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SARS preventive and risk behaviours of Hong Kong air travellers.

This study aims to investigate Severe Acute Respiratory Syndrome (SARS)-related behaviours of travellers returning to Hong Kong by air. A total of 820 travellers returning to Hong Kong by air were interviewed about their SARS-related behaviours in April 2003. Three quarters of the respondents wore a mask most/all of the time on board, 15% did so in public places at the travel destination. Perceived susceptibility to SARS at the destination predicted mask-wearing in public places and avoidance of crowded places, and perceived efficacy was a predictor for mask-wearing during flight. Approximately 16% of the respondents stated that they would delay their medical consultation for flu-like symptoms until returning to Hong Kong. Nearly 18.2% stated that they would not wear a mask in public places at the destination if they had flu-like symptoms. Education programmes, special services and effective thermal screening are required to minimize the chance of the spread of SARS by air travellers.

Adolescent↗

One frog, two frog, red frog, blue frog: factors affecting children's syntactic choices in production and comprehension.

Two experiments are reported which examine children's ability to use referential context when making syntactic choices in language production and comprehension. In a recent on-line study of auditory comprehension, Trueswell, Sekerina, Hill, and Logrip (1999) examined children's and adults' abilities to resolve temporary syntactic ambiguities involving prepositional phrases (e.g., "Put the frog on the napkin into..."). Although adults and older children used the referential context to guide their initial analysis (pursuing a destination interpretation in a one-frog context and a modifier interpretation in a two-frog context), 4 to 5-year olds' initial and ultimate analysis was one of destination, regardless of context. The present studies examined whether these differences were attributable to the comprehension process itself or to other sources, such as possible differences in how children perceive the scene and referential situation. In both experiments, children were given a language generation task designed to elicit and test children's ability to refer to a member of a set through restrictive modification. This task was immediately followed by the "put" comprehension task. The findings showed that, in response to a question about a member of a set (e.g., "Which frog went to Mrs. Squid's house?"), 4- to 5-year-olds frequently produced a definite NP with a restrictive prepositional modifier (e.g., "The one on the napkin"). These same children, however, continued to misanalyze put instructions, showing a strong avoidance of restrictive modification during comprehension. Experiment 2 showed that an increase in the salience of the platforms that distinguished the two referents increased overall performance, but still showed the strong asymmetry between production and comprehension. Eye movements were also recorded in Experiment 2, revealing on-line parsing patterns similar to Trueswell et al.: an initial preference for a destination analysis and a failure to revise early referential commitments. These experiments indicate that child-adult differences in parsing preferences arise, in part, from developmental changes in the comprehension process itself and not from a general insensitivity to referential properties of the scene. The findings are consistent with a probabilistic model for uncovering the structure of the input during comprehension, in which more reliable linguistic and discourse-related cues are learned first, followed by a gradually developing ability to take into account other more uncertain (or more difficult to learn) cues to structure.

Child↗

Dopamine is a key factor for the induction of egg diapause of the silkworm, Bombyx mori.

The silkworm, Bombyx mori, enters diapause in the early embryonic stage. Embryonic diapause is induced by incubating eggs of the maternal generation at high temperature (diapause type), whereas incubation at low temperature results in non-diapausing progeny (non-diapause type). Measurement of catecholamine concentrations in haemolymph and brain-subesophageal ganglia (Br-SGs) showed that only dopamine concentrations in both tissues are consistently higher in diapause-type than non-diapause-type larvae and pupae. In particular, the difference in dopamine concentrations in both tissues increases around pupal ecdysis. During the early pupal stage, Dopa decarboxylase activities and mRNA concentrations in Br-SGs were also much higher in diapause-type than non-diapause-type insects. Elevation of dopamine levels induced by feeding Dopa to penultimate-instar and last-instar larvae, and by injecting Dopa or dopamine into pupae 2 days after pupation made the non-diapause-destined insects lay diapause-destined eggs at 59% and approximately 70% frequencies, respectively. Furthermore, injection of Dopa or dopamine elevated mRNA levels of the diapause hormone in the Br-SGs of non-diapause-type pupae 1 day after injection. Incubation of Br-SGs isolated from non-diapause-type day-2 pupae with Dopa or dopamine also stimulated the expression of diapause hormone mRNA. These data indicate that environmental stimuli during embryonic development increase dopamine levels in both hemolymph and Br-SGs from the larval stage to early pupal stage, which results in laying of diapause-destined eggs by female adults through enhanced expression of the diapause hormone gene.

