Quantitative fetomaternal hemorrhage assessment with the use of five laboratory tests.

INTRODUCTION: In various countries, standard doses of anti-D IgG used for postpartum immunoprophylaxis of hemolytic disease of fetus and newborn (HDFN) vary from 100 µg to 300 µg. There are also different regulations concerning FMH assessment, and opinions about applicable tests are inconclusive. METHODS: Three flow cytometry tests (FCTs) with anti-D, anti-HbF, anti-HbF+CA antibodies, and two modifications of microscopic Kleihauer-Betke test (KBT) were used. RESULTS: In all artificial mixtures with known concentrations, FCTs and KBT with counting 10 000 RBCs had similar satisfying sensitivity and specificity. KBT with counting 2000 RBCs had to be disqualified because of significant discrepancies between expected and measured values of FMH. The test procedure with anti-D was easier and shorter than the remaining tests, but it can be only used for FMH assessment in RhD-negative mothers with RhD-positive newborns. In one clinical sample, it was impossible to distinguish fetal RBCs from maternal F cells in KBT and FC with anti-HbF but other tests were useful. CONCLUSION: In the four tests, correlation between expected and obtained results was appropriate (CCC Ì´1). Each test had some advantage and limitation in any clinical situation. Therefore, it is best to have opportunity to perform two or three assays in the laboratory.

The protective role of antiplatelet treatment against ulcer formation due to argon plasma coagulation in patients treated for chronic radiation proctitis.

AIM: Following treatment with argon plasma coagulation (APC), rectal ulceration is seen in approximately 50% of patients with haemorrhagic chronic radiation proctitis (CRP). This study aimed to assess the frequency of rectal ulcers (defined as a mucosal defect of 3 mm or more in diameter) in relation to the use of antiplatelet treatment for concomitant cardiovascular disease. METHOD: Sixty-two patients with CRP were included in this retrospective study. Patients underwent pelvic irradiation due to prostate cancer (n = 28), cervical cancer (n = 16), endometrial cancer (n = 17) or rectal cancer (n = 1). APC was performed in all patients. Control endoscopies were performed at 8 and 16 weeks after enrolment. RESULTS: Rectal ulcers were observed after APC in 35 (56%) patients. They were symptomatic in 5 and asymptomatic in 30. The 20 (32%) patients who were on antiplatelet therapy had a significantly lower risk of ulceration after APC (OR = 0.21; 95% CI 0.049-0.91; P = 0.019). The number of symptomatic ulcers (5% vs 10%; P = 1.0) and asymptomatic ulcers alone (30% vs 58%; P = 0.06) was also lower in patients respectively taking and not taking antiplatelet therapy, but these differences did not reach statistical significance. CONCLUSION: Argon plasma coagulation-related ulceration in patients treated for CRP is less common when concomitant antiplatelet treatment is administered. This preliminary finding suggests that antiplatelet therapy may benefit patients treated with APC for CRP.

Sucralfate or placebo following argon plasma coagulation for chronic radiation proctitis: a randomized double blind trial.

AIM: Chronic radiation proctitis is a long-term complication of radiation therapy for pelvic malignancy. The aim of this study was to compare the efficacy and safety of two treatment regimens, sucralfate or placebo, following argon plasma coagulation (APC) for chronic haemorrhagic radiation proctitis. METHOD: A single-centre, randomized, placebo-controlled, double-blind study was performed on patients with haemorrhagic chronic radiation proctitis after irradiation for prostate, uterine, cervical, rectal or vaginal cancer. All patients received APC, and were then randomized to oral sucralfate (6 g twice a day) or placebo treatment for 4 weeks. APC was repeated every 8 weeks if necessary after the first session. Patients were graded clinically and endoscopically according to the Chutkan and Gilinski scales before and at 8 and 16 weeks after initial APC treatment (1.5-2 l/min, 25-40 W) and after 52 weeks (clinical only). RESULTS: Of 122 patients, 117 completed the entire protocol, with 57/60 in the sucralfate group and 60/62 in the placebo group. At baseline there were no significant differences between the sucralfate and placebo groups. At 1 year, a significant improvement in the clinical scale in both groups occurred compared with baseline. After 16 weeks, the median overall clinical severity scores fell from 4 to 2 points and the median bleeding score from 2 to 0 in both groups. CONCLUSION: APC is safe and effective for the management of chronic radiation proctitis. Additional sucralfate treatment did not influence the clinical or endoscopic outcome.

