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1.
Occup Med (Lond) ; 71(1): 20-24, 2021 02 06.
Article in English | MEDLINE | ID: mdl-33399827

ABSTRACT

BACKGROUND: Post-exposure prophylaxis (PEP) for human immunodeficiency virus (HIV) is recommended to start within hours of needlestick injuries (NSIs) among healthcare workers (HCWs). Delays associated with awaiting the results of testing from the source patient (whose blood was involved in the NSI) can lead to psychological consequences for the exposed HCW as well as symptomatic toxicities from empiric PEP. AIMS: After developing a 'stat' (immediate) workflow that prioritized phlebotomy and resulting of source patient bloodwork for immediate handling and processing, we retrospectively investigated whether our new workflow had (i) decreased HIV order-result interval times for source patient HIV bloodwork and (ii) decreased the frequency of HIV PEP prescriptions being dispensed to exposed HCWs. METHODS: We retrospectively analysed NSI records to identify source patient HIV order-result intervals and PEP dispensing frequencies across a 6-year period (encompassing a 54-month pre-intervention period and 16-month post-intervention period). RESULTS: We identified 251 NSIs, which occurred at similar frequencies before versus after our intervention (means 3.54 NSIs and 3.75 NSIs per month, respectively). Median HIV order-result intervals decreased significantly (P < 0.05) from 195 to 156 min after our intervention, while the proportion of HCWs who received one or more doses of PEP decreased significantly (P < 0.001) from 50% (96/191) to 23% (14/60). CONCLUSION: Using a 'stat' workflow to prioritize source patient testing after NSIs, we achieved a modest decrease in order-result intervals and a dramatic decrease in HIV PEP dispensing rates. This simple intervention may improve HCWs' physical and psychological health during a traumatic time.


Subject(s)
HIV Infections , Needlestick Injuries , Occupational Exposure , HIV Infections/prevention & control , Health Personnel , Humans , Needlestick Injuries/prevention & control , Post-Exposure Prophylaxis , Retrospective Studies , Workflow
2.
J Gastrointest Surg ; 13(2): 261-8, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18791770

ABSTRACT

BACKGROUND: Restorative proctocolectomy followed by an ileoanal J-pouch procedure is the therapy of choice for patients with familial adenomatous polyposis and ulcerative colitis. After low anterior rectal resection, the authors have reported on a novel, less complex pouch configuration, a transverse coloplasty pouch. The aim of the present work was to apply this new design to the ileal pouch construction, to evaluate feasibility, and to measure functional results in comparison with the J-pouch and the straight ileoanal anastomosis using the pig as an animal model. METHODS: Twenty-three pigs underwent restorative proctocolectomy followed by reconstruction with straight ileoanal anastomosis (IAA; n = 5), J-pouch (n = 7), and a transverse ileal pouch (TIP; n = 11). Pigs were followed for 6 days postoperatively. Peristaltic function was assessed by manometry proximal to the pouch, in the reservoir, and at the level of the ileoanal anastomosis. Functional outcome was monitored by semiquantitative assessment of the general condition of the animals, postoperative feeding habits, and stool frequency and consistency. A Fourier analysis was performed in order to compare peristalsis in the ileal reservoirs. The reservoir volume was measured in situ by triple contrast computed tomography scan with 3D reconstruction. RESULTS: Seventeen animals survived for 1 week. There was no difference in the general condition or the feeding habits of the groups. A significant number of pigs with the TIP pouch (7/10) had semisolid or formed stools as opposed to liquid stools after J-pouch (6/6) and IAA (4/5; p = 0.01). TIP animals had a lower stool frequency (3.2 +/- 1.14 per day) on day 6 after the operation than pigs with J-pouch, 5.33 +/- 1,03, and IAA, 4.6 +/- 1.82 (p = 0.0036). The in situ volume of the pouches did not differ significantly. The Fourier analysis demonstrated a disruption of peristalsis by the J-pouch and the TIP reconstruction but not after IAA. CONCLUSION: The function of ileoanal reservoirs after proctocolectomy may result from the disruption of properistaltic waves after pouch formation. The mechanism of peristalsis disruption is independent of the in situ volume of the pouch.


