Search PubMed⌕ Search

Biomedical subjects

J Christiansen

Publications and source records attributed to J Christiansen.

At least 109 records · Page 6Linked to original sources
PubMed1994

A guanosine quadruplex and two stable hairpins flank a major cleavage site in insulin-like growth factor II mRNA.

Insulin-like growth factor II (IGF-II) mRNAs are cleaved by an endonucleolytic event in a conserved part of their 3' untranslated region that is predicted to exhibit a complex higher-order RNA structure. In the present study, we have examined the putative secondary structures of in vitro transcripts from the conserved part of human and rat mRNAs by enzymatic and chemical probing. The results show that the cleavage site is situated between two highly structured domains. The upstream domain consists of two large hairpins, whereas the downstream domain is guanosine-rich. The guanosine-rich domain adopts a compact unimolecular conformation in Na+ or K+ but not in Li+, and it completely arrests reverse transcription in K+ but only partially in Na+, indicating the presence of an intramolecular guanosine quadruplex. The flanking higher-order structures may ensure that the cleavage site is not sequestered in stable RNA structures, thus allowing interactions with RNA or proteins at posttranscriptional stages of IGF-II expression.

Animals↗
PubMed1994

[Treatment of complicated forms of anal incontinence].

In recent years, several techniques for the treatment of more complex forms of faecal incontinence have emerged. These consist of either transposition of skeletal muscle (gracilis muscle or gluteus maximus muscle) around the anal canal, implantation of an artificial sphincter or implantation of a neuromuscular stimulator having previously transposed gracilis muscle. The latter method seems to hold most promise.

Anal Canal↗
PubMed1994

Spinach carbonic anhydrase: investigation of the zinc-binding ligands by site-directed mutagenesis, elemental analysis, and EXAFS.

The enzyme carbonic anhydrase has been well characterized in mammalian systems, but the structural properties of the plant isozymes remain elusive. To investigate the nature of the zinc-binding site in spinach carbonic anhydrase, we targeted potential zinc ligands for mutagenesis and examined the resulting enzymes for catalytic activity and stoichiometric zinc binding. In addition, we examined the wild-type protein using extended X-ray absorption fine structure analysis. Our results suggest that spinach carbonic anhydrase utilizes a Cys-His-Cys-H2O ligand scheme to bind the zinc ion at the active site.

Amino Acid Sequence↗
PubMed1994

Isolation and genetic mapping of two novel members of the murine Wnt gene family, Wnt11 and Wnt12, and the mapping of Wnt5a and Wnt7a.

The murine Wnt genes are implicated in the control of a variety of developmental processes. Using a PCR-based approach, we have isolated two novel members of the murine Wnt gene family, Wnt11 and Wnt12. These cDNAs display an amino acid sequence identity of between 38 and 49% with all other murine Wnts over the regions that we have isolated. In addition, two previously described Wnt genes, Wnt5a and Wnt7a, were detected in RT-PCR products. Interspecific crosses were used to demonstrate close linkage between Wnt12 and Wnt1 on Chromosome (Chr) 15. Wnt7a was mapped to mouse Chr 6, Wnt5a to the centromeric region of Chr 14, and Wnt11 to Chr7.

Amino Acid Sequence↗
PubMed1994

[Sphincter rupture in the course of labor].

Thirty-eight women with anal sphincter rupture during childbirth were followed for three to 12 months. Fourteen patients presented with continence disturbances, nine to solid or fluid faeces and five to gas. Incontinence was present in nine patients three months after childbirth. Anal manometry and anal electromyography were performed on the patients three to five days after delivery and repeated at three, six and twelve months after childbirth. Manometry and electromyography were performed on 16 control subjects and 24 primiparous control patients who were investigated three to five days and three months after delivery. Anal manometry and anal electromyography showed significant differences between both incontinent and continent patients compared to control subjects and primiparous control patients. Primiparous control patients had decreased squeeze pressure as well as decreased electromyographic activity during the first days after delivery compared to control subjects. After three months no differences were found. Continence disturbances are frequent after sphincter rupture and these patients should be monitored after delivery and those with persisting incontinence offered sphincter repair.

Adult↗
PubMed1994

Insulin-like growth factor II mRNA, peptides, and receptors in a thoracopulmonary malignant small round cell tumor.