Coagulation disorders in patients with locally advanced head and neck cancer - should they really be disregarded?

The aim of the study was to analyse coagulation disorders in patients with locally advanced cancer of the head and neck (CHN)and with no other clinical cause for coagulation disorders treated with radiation therapy alone or concurrent chemoradiotherapy. We also assessed the duration of disorders in the course of therapy. The analysed group consisted of 33 patients with locally advanced CHN documented as stage T3 or T4 acc. to the TNM classification. Coagulology tests (activated partial thromboplastic time /APTT/, prothrombin time, fibrinogen concentration, euglobulin lysis time, C - reactive protein and anti-thrombin III concentration, d-dimer level, PAI-1, plasminogen level and plasmin-anti-plasmin assays) were performed before, during and after the completion of treatment. In all cases pre-tratment abnormal fibrinolysis was observed. We observed elevated PAI-1 levels in all blood tests regardless of the treatment stage, while elevated plasminogen concentration and euglobulin lysis time was observed in a majority of tests. Increased PAI-1 level persisted independently of tumor regression during treatment. Half of our patients also presented with a tendency towards shortened APTT. One patient had a significantly higher d-dimer level at the end of the treatment. Decreased APTT was the sole factor influencing overall survial (OS) confirmed in multivariate analysis (Cox's proportinal hazard model). Despite the occurence of abnormal fibrinolysis and decreased APTT, we did not observe an increased risk of coagulation disorders. We conclude that among caogulation tests only a decrease in APTT is, at present, a stasistically confirmed predective factor of shorter OS in CHN patients. Autothrombotic prophylactic treatment may be an effective option in this clinical setting. There is need for further studies on large patient groups.

Presence of t(14;18) positive cells in blood and bone marrow does not predict outcome in follicular lymphoma.

Follicular Lymphoma International Prognostic Index-FLIPI is an established clinical predictor for outcome in follicular lymphoma. The role of molecular abnormalities in blood and bone marrow of follicular lymphoma patients including t(14;18) is less clear. Seventy-five patients from a single institution diagnosed with follicular lymphoma between1999 and 2005 were included into the study. Diagnosis was based on lymph node biopsy in 62 cases (83%). Thirty-nine patients (52%) had G1 histological grade and 47 (63%) had entirely follicular growth pattern, as well as 9 patients (12%) had systemic symptoms and 33 (44%) were assigned to a good risk according to FLIPI. Median age of patients was 53 years. During a median observation time of 3 years 63 patients (84%) required initiating anti-lymphoma treatment. Seventy-five samples of peripheral blood and 65 samples of bone marrow were collected at the diagnosis. Bcl2 rearrangements including major breakpoint region and minor breakpoint cluster region were investigated using nested polymerase chain reaction technique. The primary end points of the study were time to first line lymphoma treatment and progression-free survival. Cells carrying t(14;18) were found in 31 cases (41%) including 29 samples of peripheral blood and 26 samples of bone marrow. Detection of t(14;18) in blood and bone marrow at diagnosis had no influence on clinical outcome. Age, follicular growth pattern systemic symptoms, and FLIPI score above 1 were predictive for initiation of the first lymphoma therapy. Follicular growth pattern, initial nodal involvement, serum LDH level, and FLIPI score above 1 were predictive for longer progression-free survival.

Geographical variations in TP53 mutational spectrum in ovarian carcinomas.

