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J Worm

Publications and source records attributed to J Worm.

At least 19 recordsLinked to original sources
PubMed2006

Insulin-like growth factor binding protein 2 is a marker for antiestrogen resistant human breast cancer cell lines but is not a major growth regulator.

Antiestrogens target the estrogen receptor and counteract the growth stimulatory action of estrogen on human breast cancer. However, acquired resistance to antiestrogens is a major clinical problem in endocrine treatment of breast cancer patients. To mimic acquired resistance, we have used a model system with the antiestrogen sensitive human breast cancer cell line MCF-7 and several antiestrogen resistant cell lines derived from the parental MCF-7 cell line. This model system was used to study the expression and possible involvement in resistant cell growth of insulin-like growth factor binding protein 2 (IGFBP-2). By an oligonucleotide based microarray, we compared the expression of mRNAs encoding insulin-like growth factor binding protein 1,2,3,4,5 and 6 (IGFBP-1 to -6) in the parental MCF-7 cell line to three human breast cancer cell lines, resistant to the antiestrogen ICI 182,780 (Faslodex/Fulvestrant). Only IGFBP-2 mRNA was overexpressed in all three resistant cell lines. Thus, we compared the IGFBP-2 protein expression in MCF-7 cells to nine antiestrogen resistant breast cancer cell lines, resistant to either ICI 182,780 or tamoxifen or RU 58,668 and found that IGFBP-2 was overexpressed in all nine resistant cell lines. Three of the resistant cell lines, resistant to different antiestrogens, were selected for further studies and IGFBP-2 overexpression was demonstrated at the mRNA level as well as the intra- and extracellular protein level. The objective of this study was to examine if IGFBP-2 is involved in growth of antiestrogen resistant human breast cancer cells. Therefore, IGFBP-2 expression was inhibited by antisense oligonucletides and siRNA. Specific inhibition of IGFBP-2 protein expression was achieved in MCF-7 and the three selected antiestrogen resistant cell lines, but no effect on resistant cell growth was observed. Thus, we were able to establish IGFBP-2 as a marker for antiestrogen resistant breast cancer cell lines, although IGFBP-2 was not a major contributor to the resistant cell growth.

Biomarkers, Tumor↗
PubMed2004

Loss of heterozygosity at 9q33 and hypermethylation of the DBCCR1 gene in oral squamous cell carcinoma.

The DBCCR1 gene at chromosome 9q33 has been identified as a candidate tumour suppressor, which is frequently targeted by promoter hypermethylation in bladder cancer. Here, we studied the possible involvement of DBCCR1 in the development of oral squamous cell carcinoma. DNA from 34 tumours was examined for loss of heterozygosity (LOH) at three markers surrounding DBCCR1 and for hypermethylation of the DBCCR1 promoter, using methylation-specific PCR and methylation-specific melting-curve analysis. LOH was found in 10 of 31 cases (32%), and DBCCR1 hypermethylation was present in 15 of 34 cases (44%). Hypermethylation of DBCCR1 was also present in three of seven epithelial tissues adjacent to the tumours, including two hyperplastic and one histologically normal epithelia. Furthermore, of four oral leukoplakias with dysplasia, one showed LOH at 9q33 and two showed DBCCR1 hypermethylation. These data suggest that LOH at 9q33 and hypermethylation of the DBCCR1 promoter are frequent and possibly early events in oral malignant development.

Adult↗
PubMed2001

Methylation-dependent silencing of the reduced folate carrier gene in inherently methotrexate-resistant human breast cancer cells.

The molecular basis of methotrexate resistance was studied in human MDA-MB-231 breast cancer cells, which are inherently defective in methotrexate uptake and lack expression of the reduced folate carrier (RFC). Transfection of MDA-MB-231 cells with RFC cDNA restored methotrexate uptake and increased methotrexate sensitivity by approximately 50-fold. A CpG island in the promoter region of RFC was found to be methylated in MDA-MB-231 cells, but was unmethylated in RFC expressing, methotrexate-sensitive MCF-7 breast cancer cells. Chromatin immunoprecipitation with antibodies against acetylated histones H3 and H4 showed that the RFC promoter was enriched for acetylated histones on expressed, unmethylated alleles only. Treatment of MDA-MB-231 cells with 5-aza-2'-deoxycytidine restored RFC expression but also led to increased methotrexate efflux and did not reverse methotrexate resistance. This suggests that 5-aza-2'-deoxycytidine up-regulates both methotrexate uptake and some methotrexate-resistance mechanism(s). Reverse transcription-polymerase chain reaction analysis showed increased expression levels of several ATP-dependent efflux pumps in response to 5-aza-2'-deoxycytidine treatment, including P-glycoprotein and members of the multidrug resistance-associated protein family. Up-regulation of P-glycoprotein in response to 5-aza-2'-deoxycytidine was associated with demethylation of a CpG island in the MDR1 promoter, whereas the mechanism(s) for 5-aza-2'-deoxycytidine-induced up-regulation of multidrug resistance-associated proteins is probably indirect. Dipyridamole inhibited methotrexate efflux and reversed methotrexate resistance in 5-aza-2'-deoxycytidine-treated MDA-MB-231 cells.

