Seropositivity in blood donors and pregnant women during the first year of SARS-CoV-2 transmission in Stockholm, Sweden.

BACKGROUND: In Sweden, social restrictions to contain SARS-CoV-2 have primarily relied upon voluntary adherence to a set of recommendations. Strict lockdowns have not been enforced, potentially affecting viral dissemination. To understand the levels of past SARS-CoV-2 infection in the Stockholm population before the start of mass vaccinations, healthy blood donors and pregnant women (n = 5,100) were sampled at random between 14 March 2020 and 28 February 2021. METHODS: In this cross-sectional prospective study, otherwise-healthy blood donors (n = 2,600) and pregnant women (n = 2,500) were sampled for consecutive weeks (at four intervals) throughout the study period. Sera from all participants and a cohort of historical (negative) controls (n = 595) were screened for IgG responses against stabilized trimers of the SARS-CoV-2 spike (S) glycoprotein and the smaller receptor-binding domain (RBD). As a complement to standard analytical approaches, a probabilistic (cut-off independent) Bayesian framework that assigns likelihood of past infection was used to analyse data over time. SETTING: Healthy participant samples were randomly selected from their respective pools through Karolinska University Hospital. The study was carried out in accordance with Swedish Ethical Review Authority: registration number 2020-01807. PARTICIPANTS: No participants were symptomatic at sampling, and blood donors were all over the age of 18. No additional metadata were available from the participants. RESULTS: Blood donors and pregnant women showed a similar seroprevalence. After a steep rise at the start of the pandemic, the seroprevalence trajectory increased steadily in approach to the winter second wave of infections, approaching 15% of all individuals surveyed by 13 December 2020. By the end of February 2021, 19% of the population tested seropositive. Notably, 96% of seropositive healthy donors screened (n = 56) developed neutralizing antibody responses at titres comparable to or higher than those observed in clinical trials of SARS-CoV-2 spike mRNA vaccination, supporting that mild infection engenders a competent B-cell response. CONCLUSIONS: These data indicate that in the first year since the start of community transmission, seropositivity levels in metropolitan in Stockholm had reached approximately one in five persons, providing important baseline seroprevalence information prior to the start of vaccination.

Virome characterisation from Guthrie cards in children who later developed acute lymphoblastic leukaemia.

BACKGROUND: Some childhood acute lymphoblastic leukaemias (ALL) can be traced back to a prenatal origin, where a virus infection could be involved in the first pre-leukaemic clone development. The DNA virome of 95 children who later developed ALL was characterised from neonatal blood spots (NBS) using unbiased next-generation sequencing (NGS) and compared with the virome of 95 non-ALL controls. METHODS: DNA was individually extracted from the ALL-patients and controls, pooled, randomly amplified and sequenced using the Illumina MiSeq Sequencing System. RESULTS: Virus-like sequences identified in both groups mapped to human endogenous retroviruses and propionibacterium phage, considered a part of the normal microbial flora. Potential pathogens human herpesvirus type 6 (HHV-6) and parvovirus B19 were also identified, but only few samples in both ALL and controls tested positive by PCR follow-up. CONCLUSIONS: Unbiased NGS was employed to search for DNA from potential infectious agents in neonatal samples of children who later developed ALL. Although several viral candidates were identified in the NBS samples, further investigation by PCR suggested that these viruses did not have a major role in ALL development.

Studies of human polyomaviruses, with HPyV7, BKPyV, and JCPyV present in urine of allogeneic hematopoietic stem cell transplanted patients with or without hemorrhagic cystitis.

