Rates In Different Groups Research Articles

Value of liver herniation in prediction of outcome in fetal congenital diaphragmatic hernia: a systematic review and meta‐analysis

Intrathoracic liver herniation (ILH) is being used to estimate prognosis and hence guide antenatal interventions in fetal congenital diaphragmatic hernia (CDH). However, the literature regarding its utility in this role is conflicting. This review systematically examines the currently available evidence of ILH use in fetal CDH. MEDLINE and EMBASE databases were searched for the terms ((congenital diaphragmatic hernia) OR CDH) AND liver. Inclusion criteria were human case series of fetuses diagnosed with CDH using either ultrasound or magnetic resonance imaging. Included studies were required to have reported the antenatal liver position and the outcome (survival or not). Case reports, reviews and eventration series were excluded. Studies reporting similar cases from the same center over an overlapping time period were considered duplicates; only the larger of the studies were therefore included. Absolute totals were extracted and sums calculated. Fisher's exact test (FET) was used to compare survival rates in different groups. The original search retrieved 338 studies. Applying inclusion/exclusion criteria and removing duplicates left 21 case series in 20 studies. Retrieved studies differed in the definitions of liver herniation, survival and treatment modality. In total, there were 407 fetuses in the liver-up (herniated) and 303 in the liver-down (not herniated) groups. Survival rates were 45.4% and 73.9%, respectively. The difference was statistically significant (FET = 56.4, P < 0.005). Sensitivity analysis for cases that had only conventional postnatal treatment was still significant (FET = 52.8, P < 0.005). Liver herniation is associated with poorer prognosis in fetal CDH. Grading liver herniation or using it as part of a panel of markers may enhance the value of liver herniation as a prognostic test in fetal CDH.

Combined analysis of endometrial thickness and pattern in predicting outcome of in vitro fertilization and embryo transfer: a retrospective cohort study

ObjectiveTo evaluate the combined effect of endometrial thickness and pattern on clinical outcome in patients undergoing in vitro fertilization/intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET).MethodsCycles of IVF/ICSI-ET conducted between January 2003 and December 2008 at a university-based reproductive center were reviewed retrospectively. Endometrial ultrasonographic characteristics were recorded on the day of hCG administration. In the combined analysis, endometrial thickness groups (group 1: equal or <7 mm; group 2: 7-14 mm; group 3: >14 mm) were subdivided into two endometrial patterns (pattern A: triple-line; pattern B: no-triple line). Clinical pregnancy rate (CPR) and early miscarriage rate in different groups were analyzed.ResultsA total of 2896 cycles were reviewed. Clinical pregnancy rate (CPR) was 24.4% in group1-A. There were no second trimester pregnancies in group 1-B. Miscarriage rate in group 2-A was significantly lower compared to group 2-B (P < 0.01), although CPR did not show any significant differences between the groups. A no-triple line endometrial pattern with moderate endometrial thickness (7-14 mm) had a detrimental effect on pregnancy outcome, but not the occurrence of pregnancy. In group 3, there was no difference in CPR and miscarriage rates between the two patterns; adequate endometrial thickness (>14 mm) seemed to mitigate the detrimental impact (high miscarriage rate) of pattern B.ConclusionCombined analysis of endometrial thickness and pattern on the day of hCG administration was a better predictor of the outcome of IVF/ICSI-ET and may be more helpful for patient counseling than the separate analyses.