Insulin-like growth factor-(IGF) II and IGF-I and IGF-II/mannose 6-phosphate receptors were expressed in a thoracopulmonary malignant small round cell tumor (MSRCT) from a 14-year-old boy. Northern analysis showed that the MSRCT expresses multiple IGF-II mRNA of 6.0, 4.8, 4.2, and 2.2 kilobase from promoters P3 and P4 of the human IGF-II gene. Chromatography and radioimmunoassay revealed two forms of IGF-II with molecular masses of 7.5 kilodalton (kDa) and 10 kDa, corresponding to mature IGF-II and IGF-II with a C-terminal extension, in concentrations of 61 and 41 ng/g/tumor tissue, respectively. By a combined reverse transcription-polymerase chain reaction analysis, the authors also show that the MSRCT expresses IGF-I and IGF-II/mannose 6-phosphate receptor mRNA. The plasma concentration of IGF-II was 600 ng/ml and within the normal range of serum IGF-II. IGF binding proteins (IGFBP) of 41.5, 38.5, 34, 30, and 24 kDa were present in serum. Compared with normal plasma from healthy subjects and an age-matched group of boys, the level of the 41.5, 38.5, and 30 kDa IGFBP were approximately 3-fold elevated. The authors conclude that transcription of the IGF-II gene leads to the production of significant amounts of 10 kDa IGF-II and 7.5 kDa IGF-II. IGF-II may stimulate the proliferation of MSRCT by interaction with IGF-I receptors on the cells.

Adolescent↗
PubMed1994

Electromyography of the internal anal sphincter performed under endosonographic guidance. Description of a new method.

PURPOSE: The aim of our study was to investigate internal anal sphincter electromyographic signals. METHODS: Electromyography of the internal anal sphincter was performed with platinum wire electrodes in six healthy volunteers (three males and three females), inserted under endosonographic guidance. Platinum wire electrodes were also inserted into the external anal sphincter. Activity of both the internal and external and sphincter in a 40-second period was measured. RESULTS: Internal anal sphincter median activity was 22.1 (range, 5.5-67.6) microV. Slow-wave activity was 47 cycles/minute (range, 34-55 cycles/minute). After inflation of a rectal balloon with air until a constant relaxation of the anal canal was obtained, a decrease in internal and sphincter activity to 15.9 (1.2-31.3) microV as well as a decrease in slow-wave activity to 34 cycles/minute (range, 27-40 cycles/minute) was found. The original internal anal sphincter EMG was resumed after deflation of the rectal balloon. External anal sphincter median activity was 3.1 (range, 0.77-18.6) microV. During inflation of the rectal balloon, a reflex increase in external sphincter EMG activity was found. With the rectal balloon fully inflated a part of this increase was still present, 11.0 (1.9-24.6) microV. In some of the subjects, this increased activity was superimposed on the internal anal sphincter recordings as well. During a voluntary squeeze it was not possible to identify internal anal sphincter activity due to activity of the external anal sphincter totally overriding the internal anal sphincter signal. CONCLUSION: Precise EMG recordings from the internal anal sphincter is possible with endosonographic guidance of the electrodes, except during voluntary squeezing of the external and sphincter.

Adult↗
PubMed1994

Laparoscopic loop ileostomy for fecal diversion.

PURPOSE: The aim of this study was to describe the procedure for laparoscopic loop ileostomy. METHODS: Technique description is given. CONCLUSION: The method is suitable for temporary fecal diversion in patients with anal disorders, where no other intraperitoneal operation is required.

Anus Diseases↗
PubMed1994

Pharmacological characterization of a biosynthetic trisulfide-containing hydrophobic derivative of human growth hormone: comparison with standard 22 K growth hormone.

Growth hormone is the classical anabolic hormone which promotes organ growth after binding to somatogenic target cell receptors, present in various target tissues. The present study elucidated the pharmacological characteristics in vitro and in vivo of human growth hormone and a recently identified by-product of a recombinant human growth hormone preparation; i.e. a trisulfide-containing (cys 182-cys 189) hydrophobic, folding derivative of growth hormone, hydrophobic derivative-growth hormone. Standard growth hormone and hydrophobic derivative-growth hormone possessed similar characteristics in vitro, both as regards binding to the somatogenic receptor on the human IM-9 cell line, and the prolactin receptor-mediated proliferation of rat Nb2 cells. This indicates that no change occurs in the binding characteristics in spite of a change in conformation of the molecule. Using an ELISA assay that detected standard and hydrophobic derivative-growth hormone equally well, the plasma pharmacokinetical profiles of the preparations following a single intravenous or subcutaneous dose were indistinguishable. Thus, following initial disposition of hydrophobic derivative-growth hormone and standard growth hormone into a volume, V1, of one to two times the plasma volume, almost 90% of either compound disappeared from plasma during the alpha-phase of the plasma decay curve. Similar half-lives of 4-5 min. were found for hydrophobic derivative-growth hormone and standard growth hormone during this phase, indicating rapid removal of drug from the circulation. Also, the AUC and Cmax values for standard and hydrophobic derivative-growth hormone did not differ following intravenous or subcutaneous administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Glucagon-like peptide-1 7-36 amide and peptide YY from the L-cell of the ileal mucosa are potent inhibitors of vagally induced gastric acid secretion in man.