Subject(s)
Colonic Pouches , Ileum/surgery , Proctocolectomy, Restorative/methods , Recovery of Function/physiology , Anastomosis, Surgical/methods , Animals , Defecation/physiology , Feasibility Studies , Female , Gastrointestinal Motility/physiology , Swine , Time Factors
3.
J Med Eng Technol ; 31(1): 62-74, 2007.
Article in English | MEDLINE | ID: mdl-17365428

ABSTRACT

Electrical stimulation has been used for exercise, healing wounds, relieving pain, and strengthening muscle. The assumption is that current will flow predictably between electrodes and, therefore, there will be predictability in the clinical response to electrical stimulation. This may not be the case. The present investigation shows that considerable channelling of current occurs when the skin is heated or when there is a wound between the electrodes. By studying current movement in nutrient agar (a homogenous medium), blood agar and layered blood and nutrient agar to simulate areas of increased blood flow, it was found that areas of high or low resistance, especially in the surface layer, caused significant current movement toward (low resistance area) or away (high resistance area) from those areas. When a resister model was used to measure dispersion characteristics of current in a three-dimensional array, it was shown that if even a single resister value was lowered by 20% in the upper layer, current sinking occurred in all three layers of the array. The results seem to imply that where the tissue is non homogeneous due to injury or inflammation, electrode design or current delivery systems need to be modified appropriately to have the intended effect of the electrical stimulation.


Subject(s)
Electric Stimulation Therapy , Skin/blood supply , Wound Healing , Aged , Electrodes , Female , Humans , Inflammation , Male , Middle Aged , Models, Biological , Necrosis , Regional Blood Flow , Skin/injuries , Skin Temperature
4.
J Med Eng Technol ; 30(6): 368-81, 2006.
Article in English | MEDLINE | ID: mdl-17060165

ABSTRACT

Carbonized rubber electrodes were tested extensively when they were first developed 30 years ago, but modern carbonized rubber electrodes have not received the type of scrutiny that the first electrodes received. Modern electrodes differ from the original electrodes in that they come with a self-adhesive electrode gel called hydrogel as part of their composition. The present study was undertaken to examine the current distribution and impedance characteristics of five brands of carbonized rubber electrodes and to examine the current distribution between electrodes during electrical stimulation in six subjects. Several different electrode sizes were tested between 3 and 10 cm. The current flow between the electrodes was determined by measuring the voltage across the skin on human subjects in 15 discrete locations between the electrodes. Blood flow was also measured between the electrodes with a laser Doppler flow meter to assess the physiological effect of current distribution on the skin at several skin temperatures. The results of these studies showed that at low currents, such as is used in TENS, very little current is actually applied through the skin due to the high impedance of the electrodes. At current levels normally used for electrical stimulation for functional movement, while current flow is better in most electrodes, it is very uneven, resulting in high current density in the centre of the electrodes and a fall off of at least 50% in current intensity at the edges of the electrode. There was very little difference in current density between small and large electrodes due to the high current density in the centre. Skin blood flow altered the movement of current between the electrodes and also may contribute to electrode performance. The implication of these studies is that electrode design needs to be altered for better current distribution, especially at low stimulation currents.


Subject(s)
Blood Flow Velocity/physiology , Electric Stimulation Therapy/instrumentation , Electric Stimulation/instrumentation , Electric Stimulation/methods , Electrodes , Skin Physiological Phenomena , Skin/blood supply , Adult , Electric Stimulation Therapy/methods , Electromagnetic Fields , Female , Humans , Male , Radiation Dosage , Radiometry
5.
Phys Rev Lett ; 96(7): 072301, 2006 Feb 24.
Article in English | MEDLINE | ID: mdl-16606077

ABSTRACT

Differential production cross sections of K+/- mesons have been measured in p + C and p + Au collisions at 1.6, 2.5, and 3.5 GeV proton beam energy. At beam energies close to the production threshold, the K- multiplicity is strongly enhanced with respect to proton-proton collisions. According to microscopic transport calculations, this enhancement is caused by two effects: the strangeness exchange reaction NY --> K- NN and an attractive in-medium K- N potential at saturation density.