Substance Use as a Predictor of Driving under the Influence (DUI) Rearrests. A 15-Year Retrospective Study

Background : Recidivism is a major problem in the prevention of DUI offenses. It is suggested that impairing substances used by drivers may relate to a higher risk of recidivism. This study aims to determine rearrest rates in different groups of arrested drivers focusing on different substances found in the blood. Material and Methods : The data utilized were obtained from the register of suspected DUI offenders maintained by the Finnish National Institute for Health and Welfare (THL). Data were available for the 15-year period between 1993 and 2007. The number of rearrests was traced from the individuals' ID codes. The mean blood alcohol concentration (BAC) of the DUI offenders was studied as well as their age at the time of the first arrest. Rearrest rates according to alcohol and drug findings were estimated using survival analysis methods. Results : At the time of the first arrest, the drivers with a single DUI arrest were older and had a lower BAC than those who had a later arrest. The proportion of female drivers decreased as the number of rearrests increased. Drivers with drugs only or a combination of drugs and alcohol had a significantly higher rearrest rate than drivers with alcohol alone. Drivers with amphetamines only had the highest rearrest rates. Findings of benzodiazepine and opioids alone did not increase the risk of rearrest in the long run. Young age, male sex, high blood alcohol level, and arrest during the nighttime and during weekdays constituted a higher risk for rearrest. Conclusions : A third of those suspected of driving under the influence of alcohol and/or drugs are rearrested within 15 years. Drugs, especially amphetamines, are a risk factor for faster rearrest. These results show that the groups at risk of recidivism can be pinpointed. Interventions to prevent recidivism should be developed particularly for drugged drivers. Substance abuse beginning in adolescence seems to be a greater risk.

Type of dominance modification in schizophrenia.

New family data on schizophrenia, gathered in Iceland, are evaluated in terms of different forms of modified dominant inheritance. In this material the risk of psychosis appears to be proportional to the likelihood of receiving a postulated major gene. Comparative rates in different groups can be adequately expressed by the formula 1.0 + 6.0(1/2)n where n represents the number of genetic steps from an affected relative. While older data on monozygotic cotwins and on children of two psychotic parents do not seem to fit this formulation, satisfactory explanations exist, so that the overall pattern of transmission appears to be consistent with dominant inheritance with incomplete penetrance. In contradistinction to this conclusion, the family data reported by other authors actually agree better with a previously proposed two locus genetic hypothesis, but in view of the improved methodology employed in the Icelandic study, the new data are felt to have greater validity.

Effect of Liposome Encapsulated Vesicular Stomatitis Virus Matrix Protein in Hematological Malignancy