Acetylation↗
PubMed2001

Measurement of biodegradable dissolved organic carbon (BDOC) in lake water with a bioreactor.

Once-through, plug-flow bioreactors were colonised and maintained with a microbial community from a mesotrophic lake and used to measure the concentration of biodegradable dissolved organic carbon (BDOC). A BDOC measurement can be done within 3-4h by this method. Glucose was used to test whether oxygen consumption (BOD) could substitute for measurements of dissolved organic carbon (DOC). All added glucose was utilised, however, without a concomitant increase in oxygen demand. Oxygen consumption should not be used in bioreactor measurements. The site-specificity was tested by comparing DOC utilisation in bioreactors with batch cultures inoculated with indigenous bacteria and incubated for 28 days. The bioreactors were not site-specific and required no acclimation to measure BDOC from three different systems. However, humic substances were adsorbed in the reactors and about two days were needed to equilibrate the reactors. The BDOC concentrations in two lakes varied 2-fold over diurnal cycles and 3-fold during the period February-June. No significant relations to the light, dark cycle, chlorophyll, and DOC were found. The absolute BDOC concentrations ranged from 20 to almost 200 microM and averaged 13% of the DOC in the lakes. It is concluded that BDOC in lakes and other fresh waters can be measured quickly and reliably with a bioreactor.

Biodegradation, Environmental↗
PubMed2001

Input of protein to lake water microcosms affects expression of proteolytic enzymes and the dynamics of Pseudomonas spp.

The objective of this study was to determine how an input of protein to lake water affects expression of a proteolytic potential and influences the abundance and composition of a specific group of bacteria. Pseudomonas spp. were chosen as a target group that can be recovered on selective growth media and contain both proteolytic and nonproteolytic strains. Amendment with 2 mg of casein per liter increased total proteinase activity (hydrolysis of [(3)H]casein) by 74%, leucine-aminopeptidase activity (hydrolysis of leucine-methyl-coumarinylamide) by 133%, bacterial abundance by 44%, and phytoplankton biomass (chlorophyll a) by 39%. The casein amendment also increased the abundance of culturable Pseudomonas spp. by fivefold relative to control microcosms but did not select for proteolytic isolates. Soluble proteins immunochemically related to the Pseudomonas fluorescens alkaline proteinase, AprX, were detected in amended microcosms but not in the controls. The expression of this class of proteinase was confirmed exclusively for proteolytic Pseudomonas isolates from the microcosms. The population structure of Pseudomonas isolates was determined from genomic fingerprints generated by universally primed PCR, and the analysis indicated that casein amendment led to only minor shifts in population structure. The appearance of AprX-like proteinases in the lake water might thus reflect a general induction of enzyme expression rather than pronounced shifts in the Pseudomonas population structure. The limited effect of casein amendment on Pseudomonas population structure might be due to the availability of casein hydrolysates to bacteria independent of their proteinase expression. In the lake water, 44% of the total proteinase activity was recovered in 0.22-microm-pore-size filtrates and thus without a direct association with the bacteria providing the extracellular enzyme activity. Since all Pseudomonas isolates expressed leucine-aminopeptidase in pure culture, proteolytic as well as nonproteolytic pseudomonads were likely members of the bacterial consortium that metabolized protein in the lake water.

Bacterial Proteins↗
PubMed2001

Carbon limitation induces sigma(S)-dependent gene expression in Pseudomonas fluorescens in soil.