7.
J Dairy Sci ; 89(1): 174-87, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16357281

ABSTRACT

The objective of this experiment was to quantify intakes, duodenal flows, and ruminal apparent synthesis (AS) of B-vitamins in lactating dairy cows fed diets varying in forage and nonfiber carbohydrate (NFC) contents. Eight (4 primiparous and 4 multiparous) ruminally and duodenally cannulated Holstein cows were assigned to 4 dietary treatments in a replicated 21-d period, 4 x 4 Latin square design with a 2 x 2 factorial treatment arrangement. Diets, fed as TMR, contained (DM basis) 2 levels of forage (35 and 60%) and 2 levels of NFC (30 and 40%). The forage portion of the diets contained 50% corn silage, 33% alfalfa hay, and 17% grass hay. Soybean hulls and beet pulp (2:1) and corn meal and ground barley (2:1) were included to achieve desired NFC concentrations. No supplemental B-vitamins were fed. B-vitamin AS was calculated as the amount of a specific B-vitamin flowing to the duodenum minus its daily orts-corrected intake. Dry matter and organic matter intakes were higher for cows fed the 35% forage diets and the 40% NFC diets. Increasing dietary forage content decreased ruminal AS of pyridoxine, folic acid, and B12. Increasing dietary NFC content increased ruminal AS of nicotinic acid, nicotinamide, niacin, pyridoxal, B6, and folic acid but decreased AS of B12. Across diets, amounts of B-vitamins synthesized were highest for niacin, followed by riboflavin, B12, thiamin, B6, and folic acid. Biotin AS values were negative for all diets, suggesting either no ruminal synthesis or that destruction by ruminal microflora was greater than synthesis. B-vitamin intake, duodenal flow, and ruminal synthesis are influenced by dietary forage and NFC contents.


Subject(s)
Cattle/physiology , Diet/veterinary , Dietary Carbohydrates/administration & dosage , Duodenum/physiology , Rumen/metabolism , Vitamin B Complex/administration & dosage , Animals , Beta vulgaris , Fats/analysis , Female , Folic Acid/biosynthesis , Gastrointestinal Motility , Hordeum , Hydrogen-Ion Concentration , Lactation , Medicago sativa , Milk/chemistry , Milk Proteins/analysis , Poaceae , Silage , Glycine max , Vitamin B 12/biosynthesis , Vitamin B 6/biosynthesis , Vitamin B Complex/biosynthesis , Zea mays
8.
Phys Rev Lett ; 95(1): 012301, 2005 Jul 01.
Article in English | MEDLINE | ID: mdl-16090609

ABSTRACT

Azimuthal distributions of pi+, K+, and K- mesons have been measured in Au+Au reactions at 1.5A GeV and Ni+Ni reactions at 1.93 A GeV. In semicentral collisions at midrapidity, pi+ and K+ mesons are emitted preferentially perpendicular to the reaction plane in both collision systems. In contrast for K- mesons in Ni+Ni reactions, an in-plane elliptic flow was observed for the first time at these incident energies.

9.
Phys Rev Lett ; 91(15): 152301, 2003 Oct 10.
Article in English | MEDLINE | ID: mdl-14611460

ABSTRACT

Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.

10.
Phys Rev Lett ; 90(23): 232501, 2003 Jun 13.
Article in English | MEDLINE | ID: mdl-12857251

ABSTRACT

An exclusive measurement of the Coulomb breakup of 8B into 7Be+p at 254A MeV allowed the study of the angular correlations of the breakup particles. These correlations demonstrate clearly that E1 multipolarity dominates and that E2 multipolarity can be neglected. By using a simple single-particle model for 8B and treating the breakup in first-order perturbation theory, we extract a zero-energy S factor of S17(0)=18.6+/-1.2+/-1.0 eV b, where the first error is experimental and the second one reflects the theoretical uncertainty in the extrapolation.