Objective: Vesicular Stomatitis Virus (VSV) has shown antitumor effects in many studies, however as an active virus,it has biosafety problems when being used in human body. Matrix protein (M protein) of VSV also has antitumor effects without the existence of other portions of VSV.Recently liposome is widely used as a gene delivery vector. So the present study was to investigate the effect of liposome as a gene delivery vector in hematological malignant cell lines and to investigate the effect of liposome encapsulated Vesicular Stomatitis Virus Matrix protein in hematological malignancy in vitro.Methods: First, Lipofectamine 2000 was selected as a kind of gene delivery vector and its efficacy in different cell lines was identified by transfecting the plasmid DNA encoding GFP gene into suspension cell lines, including K562 cells (human chronic myeloid leukemia), Jurkat cells (human T cell lymphoma), Raji cells (human B cell lymphoma) and both attachment and suspension cell line CZ-1 cells (human multiple myeloma) according to the instruction provided by the Invitrogen company when the ratios of DNA to Lipofectamine2000 were 1:2,1:2.5,1:3,1:4 and 1:5, respectively. Selecting those cell lines was based on that the transfection efficiency of liposome was above 20% and the ratios which could help to receive the greatest efficiency. The human ovarian cancer cell line A2780 was the positive control and the ratio of DNA to Lipofectamine varied from 1:2.5 to 1:3.Secondly, in vitro study, the P-M group was the one in which the plasmid DNA encoding M protein of Vesicular Stomatitis Virus (VSV-M) was transfected into the selected cell lines by the best ratios of DNA to Lipofectamine2000.The groups of Lipofectamine2000- treated (LIPO) , Lipofectamine2000 encapsulated empty plasmid pVAX -treated (P) and untreated one (BLK) were set as the control groups. Morphological changes were observed and the cell growth inhibition rates in different groups were measured by MTT (Methylthiazolyldiphenyl-tetrazolium bromide) method at 24h, 48h and 72h after transfection. The cell apoptosis rates of K562 cells were tested by Flow Cytometry at 48h after transfection.ResultsThe Lipofectamine2000 transfection efficiency in K562 cells could reach up to 50%, while in different conditions the efficiency in CZ-1 was only 20% and that in Raji and jurkat cells was below 10%. The efficiency could also reach 50% in A2780 cells when the ratio was1:3.Study of the effect of liposome encapsulated Vesicular Stomatitis Virus Matrix protein in hematological malignancy: 2.1 K562 and CZ-1 cells: The morphology of K562 and CZ-1 cells in P-M groups was nearly not changed at 24h,48h and 72h after transfection. Futhermore, MTT method showed that, compared with the P and LIPO groups, there were no growth inhibition in K562 and CZ-1 cells at different time points(P>0.05). 2.2 A2780 cells: In the P-M groups, the morphology of A2780 cells was changed ,and a lot of suspension cells were observed in the medium after 48h. Compared with the P and LIPO groups, there was obvious growth inhibition in A2780 cells at different time points (P<0.05).In the P groups, the morphology of A2780 cells was also changed little. Compared with the LIPO group, there was some growth inhibition in A2780 cells at different time points (P<0.05). In the LIPO and BLK groups, these cells had no morphological changes and no growth inhibition.Flow Cytometry showed that there was no difference between the P-M group and P,LIPO groups in K562 cell line in terms of cell apoptosis rates after 48 hours of transfection with VSV-M by means of- liposome(P>0.05).ConclusionsLiposome was not a good choice for the gene transfection in hematological cell lines, including Raji,CZ-1 and Jurkat; however it had good efficacy in K562 and A2780 cell lines.M protein of Vesicular Stomatitis Virus had no obvious inhibition effect in several hematological malignancy cell lines in the current transfection conditions in vitro, while it had good inhibition effect in A2780 cell line. Futhermore, M protein could not induce cell apoptosis in K562 cells in this study.

Influence of astrocyte-conditioned medium on the formation of synapses in neural stem cells: the role of neurotrophin proteins

To discuss whether neurotrophin proteins, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neural growth factor (NGF), in the astrocyte-conditioned medium (ACM) are involved in the synapse formation in neural stem cells (NSCs). (1) Cells derived from a pheochromocytoma of the rat adrenal medulla of the line PC12 were induced by amyloid-beta protein (Abeta)1-40 for 0, 4, 6, 12, and 24 h respectively. Then part of these PC12 cells underwent flow cytometry to examine the apoptotic rates. Different cells were added into Falcon Cell Culture Insert: Group A containing astrocytes isolated from Wistar rat, Group B with PC12 cells and astrocytes, Groups C1-C5 containing astrocytes and PC12 cells induced by Abeta(1-40) for 0, 4, 6, 12, and 24 h respectively, Group D1-5 with PC12 cells induced by Abeta(1-40) for 0, 4, 6, 12, and 24 h respectively, and Group E containing astrocytes induced by Abeta(1-40) for 6 h. Flow cytometry was used to detect the apoptotic rates of different groups. Double-antibody sandwich ELISA was used to detect the levels of BDNF, NT-3, and NGF. (2) The different kinds of the astrocyte-conditioned medium as described above were mixed with DMEM/F12 medium according to the proportion of 1:3 and then divided into 13 groups: Group I (Group A + NSCs), Group II (Group B + NSCs), Group III-VII (Groups C1-C5 + NSCs), Group VIII (NSCs without ASM), Group IX-XIII (Groups D1-D5 + Mscs), and Group XIV (Group E + NSCs). The expression of synaptophysin and growth-associated protein-43 (GAP-43 protein) were detected by co-focal laser scanning microscopy. The number of mature synapse was observed by transmission electron microscope(TEM). Flow cytometry showed that the apoptotic rates of the PC12 cells were low 0, 2, and 4 h after Abeta(1-40) induction, with the peak 6 h after induction (P < 0.05). The BDNF total protein level in the ACM of Group C3 was the highest (A = 1.53 +/- 0.25) (P < 0.05). The expression levels of synaptophysin (A = 33.39 +/- 2.71) and GAP-43 (A = 49.18 +/- 6.45), and the mature synapse number of NSCs (4.70 +/- 0.52 synapse/field of vision) of Group V were the highest in comparison with the other groups (all P < 0.05). After incubation of astrocytes with Abeta(1-40)-induced PC12 cells(Abeta-PC12), the ACM induces the synapse formation in the NSCs. The BDNF in the ACM is probably involved in this process.