BACKGROUND: BK polyomavirus (BKPyV) can cause hemorrhagic cystitis (HC) in allogeneic hematopoietic stem cell transplant (allo-HSCT) patients and polyomavirus-associated nephritis in renal transplant patients, while JC polyomavirus (JCPyV) can generate progressive multifocal leukoencephalopathy in immunocompromised individuals. Since 2007, additional human polyomaviruses (HPyVs) have been identified. In this study, we examined the urines of allo-HSCT patients for possible presence of polyomaviruses BKPyV, JCPyV, KIPyV, WUPyV, MCPyV, HPyV6, HPyV7, TSPyV, HPyV9, and HPyV10 (MWPyV). METHODS: A total of 185 urinary samples obtained 2002-2007 from 105 allo-HSCT patients, 32/105 with HC, were tested for the above-listed HPyVs by a bead-based multiplex assay. Of these, 142 urine samples had previously been tested for BKPyV and JCPyV by nested polymerase chain reaction (PCR). RESULTS: Aside from BKPyV and JCPyV, which dominated, HPyV7 was detected in 5 BKPyV-positive urinary samples from 1 patient. The multiplex assay was more sensitive and specific than the nested PCR. BKPyV and/or JCPyV were found in all but 1 of the previously BKPyV- or JCPyV-positive samples, although 6 previously BKPyV-positive cases were now JCPyV-positive or the reverse. Furthermore, 18/79 previously negative samples were found to be BKPyV and/or JCPyV positive, and a total of 21 double infections were found. Lastly, in 1/29 HC patients, only JCPyV was detected. CONCLUSION: HPyV7 was found for the first time in urine of an allo-HSCT patient, and BKPyV and JCPyV were more commonly found in urine samples using the bead-based assay compared to testing by nested PCR. Finally, only JCPyV was detected in the urine of 1 HC patient.

Science ethics education part II: changes in attitude toward scientific fraud among medical researchers after a short course in science ethics.

PURPOSE: To determine the impact of the short science ethics courses on the knowledge of basic principles of responsible conduct of research (RCR), and on the attitude toward scientific fraud among young biomedical researchers. METHODS: A total of 361 attendees of the course on science ethics answered a specially designed anonymous multiple- choice questionnaire before and after a one-day course in science ethics. The educational course consisted of 10 lectures: 1) Good scientific practice - basic principles; 2) Publication ethics; 3) Scientific fraud - fabrication, falsification, plagiarism; 4) Conflict of interests; 5) Underpublishing; 6) Mentorship; 7) Authorship; 8) Coauthorship; 9) False authorship; 10) Good scientific practice - ethical codex of science. RESULTS: In comparison to their answers before the course, a significantly higher (p<0.001) number of students qualified their knowledge of science ethics as sufficient after the course was completed. That the wrongdoers deserve severe punishment for all types of scientific fraud, including false authorship, thought significantly (p<0.001) more attendees than before the course, while notably fewer attendees (p<0.001) would give or accept undeserved authorship CONCLUSION: Even a short course in science ethics had a great impact on the attendees, enlarging their knowledge of responsible conduct of research and changing their previous, somewhat opportunistic, behavior regarding the reluctance to react publicly and punish the wrongdoers.

Science ethics education: effects of a short lecture on plagiarism on the knowledge of young medical researchers.

PURPOSE: Plagiarism is the most common form of scientific fraud. It is agreed that the best preventive measure is education of young scientists on basic principles of responsible conduct of research and writing. The purpose of this article was to contribute to the students' knowledge and adoption of the rules of scientific writing. METHODS: A 45 min lecture was delivered to 98 attendees during 3 courses on science ethics. Before and after the course the attendees fulfilled an especially designed questionnaire with 13 questions, specifically related to the definition and various types of plagiarism and self-plagiarism. RESULTS: Although considering themselves as insufficiently educated in science ethics, the majority of the attendees responded correctly to almost all questions even before the course, with percentages of correct responses to the specific question varying from 45.9-85.7%. After completion of the course, these percentages were significantly (p<0.01) higher, ranging from 66.3-98.8%. The percentage of improvement of the knowledge about plagiarism ranged from 9.18- 42.86%. The percentage of impairment ranged from 1.02- 16.33%, the latter being related to the question on correct citing unpublished materials of other people; only for this question the percentage of impairment (16.33%) was greater than the percentage of improvement (11.22%). CONCLUSION: Even a short lecture focused on plagiarism contributed to the students' awareness that there are many forms of plagiarism, and that plagiarism is a serious violation of science ethics. This result confirms the largely accepted opinion that education is the best means in preventing plagiarism.