Recent studies employing reporter gene technology indicate that the availabilities of the major nutrients nitrogen, phosphate, and iron to Pseudomonas are not severely limited in bulk soil. Indirect evidence has pointed to carbon limitation as a severe nutritional stress in this environment. We show that a plasmid (pGM115)-borne transcriptional fusion between the sigma(S)-dependent Escherichia coli promoter P(fic) and lacZ functions as a reliable reporter for carbon availability in Pseudomonas fluorescens. When P. fluorescens strain DF57(pGM115) was introduced into bulk soil, carbon-limiting conditions were indicated by citrate-repressible induction of beta-galactosidase activity. To address carbon availability at the single-cell level, we developed an immunofluorescence double-staining procedure for individual DF57 cells expressing beta-galactosidase from P(fic). Changes in cell size and expression of beta-galactosidase were analyzed by flow cytometry. Cells extracted from soil microcosms reduced their size less than carbon-starved cells in pure culture and showed an increased tendency to aggregate. The single-cell analysis revealed that for cells residing in soil, the expression of beta-galactosidase became heterogeneous and only a DF57 subpopulation appeared to be carbon limited. In soil amended with barley straw, limited nitrogen availability has been determined by use of the bioluminescent reporter strain P. fluorescens DF57-N3. We used strain DF57-N3(pGM115) as a double reporter for carbon and nitrogen limitation that allowed us to study the dynamics of carbon and nitrogen availabilities in more detail. In straw-amended soil beta-galactosidase activity remained low, while nitrogen limitation-dependent bioluminescence appeared after a few days. Hence, nitrogen became limited under conditions where carbon resources were not completely exhausted.

Bacterial Proteins↗
PubMed2001

In-tube DNA methylation profiling by fluorescence melting curve analysis.

BACKGROUND: Most PCR assays for detection of 5-methylcytosine in genomic DNA entail a two-step procedure, comprising initial PCR amplification and subsequent product analysis in separate operations that usually require manual transfer. These methods generally provide information about methylation of only a few CpG dinucleotides within the target sequence. METHODS: An in-tube methylation assay is described that integrates amplification of bisulfite-treated DNA and melting analysis by using a thermal cycler coupled to a fluorometer (LightCycler). DNA melting curves were acquired by measuring the fluorescence of a double-stranded DNA-binding dye (SYBR Green I) during a linear temperature transition. RESULTS: Analysis of a region comprising 11 CpG sites at the SNRPN promoter CpG island showed that the melting temperature (T(m)) differed by approximately 3 degrees C between unmethylated and fully methylated alleles. This assay could easily distinguish patients with Prader-Willi syndrome or Angelman syndrome from individuals without these conditions. Melting curve analysis also allowed resolution of methylation "mosaicism" at the p15(Ink4b) promoter in bone marrow samples from patients with acute myeloid leukemia (AML). AML samples representing pools of heterogeneously methylated p15(Ink4b) alleles showed broadened melting peaks with overall T(m)s between those of the unmethylated and fully methylated alleles. CONCLUSIONS: Integration of PCR and fluorescence melting analysis may be useful for simple and cost-effective detection of aberrant methylation patterns.

Acute Disease↗
PubMed2000

Aberrant p27Kip1 promoter methylation in malignant melanoma.

p27Kip1 is a regulator of the mammalian cell cycle and a putative tumor suppressor. Distinct altered patterns of p27Kip1 protein expression are found in a variety of human carcinomas, and p27Kip1 expression levels usually correlate directly with disease-free survival. The mechanism(s) by which p27Kip1 expression is reduced or lost during tumorigenesis remains unclear. Specific alterations of the p27Kip1 gene, including mutations and homozygous deletions, are exceedingly rare in human cancers. We have used methylation-specific PCR and bisulfite genomic sequencing to examine the methylation status of p27Kip1 in 61 primary and metastatic tumors and 35 cell lines from patients with malignant melanoma. Dense methylation of a CpG island in the promoter region of p27Kip1 was detected in four of 45 metastatic tumors (9%) and three of the cell lines (9%), including two cell lines established from two different metastases from the same patient. Examination of a naturally occurring, allele-specific sequence variant demonstrated that p27Kip1 methylation is associated with transcriptional silencing in situ. Cell lines with p27Kip1 methylation showed retention of the wild-type allele and detectable p27Kip1 protein whose abundance was reduced compared with normal melanocytes. Collectively, our data suggest that DNA methylation may be a cause of monoallelic p27Kip1 silencing in malignant melanoma, which would support a role for p27Kip1 haploinsufficiency in human cancer.