Weiterbildungsbeteiligung ausgewählter Personengruppen

Auf Basis der Daten des Mikrozensus 2004 untersucht der Beitrag die unterschiedliche Beteiligung von Männern und Frauen, In- und Ausländern sowie Älteren und Jüngeren an Maßnahmen der beruflichen Weiterbildung. Während die Teilnahmequote der Deutschen die der Ausländer deutlich übersteigt und jüngere Erwerbspersonen häufiger an Weiterbildung partizipieren als ältere, sind die Unterschiede in der geschlechtsspezifischen Weiterbildungsbeteiligung gering. In multivariaten Analysen der Determinanten der Weiterbildungsbeteiligung der genannten Personengruppen lassen sich neben Faktoren, die sich in allen Schätzungen als einflussreich erweisen, auch solche identifizieren, die sich nur auf die Weiterbildungsteilhabe einzelner Gruppen auswirken. Dabei handelt es sich etwa um den familiären Kontext, der nur bei der Erklärung der Weiterbildungsbeteiligung der Frauen, nicht aber der der Männer, eine Rolle spielt, oder den schulischen Abschluss, der zur Erklärung der Weiterbildungsbeteiligung jüngerer Erwerbspersonen beiträgt, nicht aber zu der der älteren. Eine nähere Analyse der Gründe für die differierende Weiterbildungsbeteiligung der einzelnen Gruppen zeigt schließlich, dass Unterschiede in den individuellen Ausstattungsmerkmalen nur einen Teil der Differenzen erklären können. Neben diesem "erklärten„ Anteil der Weiterbildungsdifferenz spielt bei allen Gruppen auch der "unerklärte„ Anteil eine Rolle, der auf bestehende Barrieren seitens der Weiterbildungsteilnehmer sowie der die Weiterbildung finanzierenden Betriebe hindeutet.

Neuroendocrine tumors: a registry of 1000 patients

Neuroendocrine tumors (NET) can originate diffusely in most organs, with varying clinical presentations. The relative rarity of these tumors, previously referred to as carcinoids, encouraged several centers worldwide to study NET. Since 2003, a similar group was established in , the GETNE - Grupo de Estudo de Tumores Neuroendocrinos (Neuroendocrine Tumors Study Group) that included 32 centers, from all regions of Brasil. A patient database was initiated, collecting information about NET, regardless of the site of origin. The present study shows initial results of 1000 patients included. Descriptive statistical analyses, as well as overall survival rates for different groups of NET patients registered by GETNE. Most patients presented with thoracic NET (71.6%), while 20.2% had gastro-entero-pancreatic tumors. Median follow-up of all patients included was 33.7 months (range 1-141 months). At the time of the analysis, 29.3% of the patients were still alive (of these, 45.7% were alive with no evidence of disease). This is the largest database of NET in, and further accrual of new patients, as well as individual study results are expected in the near future.

