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Biomedical subjects

L Christensen

Publications and source records attributed to L Christensen.

At least 55 records · Page 3Linked to original sources
PubMed1997

Monoclonal antibodies against human tetranectin, epitope characterization and use in immunohistochemistry.

Two IgG2a/kappa- and three IgG1/kappa monoclonal antibodies (MAbs) were produced against human tetranectin (TN): this is the first report of stable hybridomas producing MAbs against TN. All the MAbs reacted with non-conformational epitopes located within amino acid residues 50-181 of the primary sequence. In relative epitope mapping with enzyme immunoassay and isotachophoresis the five MAbs defined two independent epitope groups. One of them is suggested to be immunodominant in rabbits, since MAbs inhibited binding of a polyclonal rabbit antibody. Several combinations of MAbs were suitable for TN-ELISA and two MAbs could be used for immunohistochemical detection of TN in both fresh frozen and paraffin-embedded tissues. The MAbs will facilitate future studies on structure, function, clinical significance and immunolocalization of TN.

Animals↗
PubMed1997

Treatment of Philadelphia leukemia in severe combined immunodeficient mice by combination of cyclophosphamide and bcr/abl antisense oligodeoxynucleotides.

BACKGROUND: Philadelphia cells are human chronic myelogenous leukemia (CML) cells that contain the BCR/ABL oncogene (a fusion of the BCR and ABL genes). Selective eradication of these cells in vitro can be achieved by combined treatment with antisense phosphorothioate oligodeoxynucleotides ([S]ODNs) specifically targeted to this oncogene (bcr/abl [S]ODNs) and a suboptimal (for use as a single agent) dose of mafosfamide (the in vitro active form of cyclophosphamide). PURPOSE: We evaluated the ability of bcr/abl antisense [S]ODNs, alone or subsequent to treatment with a single injection of cyclophosphamide, to suppress the leukemic process induced in severe combined immunodeficient (SCID) mice by Philadelphia cells (i.e., primary CML-blast crisis [CML-BC] cells). In addition, we studied potential mechanisms that might explain the efficacy of the bcr/abl antisense [S]ODN-mafosfamide combination against Philadelphia cells in vitro. METHODS: The effects of treating leukemic mice with cyclophosphamide (25 mg/kg body weight; 25% of the dose required to eradicate evidence of leukemia in SCID mice) and/or bcr/abl antisense [S]ODNs were assessed by analysis of survival, by examination of bone marrow for the presence of leukemia cells (using a colony formation assay or using coupled reverse transcription and the polymerase chain reaction to screen for bcr/abl messenger RNA), and by examination of a variety of tissues for the presence of infiltrating leukemia cells. The induction of apoptosis (a cell death program) in vitro in primary CML-BC cells following treatment with bcr/abl antisense [S]ODNs plus or minus prior treatment with mafosfamide was monitored by use of a commercial assay. Relative cellular uptake of [S]ODNs by CML-BC cells treated in vitro with or without prior treatment with mafosfamide was determined by use of confocal microscopy and flow cytometry (for fluorescent [S]ODNs) or by use of blotting techniques that employed radioactively labeled probes (for extracted, unlabeled [S]ODNs). Levels of specific proteins in treated and untreated cells were determined by use of western blotting methods. Reported P values are two-sided. RESULTS: The disease process in leukemic mice was retarded substantially by combination treatment with cyclophosphamide and specific bcr/abl antisense [S]ODNs (P < .001, relative to treatment with specific antisense [S]ODNs alone, cyclophosphamide alone, or cyclophosphamide plus nonspecific [i.e., control] antisense [S]ODNs); 50% of the mice treated with cyclophosphamide and specific antisense [S]ODNs appeared to be cured of leukemia. The combination treatment was associated with increased induction of apoptosis. In addition, cellular uptake of bcr/abl antisense [S]ODNs appeared to be increased twofold to sixfold by prior treatment with mafosfamide. This increased uptake of [S]ODNs was associated with enhanced suppression of p210bcr/abl protein levels. CONCLUSIONS AND IMPLICATIONS: Combination therapy with antisense [S]ODNs targeted to specific oncogenes and less toxic doses of anticancer drugs may represent a rational strategy to purpose for the treatment of human leukemias.