The TP53 gene mutational spectrum in human tumours shows variations related to tissue of origin, carcinogen exposure or molecular background. We have compared TP53 mutations in ovarian carcinomas from different geographical regions; this study was based on data extracted and verified from the IARC database (R10, 2005), and on our results from 127 carcinomas. In total 873 mutations were evaluated. Tumours from Japan and Korea had a higher frequency of exon 7 mutations (38%vs 25%, p = 0.011) and lower frequency of exon 8 mutations (11%vs 29%, p = 0.0003) than those from Western countries; they were particularly different from Norwegian tumours which showed the lowest proportion of exon 7 (19%, p = 0.001) and highest proportion of exon 8 (37%, p < 0.0001) mutations. There were also differences in the profile of TP53 hotspots. The third hotspot in tumours from Poland was amino acid (AA) 176 (8.2% of substitutions vs 1.7% in other countries, p < 0.001), while in tumours from the UK it was AA 220 (8.9%vs 2.3%, p < 0.001). Codon 273 was the only apparent hotspot in the Norwegian tumours, while it was rarely mutated in Polish and Asian tumours. In contrast to other data tumours from Norway presented with 273(HIS) codon (82% of mutations at AA 273, p = 0.002), while tumours from the UK shared the 273(CYS) codon (80%, p < 0.001). Further analysis of TP53 gene mutations in ovarian cancer by geography could provide greater insights.

Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells in leukapheresis product and bone marrow for clinical transplantation: a comparison of three methods.

Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells (HSCs) is widely used for evaluation of graft adequacy of peripheral blood and bone marrow stem cell grafts. In the present study, we review and compare the major counting techniques of stem and progenitor cells. The methods are: the Milan/Mullhouse protocol, two-platform ISHAGE (International Society of Hematotherapy and Graft Engineering) and single-platform ISHAGE analysis system. According to the Milan/Mulhouse protocol, HSCs are identified by CD34 antibody staining and easy gating strategy. The ISHAGE guidelines for detection of CD34+ cells are based on a four-parameter flow cytometry method (CD34PE/CD45PerCP staining, side and forward angle light scatter) thus employing multiparameter gating strategy. With two-platform ISHAGE protocol, an absolute CD34+ count is generated by incorporating the leukocyte count from an automated hematology analyser. The single-platform ISHAGE method to determine the absolute CD34+ count directly from a flow cytometer includes the use of Trucount tubes (Becton Dickinson) with a known number of fluorescent beads. CD34+ cells were quantified in mobilized peripheral blood, collected by leukapheresis, and bone marrow from 42 samples from patients with hematological malignancies. The differences against the means display low disagreement between the Milan/Mulhouse and ISHAGE protocols, with discrepancies of up to 2.5% (two-platform ISHAGE)--2.6% (single-platform ISHAGE) in enumeration of CD34+ cells in leukapheresis product and 4.8% (two-platform ISHAGE)--4.9% (single-platform ISHAGE) in bone marrow. Our results show high correlation among all three methods. Since the three protocols are compatible, choosing the most convenient in terms of costs, simplicity and compliance with clinical results appears to be a logical consequence.

TP53 status determines clinical significance of ERBB2 expression in ovarian cancer.

ERBB2 expression has been found in 19 to 44% of ovarian carcinomas; however, its predictive value has not been demonstrated, and trastuzumab has not found clinical application in ovarian cancer patients. We evaluated clinical significance of ERBB2 expression in relation to TP53 accumulation in ovarian carcinoma patients treated with platinum-based regimens. Immunohistochemical analysis with CB11 and a novel NCL-CBE356 antibody (against the internal and external domains of ERBB2, respectively) was performed on 233 tumours (FIGO stage IIB-IV); the US Food and Drug Administration-approved grading system with 0 to 3+ scale was used for evaluation, and the results were analysed by the Cox and logistic regression models. In all, 42% of the tumours expressed (category 1+, 2+ or 3+) either CB11 or CBE356 or both (CB11/CBE356 parameter). Associations between ERBB2 expression and clinical factors were observed only if tumours with staining category 1+ were grouped together with tumours showing staining categories 2+ and 3+. CB11/CBE356 parameter had a better predictive value than CB11 alone. CB11/CBE356 expression was negatively associated with platinum sensitivity (PS) in the TP53(-) group (P=0.022) and with disease-free survival (DFS) in the TP53(+) group (P=0.009). Our results may suggest that trastuzumab should be given postoperatively to patients with TP53(-)/ERBB2(+) ovarian carcinomas to enhance PS, and after completion of chemotherapy to patients with complete remission and TP53(+)/ERBB2(+) carcinomas to extend DFS time (in total to 30.4% of all patients analysed). Thus, novel criteria for ovarian cancer patient inclusion for clinical trials with trastuzumab should be considered and tested.