Comparison of predicted and measured concentrations of selected pharmaceuticals, fragrances and hormones in Spanish sewage

A review of consumption and excretion rates of 17 pharmaceuticals, two musk fragrances and two hormones by the Spanish population in 2003 was performed. For that purpose, three different models were used: (i) extrapolation of the per capita use in Europe to the number of inhabitants of Spain for musk fragrances; (ii) annual prescription items multiplied by the average daily dose for pharmaceuticals and; (iii) excretion rates of different groups of population for hormones. This information enabled the prediction of the expected concentrations (PEC) entering sewage treatment plants (STPs), which were subsequently compared with the measured environmental concentrations (MEC) in raw sewage. Annual drugs consumption in Spain ranges from few kilograms (Oxazepam and 17α-ethinylestradiol) to several hundred of tons (Ibuprofen). The quantities of musks used accounts for 110–450 kg d −1 and the total amount of hormones excreted daily reaches almost 1 kg d −1. 12 out of 21 selected substances were predicted to be present in raw sewage influent at concentrations greater than 100 ng l −1 and these predicted concentrations fitted with the measured values for half of them (Carbamazepine, Diazepam, Ibuprofen, Naproxen, Diclofenac, Sulfamethoxazole, Roxithromycin, Erythromycin and 17α-ethinylestradiol).

The Demographics of Tort Reform

Abstract Tort reform may not affect all segments of society equally. Studies have shown that many tort reforms disproportionately reduce compensation to women, children, the elderly, disadvantaged minorities, and less affluent people. This study goes beyond tort reform’s disproportionate effect on compensation, to explore whether tort reform also has a disproportionate effect on accidental death rates. We explain that, theoretically, tort reform’s care-level effects and activity-level effects may disproportionately impact the accident rates of different groups. Using the most accurate, comprehensive data on medical malpractice tort reforms and state-level data from 1980-2000, we examine empirically whether tort reforms indeed have such a disproportionate effect. The results from our empirical analysis are consistent with our theoretical predictions. We find that the impact of tort reform varies substantially among demographic groups. When we consider the net effect of all the reforms in our study together, our results suggest that women, children, and the elderly do not enjoy tort reform’s benefits as much as men and middle-aged people. In fact, they might even be harmed by reform.

Retrospective multicentre study of the new minimally invasive mesh repair devices for pelvic organ prolapse

To assess the complications and short-term outcomes of prolapse repair mesh devices used in the management of female pelvic organ prolapse (POP). Retrospective cohort study. Multicentre study involving a tertiary referral urogynaecology unit and two district general hospitals. 329 women who underwent surgical management of prolapse with various prolapse repair mesh devices in the period between January 2005 and December 2006. Women were identified from theatre records. An independent clinician performed a case notes review during the period March to May 2007. Complication rates and the short-term cure at 3-month follow-up (defined as </=stage I prolapse on the POP-Q or Baden Walker scoring systems). A total of 289 women were included: 219 (76%) used the Gynecare prolapse repair mesh devices, while 70 women (24%) used the American Medical Systems prolapse repair mesh devices. Operative complications included: bladder injury (1.6%), rectal injury (1.1%) and two women with serious vascular injuries. Postoperative complications included: buttock pain (5.2%), vaginal erosion (10%), one woman with bladder erosion and two women (0.7%) with serious infection, leading to necrotising fasciitis in one woman. Short-term cure rates in different groups varied from 94 to 100%, depending on vaginal compartment and device used. In total 15 women (5%) had persistent prolapse at 3-month follow up. The new prolapse repair mesh devices demonstrate excellent short-term cure and low morbidity rates. However, some complications are serious and require highly specialised management. Rigorous evaluation by means of independent, controlled studies is urgently required.