Animals↗
PubMed1997

The effect of carbohydrates on affect.

This report reviews studies addressing the issue of the effect that carbohydrates have on affective behavior. The review begins with an overview of the physiologic and psychological mechanisms that have been proposed to explain a carbohydrate-induced behavioral effect. Attention is then devoted to studies that have investigated the mood-altering effect of carbohydrates on normal individuals, depressed individuals, obese individuals, and individuals with seasonal affective disorder and premenstrual syndrome. Throughout the report it is apparent that carbohydrate consumption is relevant for individuals experiencing symptoms of emotional distress, particularly symptoms indicative of depression, and that the individuals with depressive symptoms show a preference for sweet simple carbohydrates. Enduring questions permeating the diet-behavior field are delineated and future research directions are suggested.

Affect↗
PubMed1997

Gene targeting approaches using positive-negative selection and large flanking regions.

We report here on strategies aimed at improving the frequency of detectable recombination in plants by increasing the efficiency of selecting double-recombinants in transgenic calli. Gene targeting was approached on the Gln1 and the Pzfloci of Lotus japonicus, using Agrobacterium tumefaciens T-DNA replacement vectors. Large flanking regions, up to 22.9 kb, surrounding a positive selection marker were presented as substrates for homologous recombination. For easier detection of putative recombinants the negative selectable marker cytosine deaminase was inserted at the outside borders of the flanking regions offered for cross-over. A combination of positive and negative selection allowing double-recombinants to grow, while counter-selecting random insertions, was used to select putative targeting events. The more than 1000-fold enrichment observed with replacement vectors designed to minimize gene silencing demonstrated the efficiency of the negative selection. Using five different replacement vectors an estimated total of 18,974 transformation events were taken through the positive-negative selection procedure and 185 resistant calli obtained. Targeting events could not be verified in the survivors by PCR screening and Southern blot analysis. With this approach the frequency of detectable gene targeting in L. japonicus was below 5.3 x 10(-5), despite the large flanking sequences offered for recombination.

Antimetabolites↗
PubMed1997

Myofibrosarcoma of the breast: review of the literature on myofibroblastic tumors and criteria for defining myofibroblastic differentiation.

A case of myofibrosarcoma of the breast is described. A 55-year-old woman presented with a small mammary nodule. A large recurrent lesions appeared a month later, and the patient died 11 months following initial presentation from diffuse pleuropulmonary metastases. Histologically, the primary tumor consisted mainly of spindled cells, arranged in fascicles and surrounded by varying quantities of dense hyaline collagen. The recurrent lesion had a more pleomorphic organization. In both lesions, there was positive immunostaining for vimentin, smooth-muscle actin, and fibronectin, and negative results for desmin, laminin, and type IV collagen. Electron microscopy revealed abundant rough endoplasmic reticulum, myofilaments with focal densities, and the fibronexus junctions and fibronectin fibrils characteristic of myofibroblasts. Given these cellular features and behavior, the tumor was interpreted as a malignant neoplasm showing myofibroblastic differentiation, i.e., a myofibrosarcoma. This case enlarges the group of myofibrosarcoma of breast, also with the demonstration of fibronexus and fibronectin fibrils. The paper emphasizes the criteria required for myofibroblastic differentiation and reviews lesions of the breast reported in the literature as myofibroblastic.

Breast Neoplasms↗
PubMed1997

Limited effect of sulphasalazine treatment in reactive arthritis. A randomised double blind placebo controlled trial.