P21WAF1, P27KIP1, TP53 and C-MYC analysis in 204 ovarian carcinomas treated with platinum-based regimens.

BACKGROUND: The prognostic and predictive value of cell cycle regulatory proteins in ovarian cancer has not been established. We evaluated the clinical and biological significance of P21(WAF1), P27(KIP1), C-MYC, TP53 and Ki67 expressions in ovarian cancer patients. MATERIALS AND METHODS: Immunohistochemical analysis was performed on 204 ovarian carcinomas of International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV treated with platinum-based chemotherapy. Multivariate analysis with Cox and logistic regression models was performed in the whole group, and in the TP53-negative and TP53-positive subgroups. RESULTS: High P21(WAF1) labeling index (LI) was an independent positive predictor of platinum-sensitive response (P = 0.02). Overall survival was positively influenced by P21(WAF1) LI (P = 0.02) or by P21(WAF1) plus P27(KIP1) LI (P = 0.004) in the TP53-negative group only. Ki67 LI showed borderline association with disease-free survival (P = 0.05). Growth fraction was negatively associated with P21(WAF1) and P27(KIP1) indices in the TP53-negative group (P = 0.023 and 0.008, respectively), and these associations were borderline or lost in the TP53-positive group. Endometrioid and clear cell carcinomas differed from other carcinomas by having a low incidence of TP53 accumulation, a high incidence of C-MYC overexpression (70%) and a low median Ki67 LI (all with P <0.001). CONCLUSIONS: We have shown an independent predictive value of P21(WAF1) LI in ovarian carcinoma patients. The prognostic value of P21(WAF1) and P21(WAF1) plus P27(KIP1) LI was determined by TP53 status. A high frequency of C-MYC overexpression in endometrioid and clear cell carcinomas may suggest its role in the development of these tumor types.

Evaluation of clinical significance of TP53, BCL-2, BAX and MEK1 expression in 229 ovarian carcinomas treated with platinum-based regimen.

In cell line studies, BCL-2, BAX, as well as novel MEK1 protein levels have strong influence on ovarian cancer response to cisplatin-based chemotherapy. However, such associations have not been demonstrated clinically. We evaluated prognostic/predictive significance of these proteins with regard to TP53 status. Immunohistochemical analysis was performed on 229 ovarian carcinomas FIGO stage IIB-IV treated with platinum-based chemotherapy; the results were analysed by the Cox and logistic regression models. Clinical parameters (residual tumour size, patient age, FIGO stage) were the only indicators of overall survival (OS) and the strongest predictors of complete remission (CR). On the other hand, BAX expression was the strongest (P=0.005) or the only (in FIGO IIIC, P=0.02) prognostic indicator of disease-free survival (DFS) in the TP53(+) group. TP53(+) and TP53(-) ovarian carcinomas differed in clinical and molecular prognostic and predictive factors. Another novel finding is that CR was negatively influenced by high BAX expression in all patients group (P=0.047) and by BCL2 expression in the TP53(-) group (P=0.05). High MEK1 expression was associated with endometrioid and clear cell carcinomas (P=0.049); its loss was found with advancing FIGO stage (P=0.002). Our results suggest that binomial TP53 status divides ovarian carcinomas into two biologically distinct groups. BAX expression is an important factor of DFS in the TP53(+) group. BCL-2 and BAX, but not MEK1 expressions have predictive value in ovarian cancer patients treated with platinum-based chemotherapy.

A multicentre randomized/controlled trial of a conventional versus modestly accelerated radiotherapy in the laryngeal cancer: influence of a 1 week shortening overall time.