Age Factors↗

Primary mesenchyme cell-ring pattern formation in 2D-embryos of the sea urchin.

Primary mesenchyme cell (PMC) migration during PMC-ring pattern formation was analyzed using computer-assisted time-lapse video microscopy in spread embryos (2D-embryo) of the sea urchin, Mespilia globulus, and a computer simulation. The PMC formed a near normal ring pattern in the 2D-embryos, which were shown to be an excellent model for the examination of cell behavior in vivo by time-lapse computer analysis. The average migration distance of the ventro-lateral PMC aggregate-forming cells (AFC) and that of the dorso-ventral PMC cable-forming cells (CFC) showed no significant difference. All PMC took a rather straightforward migration path to their destinations with little lag time after ingression. This in vivo cell behavior fitted well to a computer simulation with a non-diffusable chemotaxis factor in the cyber-cell migration field. This simulation suggests that PMC recognize their destination from a very early moment of cell migration from the vegetal plate, and implicates that a chemoattractive region is necessary for making the PMC migration pattern. The left- and right-lateral AFC and dorso and ventral CFC were each derived from an unequally divided one-quarter segment of the vegetal plate. This suggests that AFC and CFC have a distinctive ancestor in the vegetal plate, and the PMC are a heterogeneous population at least in terms of their destination in the PMC-ring pattern.

Animals↗

Urinary incontinence in stroke patients after admission to a postacute inpatient rehabilitation program.

OBJECTIVE: To determine the incidence of poststroke urinary incontinence in stroke patients admitted for a postacute inpatient rehabilitation program and its association with discharge destination. DESIGN: Cohort study of first-time stroke patients admitted for a postacute inpatient rehabilitation program from August 1994 to August 1997. SETTING: Rehabilitation center in the Netherlands. PARTICIPANTS: Consecutive first-time stroke patients (n = 143). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Incidence rates calculated with observation time at risk in the denominator. Measures for outcome include the Modified Barthel Index (MBI) and the discharge destination. RESULTS: The incidence rate of urinary incontinence was 29/1000 persons per month (95% confidence interval [CI], 18-48/1000 persons monthly). For incontinent patients, the mean initial MBI score +/- standard deviation was 6.0 +/- 2.3 (range, 2-12); for continent patients, it was 11.5 +/- 9.8 (range, 2-18). This difference was statistically significant (t(139) = 2.12; p = .036; 95% CI for difference of the means, .379-10.84). Patients continent at time of discharge were more often discharged to their own homes than were incontinent patients (Fisher's exact test, p = .0006). CONCLUSIONS: In this select cohort, the incidence of urinary incontinence was lower than that reported in the literature. An association was found between urinary incontinence and discharge destination and between urinary incontinence and functional ability on admission.

Adult↗

Changes in the status of hospitalized stroke patients since inception of the prospective payment system in 1983.

OBJECTIVE: To describe epidemiologically the changes in acute-care delivery services for stroke victims since the inception of the 1983 prospective payment system (PPS). DESIGN: A cross-sectional comparison of 2 acute-care hospitalized samples of stroke patients before and after implementation of PPS. SETTING: Fifteen acute-care hospitals. PARTICIPANTS: A total of 1992 stroke patients discharged from 15 acute care hospitals in 1995-1996 were compared with 1665 patients studied in the same geographic area in 1981-1982. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Incidence rates, length of stay (LOS), discharge destinations, in-hospital transfers, and mortality. RESULTS: Incidence rates between the 2 time periods remained similar (1.13-1.14/1000). Major changes between 1981-1982 and 1995-1996 included reengineering of hospitals to establish subacute units with an increased use of rehabilitation units, a 63% decrease in acute hospital LOS, a 44% increase in discharges to long-term care facilities, a 39% decrease in mortality, and a 5% decrease in discharge to home. Age (avg, 71y), gender, and living arrangements confounded discharge destinations. Significantly more men in 1995-1996 had strokes at younger ages, but overall 53% were women. CONCLUSIONS: Institution of the PPS has dramatically influenced hospital LOS, location of treatment, and discharge destinations with no improvement in home discharges.

Adolescent↗

[Infections and diseases after travelling].