OBJECTIVE: To assess the efficacy and safety of sulphasalazine in reactive arthritis. METHODS: Double blind placebo controlled trial of six months duration comparing sulphasalazine 2-3 g per day (n = 37) with matching placebo (n = 42) in adults with active reactive arthritis (age 19-57 years, median 34). Treatment response was evaluated once a month by changes in erythrocyte sedimentation rate (ESR), pain, peripheral arthritis, tender iliosacral joints, entesopathy, extra-articular manifestations, and working ability. RESULTS: 15 patients in the sulphasalazine group and eight in the placebo group withdrew from the study prematurely. Adverse events, primarily gastrointestinal, were the main reason for withdrawal in the actively treated group. Intention-to-treat analyses showed significant improvements over time in both groups in ESR, pain, and number of swollen joints (P < 0.01). Number of days on sick leave decreased significantly in the sulphasalazine group only (P < 0.01). No significant differences between the two groups were present after six months. Among the patients completing the trial according to protocol, persistent complete remission had occurred within two months in five (23%) of the actively treated, but in no placebo treated patients (P = 0.013). CONCLUSIONS: Sulphasalazine seemed to improve only the very short term outcome of reactive arthritis. The possible beneficial effect of the drug should also be weighed against the risk of adverse events. Although these were mainly mild, almost 25% of the patients in the actively treated group gave up treatment for this reason.

Adult↗
PubMed1997

An external quality assessment study on the analysis of methylmalonic acid and total homocysteine in plasma.

In spite of the increasing interest in the analysis of methylmalonic acid and total homocysteine in plasma, data on interlaboratory variation is lacking. We report the results of an external quality assessment study with the participation of 15 laboratories in the Scandinavian countries performing these analyses on a regular basis. For methylmalonic acid, using serum, heparin fluoride plasma and an aqueous sample, CVs were found in the range of 11-17%. For total homocysteine using EDTA plasma, heparin fluoride plasma and an aqueous sample, CVs were in the range of 6-12%. For both analytes, a significant correlation between the individual recoveries of added analyte and the results for the aqueous sample was found, suggesting that the use of inconsistent calibrations in the participating laboratories are contributing to the interlaboratory variation. An acceptable range for results from the individual laboratory was calculated using data on the biological within-subject and between-subject variations reported in the literature. These ranges were violated by several laboratories when using the consensus mean or median as target values. Even if the results of the present study document a reasonable standard in the measurement of methylmalonic acid and total homocysteine in plasma in the participating laboratories there is room for improvement and a permanent scheme of external quality assessment using relevant samples is essential. From 1997, a regular scheme has been available from our laboratory.

Anticoagulants↗
PubMed1997

Angio-tumoral complex in human malignant melanoma characterised by free laminin: ultrastructural and immunohistochemical observations.

Neo-vessel density in primary tumours as a prognostic factor for metastasis has been questioned. For this reason we have investigated qualitative aspects of tumour vascularity and particularly the association of cancer cells with endothelium, focussing on the peri-endothelial matrix. We have examined the matrix between endothelium and tumour cells in human invasive and metastatic malignant melanoma using transmission electron microscopy and immunohistochemistry. We have identified a hitherto unrecognised image (the angio-tumoral complex) in which the tumour cell and endothelium are in direct contact via an amorphous matrix. This amorphous matrix lacks an organised lamina and contains predominantly laminin with noticeably less collagen type IV. In this image endothelial cells showed no signs of physiological damage, no tumoral intravasation, and tumour cells occupied a pericytic location. This typical image was absent from naevi. We regard the laminin in this amorphous matrix as "free' laminin as distinct from laminin integrated into an organised lamina. We discuss the role of this free laminin in promoting the migration of melanoma cells in contact with vessels and suggest the possibility that this angio-tumoral complex represents a marker for metastasis.

Humans↗
PubMed1997

A natural language parsing system for encoding admitting diagnoses.

Free-text or natural language documents make up an increasing part of the computerized medical record. While they do provide accessible clinical information to health care personnel, they fail to support processes that require clinical data coded according to a shared lexicon and data structure. We have developed a natural language parser that converts free-text admitting diagnoses into a coded form. This application has proven acceptably accurate in the experimental laboratory to warrant a test in the target clinical environment. Here we describe an approach to moving this research application into a production environment where it can contribute to the efforts of the Health Information Services Department. This transition is essential if the products of natural language understanding research are to contribute to patient care in a routine and sustainable way.