BACKGROUND AND PURPOSE: To compare in a phase III study the loco-regional control, disease-free survival and overall survival induced by an accelerated regimen (AF) as compared with conventional regimen (CF) and to analyze the early and late post-radiation morbidity in both arms. MATERIALS AND METHODS: Patients with age < or = 75, WHO 0-1, suitable for a radical course of radiotherapy T1-T3, N0, M0, stage of glottic and supraglottic laryngeal cancer were randomized to either CF: 66Gy given in 33 fractions over 45 days or AF: 66Gy given in 33 fractions over 38 days (2 fractions every Thursday). A total of 395 patients were included from 05.1995 to 12.1998. RESULTS: Early toxicity: At the end of radiotherapy patients treated with AF complained for more severe reactions than patients treated with CF. In 8 weeks after treatment completion patients treated with AF complained only for more severe pain on swallowing (P=0.027). In 4 months after treatment completion all types of toxicity except for skin teleangiectasia (P=0.001) were similar in the two groups. Loco-regional control: comparison between CF and AF showed no difference in terms of loco-regional control (P=0.37). CONCLUSIONS: The improvement in AF in terms of loco-regional control is estimated to be 3-5% in comparison with conventional regimen and is not significant. The intensity of reactions after 4 months was similar in both arms, what suggests the possibility of further shortening of the overall time by few days or enhancing the total dose within the limits of acceptable morbidity.

Molecular cytogenetic analysis of DNA sequences with flanking telomeric repeats in Triticum aestivum cv. Begra.

A cloned genomic DNA fragment (pTa241) formerly derived from a DNA fraction obtained from isolated nuclei of embryos of a Polish cultivar of wheat (Triticum aestivum cv. Begra) comprises a tandem repeat of the telomeric array CCCTAAA, and hybridizes in situ exclusively to the telomeres of all chromosome arms of the somatic chromosome complement of wheat. A second cloned fragment (pTa637) derived from the same fraction is 637 bp long, flanked by 28 bp of the same telomeric repeat unit, and hybridizes in situ to the entire lengths of all the chromosomes of the complement. The same pattern of hybridization was observed when the flanking telomeric sequences were removed. A third DNA fragment (pTa1439), derived from unfractionated genomic DNA and flanked with 62 bp of the same telomeric unit, showed the same patterns of distribution. Together with additional evidence from Southern analysis, these observations were interpreted to mean that these sequences are associated with mobile DNA elements and are distributed widely throughout the genome. The chromosomal distribution of the non-telomeric parts of the clones is consistent with the dispersed genomic distribution characteristic of transposons and retroelements.

Rituximab (Mabthera, Rituxan) in patients with recurrent indolent lymphoma: evaluation of safety and efficacy in a multicenter study.

The objective of this multiinstitutional study was to evaluate the safety and efficacy of rituximab at standard four weekly doses in patients with recurrent indolent lymphoma. Thirty-eight patients entered into this study, 63% had follicular lymphoma and 61% had an IPI score of 2 or more. Median disease duration was 3 yr, median number of prior treatments was three, and 66% of patients responded to the immediate past treatment with a median remission duration of 3 mo. A total of 158 antibody doses were given, including two patients who received two courses of four infusions each. One patient developed acute respiratory failure after the second dose and required assisted ventilation. There was no immediate relationship to the antibody infusion and no evidence of infection. This complication resolved and the patient successfully completed the full course of the antibody treatment. Another patient discontinued therapy after the second dose owing to intolerable fever and painful erythema. Sixty percent of the first, and 20% of subsequent rituximab infusions were associated with infusion-related reactions including mild fever, chills, and occasional skin eruptions. Complete and partial responses were achieved in 24% and 35% of 34 evaluable patients, respectively, for an overall response rate of 59%. The median time to progression/relapse in responding patients was 16 mo (95% CI, 6.4, 25.6) compared with a median of 3 mo duration of response to the immediate previous therapy in these patients. Longer response duration post rituximab monotherapy than with previous treatment in this series of heavily pretreated patients suggests a major role for the antibody in the therapy of patients with indolent lymphoma.

[Cervical cancer prevention - awareness and health behavior changes of women in 1976, 1986, 1990 and 1998]. / Zmiany uswiadomienia i zachowan zdrowotnych kobiet dotyczace profilaktyki raka szyjki macicy w latach 1976, 1986, 1990 i 1998.