Expression analysis of genes involved in apoptosis, proliferation and endoplasmic reticulum stress in ionomycin/PMA treated Jurkat cells.

PURPOSE: Activation of T cells by direct stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io) results in numerous downstream signals that activate pathways enabling T cells to proliferate and produce cytokines. Inducible T cell activation is regulated predominantly at the transcriptional level. Therefore, we were interested to analyze the transcriptional activity of the 19 genes involved in the regulation of several important cellular processes. METHODS: Quantitative real-time (RT) PCR analysis was performed using mRNA-specific primers and SybrGreen for relative mRNA expression levels of all the examined genes. RESULTS: Our results showed c-kit expression in Jurkat cells, further confirmed by sequencing of c-kit mRNAspecific PCR product. The expected increased expression of interleukin (IL)-2 mRNA, together with moderate Ki-67 upregulation, indicate the proliferation of PMA/Io treated Jurkat cells. Significant upregulation of nuclear factor (NF)-κB, JNK and the prosurvival Bcl-2 was followed by activation of only one protein kinase RNA-like endoplasmic reticulum kinase (PERK) out of 3 main endoplasmic reticulum (ER) stress subpathways (ATF6 and spliced XBP were downregulated). NF-κB and JNK activation, as well as ERK downregulation were reactive oxygen species (ROS)-independent, shown by the lack of activation of antioxidative enzymes (SOD, NOS, GSTP1, gGCS and GR). C-kit was downregulated in the absence of exogenous SCF (c-kit ligand). CONCLUSION: Based on these data it is concluded that the PMA/Io treatment of Jurkat cells induced increased expression of IL-2, followed by upregulation of prosurvival genes belonging to the Bcl-2 family. Neither c-kit nor the antioxidative system were activated, excluding their role in Jurkat T-cell activation in the absence of exogenous c-kit ligand SCF.

Science ethics education part I. Perception and attitude toward scientific fraud among medical researchers.

PURPOSE: To assess the knowledge of basic principles of responsible conduct of research and attitude toward the violations of good scientific practice among graduate biomedical students. METHODS: A total of 361 subjects entered the study. The study group consisted mainly of graduate students of Medicine (85%), and other biomedical sciences (15%). Most participants were on PhD training or on postdoctoral training. A specially designed anonymous voluntary multiple-choice questionnaire was distributed to them. The questionnaire consisted of 43 questions divided in 7 parts, each aimed to assess the participants' previous knowledge and attitudes toward ethical principles of science and the main types of scientific fraud, falsification, fabrication of data, plagiarism, and false authorship. RESULTS: Although they considered themselves as insufficiently educated on science ethics, almost all participants recognized all types of scientific fraud, qualified these issues as highly unethical, and expressed strong negative attitude toward them. Despite that, only about half of the participants thought that superiors-violators of high ethical standards of science deserve severe punishment, and even fewer declared that they would whistle blow. These percentages were much greater in cases when the students had personally been plagiarized. CONCLUSION: Our participants recognized all types of scientific fraud as violation of ethical standards of science, expressed strong negative attitude against fraud, and believed that they would never commit fraud, thus indicating their own high moral sense. However, the unwillingness to whistle blow and to punish adequately the violators might be characterized as opportunistic behavior.

Expression analysis of genes involved in epigenetic regulation and apoptosis in human malignant haematopoietic cell lines treated with 5-azacytidine.