Diagnosis-Related Groups↗
PubMed1997

Elevated levels of sex hormones and sex hormone binding globulin in male patients with insulin dependent diabetes mellitus. Effect of improved blood glucose regulation.

In a prospective study we have measured serum levels of sex hormone-binding globulin (SHBG), androgens, oestrogens and gonadotropins in 20 male IDDM patients with the aim of evaluating the effect of improved glycaemic control on these levels and to compare the IDDM patients with an age- and weight-matched healthy non-diabetic control group. The patients were chosen from the male IDDM patients attending the outpatient clinic at the Department of Endocrinology, Odense University Hospital. Glycaemic control was optimized by a trained diabetologist according to the patients' measurements of home blood glucose concentrations and reported hypoglycaemic episodes during a three month period. Prior to regulation the patients, compared to healthy control subjects, had significantly higher serum levels of oestrone (0.29 +/- 0.02 vs 0.16 +/- 0.01 nmol/l (Mean +/- SEM), p < 0.01), 17 beta-oestradiol (0.12 +/- 0.01 vs 0.08 +/- 0.01 nmol/l, p < 0.01), dihydrotestosterone (4.20 +/- 0.18 vs 1.66 +/- 0.09 nmol/l, p < 0.01), total testosterone (20.7 +/- 0.9 vs 17.8 +/- 1.1 nmol/l, p < 0.05) and SHBG (42.3 +/- 2.9 vs 15.5 +/- 3.5 nmol/l, p < 0.05), while the calculated free-testosterone was lower (0.34 +/- 0.02 vs 0.40 +/- 0.02 nmol/l, p = 0.068). After regulation, the patients obtained significantly lower levels of glycosylated haemoglobin (10.4 +/- 0.3 vs 8.9 +/- 0.2%, p < 0.005) and serum fructosamine (1.50 +/- 0.05 vs 1.34 +/- 0.04 nmol/l, p < 0.005) on a higher 24 hour insulin dose (52.7 +/- 4.4 vs 59.2 +/- 4.6 IU/24 h, p < 0.005). Levels of free-testosterone (0.41 +/- 0.04 nmol/l), oestrone (0.33 +/- 0.03 nmol/l), oestradiol (0.14 +/- 0.01 nmol/l), delta 4-androstenedione (4.44 +/- 0.43 vs 3.85 +/- 0.42 nmol/l), and prolactin (249 +/- 24 vs 200 +/- 19 mIU/l) increased compared to values obtained before regulation (all p < 0.05). We conclude that SHBG, testosterone, dihydrotestosterone and oestrogen levels are increased in male IDDM patients. High SHBG levels tend to keep the free fractions of sex hormones within normal limits. During improvement of glycaemic control with insulin, levels of free-testosterone and its bioprecursors and metabolites rise. This may partly be due to the increased daily insulin dose and/or to the improvement in glycaemic control itself.

Adult↗
PubMed1996

Psychosis and vulnerability to ECT-induced seizures.

Medical records of patients with major depressive disorders who had received electroconvulsive therapy (ECT) for the first time were studied to test the hypothesis that psychotic patients are more vulnerable to seizures than nonpsychotic patients. This hypothesis was based on studies suggesting a putative purinergic deficiency in psychosis. Results showed that the duration of ECT-induced seizures as a measure of seizure vulnerability was significantly longer in psychotic than in nonpsychotic depressive patients. The association applied for the first ECT as well as for the course of eight ECTs. These findings were still present when covariates such as age, electrical energy applied, dosage of methohexital and succinylcholine, and psychotropic medications such as neuroleptics, benzodiazepines, and tricyclics were included in the statistical analysis. The results are discussed in the context of the role of neurotransmitters such as glutamate, gamma-aminobutyric acid, adenosine, and dopamine on seizure vulnerability and psychosis.

Adult↗
PubMed1996

Immunohistochemical localization of urokinase-type plasminogen activator, type-1 plasminogen-activator inhibitor, urokinase receptor and alpha(2)-macroglobulin receptor in human breast carcinomas.