Alfred Marshall's Mecca: Reconciling the Theories of Value and Development*

The purpose of this paper is to explore the evolutionary nature and content of Marshall's theory of value and the relation it bears to his theory of growth and development. In Marshall's work the two theories are inextricably linked, and the subsequent attempt to separate them has not only marginalised Marshall's rich analysis but also made it impossible to appreciate the role he gave to innovation, and its corollary the growth of knowledge and organisation, in the workings of a market economy. At its core is the relation between the growth of firms and the growth of markets, but this is not steady‐state growth theory; rather, it is the different, mutually determined and ever changing growth rates of different groups of firms that is at the centre of attention. Quite how variation is linked to progress is the central topic of this essay, and the elucidation of its central role necessarily means that we must resurrect the representative firm. We conclude that Marshall was correct in stating that ‘the tendency to variation is a chief source of progress’ (Principles, V, 4, p. 355). We develop a set of evolutionary tools to show how and why this is so. But evolution is more than variation; it requires the organisation of firms and the market process to generate that correlation between differential knowledge and economic advance. Most importantly of all, the concept of a representative firm is re‐established as an indispensable element in a Marshallian evolutionary analysis.

Statistical methods for assessing the fairness of the allocation of shares in initial public offerings

In the late 1990s the stocks of technology companies, especially those involved with the Internet, were highly profitable. Customers of investment firms requested many more shares of new issues or initial public offerings (IPOs) than were available. Some customers allegedly made questionable arrangements with brokers for favourable treatment. This article describes statistical measures for assessing the fairness of an investment firm's or broker's allocations of IPO shares to their customers. One approach compares the success rates of different groups of customers, e.g. those alleged to be favoured with those of other groups. The second method incorporates the prior business each customer gave the firm into the comparison as an allocation criterion. This metric is an objective quantification of the fact that it is economically sensible for a firm to allocate more IPO shares to its ‘best’ customers.

Unemployment Rates and Population Changes in Spain

This paper discusses the long run effect of changes in the age distribution of Spanish population on the unemployment rate, disaggregated by sex and age segments in the light of cointegration theory given the non stationarity of the series. Four main results are obtained. First, empirical analysis does not provide a clear scheme concerning the long run relationships between population variables and the specific unemployment rates for different groups. Second, as a first approximation one can detect the existence of, at least, one long run equilibrium relationship in all sex-age groups, except for the ones including the middle aged unemployed female workers and oldest unemployed female workers. Third, a more thorough analysis enables us to justify the existence of such long run relationships for the youngest male workers and middle aged male workers. One cannot argue, however, a joint evolution of population variables and the unemployment rates associated with female workers and to the oldest male workers. Fourth, the short run dynamics of unemployment rates for the youngest (male and female workers) and the middle age male workers is affected by the transitory deviations from these long run relationships. Hence, from an applied economics point of view, the result stresses the likely failure of employment policies which do not take into account the heterogeneous composition of unemployed workers. It stresses the need to design particular policies for specific groups of workers depending on their age and sex characteristics.

Testing the proportional odds model under random censoring

SUMMARY In practical applications, it is not uncommon for the hazard functions of two groups to converge with time. One approach that allows for converging hazard functions is the proportional odds model. We develop a procedure for testing the proportional odds assumption when the available data consist of two independent random samples of ran- domly right-censored lifetimes. Asymptotic normality of the test statistic is proved and the procedure is applied to two well-known datasets. The effective significance level and power of the proposed test are assessed through a simulation study. The objective of this paper is to develop a test for comparison of survival times under random censorship when the hazard functions for the two groups of interest are not proportional through time but their ratio appears to be tending to 1. Such a situation is encountered, for example, when the initial effects of treatment, or the differences between stages of the disease at diagnosis, tend to diminish with time, and the hazard rates of different groups of patients become more similar. A decaying treatment effect was found in the analysis of University of California San Francisco's kidney-transplant data by Dabrowska et al. (1992) and in the analysis of malignant melanoma data by Andersen et al. (1993, Ch. 7). Frequently, converging hazard functions are modelled by extending Cox's proportional hazards model to include time-dependent explanatory variables or by introducing a frailty parameter. We refer to Andersen et al. (1993, Ch. 7, 9), Hougaard (2000, Ch. 2, 7) and Klein & Moeschberger (2003, Ch. 9, 13) for detailed discussion. An alternative approach to the problem of converging hazard functions is through the pro- portional odds model. If Fg(t) is the true survival function underlying the data for groupi (i-= and Fi(t) then qi(t) for i-= are the true odds of a group iindividual surviving beyond time t. We say that the two groups satisfy a proportional odds model if b2(t)-= for all t and some constant > If aksk is the hazard

Basic science research publications in general surgical journals: are they obsolete?