BACKGROUND AND OBJECTIVE: With intensifying international travel numbers of travel associated infections and diseases will increase. Systematic studies on infections and diseases with regard to the travel destination in tropical and subtropical areas are scarce in Germany. PATIENTS AND METHODS: Data regarding travel destination, reason, type and duration of travel, symptoms, clinical findings, laboratory results as well as diagnoses of 2024 patients (male 1010, mean age 35 years; female 1014, mean age 33 years) presenting at the outpatient clinic of the Institute of Tropical Medicine Berlin after returning from travel to tropical or subtropical areas were assessed. RESULTS: The most frequent reasons for consultation were diarrhea (33 %), fever (17 %) and skin affections (14 %). A definitive diagnosis was established in 31 % (635). Significant differences were found for prevalences of infectious diseases with regard to travel destinations. 1.5 % of the travellers had contracted malaria. Only 34% of the returnees from malaria-endemic areas had taken chemoprophylaxis; in case of travel to Africa and Asia, chemoprophyplaxis corresponded to international standards in only 48 % and 23%, respectively. Giardia lamblia was the most frequently detected intestinal pathogen. Blastocystis hominis was found to be significantly associated with diarrhea. CONCLUSIONS: Most of the travel-associated infections are self-limited. In case of fever, malaria and potentially hemorrhagic fever should be excluded and be followed by a stepwise investigation on the cause of fever. In case of diarrhea, parasitologic investigations should be performed by an experienced laboratory and fresh stool samples should be used. Intensive co-operation will be necessary between physician, pharmacists and others active in the field of travel medicine in order to address the shortcomings in chemoprophylaxis for malaria. An increasing need for expertise in tropical and travel medicine, especially among private physicians is expected.

Adult↗

A protein kinase family in Arabidopsis phosphorylates chloroplast precursor proteins.

A serine/threonine protein kinase that is able to phosphorylate chloroplast-destined precursor proteins was purified from leaf extract of Arabidopsis thaliana and was identified by mass spectrometry. The protein kinase, encoded by AT2G17700, belongs to a small protein family comprising in addition AT4G35780 and AT4G38470. All three proteins were expressed heterologously in Escherichia coli and characterized with regard to their properties in precursor protein phosphorylation. They were able to phosphorylate several chloroplast-destined precursor proteins within their cleavable presequences. In contrast, a mitochondria-destined precursor protein was not a substrate for these kinases. For all three enzymes, the phosphorylation reaction was specific for ATP with apparent K(m) values between 14 and 67 microM. They did not utilize other NTPs nor were those able to compete for ATP in the reaction. An excess of ADP was able to inhibit ATP-dependent phosphorylation. Furthermore, all three kinases exhibited autophosphorylation. The protein kinases described here could represent subunits of a regulatory network involved in the cytosolic events of chloroplast protein import.

Amino Acid Sequence↗

Prevention of travel-related infectious diseases: knowledge, practices and attitudes of Swedish travellers.

More Swedish residents travel to countries where they are at risk for contracting malaria, hepatitis, and other serious travel-related diseases. To safeguard the public's health, it is important to determine if travellers accurately perceive health risks and take appropriate preventative measures before and during their trips. This study examined travel health knowledge, attitudes and practices among Swedish residents traveling to destinations with risk of malaria and hepatitis. Self-administered anonymous questionnaires were distributed to Swedish residents (n=957) waiting to board intercontinental flights at the Stockholm-Arlanda International Airport. A majority of travellers sought general information (74%) and travel health advice (59%) prior to departure. Most perceived vaccination as safe and effective, but only 40% and 3% of travellers reported adequate vaccine coverage against hepatitis A or hepatitis B, respectively. Although most did not know the actual malaria risk at the destination, 97% of persons flying to high-risk areas were carrying malaria medication. The study results were in line with those found in surveys conducted in other countries, and demonstrate need for further health education among travellers to risk destinations. Efforts should focus on reaching more travellers, providing clear information and improving compliance with recommended travel health advice.

Adolescent↗

The establishment of provisional quality assurance guidelines for assessing the hygienic adequacy of the lamb carcass cooling process.