We have investigated the localization of urokinase-type plasminogen activator (u-PA), type-1 plasminogen-activator inhibitor (PAI-1), u-PA receptor (u-PAR) and alpha(2)-macroglobulin- receptor/low-density-lipoprotein-receptor-related protein (alpha(2)MR/LRP) in human breast tumors by immunohistochemical methods. Frozen sections of 133 primary breast carcinomas, 6 ductal carcinomas in situ and 33 lymph-node metastases were stained with monoclonal antibodies. Formalin-fixed sections of 15 primary tumors and 2 lymph-node metastases were stained with polyclonal antibodies. In primary tumors, u-PA and PAI-1 immunoreactivities were intense in macrophages and mast cells, and moderate in benign and malignant epithelial cells as well as in myofibroblasts and endothelial cells. A sub-group of poorly differentiated tumors showed particularly strong staining of stromal fibroblasts. u-PA immunoreactivity was also present in lymphocytes. alpha(2)MR/LRP and u-PAR immunoreactivities were intense in macrophages, but apart from these cells, alpha(2)MR/LRP was found only in fibroblasts, and u-PAR only in tumor cells located peripherally in tumor-cell clusters and glands and some myofibroblasts in the adjacent stroma. Lymph-node metastases showed staining for u-PA and PAI-1 both of cancer cells and of stromal fibroblasts, also staining for u-PA of lymphocytes. Similarly to some of the poorly differentiated primary tumors, approximately half of the metastases showed very strong staining of stromal fibroblasts, and extracts of these metastases had higher u-PA and PAI-1 levels, as determined by ELISA, than extracts of metastases without this staining pattern. alpha(2)MR/LRP was present only in fibroblasts and u-PAR only in some tumor cells. The presence of u-PA, PAI-1, alpha(2)MR/LRP and u-PAR was controlled biochemically by immunoblotting analyses, ligand-blotting analyses, and direct and reverse zymography. The spatial distribution and the variation in concentration of the various components of the plasminogen-activation system point to a complex, multifunctional role for the 4 proteins in and/or during the development and spread of breast cancer.

Blotting, Western↗
PubMed1996

Development of a novel scintillation proximity competitive hybridization assay for the determination of phosphorothioate antisense oligonucleotide plasma concentrations in a toxicokinetic study.

A novel scintillation proximity competitive hybridization assay was developed for determining plasma concentrations of compound 4003W94, a 15-base phosphorothioate antisense deoxyribonucleotide that is currently under preclinical evaluation for the treatment of restenosis following coronary artery angioplasty. The principle of the assay involves the hybridization binding of antisense (4003W94) to a biotinylated sense oligonucleotide to form a double-stranded nucleic acid complex on the surface of scintillation proximity beads derivatized with streptavidin. As in a competitive radioimmunoassay, there is an inverse relationship between the amount of radioactivity in the final binding complex and the amount of 4003W94 present in the sample being analyzed. Because this is a homogenous assay, no physical separation of bound from free radioligand is necessary. Conventional cross-reactivity studies with either 3'- or 5'-deletion oligomers of 4003W94 indicated that cross-reactivity generally decreased with each base deletion. The assay was used to determine plasma concentrations of 4003W94 equivalents in rhesus monkeys during an exploratory 14-day toxicity study. This method conceivably could be adapted for use as an effective in vitro screening tool for the identification of potential antisense oligonucleotide drug candidates or as a diagnostic tool for the detection of pathological disorders.

Analysis of Variance↗
PubMed1996

Comparison of nutrient intake among depressed and nondepressed individuals.

OBJECTIVE: The study investigated the nutrient intake of depressed and nondepressed subjects. METHOD: Twenty-nine depressed subjects and a matched group of nondepressed subjects completed a 3-day food record. RESULTS: Results revealed that depressed and nondepressed groups consume similar amounts of all nutrients except protein and carbohydrates. Nondepressed subjects consume more protein and depressed subjects consume more carbohydrates. The increase in carbohydrate consumption comes primarily from an increase in sucrose consumption. DISCUSSION: The increased carbohydrate consumption is consistent with the carbohydrate cravings characteristic of the depressed and may relate to the development or maintenance of depression.