Introduction: Basic science research (BSR) publications in general surgical journals are an important ‘translational bridge’ for practicing surgeons and surgical trainees. However, these articles are considered by some as left-over from higher impact basic science journals, and perhaps as obsolete. The purpose of this study is to characterize BSR articles published in general surgical journals and to analyze their citation frequencies. Methods: All BSR articles published in the five highest rated US general surgical journals (by Impact Factor, ISI Journal Citation reports) in the year 1996 were reviewed, characterized and their citation frequencies analyzed (total citations, citations within a year of publication, and citations in journals with impact factor greater than 5). The Wilcoxon rank-sum test was used to compare citation rates in different groups. Results: In 1996, 226 BSR articles were published in the five general surgical journals studied (10–43% of the total articles in each journal). Three fourths of BSR articles were from the USA (12% of total BSR articles by US surgeons in 1996), 12% from Europe and 8% from Japan. In 58% of the BSR articles, one of the authors was a basic scientist (PhD). Fifty-six percent of the publications were presented at a society conference. One in two US BSR publications was funded by the government (14% by private non-profit, 3% industry). On average a BSR article from these journals is cited 32 times (range 1–141, median 11). Half of the articles were cited more than ten times in six years (1–5: 24%; 6–10: 23%; >10: 52%) and 22% were cited twice or more within a year of publication. One in four publications were cited twice or more in journals with an impact factor greater than five (0: 35%; 1: 23%; 2: 17%; >2: 25%). Citation frequencies of BSR publications in general surgical journals were related to the journal impact factor (p = 0.07), to having a basic scientist (i.e. PhD) as one of the authors (p < 0.01) and to the research having been presented at a conference. Conclusions: Basic science research articles in US general surgical journals in the year studied have significant citation frequencies and were not obsolete.

Cancer incidence in Ukraine after the Chernobyl accident

We analyzed the temporal trend in cancer incidence rate in different groups of Ukrainian population affected by the Chernobyl accident using the data obtained from the following two main information sources: (1) local cancer registry, which was established in 1987 and covers 150,000 population in the most radio-contaminated areas close to Chernobyl; and (2) state registry of people affected by the Chernobyl accident. The latter registry covers 90,000 emergency workers in 1986–1987 and 50,000 evacuees from Pripyat city and 30-km zone who received different doses of radiation. The mean dose was evaluated as 100–200 mSv for emergency workers in 1986, 50–100 mSv for those in 1987, and 10–12 and 20–30 mSv for evacuees from Pripyat city and 30-km zone, respectively. The lifetime dose in residents of contaminated areas with deposition density exceeding 555 kBq/m 2 was estimated to reach 100 mSv. A significant risk of thyroid cancer due to exposure to radioactive iodine was noted, especially in children. According to the evaluation of dose distribution in Ukrainian population, about 85% of children aged below 3 years received the dose of 0.1–1.0 Gy; 60% of children aged 4–15 years and 50% of adolescents received 0.05–0.3 Gy; and 15,000 children born on 1979–1986 before the accident received more than 2 Gy. Cancer incidence in people still living in contaminated areas has shown a slow increase with time more than 10 years after the accident. Comparison of the standardized incidence ratio (SIR) in the three groups of affected people, i.e., residents of contaminated areas, emergency workers in 1986–1987, and evacuees, the periods of 1990–1993 and 1994–1997 showed a significant increase in emergency workers in 1986–1987 only. As to site-specific cancer, a significant increase in thyroid cancer incidence in the three groups of population, especially in evacuees, should be noted. Breast cancer incidence rate showed a significant increase in female residents of contaminated areas and women who participated in emergency work in 1986–1987.