11.
J Dairy Sci ; 86(6): 2106-12, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12836947

ABSTRACT

The objective of Trial 1 was to evaluate in dairy cows the effects of dietary supplementation with biotin and a B-vitamin blend on dry matter intake (DMI), milk yield, composition and component yields, total tract nutrient digestion, and plasma metabolites. Twenty-four multiparous Holstein cows averaging 46 +/- 8 d in milk at trial initiation were randomly assigned to treatments in a replicated 4 x 4 Latin square design with 28 d periods. The four treatments were: 1) a control diet (C) with no supplemental B-vitamins; 2) C plus supplemental biotin at 20 mg/d (B); 3) C plus supplemental thiamin (150 mg/d), riboflavin (150 mg/d), pyridoxine (120 mg/d), B12 (0.5 mg/d), niacin (3000 mg/d), pantothenic acid (475 mg/d), folic acid (100 mg/d), and biotin (20 mg/d) (BBVIT1X); 4) C plus supplemental thiamin (300 mg/d), riboflavin (300 mg/d), pyridoxine (240 mg/d), B12 (1.0 mg/d), niacin (6000 mg/d), pantothenic acid (950 mg/d), folic acid (200 mg/d), and biotin (40 mg/d) (BBVIT2X). Intake of DM was increased 0.7 kg/d for B vs. C and BBVIT1X and 1.3 kg/d for B vs. BBVIT2X. Milk yield was increased 1.7 kg/d for B vs. C. For BBVIT1X, milk yield was similar to B and BBVIT2X and tended to be higher than C. Yields of milk protein and lactose but not fat were higher for B than C. For BBVIT1X, milk component yields were similar to B and tended to be higher than C, with the exception of lactose yield where BBVIT1X was higher than C. The objective of Trial 2 was to evaluate DMI and milk yield, composition and component yields by dairy cows fed diets supplemented with either 40 mg/d biotin or the B-vitamin blend (BBVIT1X) compared to cows supplemented with 20 mg/d dietary biotin. Neither the 40 mg/d biotin treatment nor the B-vitamin blend enhanced lactation performance over the 20 mg/d biotin treatment. Biotin efficacy in short-term trials suggests that biotin may improve milk yield directly via effects on intake and (or) nutrient metabolism rather than indirectly via improved hoof health. More research is needed to determine the mode of action for supplemental dietary biotin.


Subject(s)
Biotin/administration & dosage , Cattle/physiology , Diet , Lactation , Vitamin B Complex/administration & dosage , 3-Hydroxybutyric Acid/blood , Animals , Blood Glucose/analysis , Body Weight , Dietary Supplements , Digestion , Eating , Fatty Acids, Nonesterified/blood , Female , Lactose/analysis , Lipids/analysis , Milk/chemistry , Milk Proteins/analysis
12.
J Dairy Sci ; 85(3): 613-23, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11949866

ABSTRACT

In this experiment, we evaluated the influence of increasing chop length and mechanical processing of whole-plant brown-midrib corn silage on intake, digestion, and milk production by dairy cows. Corn silage treatments were harvested at three-quarter milk line stage of maturity at 13- and 19-mm theoretical chop length without processing, or at 19- and 32-mm theoretical chop length with processing at a 2-mm roll clearance. Twenty-four multiparous Holstein cows that averaged 102 +/- 17 d in milk at trial initiation were randomly assigned to treatments in a replicated 4 x 4 Latin square design with 28-d periods. Preplanned orthogonal contrasts were used to evaluate effects of processing (19 processed vs. 19 mm unprocessed) and chop length (13 vs. 19 mm unprocessed and 19 vs. 32 mm processed). Treatments were fed in total mixed rations containing 60% forage (67% corn silage and 33% alfalfa silage) and 40% shelled corn and soybean meal-based concentrate (dry matter basis). Milk yield was unaffected by treatment. Dry matter intake was unaffected by corn silage processing, but increasing corn silage chop length reduced dry matter intake in unprocessed (26.6 vs. 25.5 kg/d) and processed (25.9 vs. 25.1 kg/d) chop length contrasts. Processing reduced milk fat content (3.36 vs. 3.11%) and yield (1.43 vs. 1.35 kg/d), increased total-tract starch digestion (92.9 vs. 97.4%), and decreased total-tract neutral detergent fiber digestion (51.0 vs. 41.8%). Total chewing time (min/d) was unaffected by treatment. Masticate mean particle length was unaffected by chop length in unprocessed and processed corn silage treatments. In this study with brown-midrib corn silage fed to dairy cows producing 43 kg/d of milk, there were no benefits from crop processing or increasing chop length on lactation performance.