Amino Acid Substitution↗
PubMed2000

Interactions between proteolytic and non-proteolytic Pseudomonas fluorescens affect protein degradation in a model community.

The metabolic interactions between proteinase-producing bacteria and other members of bacterial communities are poorly investigated, although they are important for the understanding of structure-function relationships in complex ecosystems. We constructed simple model communities consisting of proteolytic and non-proteolytic Pseudomonas fluorescens strains to identify relevant interactions and to assess their specific significance during the mobilization of protein for growth. The proteolytic or non-proteolytic model communities were established by co-inoculating proteolytic or proteinase-deficient Tn5-mutants of P. fluorescens strain ON2 with the non-proteolytic reporter strain DF57-N3 that expresses bioluminescence in response to nitrogen limitation. The growth medium was composed such that growth would be nitrogen limited in the absence of proteolytic activity. In the proteolytic communities data on growth and nitrogen availability showed that the protein hydrolysates were available to both the proteolytic and the non-proteolytic strain. Competition between these strains profoundly affected both growth and proteinase production. Hence, the mobilization of protein was closely coupled to the competitive success of the proteolytic strain. These findings provide new insight into the metabolic interactions that occur when protein is degraded in mixed bacterial communities.

Journal Article↗
PubMed1998

Polypharmacy and the risk of drug-drug interactions among Danish elderly. A prescription database study.

OBJECTIVE: To analyze the use of all subsidized prescription drugs with special attention to the elderly (> or = 70 years of age), including their use of drug combination generally accepted as carrying a risk of severe interactions. DESIGN: Descriptive prevalence study. SETTING: Odense Pharmacoepidemiological Database, Denmark. The fourth quarter of 1994. SUBJECTS: All inhabitants in the county of Funen, Denmark. MAIN OUTCOME MEASURES: Prevalence of drug use for persons < 70 and > or = 70 years of age including number of drugs used and of drug combinations. Occurrence of 45 drug combinations generally accepted as carrying a risk of severe interactions. RESULTS: Among persons less than 70 years, 67.9% used none, 16.5% used one drug and 15.6% used two or more prescription drugs. The corresponding prevalences for the elderly were 35.7%, 15.9% and 48.4%. The 26,337 elderly patients with at least two drugs used 21,293 different combinations. Of the elderly patients who had purchased > or = two drugs, 4.4% had combinations of drugs carrying a risk of severe interactions. CONCLUSIONS: Most elderly use drugs and usually several drugs concomitantly. The elderly form a heterogeneous group of drug users. Drug combinations carrying a risk of severe interactions are relatively frequent.

Aged↗
PubMed1993

Drug related hospital admissions. Results from an intervention program.

As part of a high-intensity monitoring study of drug events as the cause of admission to departments of internal medicine, the effect of an educational intervention programme was studied. Two departments were included, one specialising in geriatrics and one that received patients by non-selected referral. The series consisted of 607 consecutive admissions studied before and 703 after the intervention. The drug events considered were adverse drug reactions and dose-related therapeutic failures, mainly due to non-compliance. A modest, statistically non-significant decrease in drug related hospital admissions (DRH) was seen, from 14% before to 13% after the intervention period. However, DRHs classified as definitely avoidable showed the significant decrease of 83%. There was no apparent relationship between the topics selected for the intervention programme and changes in the pattern of DRHs. No relationship between alterations in sales data and hospital admissions caused by a given drug could be demonstrated. A blinded external evaluation of case abstracts did not disclose any significant shift in the investigators' assessments. The intervention may have had an non-specific effect on avoidable DRHs.

Denmark↗
PubMed1992

Drug related admissions to medical wards: a population based survey.