PURPOSE: The aim of this study was to investigate the modulation of the expression status of 10 different genes involved in epigenetic regulation and apoptosis by the DNA methyltransferase (DNMT) inhibitor 5-azacytidine (5-Aza), as markers of response to treatment, in two different human malignant haematopoietic cell lines. METHODS: In our analysis we used the SybrGreen technology and gene-specific primers for the qRT-PCR analysis of 10 genes, in cDNA of PC-MDS and K562 cell lines, treated by 1 micromole of 5-Aza for 24h. RESULTS: DNMT1 and DNMT3A showed statistically significant decrease of expression in 5-Aza-treated PC-MDS cells, whereas DNMT3B showed significantly decreased expression in 5-Aza-treated K562 cells. The members of the Bcl- 2 family of apoptosis-regulating genes Bcl-2 and Bax showed statistically significant differences in expression, in comparison with non-treated PC-MDS cells. Our most interesting result was the significant upregulation (re-expression) of p15, in 5-Aza-treated PC-MDS cells. CONCLUSION: The re-expression of p15 in PC-MDS cell line evaluated by qRT-PCR makes this novel cell line a suitable model for the studies of pharmacologic demethylation as a plausible mechanism resulting in hematologic response in myelodysplastic syndrome (MDS).

Adenovirus DNA in Guthrie cards from children who develop acute lymphoblastic leukaemia (ALL).

BACKGROUND: In search of a proposed viral aetiology of childhood acute lymphoblastic leukaemia (ALL), the common species C adenoviruses were analysed in Guthrie cards. METHODS: Guthrie cards from 243 children who later developed ALL and from 486 matched controls were collected and analysed by nested polymerase chain reaction for the presence of adenovirus DNA. RESULTS: Adenovirus DNA was reliably detected from only two subjects, both of whom developed ALL. CONCLUSION: Adenovirus DNA is detected in Guthrie card samples at too low a frequency to reveal an association between adenovirus and the development of leukaemia.

Analysis of cutaneous melanoma in the province of Vojvodina.

PURPOSE: To analyse the incidence and mortality of melanoma in the province of Vojvodina - the north part of Serbia- from the epidemiologic and clinical point of view. PATIENTS AND METHODS: In this retrospective study, we used databases of the Cancer Registry of Vojvodina, Oncology Institute of Vojvodina in Sremska Kamenica; Clinical Centre of Vojvodina in Novi Sad; Institute of Public Health of Vojvodina in Novi Sad; and Institute of Public Health of Serbia in Belgrade. RESULTS: The incidence and mortality of melanoma in Vojvodina is permanently increasing over the last three decades. The number of newly diagnosed and deceased patients was higher in men and in women in Vojvodina than in central Serbia. Considering the incidence rate, the region of Vojvodina would be placed in the middle of the European countries. The results are more unfavorable with mortality, especially in male population, similar to the range of higher mortality rates among European countries. CONCLUSION: These upsetting facts call for improvement of primary and secondary prevention. Education of the population, continuous efforts to recognize groups of population at high risk for developing melanoma and detection of early phases of the disease increases the chances for cure and significantly reduces treatment costs.

BK-viruria and haemorrhagic cystitis are more frequent in allogeneic haematopoietic stem cell transplant patients receiving full conditioning and unrelated-HLA-mismatched grafts.

The influence of conditioning regimen, donor background and HLA matching on development of BK virus (BKV)-associated haemorrhagic cystitis (HC) was examined in 175 allogeneic haematopoietic stem cell transplant (HSCT) patients, undergoing 179 HSCT events. Twenty-seven patients presented late-onset HC, and BK viruria was verified in 23/27 HC events. Seventy-one (40%) HSCTs were performed with myeloablative conditioning (MC), 108 (60%) were performed with reduced intensity conditioning (RIC), 66 (37%) were performed with a related donor (RD) grafts and 113 (63%) with an unrelated donor (URD) graft. BK viruria was more common during HC, than non-HC events, after MC as compared to RIC (both P<0.001), and with an HLA-mismatched donor (P<0.01). By multivariate logistical regression analysis, independent risk factors for HC were BKV (OR 6.7; 95% CI 2.0-21.7; P=0.001), MC (OR 6.0; 95% CI 2.1-17.3; P<0.001) and URD (OR 3.4; 95% CI 1.1-10.6; P=0.03). However, when analysing HSCT performed with URD or RD grafts separately, BKV (OR 8.5; 95% CI 1.8-19.3; P=0.004) and MC (OR 5.9; 95% CI 1.3-11.3; P=0.009) increased the risk for HC only with a URD, but not with an RD graft.