Subject(s)
Cattle/physiology , Digestion , Eating , Energy Intake , Food Handling/methods , Milk/metabolism , Zea mays , Animal Feed , Animals , Female , Lactation/physiology , Mastication/physiology , Medicago sativa , Milk/chemistry , Particle Size , Random Allocation , Silage , Weight Gain , Zea mays/chemistry
13.
J Infect Dis ; 184(8): 1065-9, 2001 Oct 15.
Article in English | MEDLINE | ID: mdl-11574923

ABSTRACT

To quantitatively assess the role of Candida species in antibiotic-associated diarrhea (AAD), stool samples from a total of 395 patients and control subjects were cultured in differential isolation medium: 98 patients had AAD, 93 patients were taking antibiotics but did not have diarrhea (A(+)D(-)), 97 patients were not taking antibiotics but had diarrhea (A(-)D(+)), and 107 patients were control subjects (A(-)D(-)). In addition, secreted aspartyl proteinase (Sap) production was tested. In AAD patients, Candida positivity (77/98) and Candida overgrowth (62/98) were not different from that among A(+)D(-) patients (75/93 [P= .860] and 52/93 [P= .375], respectively). Candida overgrowth among A(-)D(+) patients (40/97, P= .003) was less frequent than among AAD patients, but Candida positivity was not different (80/97, P= .612). In control subjects, Candida positivity and overgrowth were less common than in all other groups. Production of Sap did not differ between patients with AAD and control subjects (P= .568 and P= .590, respectively). Data indicate that elevated Candida counts are a result of antibiotic treatment or diarrhea rather than a cause of AAD.


Subject(s)
Anti-Bacterial Agents/adverse effects , Candida/isolation & purification , Diarrhea/chemically induced , Diarrhea/drug therapy , Age Distribution , Candida/classification , Candida/growth & development , Feces/microbiology , Female , Humans , Male , Patient Selection , Reference Values
14.
Phys Rev Lett ; 86(1): 39-42, 2001 Jan 01.
Article in English | MEDLINE | ID: mdl-11136088

ABSTRACT

The production of pions and kaons has been measured in 197Au+197Au collisions at beam energies from 0.6 to 1.5A GeV with the kaon spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions, whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.

15.
Chirurg ; 72(11): 1277-82, 2001 Nov.
Article in German | MEDLINE | ID: mdl-11766650

ABSTRACT

The incidence of fractures in the trochanteric region is high in the elderly, and early stabilization is required that allows immediate weight bearing. Older patients with low bone quality, limited compliance and strength, and the inability for partial weight-bearing, benefit from intramedullary stabilization of these fractures. The choice of implant and the operative technique depends on the degree of instability in the individual fracture type. Intertrochanteric fractures are frequently combined with subtrochanteric fracture types. Their treatment is still a challenge because of the high degree of instability.


Subject(s)
Fracture Fixation, Intramedullary/instrumentation , Hip Fractures/surgery , Aged , Aged, 80 and over , Early Ambulation , Female , Follow-Up Studies , Hip Fractures/diagnostic imaging , Humans , Male , Postoperative Complications/diagnostic imaging , Radiography , Reoperation , Weight-Bearing/physiology
16.
Phys Rev Lett ; 85(1): 18-21, 2000 Jul 03.
Article in English | MEDLINE | ID: mdl-10991148

ABSTRACT

The emission pattern of charged pions has been measured in Au+Au collisions at 1 GeV/nucleon incident energy. In peripheral collisions and at target rapidities, high-energy pions are emitted preferentially towards the target spectator matter. In contrast, low-energy pions are emitted predominantly in the opposite direction. The corresponding azimuthal anisotropy is explained by the interaction of pions with projectile and target spectator matter. This interaction with the spectator matter causes an effective shadowing which varies with time during the reaction. Our observations show that high-energy pions stem from the early stage of the collision whereas low-energy pions freeze out later.

17.
Unfallchirurg ; 103(7): 557-63, 2000 Jul.
Article in German | MEDLINE | ID: mdl-10969543

ABSTRACT

Methicillin resistant Staphylococcus aureus-strains, isolated from 1994 to 1997 from patients of the traumatic surgery hospital Tübingen, were compared using lysotyping and pulsed-field gel electrophoresis. Both typing methods detected two clones causing an outbreak 1994 in 6 patients and a third endemic clone of MRSA, which was isolated from 5 patients (1995), 4 patients (1996), and 6 patients (1997). Additionally other MRSA-types were found in 6 cases of which transmissions occurred in up to three patients. An epidemiological connection to MRSA isolated from patients of the university hospital of Tübingen was made. Possible consequences for patient management and antibiotic strategies in MRSA-infections were discussed.