Computing Estimates in the Proportional Odds Model

The semiparametric proportional odds model for survival data is useful when mortality rates of different groups converge over time. However, fitting the model by maximum likelihood proves computationally cumbersome for large datasets because the number of parameters exceeds the number of uncensored observations. We present here an alternative to the standard Newton-Raphson method of maximum likelihood estimation. Our algorithm, an example of a minorization-maximization (MM) algorithm, is guaranteed to converge to the maximum likelihood estimate whenever it exists. For large problems, both the algorithm and its quasi-Newton accelerated counterpart outperform Newton-Raphson by more than two orders of magnitude.

Freshwater Fish Habitats in Amazonia: State of Knowledge, Management, and Protection

Abstract With an estimated 2,500 to 3,000 fish species, the Amazon basin is the largest biodiversity center of freshwater fishes. The large number is related to the size of the basin, a large habitat diversity, high speciation rates of different groups, and low extinction rates resulting from a rather stable tropical climate which has persisted over long geological periods. Amazonia is characterized by a very dense network of streams and rivers, connected to extended floodplains and wetland areas. There are only a few small permanently isolated deep lakes in the area. Rapids and waterfalls along the border of the Guyana shield, the Central Brazilian shield and the Andes separate the downstream and upstream fish faunas of major rivers. Estimates indicate that about half of the fish fauna colonizes the large river floodplain systems along the lower and middle reaches of the rivers and the other half the headwater streams. Knowledge about fish habitats is concentrated mostly on large river floodplains near large cities, which provide infrastructure for research, and habitat conditions in large areas are virtually unknown. Information is scattered in limnological, botanical, geographical, and aquarium literature. Ongoing research concentrates mostly on the inland fisheries. Large parts of the Amazon River basin are still in pristine condition as are the fish habitats. However, human activities, including the transformation of large savanna and rain forest areas into agricultural land, the construction of large reservoirs for hydroelectric power generation, and mining profoundly modify fish habitats, and threaten species diversity mainly in small streams. Environmental legislation for the protection of streamside vegetation is sometimes contradictory and often not respected by the landowners. In the long run, specific fish communities and their habitats will only be fully protected in national parks and other protected areas. Even these areas suffer illegal human activities because of insufficient administration. There is an urgent need for the classification of fish habitats throughout the basin and the proposal of specific protection measures.

Interaction between chloroquine and diverse pharmacological agents in chloroquine resistant Plasmodium yoelii nigeriensis

The effect of a number of pharmacological agents on the enhancement of antimalarial activity of chloroquine was evaluated against chloroquine resistant line of Plasmodium yoelii nigeriensis (N-67). The response after combination therapy was monitored on the basis of alteration in the course of parasitaemia, the extension of mean survival time and the percent cure rate in different groups. The study was designed to compare the in vivo efficacy of a number of resistance modulating agents found effective in several in vitro studies against chloroquine resistant P. falciparum isolates. Based on their efficacy in this rodent model, the response of combination of chloroquine with agents representing diverse chemical moieties has been categorised as curative, moderately active and inactive. Out of the 22 agents evaluated, only cyproheptadine-chloroquine combination produced curative response. Ketotifen, azatadine, pheniramine, amitriptyline, fluoxetine, verapamil, penfluridol and trifluoperazine demonstrated moderate activity while loratadine, terfenadine, promethazine, ranitidine, nifedipine, diltiazem, chlorpromazine, amiodarone, tamoxifen, dipyridamol, propranolol, acyclovir and amantidine were inactive. The study advocates the suitability of proposed rodent model to shortlist potential resistance reversal agents.