Investigation of the possibility of copper recovery from the flotation tailings by acid leaching.

The flotation tailings pond of the Bor Copper Mine poses a great ecological problem not only for the town of Bor but also for the surrounding soils and watercourses. Since the old flotation tailings contain about 0.2% of copper on the average, we investigated their leaching with sulphuric acid in the absence and presence of an oxidant. The aim was to determine the leaching kinetics of copper and iron as affected by various factors such as: the pH value of the leach solution, stirring speed, pulp density, particle size, concentration of ferric ions, temperature and time for leaching. The average copper and iron recovery obtained was from 60% to 70% and from 2% to 3%, respectively. These results indicate that the old flotation tailings pond represents an important source of secondary raw material for the extraction of copper and that it should be valorized rather than land reclamation. At the end of the paper, a mechanism of dissolution of copper and iron minerals from the tailings was described.

Antiproliferative and antimicrobial activity of traditional Kombucha and Satureja montana L. Kombucha.

PURPOSE: To carry out a preliminary investigation of the biological activity of Kombucha beverages from Camellia sinensis L. (black tea) and Satureja montana L. (winter savory tea), that have consuming acidity. MATERIALS AND METHODS: Cell growth effect was measured by sulforhodamine B colorimetric assay on HeLa (cervix epithelioid carcinoma), HT-29 (colon adenocarcinoma), and MCF-7 (breast adenocarcinoma). Antimicrobial activity to bacteria, yeasts and moulds was determined by agar-well diffusion method. RESULTS: Consuming Kombuchas had the most expressive antimicrobial activity against all investigated bacteria, except Sarcina lutea, while unfermented tea samples had no activity. Traditional Kombucha showed higher activity against Staphylococcus aureus and Escherichia coli than acetic acid, while both neutralized Kombuchas had bacteriostatic activity on Salmonella enteritidis. Examined Kombuchas did not stimulate cell proliferation of the investigated cell lines. Antiproliferative activity of winter savory tea Kombucha was comparable to that of traditional Kombucha made from black tea. Furthermore, in HeLa cell line Satureja montana L. Kombucha induced cell growth inhibition by 20% (IC20) at lower concentration compared to the activity of water extract of Satureja montana L. obtained in our previous research. CONCLUSION: Presence of more active antiproliferative component(s) in Satureja montana L. Kombucha compared to Satureja montana L. water extract and antimicrobial component(s) other than acetic acid in both Kombuchas is suggested.

Antiproliferative effect of synthetic lignin against human breast cancer and normal fetal lung cell lines. Potency of low molecular weight fractions.

PURPOSE: Due to a lack of chemotherapeutics to efficiently control neoplastic processes, there is a need for discovering new, more efficient anticancer drugs that would distinguish malignant from normal cells. MATERIALS AND METHODS: We studied the effect of short (4 h) and long (72 h) treatment with different concentrations of the enzymatically synthesized lignin model compound (DHP) on the proliferation of two human cell lines grown in tissue culture: breast adenocarcinoma (MCF7) and normal fetal lung fibroblast (MRC5) cell lines. RESULTS: The growth of both MRC5 and MCF7 cell lines was inhibited by DHP after 4 h-treatment, while the carcinoma cell line was also sensitive to the long-term treatment with lower dose of DHP in comparison with the fetal cells. The low molecular weight DHP fractions inhibited growth of the MRC5 cells at lower concentrations compared to the treatment with all DHP fractions. CONCLUSION: The higher sensitivity to DHP of the human malignant cells compared to the normal transformed ones gives the possibility to further study DHP as a therapeutic agent.

Virome definition in cerebrospinal fluid of patients with neurological complications after hematopoietic stem cell transplantation.