1. In total 1999 consecutive admissions to six medical wards were subjected to a prospective high-intensity drug event monitoring scheme to assess the extent and pattern of admissions caused by adverse drug reactions (ADRs) or dose related therapeutic failures (TF), in a population-based design. The wards were sub-specialised in general medicine, geriatrics, endocrinology, cardiology, respiratory medicine and gastroenterology. 2. Considering definite, probable and possible drug events, the prevalence of drug related hospital admissions was 11.4% of which 8.4% were caused by ADRs and 3.0% by TFs. There were large inter-department differences. 3. The six classes of drugs most frequently involved in admissions caused by ADRs were anti-rheumatics and analgesics (27%), cardiovascular drugs (23%), psychotropic drugs (14%), anti-diabetics (12%), antibiotics (7%), and corticosteroids (5%). Noncompliance accounted for 66% of the TFs with diuretics and anti-asthmatics most frequently involved. 4. The pattern of drugs involved in ADRs was compared with the regional drug sales statistics. Drugs with a particularly high rate of ADR related admissions per unit dispensed were nitrofurantoin and insulin (617 and 182 admissions per 1,000,000 defined daily doses), while low rates were seen for diuretics and benzodiazepines (10 and 7 admissions per 1,000,000 defined daily doses). Confidence intervals were wide. 5. Patients who had their therapy prescribed by a hospital doctor had a slightly higher prevalence of drug events than those who were treated by a general practitioner (12.6% vs 11.8%). The reverse applied for drug events assessed as avoidable (3.3% vs 4.6%). Although these differences were not statistically significant, it may suggest general practitioners as the appropriate target for interventive measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Causes of death during the first 5 years of a randomized trial of mass screening for colorectal cancer with fecal occult blood test.

The main purpose of population screening for colorectal cancer is to reduce mortality from the disease. The criteria of death from colorectal cancer are defined in the present randomized trial of 61,938 persons between 45 and 74 years old, and the need for an impartial death review committee was demonstrated. Causes of death within the first 5 years are described within subgroups of the test group and compared with those in the control group. Death rates were higher among non-responders to screening than among controls and among those in whom Hemoccult-II had been performed at least once. Persons with negative Hemoccult-II had a lower death rate than controls. The overall autopsy rate was 32%. Lethal complications from treatment of colorectal neoplasia were evaluated per se. Death from colorectal cancer occurred in 74 persons in the total screening group and in 91 among controls. Sources of bias are discussed. A method of evaluating possible benefit to those being screened is suggested. Final results cannot be expected before 1996.

Aged↗
PubMed1991

Drug related events and drug utilization in patients admitted to a geriatric hospital department.

Two hundred ninety-four consecutive admissions to a geriatric department were evaluated for drug events as cause of admission. The drug events considered were adverse drug reactions (ADRs) and dose-related therapeutic failures. In 39 cases (13.3%), a definite, probable or possible drug event was a dominant or contributing cause of the admission (11.2% ADRs and 2.0% dose-related therapeutic failures). Five of these cases (1.7%) were judged to be due to errors in prescription and a further seven (2.4%) were found to have been avoidable by efforts exceeding the obligatory. There were no statistically significant differences between drug-related and non-drug related admissions in terms of age, sex, number of drugs taken at the admission or duration of hospitalization. ADRs in the geriatric patients are difficult to recognize and may be interpreted as senile loss of function. Sixty-seven percent of the patients took drugs with a sedative action, 68% took drugs with a hypotensive action, 67% took drugs with a potential for confusional states, 15% took drugs with a potential for depression, and 64% took drugs with a potential for constipation. A reduction of the number of drug-related hospital admissions by means of a large-scale intervention would be a difficult task for several reasons: no particular class of drugs caused the drug events, no particular mechanism dominated, no particular group of doctors were responsible for the drug events, and only a part of the drug events were judged to be avoidable.

Aged↗
PubMed1978

Relationship between haemoglobin and serum testosterone in normal children and adolescents and in boys with delayed puberty.

The concentrations of haemoglobin and of serum testosterone were measured in 215 normal children and adolescents aged 7--20 years, and in 8 boys with constitutional delayed puberty. From the age of 14 years onward haemoglobin and testosterone rose in normal boys and differed significantly from the stable levels observed in prepubertal children and pubertal girls. In the entire series of normal boys (n = 118, age 7--20 years) concentrations of haemoglobin and testosterone were found to be closely correlated (r = 0.73, p less than 0.001). These results provide further evidence for a major role of testosterone in the control of erythropoiesis. Therefore, this correlation suggests the use of serum testosterone determination for the proper selection of haemoglobin reference ranges in boys. The respective reference ranges of haemoglobin corresponding to testosterone levels at 0 and 30 nmol/l were 120.5--148.5 and 143.5--171.5 g/l (95% confidence limits). Boys with delayed puberty were found to have significantly reduced median values of haemoglobin and testosterone for their chronological age, and 6 of the 8 boys investigated were truly anaemic on this background. Nevertheless, their haemoglobin concentration did appear appropriate as judged from their testosterone levels. This observation supports the idea that the selection of the relevant reference range for haemoglobin in boys should depend on the state of physical development as expressed by serum testosterone.

Adolescent↗