Subject(s)
Methicillin Resistance/genetics , Methicillin/pharmacology , Penicillins/pharmacology , Staphylococcus aureus/drug effects , Bacteriophage Typing , Electrophoresis, Gel, Pulsed-Field , Humans , Lysogeny , Phenotype , Staphylococcus aureus/genetics , Staphylococcus aureus/isolation & purification
18.
Biotechniques ; 28(2): 272-4, 276-7, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10683736

ABSTRACT

Several techniques are available that detect variations in gene expression between cellular populations. These include subtractive hybridization (SH), differential colony hybridization (DCH) and mRNA differential display, all based on the analysis of mRNA. The first two techniques, however, are limited because they require large amounts of mRNA for SH or several rounds of screening for DCH. Differential display overcomes both of these limitations. However, the conventional differential display technique is plagued by false positives and is labor intensive. The identification of genes that are truly differentially expressed, therefore, becomes a formidable task. We describe a modified differential display technique that overcomes the limitations of the conventional technique. This new technique eliminates a source of false positives, decreases the time required to screen a set of primers and reduces the use of radioactivity.


Subject(s)
Gene Expression , Genetic Techniques , Animals , Biotechnology , Blotting, Northern , Male , Polymerase Chain Reaction , Prostatic Neoplasms/genetics , Prostatic Neoplasms/secondary , RNA, Messenger/genetics , RNA, Neoplasm/genetics , Rats
19.
Anticancer Res ; 18(5A): 3603-7, 1998.
Article in English | MEDLINE | ID: mdl-9858946

ABSTRACT

BACKGROUND: The etiology of prostate cancer is currently a mystery. Several epidemiological studies suggest a link between dietary fat and prostate cancer. In vitro and in vivo studies support this evidence. Using the Dunning model of rat prostate cancer we hypothesized that a high-fat diet (20%) would increase the growth of the R3327-H tumor. MATERIALS AND METHODS: R3327-H tumors were implanted subcutaneously into male Copenhagen rats which were fed diets with 5 or 20% total fat. Tumors were allowed to grow for 16 weeks; they were then excised and weighed. The initial and final weights of the rats were also recorded. RESULTS: Statistical analysis revealed the level of dietary fat was a positive predictor of weight gain (p < 0.01). No effect on tumor growth was seen when compared to dietary fat, fiber type, or the interaction of fat and fiber. DISCUSSION: Growth of the R3327-H tumor, when implanted subcutaneously, is not affected by the level of dietary fat.


Subject(s)
Dietary Fats/pharmacology , Prostatic Neoplasms/pathology , Animals , Cell Division/drug effects , Male , Organ Size , Prostate/pathology , Prostatic Neoplasms/etiology , Rats , Weight Gain
20.
Anticancer Res ; 18(4A): 2575-82, 1998.
Article in English | MEDLINE | ID: mdl-9703912

ABSTRACT

Molecular changes in the progressive state of tumorigenesis often include altered patterns of DNA methylation. Utilizing a series of breast epithelial cell lines, the overall 5-methylcytosine content in genomic DNA demonstrated an overall decrease when comparing two malignant cell lines (MCF-7 and T47D) with a mortal cell line (MCF 1 2M) and several derivative cell lines of the immortalized MCF10 cultures (MCF10A,-2A, -5A, A1neoT2, and 139B6). Further investigation on the methylation status of these cells lines indicated no difference in DNA methyltransferase activity, both at a protein and mRNA levels, in the nontumorigenic cell lines examined while activity was 3-10 fold higher in the tumorigenic lines (MCF7, T47D, SkBr3, MB-MDA-231, -468). Examination of the CpG island in the 5' promoter region of the estrogen receptor gene indicates that this region is unmethylated in the mortal and immortal nontumorigenic lines as well as the tumorigenic lines examined, with the exception of the estrogen receptor negative breast cell line MB-MDA-468 which appears to be partially methylated at this site. These results indicate methylation of this CpG island does not account for the inactivation of the estrogen receptor gene in immortalized nontumorigenic breast cells, suggesting another mechanism of transcriptional inactivation of ER in this environment.


Subject(s)
Breast Neoplasms/genetics , Breast/metabolism , DNA Methylation , Breast/cytology , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Line , Cell Line, Transformed , Chromatography, High Pressure Liquid , DNA/isolation & purification , DNA/metabolism , DNA Modification Methylases/biosynthesis , DNA, Neoplasm/isolation & purification , DNA, Neoplasm/metabolism , Dinucleoside Phosphates/analysis , Epithelial Cells/cytology , Epithelial Cells/metabolism , Female , Humans , Tumor Cells, Cultured
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