BACKGROUND: Neurological complications (NC) in allogeneic hematopoietic stem cell transplant (HSCT) recipients lead to long-term sequelae and result in significant morbidity and mortality. Since risk factors for NC include viral infection or reactivation, virome inspection after HSCT might be helpful to the clinical management of patients after HSCT. OBJECTIVES AND STUDY DESIGN: In this study we investigated whether any viruses are found in association with NC after HSCT. For this purpose, unbiased next generation sequencing (NGS) was used to characterize nucleic acid (NA) content in cerebrospinal fluid (CSF) taken at time of NC in 35 HSCT patients. Virome definition in CSF from non-transplanted subjects (controls) was also tested to define the commensal flora. RESULTS AND CONCLUSIONS: A higher number of reads/contigs mapped to viruses in patients compared to the controls (7,626 vs 235). Besides bacteriophages, Torque teno virus (TTV) was also identified in both controls and patients. Interestingly, a significantly higher number of TTV-like sequences was detected in the patient samples (7,236 vs 9), showing similarities to distinct genotypes; 3/2,575, 2/1,692 and 2/2,969 contigs/reads mapped to TTV11, TTV13 and Torque teno midi virus, respectively. In conclusion, unbiased NGS demonstrated to be a suitable approach to characterize the virome in samples containing limiting amounts of NA. The higher TTV levels and genetic diversity found in CSF of subjects with NC after HSCT might suggest a possible association between TTV reactivation and the disorder. However, further studies are needed to evaluate the possible role of TTV on NC in HSCT patients.

Potential Influence of Selenium, Copper, Zinc and Cadmium on L-Thyroxine Substitution in Patients with Hashimoto Thyroiditis and Hypothyroidism.

Background: Besides genetic factors, it is known that some trace elements, as Selenium, Copper, and Zinc are essential for thyroid gland fuction and thyroid hormone metabolism. Moreover, there were some metals effect that suggested patterns associated with overt thyroid disease. Aim of study: Hashimoto thyroiditis (HT), chronic autoimune inflamation of thyroid gland with cosequtive hipothyroidism, is common disease in Serbia, and we thought it is worthwile to explore potential effects of essential and toxic metals and metalloides on thyroid function and ability to restore euthyroid status of them. Results: This cross-sectional, case-control, study investigated the status of essential elements (Selenium,Copper,and Zinc) and toxic metals and metalloides (Al, Cr, Mn, Co, As, Cd, Sb, Ba, Be, Pb and Ni) from the blood of 22 female, patients with Hashimoto thyroiditis and overt hypothyroidism, and compared it with those of 55 female healthy persons. We tried to establish the presence of any correlation between previous mentioned elements and thyroid function in hypothyroid patients and healthy participants. Conclusions: The results of our study suggested that the blood concentration of essential trace elements, especially the ratio of Copper, and Selenium may influence directly thyroid function in patients with HT and overt hypothyroidism.Thus, our findings may have implication to life-long substitution therapy in terms of l-thyroxine dose reduction. Furthermore, for the first time, our study shown potential toxic effect of Cadmium on thyroid function in HT patients, which may implicate the dose of l-thyroxine substitution.

Fullerenes in biomedicine.

Studies on the biological properties of fullerene C(60) and its derivatives started a decade ago as curiosity-driven studies and are now flourishing as an area of transdisciplinary research. This paper summarizes the results of studies on the biological activity and applications of selected functionalized fullerenes that were published in the last few years. Apart from literature data, we present most of our results of in vitro and in vivo studies with fullerenol C(60)(OH)(24) anti-oxidative and free radical scavenger activities in chemical and biological systems; cytotoxicity against human tumor cell lines; protective effects against various cytotoxic drugs and irradiation; effects on cell cycle and apoptosis, and in vivo radioprotective and cardioprotective effects. The fullerene family of carbon molecules has been a central focus in the emerging fields of nanotechnology and nanomedicine. Fullerenes take an important place in the development of nanobiotechnology and nanomedicine-related products.

Evaluation of sister chromatid exchanges, micronuclei, and proliferating rate index in hospital workers chronically exposed to ionizing radiation.