AIM: To find the changes in the proportion of women who declared knowledge about cytological tests and underwent that test in the years 1976, 1986, 1990 and 1998, as well as in the proportion of those who declared showing up at the gynaecologist during the last year. To assess the number of women taking part in the secondary prevention of cervical cancer. To correct health education intervention targeted at women. METHODS: The results of four cervical prevention surveys on representative samples of Polish women aged over 18 years were compared. RESULTS: The substantial (58%) increase in the proportion of women who declared awareness of cytological tests was shown. As expected, smaller favourable changes were found in the field of women's health related to secondary prevention. The percent of women who declared yearly visits at the gynaecologists increased by 12% and those who declared having cytological tests done during last three years by 7%. The lowest level of awareness and the lowest frequency of using prevention services were declared among women aged over 60, represented the lowest education level and resided in rural areas. CONCLUSIONS: It is important to continue educational work and intervention measures concerning cervical cancer prevention, with special attention to the most neglected groups of women.

CN3OP: an active regimen in patients with relapsed/refractory Hodgkin's lymphoma.

Patients with recurrent or refractory Hodgkin's and non-Hodgkin's lymphoma are increasingly being treated with high-dose therapy and hematopoietic cell transplantation. As minimal disease status at the time of transplant has been a repeatedly proven significant prognostic factor for long-term survival, effective initial cytoreduction is an important step in the process. Modern chemotherapy programs for Hodgkin's lymphoma include virtually all active agents and little is left for effective salvage. Mitoxantrone is an active agent in lymphoma that is not generally used in first-line treatment. The aim of this study was to determine toxicity and response rate to CN3OP (fractionated mitoxantrone 6 mg/m2 on days 1, 2, and 3, combined with standard dose cyclophosphamide, vincristine, and prednisone) in 44 patients with relapsed or refractory lymphoma. Most of patients had advanced disease and one or more extranodal sites at relapse. Median response duration to immediate past therapy was four months, and one third of patients had not responded to prior treatment. A median of 4 cycles of CN3OP were given per patient for a total of 173 cycles. Grade III-IV neutropenia occured in 53% of cycles, Grade I-III mucositis in 24%, and Grade I-III infection in 17% of cycles. Of 34 evaluable patients with Hodgkin's lymphoma 12 (35%) achieved complete remission (CR) and 15 (44%) partial remission (PR) for an overall response rate of 79%. Two of five evaluable non-Hodgkin's lymphoma patients responded with PR. Median overall survival and event free survival in the entire group was 29 months and 11 months respectively. At this time 16 patients have died; 12 of lymphoma, two of unknown cause and two of other causes. Complete response to CN3OP correlated with survival. CN3OP is an effective and safe regimen for cytoreduction in Hodgkin's lymphoma patients pretreated with doxorubicin/alkylator/etoposide-containing primary therapies.

Spontaneous apoptosis in ovarian carcinomas: a positive association with p53 gene mutation is dependent on growth fraction.

Changes in cell survival contribute to tumour development, influence tumour biology and its response to chemotherapy. p53 gene alterations should negatively affect apoptosis by impaired p53-dependent apoptotic response. We looked for associations between spontaneous apoptosis, p53 gene mutation, p53 protein accumulation, growth fraction, bcl-2 expression and histological parameters in 64 ovarian, four tubal and three peritoneal carcinomas. Apoptotic cells were detected with the TUNEL method. p53 gene variants were detected by the single-strand conformation polymorphism and were sequenced directly. P53, Ki-67 and bcl-2 protein expressions were detected immunohistochemically. A weighed multiple logistic regression model was applied. Apoptotic index (AI) ranged 0.02-0.18 (mean 0.11); proliferation index (PI) ranged 3-90% (mean 54%). p53 gene mutations were present in 51, p53 protein accumulation in 46, and diffuse bcl-2 expression in 29 of 71 tumours. The AI was positively associated with the presence of p53 gene mutation (P = 0.011). However, the PI included into the analysis did positively influence the AI (P = 0.02) and diminished the association with p53 gene mutation (P = 0.082). The AI was negatively associated with good histological differentiation (P = 0.0006), the serous tumour type (P = 0.002), and diffuse bcl-2 expression (P = 0.025). Strong bcl-2 expression was associated with endometrioid tumour type (P = 0.002). FIGO stage and p53 protein accumulation were the only parameters that influenced overall survival time. Thus, our results suggest that histological tumour type and grade are major determinants of spontaneous apoptosis in ovarian carcinomas; p53 alterations do not adversely but rather positively affect spontaneous apoptosis by increasing growth fraction. This, in turn, suggests p53-independency of spontaneous apoptosis in ovarian carcinomas.