Adult↗
PubMed1996

Comparison of two monoclonal antibodies for the detection of estrogen receptors in primary breast carcinomas.

A new monoclonal antibody against estrogen receptor (ID5, Dako) has shown promising results when applied to formalin fixed, paraffin embedded tissue. In order to determine whether this antibody can compete in specificity and sensitivity with the ER-ICA antibody (Abbott Laboratories), a comparative, prospective study of the two antibodies was carried out on paraffin embedded and fresh frozen tissue in three laboratories. Two hundred and fifteen breast carcinomas were examined. Formalin fixed, paraffin embedded tissue was available from 215 tumors, and fresh frozen tissue from 189 of the tumors. Of these, 124 tumors were also investigated by the enzyme-linked immunosorbent assay. The results from each of the three laboratories correspond with those obtained for the whole material. The percentage of tumors positive for estrogen receptors within the different methods, was as follows: 71% by ID5 on paraffin sections, 50% by ER-ICA on paraffin sections, 65% ER-ICA on frozen sections and 88% by the EIA. When comparing the different immunohistochemical results and the EIA in 2 x 2 tables, agreement was reached in 69% to 91% of the cases. The best agreement (91%) was found between results obtained with the ID5 antibody used on formalin fixed, paraffin embedded tissue and the ER-ICA kit used on fresh frozen tissue. The advantages of using the ID5 antibody are associated with its applicability to formalin fixed, paraffin embedded tissue: improved morphology, reproducibility, retrospective studying and low costs. Finally, it is reproducible not only within the same laboratory but also among different laboratories.

Antibodies, Monoclonal↗
PubMed1996

Percutaneous transluminal treatment of an iliac pseudoaneurysm with endoprosthesis implantation. A case report.

PURPOSE: Evaluation of a covered stent in the treatment of an iliac pseudoaneurysm. MATERIAL AND METHODS: During PTCA, a 61-year-old man with angina pectoris was shown to have an asymptomatic pseudoaneurysm, 5 x 4 x 4 cm, of the left common iliac artery (CIA). The patient was not a candidate for surgery. The pseudoaneurysm was treated by insertion of a covered stent (8 mm/6 cm). RESULTS: By 30 s after stent placement, the pseudoaneurysm was angiographically excluded. Twelve and 17 months after stent implantation, the patient had no symptoms from the lower extremities and the left CIA was open with normal flow in the stent. CONCLUSION: Our case illustrates the ability of a covered stent to exclude a pseudoaneurysm. Percutaneous intravascular stent placement in the management of iliac pseudoaneurysms might be the treatment of choice in patients with increased risk of major anesthesia and surgery.

Aneurysm, False↗
PubMed1996

Ectopic production of intact parathyroid hormone by a squamous cell lung carcinoma in vivo and in vitro.

Ectopic tumoral production of intact parathyroid hormone (PTH) is rare. The PTH-related protein is the common cause of hypercalcemia in most solid tumors, particularly squamous and renal carcinomas. We report the case of a 71-yr-old man with a PTH-producing squamous cell lung carcinoma. Immunocytochemical analysis of the tumor tissue as well as of cultured tumor cells revealed PTH positive staining. Cultured tumor cells released PTH and were calcium sensitive, producing 122 +/- 16 pg/microgram DNA of intact PTH (mean +/- SEM) at 0.5 mmol/L calcium compared with 26 +/- 2 pg/microgram DNA at 3.0 mmol/L calcium. Somatostatin analogues have been used in the treatment of humoral hypercalcemia of malignancy (HHM). However, we found that somatostatin (0.1 microgram/L) in cultured tumor cells increased the release of intact PTH (123 +/- 19 versus 82 +/- 1 pg/microgram DNA, P < 0.05) and thus might have a negative effect on the HHM. This report is the first to describe a true ectopic PTH-producing squamous cell lung carcinoma associated with HHM.

Aged↗