The hygienic consequence of a lamb carcass cooling process can be assessed by evaluating the product's time-temperature history at a site within the carcass cavity adjacent to the 5th and 6th lumbar vertebrae. From these data, a numerical value, the process hygiene index, is generated which reflects the amount of potential bacterial growth the process allows and is proposed as an alternative quality assurance tool for assessing lamb cooling processes. Two hygienically acceptable lamb cooling processes, one producing carcasses destined for freezing and the other producing carcasses destined for chilled processing, were monitored. Acceptable cooling processes can be conveniently described in terms of a three class sampling plan where the maximum acceptable value (M) is the highest value obtained and the target value (m) is determined as the 80th percentile value of the pooled data from acceptable runs. The number (c), the proportion of sample values that may lie between (m) and (M), is determined from the acceptable run with the highest sample values. For the process yielding carcasses destined for freezing M = 15, m = 14 and c = 20% while for that producing carcasses for chilled processing M = 9, m = 6 and c = 60%. For both processes a minimum of five samples was tested per process run. Based on these values, provisional processing guidelines for the hygienic cooling of lamb carcasses are suggested.

Journal Article↗

The effect of additional physiotherapy to hospital inpatients outside of regular business hours: a systematic review.

Provision of out of regular business hours (OBH) physiotherapy to hospital inpatients is widespread in the hospital setting. This systematic review evaluated the effect of additional OBH physiotherapy services on patient length of stay (LOS), pulmonary complications, discharge destination, discharge mobility status, quality of life, cost saving, adverse events, and mortality compared with physiotherapy only within regular business hours. A literature search was completed on databases with citation tracking using key words. Two reviewers completed data extraction and quality assessment independently by using modified scales for historical cohorts and case control studies as well as the PEDro scale for randomized controlled trials and quasi-randomised controlled trials. This search identified nine articles of low to medium quality. Four reported a significant reduction in LOS associated with additional OBH physiotherapy, with two articles reporting overall significance and two reporting only for specific subgroups. Two studies reported significant reduction in pulmonary complications for two different patient groups in an intensive care unit (ICU) with additional OBH physiotherapy. Three studies accounted for discharge destination and/or discharge mobility status with no significant difference reported. Quality of life, adverse events, and mortality were not reported in any studies. Cost savings were considered in three studies, with two reporting a cost saving. This systematic review was unable to conclude that the provision of additional OBH physiotherapy made significant improvement to patient outcomes for all subgroups of inpatients. One study in critical care reported that overnight physiotherapy decreased LOS and reduced pulmonary complications of patients in the ICU. However, the studies in the area of orthopaedics, neurology, postcardiac surgery, and rheumatology, which all considered additional daytime weekend physiotherapy intervention, did not provide strong evidence to indicate effective reduction in patient LOS or improving patient discharge mobility status or discharge destination. Investigation should continue in this area, but future trials should ensure factors such as random allocation, groups equal at baseline, blinded investigators, and proven intervention are included in the study design.

Case-Control Studies↗

Using an orientation system for indoor travel and activity with persons with multiple disabilities.

PURPOSE: The study assessed the effectiveness of an orientation system, consisting of a programmable control device linked to acoustic and light sources, for facilitating independent indoor travel and activity in two persons with profound intellectual disability and blindness or severe visual impairment. METHOD: The control device was programmed to activate each destination the persons were to reach and the acoustic or light sources leading to it automatically (i.e. after a preset time from the persons reaching the previous destination). One person was exposed to two baseline phases without the system being alternated with two orientation phases with the system; the other person received only one baseline and one orientation phase. RESULTS: Data showed that during the orientation phases, both persons benefited from the use of the system and could reach the destinations successfully and carry out the activities. CONCLUSIONS: The possibility of promoting independent indoor travel and activity in persons with multiple disabilities may have important implications for the condition of these persons and for rehabilitation and care centres.

Acoustic Stimulation↗

Hepatitis A virus infections in travelers, 1988-2004.

BACKGROUND: Uncertainty exists about the current risk of hepatitis A virus infection in nonimmune travelers to destinations with high or intermediate risk of transmission. We analyzed recent epidemiological data on imported hepatitis A to determine region-specific attack rates and incidences. METHODS: Surveillance data on hepatitis A virus infections diagnosed during 1988-2004 were evaluated on the basis of notification by laboratories, additional reports of physicians, and traveler's statistics. This study focuses on international travelers with hepatitis A virus infection detected after their return to Switzerland. RESULTS: The rate of imported hepatitis A virus infections decreased 75% from 1988 to 2004 and accounted overall for 42% of all hepatitis A cases reported in Switzerland. The actual incidence of hepatitis A in travelers to countries of high or intermediate risk of transmission was 3.0-11.0 per 100,000 person-months abroad for all travelers and 6.0-28.0 per 100,000 for those presumed to be nonimmune. The actual proportion of those visiting friends and relatives among patients with hepatitis A has increased to 28.2%, with children aged 0-14 years predominating. Reductions in the incidence by hepatitis A vaccination were estimated to vary between 35.0% and 61.8% for different destinations. CONCLUSIONS: The risk of hepatitis A virus infections has decreased by a factor of 10-50-fold over time, compared with findings from older studies. The risk, however, remains very considerable at many destinations, including frequently visited places, such as Mexico. Children of immigrants are a high-risk population. Strategies are needed to reach those at highest risk.

