term exposures (30-120 min) of 3AB did not inhibit the overall rate of DNA synthesis and this result was independent of the amount of bromodeoxyuridine (BrdU) in the DNA. Longer exposure times (greater than 24 h) did result in an extended S phase, but this was not due to an effect on the rate of DNA chain elongation. 3AB also delayed the entry of cells into S phase. The overall cell cycle delay was dose dependent, approaching 9 h after a 54 h exposure to 10 mM 3AB. Earlier reports that 3AB is neither mutagenic nor cytotoxic were confirmed. Thus 3AB acts to increase SCE frequency by a mechanism distinct from that which causes cytotoxicity and mutagenicity, and does not involve any inhibition in the rate of DNA chain growth.

Animals↗
PubMed1983

Absence of an effect of diagnostic ultrasound on sister-chromatid exchange induction in human lymphocytes in vitro.

The frequency of sister-chromatid exchanges in human lymphocytes cultured in vitro was not changed after a 30-min exposure to a 2 MHz focused, diagnostic ultrasound beam with a pulse repetition rate of 1000 Hz, 1 musec burst duration, 100 W/cm2 temporal peak, spatial peak intensity. These results are consistent with those obtained with a number of other cell types and are contrary to some previously reported effects for human lymphocytes.

Bromodeoxyuridine↗
PubMed1983

Induction of sister-chromatid exchanges in human lymphocytes by microsomal activation of benzene metabolites.

Metabolic activation of the benzene metabolites, catechol, hydroquinone, and phenol, by rat-liver microsomes and an NADPH-generating system (S9 mix) caused an increased induction of sister-chromatid exchanges (SCEs) in cultured human lymphocytes. There were different optimal concentrations of S9 mix for converting each benzene metabolite into further reactive forms that could induce SCE-forming lesions. The data indicate that catechol and hydroquinone can be optimally metabolized to produce reactive species, presumably benzo(semi)quinones, under conditions of lower metabolic activity than those necessary for phenol and benzene.

Benzene↗
PubMed1983

Activation of coagulation and fibrinolytic systems following stroke.

When the human blood coagulation and fibrinolytic systems are activated thrombin cleaves fibrinopeptide A (FPA) and plasmin cleaves b beta1 leads to 42 from fibrin(ogen). Elevated plasma concentrations of FPA and B beta 1 leads to 42 are evidence for enhanced thrombin and plasma activities in plasma. We have determined the plasma concentrations of FPA and B beta 1 leads to 42 in patients who have had thrombotic stroke. Patients who were studied immediately following stroke were found to have greatly elevated plasma FPA and B beta 1 leads to 42 levels, but these decreased to the concentrations found in an apparently healthy age-matched control group 1 month after the infarct. In contrast, the plasma concentrations of the platelet release product beta-thromboglobulin (beta TG) were slightly, but significantly, elevated immediately following the stroke and these did not alter with time after the infarct. It is concluded that following thrombotic stroke increased thrombin and plasmin activities are to be found in plasma. These increased protease activities are probably not directly associated with an increased in vivo platelet release reaction and may be useful in deciding which patients are at risk of reinfarction or stroke progression.

Aged↗
PubMed1983

Effect of 3-aminobenzamide on sister chromatid exchange frequency in X-irradiated cells.

To investigate whether a delay in the rejoining of radiation-induced strand breakage can lead to sister chromatid exchange formation, Chinese hamster ovary cells were prelabeled with 5-bromodeoxyuridine and X-irradiated in the presence of 3-aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase. The resulting sister chromatid exchange frequencies were consistent with those expected if 3-aminobenzamide and X-ray treatments were independent and additive. A similar but much smaller additive effect was also observed in cells cultured in the presence of 3-aminobenzamide and X-irradiated immediately before the addition of bromodeoxyuridine to the culture medium. These findings support previous studies indicating that X rays are poor inducers of sister chromatid exchanges and suggest that the normally rapid resealing of DNA strand breaks does not account for this inefficiency.

Animals↗
PubMed1983

Sister chromatid exchanges and cell division delays induced by diethylstilbestrol, estradiol, and estriol in human lymphocytes.

It had been found previously that exposure of human lymphocytes in vitro to diethylstilbestrol (DES), a synthetic estrogen and known human carcinogen, led to the induction of sister chromatid exchanges. More sister chromatid exchanges were induced in cells from pregnant women than from men. To see if the effects of DES could be induced by other estrogens, lymphocytes from a man and a pregnant woman were treated in vitro with the natural estrogens estradiol and estriol. These did not induce sister chromatid exchanges. To see if the presence of exogenous female hormones might be responsible for the increase in DES-induced sister chromatid exchanges seen in cells from pregnant women, lymphocytes from a man and a pregnant woman were also treated in vitro simultaneously with DES, estradiol, estriol, and progesterone. Treatments with these exogenous hormones did not alter the number of DES-induced sister chromatid exchanges. Our previous studies showed that DES also inhibits in vitro proliferation of lymphocytes. The results reported here show that estradiol also strongly inhibits this proliferation but that estriol is only a weak inhibitor. The cause of delayed cell proliferation induced by DES and estradiol was 2-fold: some of the cells were delayed in phytohemagglutinin-mediated blast cell transformation but, additionally, most cells had a prolonged cell cycle because of an extended G2 phase. These studies also showed that DES, but not estradiol or estriol, induced a low level of polyploidy in human lymphocytes.

Cell Cycle↗
PubMed1982

In vivo platelet release in myeloproliferative disorders.

The in vivo platelet release reaction in 22 patients with myeloproliferative disorders has been studied by measuring plasma concentrations of the platelet release product beta-thromboglobulin (beta TG). Mean beta TG and mean beta TG: whole blood platelet count ratio were significantly raised in the patient group taken as a whole compared to an age matched control group. No significant increases were observed in the plasma concentrations of thrombin and plasmin sensitive fibrinogen fragments fibrinopeptide A (FpA) and B beta 1-42. The patients were divided into those who had normal, increased or decreased responses to in vitro ADP-induced platelet aggregation. Mean beta TG and the mean beta TG: whole blood platelet count ratio were higher in the increased and decreased responders to ADP than in the normal aggregation group, but the differences in means were not statistically significant. Aspirin given to six patients at a dose sufficient to eliminate the secondary phase of ADP-induced platelet aggregation reduced mean beta TG and the mean beta TG: whole blood platelet count ratio but did not alter mean FpA and B beta 1-42. It is concluded that the enhanced platelet release reaction seen in myeloproliferative disorders is independent of plasma protease activity that arises when coagulation and fibrinolytic systems are activated.

Aged↗
PubMed1982

Plasma concentrations of fibrinopeptide A, fibrinogen fragment B beta 1-42 and beta-thromboglobulin following total hip replacement.

Plasma concentrations of thrombin sensitive peptide fibrinopeptide A (FpA), plasmin sensitive fibrinogen fragment B beta 1-42 and the platelet release product beta-thromboglobulin (beta TG) have been measured in 36 patients before and after total hip replacement. Statistically significant elevations of all three activation products were observed in the days following operation. There were small differences in plasma concentrations of FpA, B beta 1-42 and beta TG in patients who did (n = 13) and did not (n = 23) develop post operative deep vein thrombosis, as assessed by ascending venography on post operative day 10, but these differences were not statistically significant. It is concluded that coagulation and fibrinolytic systems and also blood platelets are activated following total hip replacement operations. However, the formation of post operative deep vein thrombosis can not be effectively monitored by measurement of the activation products.

Adult↗