PURPOSE: The aim of this study was to determine the incidence of sister chromatid exchanges (SCE), micronuclei (MN) and proliferation rate of harvested lymphocytes obtained from medical stuff professionally exposed to low-dose ionizing radiation. The influence of tobacco smoking status and working conditions as confounding factors were also investigated. PATIENTS AND METHODS: Thirty subjects chronically exposed to low-dose ionizing radiation were examined (12 workers in the radiotherapy unit and 18 workers in the cardiology unit), and were compared to 15 unexposed healthy volunteers. There were 18 nonsmokers and 12 smokers among the exposed workers and 8 nonsmokers and 7 smokers among the control group. Standard cytokinesis-block MN assay, the SCE assay, and the proliferating index (PI) rate were analyzed. RESULTS: An increased frequency of SCE and MN in occupationally exposed workers were found compared to unexposed individuals. The PI was significantly lower in occupationally exposed workers in comparison to the control group. In relation to the working conditions, a significantly higher number of MN in the group of workers in the radiology unit compared to the control was found (p=0.03). The frequency of SCE was increased in occupationally exposed smokers compared with nonsmoking workers (p=0.005). Smokers in the control and radiation exposed group had lower MN frequency contrary to nonsmokers in both groups. CONCLUSION: The obtained results show higher incidence of SCE and MN in the exposed groups compared to the controls. Cigarette smoking and working conditions as confounding factors should be included into genetic monitoring studies assessing the risk associated with low-level radiation exposure.

Synthesis and antiproliferative activity of new carboplatin analogues.

PURPOSE: The aim of this study was to present the synthesis and characterization of two carboplatin analogues and to investigate their antiproliferative activity against human tumor cell lines. MATERIALS AND METHODS: The carboplatin analogues cis-1,2-propylendiammine (cyclobutane-1,1-dicarboxylato) platinum (II) (MD2), and cis-izobutylendiammine (cyclobutane-1,1-dicarboxylato)platinum (II) (MD3) were characterized by elemental analysis and (1)H-NMR-measurements. The compounds were tested for antiproliferative activity against the following human tumor cell lines: myelogenous leukemia K562, colon adenocarcinoma HT- 29, breast adenocarcinoma MCF-7, and human lung fetal fibroplast cell line MRC-5. The active substance of carboplatin (MD1) was used as reference compound. Cells were exposed to complexes for 24 h at concentrations ranging from 10(-3) to 10(-8)M. Growth inhibition was evaluated by the colorimetric SRB assay. The IC(50) value of each carboplatin compound was determined by median effects analysis. RESULTS: Both carboplatin analogues induced dose-dependent growth inhibition of human tumor cell lines after 24 h of treatment. The MD3 analogue was 60-fold and the MD2 was 2-foild more active against K562 cell line compared to the referent compound. The activity of both analogues was comparable to the refernt compound against MCF-7 cell line. Colon adenocarcinoma cell line HT-29 was found to be 4-fold less sensitive to MD2 but equally sensitive to MD3 with respect to carboplatin referent compound. Both carboplatin and its analogues induced moderate cytotoxicity on MRC-5 cell line ranging from 25% (10(-7)M) to 46%(10(-3)M). CONCLUSION: This study showed that the two novel carboplatin analogues inhibited human cell lines in a different manner depending on cell line. Carboplatin analogues were more active against human tumor cell lines than against human lung fibroplast cell line MRC-5.

Polyomavirus-infected oligodendrocytes and macrophages within astrocytes in progressive multifocal leukoencephalopathy (PML).

Polyomavirus-infected oligodendrocytes and in some instances virus-carrying macrophages were demonstrated within the cytoplasm of astrocytes by double immunostaining of brain lesions in a case of PML following bone marrow transplantation. The infected oligodendrocytes and CD68+ cells were usually partially or completely invested by the cytoplasm of reactive and infected or noninfected giant pleomorphic astrocytes. By electron microscopy (EM), internalized infected oligodendrocytes were shown to release polyomavirus particles possibly infectious to the astrocytes. These observations seem to indicate that astrocytes in PML can become infected by direct contact with internalized infected oligodendrocytes and possibly also by virus-loaded macrophages. Correspondingly, astrocyte/oligodendrocyte/macrophage cell-to-cell interactions appear to play an important role in the pathogenesis of PML lesions.