Adolescent↗

Differentiation of chromatin during DNA elimination in Euplotes crassus.

In Euplotes crassus, most of the micronuclear genome is eliminated during formation of a transcriptionally active macronucleus. To understand how this is mediated throughout the genome, we have examined the chromatin structure of the macronucleus-destined sequences and Tec transposons, which are dispersed in 15,000 copies in the micronuclear genome and completely eliminated during formation of the macronuclear genome. Whereas the macronucleus-destined sequences show a typical pattern of nucleosomal repeats in micrococcal nuclease digests, the Tec element chromatin structure digests to a nucleosome-like repeat pattern that is not typical: the minimum digestion products are approximately 300-600 base pairs, or "subnucleosomal," in size. In addition, the excised, circular forms of the Tec elements are exceedingly resistant to nucleases. Nevertheless, an underlying nucleosomal structure of the Tec elements can be demonstrated from the size differences between repeats in partial micrococcal nuclease digests and by trypsin treatment of nuclei, which results in mononucleosome-sized products. Characterization of the most micrococcal nuclease-resistant DNA indicates that micronuclear telomeres are organized into a chromatin structure with digestion properties identical to those of the Tec elements in the developing macronucleus. Thus, these major repetitive sequence components of the micronuclear genome differ in their chromatin structure from the macronuclear-destined sequences during DNA elimination. The potential role of developmental stage-specific histone variants in this chromatin differentiation is discussed.

Animals↗

Older hospitalised patients at risk of malnutrition: correlation with quality of life, aid from the social welfare system and length of stay?

BACKGROUND: malnutrition is regarded as a major risk factor for complications and delayed recovery in hospitalised elderly patients. OBJECTIVE: to examine the prevalence of malnutrition in hospitalised elderly patients and evaluate simple clinical screening criteria. To investigate whether malnutrition was related to lack of care from the health care or social welfare system, quality of life and hospital length of stay (LOS). SETTING: non-acute geriatric hospital. SUBJECTS: 294 elderly patients admitted for rehabilitation after acute hospital care; 244 patients were available for assessment. METHODS: questionnaire interview about nutrition, social network and quality of life. Anthropometric and biochemical measurements, assessment of physical and cognitive function, recording of LOS, discharge destination and diagnosis. RESULTS: 126 patients (51.6%) were at risk of malnutrition using the criteria of body mass index<22 kg/m2 and/or weight loss>or=5%/6 months. Poor quality of life in women (P<0.04) and loss of the health of a spouse (P<0.02) correlated with weight loss. No differences were found in patients at risk regarding LOS, discharge destination, or aid from the social welfare system. CONCLUSIONS: this study confirms a high prevalence of malnutrition risk in hospitalised elderly patients. The health care and social welfare system appeared to be unaware of the problem. Poor quality of life in females and loss of the health of a spouse were related to malnutrition risk. The screening variables that were used appeared not to predict hospital length of stay or discharge destination.

Aged↗

Travel and health status: a survey follow-up study.

BACKGROUND: To date there is little sound knowledge on the relationship between travel and health status as perceived by the traveller. Our aim was to investigate the frequency and risk factors of travel-associated illnesses and injuries and identify potential protective factors. METHODS: All adults enrolled in a health insurance scheme who planned to travel in 2002 were eligible for participation in a baseline survey. Pre-travel written questionnaires and post-travel telephone interviews were conducted with responders. We analysed travel-associated health problems using descriptive methods and multivariate logistic regression. RESULTS: From 8316 persons who returned a pre-travel questionnaire, a sample of 2384 were chosen, of whom 1471 completed post-travel interviews. 10.1% of all travellers reported travel-associated illnesses, and 1.8% suffered from injuries during travel. Among travellers to European destinations, 6.0% reported an illness as opposed to 16.2% of travellers to overseas destinations. Predictors for travel-associated illness were age <30 years (OR 1.48), duration of travel >4 weeks (OR 3.35) and travel destination. Perceived health status as scored by the travellers improved after travel. The frequency of medical consultations and personal health-related expenses decreased significantly shortly after travel. CONCLUSIONS: In this study, travel had a positive effect on the perceived health status of the traveller. The positive effects of travel seemed to outweigh the impact of health problems. Travel did not lead to increased health-related costs, neither in individual health expenses nor indirectly through increased medical consultation rates.