Is serum bilirubin concentration the only valid prognostic marker in primary biliary cirrhosis?

From the many prognostic models for primary biliary cirrhosis (PBC) patients based on Cox's regression analysis, the Mayo model has gained the most popularity and was successfully validated in some centers. The aim of our study was to validate the Mayo survival model for Polish PBC patients and, in case of its inapplicability, to select prognostic variables and to create time-fixed and time-dependent survival models for the patients. We used database information on patients from 6 medical centers in Poland, fulfilling clinical, serological, and/or pathological criteria of PBC. The Mayo model was validated using data from 116 PBC patients. The time-fixed and time-dependent models were created using data on clinical and biochemical variables used in the Mayo model from 162 and 208 patients, respectively. The Mayo model validation was performed graphically and by one-sample log-rank tests after dividing the study sample into 3 groups of high, medium, and low risk. The survival analysis was performed using Cox's proportional hazards regression method on clinical and biochemical variables used in the Mayo model. Treatment with ursodeoxycholic acid (UDCA) was included in the time-dependent analysis. Validation showed that the Mayo model overestimated death risk in Polish PBC patients. Of the variables used in the Mayo model, serum bilirubin concentration appeared to be the only variable of prognostic importance. The analysis shows that serum bilirubin concentration holds most of the prognostic information for our PBC patients irrespective of prior treatment with UDCA.

Tobacco BY-2 cells excise both 3-methyladenine and 7-methylguanine from methylated DNA.

Two of the major products in DNA resulting from exposure to alkylating agents are 7-methylguanine and 3-methyladenine. N-methylpurine-DNA-glycosylase is required for excision of these lesions. Recently, the 3-methyladenine-DNA-glycosylase gene of Arabidopsis thaliana was cloned and shown to be involved only in repair of 3-methyladenine. In BY-2 tobacco cells, we showed an enzymatic activity which excised both 3-methyladenine and 7-methylguanine from methylated DNA.

A reverse transcriptase-like activity of wheat (Triticum aestivum) embryo microsomal fraction.

A reverse transcriptase-like activity was isolated from germinating wheat (Triticum aestivum) embryos. The activity was found to be associated with a microsomal fraction (70,000 g pellet) of the embryo homogenate. The microsome-associated enzyme prefers homologous polyadenylated RNA to any other polynucleotides as template and requires all four deoxyribonucleoside triphosphates for maximal activity. The reaction product appears in the incubation mixture in the form of an RNA-DNA hybrid, which can be converted into single-stranded DNA by mild alkaline hydrolysis. These observations suggest that normal wheat embryo cells contain an enzyme which, functionally, is similar to retroviral reverse transcriptase.

Replication of the rRNA and legumin genes in synchronized root cells of pea (Pisum sativum): evidence for transient EcoR I sites in replicating rRNA genes.

The temporal pattern of replication of the rRNA and legumin genes differs in synchronized pea root cells. The relative number of rRNA genes replicated hourly during the first five hours of S phase ranges between 5 and 10 percent. In late S phase, during hours six through nine, the number of rRNA genes replicated increases reaching a maximum of about 25 percent at the ninth hour. Unlike the rRNA genes, the legumin genes have a wave-like pattern of replication peaking in early S phase at the third hour and again in late S phase at the eighth hour.Replicating rDNA, isolated by benzoylated naphthoylated DEAE-column chromatography, has EcoR I restriction sites that are absent in non-replicating rDNA sequences. The cleavage of these sites is independent of the time of rDNA replication. The transient nature of the EcoR I sites suggests that they exist in a hemimethylated state in parental DNA.The two Hind III repeat-size classes of rDNA of var. Alaska peas are replicated simultaneously as cells progress through S phase. Thus, even if the 9.0 kb and 8.6 kb repeat classes are located on different chromosomes, their temporal order of replication is the same.