Adult↗

Breast cancer mortality among immigrants in Australia and Canada.

BACKGROUND: By moving between geographic regions with differing levels of breast cancer risk, migrant populations of women provide a unique opportunity to examine the impact of exposure to new environments and lifestyles on breast cancer risk. Breast cancer incidence and mortality rates for the majority of migrant groups originating from countries with low breast cancer risk have been found to increase toward the rates observed in destination countries with populations at higher risk for this disease. Because very little information exists on migrants from high- to low-risk countries, it is not known whether rates for these groups decrease or whether migrant groups generally experience increases in breast cancer rates. PURPOSE: To address these questions, we determined the breast cancer mortality rates for women from both lower and higher risk countries who had immigrated to Australia and Canada and compared these rates with those exhibited by the population in the origin country and by the destination native-born population. METHODS: Individual mortality records covering the years 1984 through 1988 and 1986 census data for Australia and Canada were obtained. Direct age-standardized mortality rates and rate ratios (and their 95% confidence intervals) were calculated for immigrant groups in Australia and Canada. Age-standardized rate ratios by length of residence in Australia were calculated. Weighted regression analyses of observed and expected mortality changes were performed. RESULTS: In Australia, the mortality rates for 12 (75%) of 16 immigrant groups from lower risk countries and 10 (71.4%) of 14 groups from higher risk countries shifted toward the rate of native-born Australians. In Canada, the rates for 12 (60%) of 20 immigrant groups from lower risk countries and four (80%) of five groups from higher risk countries converged to the rate of native-born Canadians. Overall, the extent of convergence (shift of immigrant's mortality rate in origin country toward rate of native-born population) was 50% for immigrants in Australia and 38% for immigrants in Canada. Although there was not a consistent pattern of convergence with length of residence in Australia, after 30 or more years, the mortality rates of 15 (83.3%) of 18 immigrant groups had shifted toward the rate of the native-born Australians. Because of the small number of deaths in many of the immigrant groups studied, the observed differences in the breast cancer mortality age-standardized rates between the origin country and immigrant group, although often substantial, were seldom statistically significant. CONCLUSIONS: Breast cancer mortality rates among women in the majority of immigrant groups shifted from the rate observed in their country of origin toward the rate of the native-born population in the destination country. IMPLICATIONS: These findings indicate that environmental and lifestyle factors associated with the new place of residence influence the breast cancer rates of immigrants and also suggest that, since most migrants migrate as adults, the risk of breast cancer can be altered in later life.

Adult↗

Conserved DNA sequences adjacent to chromosome fragmentation and telomere addition sites in Euplotes crassus.

During the formation of a new macronucleus in the ciliate Euplotes crassus, micronuclear chromosomes are reproducibly broken at approximately 10 000 sites. This chromosome fragmentation process is tightly coupled with de novo telomere synthesis by the telomerase ribonucleoprotein complex, generating short linear macronuclear DNA molecules. In this study, the sequences of 58 macronuclear DNA termini and eight regions of the micronuclear genome containing chromosome fragmentation/telomere addition sites were determined. Through a statistically based analysis of these data, along with previously published sequences, we have defined a 10 bp conserved sequence element (E-Cbs, 5'-HATTGAAaHH-3', H = A, C or T) near chromosome fragmentation sites. The E-Cbs typically resides within the DNA destined to form a macronuclear DNA molecule, but can also reside within flanking micronuclear DNA that is eliminated during macronuclear development. The location of the E-Cbs in macronuclear-destined versus flanking micronuclear DNA leads us to propose a model of chromosome fragmentation that involves a 6 bp staggered cut in the chromosome. The identification of adjacent macronuclear-destined sequences that overlap by 6 bp provides support for the model. Finally, our data provide evidence that telomerase is able to differentiate between newly generated ends that contain partial telomeric repeats and those that do not in vivo.

Animals↗