BACKGROUND: Glucagon-like peptide (GLP-1) 7-36 amide and peptide YY (PYY) from the L-cell of the ileal mucosa are potent inhibitors of gastric acid secretion in man. It is not clear, however, by which mechanism(s) they inhibit acid secretion. In dogs the inhibitory effect of PYY on acid secretion may be mediated mainly through neural pathways. The mechanism of action of GLP-1 might be similar. The aim of the present study was to examine the effects of GLP-1 might be similar. The aim of the present study was to examine the effects of GLP-1 and PYY on the vagally induced gastric acid secretion in man. METHODS: A modified sham feeding technique, chew and spit, was used. Six healthy volunteers were randomly assigned to receive intravenous infusion of saline, GLP-1 (41 pmol/kg/h), or peptide YY (50 pmol/kg/h). RESULTS: The infusion of GLP-1 and PYY resulted in plasma concentrations of 60 +/- 9 pmol/l and 84 +/- 11 pmol/l, respectively. GLP-1 and PYY both significantly inhibited the intergrated acid output by 67 +/- 6% and 68 +/- 9%, respectively, compared with the integrated outputs in a control experiment with saline infusion. Serum gastrin and plasma somatostatin concentrations remained unchanged during saline, GLP-1, and PYY infusions. CONCLUSIONS: GLP-1 and PYY are both potent inhibitors of the cephalic phase of acid secretion, indicating that at least part of the inhibitory effect of GLP-1 and PYY in man is mediated through neural pathways. Furthermore, the inhibitory effect seems to be independent of circulating concentrations of gastrin and somatostatin.

Adult↗
PubMed1994

Purification and characterization of the bovine pituitary luteinizing hormone releasing hormone M(r) 60,000 binding protein.

Luteinizing hormone releasing hormone (LHRH) regulates the release of luteinizing hormone and follicle stimulating hormone from the pituitary. This process takes place through interaction with high affinity membrane receptors. In addition LHRH inhibits the growth of several cancer cell lines through the interaction with M(r) 60,000 LHRH receptors. Here we describe the purification to homogeneity of the M(r) 60,000 bovine pituitary LHRH binding protein in amounts allowing N-terminal sequencing and peptide mapping. The procedure describes solubilization of luteinizing hormone releasing hormone receptors from homogenized bovine pituitaries in an active form by using the detergent Triton X-114. The receptors were retained in the Triton X-114 phase during temperature-dependent phase separation. Preparative phase separations were performed directly on solubilized bovine pituitary extracts. SDS-PAGE of the purified LHRH receptor after LHRH-immobilized affinity chromatography showed the presence of a single band with M(r) 60,000. Partial sequencing of this band after trypsin digestion of gel pieces revealed unknown sequences with a possible homology to other receptors including some G-protein coupled receptors.

Amino Acid Sequence↗
PubMed1993

[Anal ultrasonography in anal incontinence].

Endosonography gives detailed information on the internal and external anal sphincters. The goals of this study were to evaluate findings on anal endosonography in patients with anal incontinence and to study the value of endosonography for selecting the most effective surgical treatment. Forty-eight patients with incontinence for either gas (17 patients) or faeces (31 patients) were studied. Nineteen patients had idiopathic incontinence, 29 were incontinent due to previous obstetrical or surgical trauma. Endosonography and measurement of anal canal pressures were performed in all patients, 40 had needle electromyography. The endosonograms were evaluated without knowledge of the clinical findings and correlated with the results of needle electromyography, with the anal pressures, and to the type of surgery subsequently performed. In 30 patients surgery was subsequently planned on the basis of the results of endosonography and the anophysiologic examinations. Endosonograms showed defects in 27 external sphincters, 12 of whom had internal sphincter defects also. One patient had an abnormal thinning of the external sphincter. Eight patients had defects of the internal sphincter as the only finding. Twenty-two of the patients with sonographically detected defects or thinning of the external sphincter had an EMG performed, this showed defects of the external sphincter in 18, four defects in the middle and upper anal canal had not been found. There was no correlation between the sphincteric defects found by endosonography and the anal canal pressures. Sphincter reconstruction was offered to most patients with damage to the external sphincter; patients with isolated defects in the internal sphincter or intact internal and external sphincters were offered a number of other surgical procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Sphincter rupture in childbirth.

Thirty-eight women with rupture of the anal sphincter occurring during childbirth were followed for 3-12 months. Nineteen had complete rupture of the external anal sphincter, 14 had a lesion involving more than half of the sphincter muscle and five had a superficial rupture. Fourteen patients presented with continence disturbances: nine to solid or liquid faeces and five to flatus. Incontinence was present in nine women 3 months after childbirth. Anal manometry and electromyography were performed in patients 3-5 days after delivery and repeated at 3, 6 and 12 months. Manometry and electromyography were also performed in 16 control subjects who were nulliparous or had given birth more than 2 years previously and 24 primiparous controls, who were investigated at 3-5 days and at 3 months. There were significant differences between both incontinent and continent patients compared with nulliparous and primiparous controls. Primiparous control subjects had decreased anal squeeze pressure as well as decreased electromyographic activity on the first days after delivery compared with nulliparous controls. After 3 months no differences were found. Continence disturbances are frequent after sphincter rupture; these patients should be monitored after delivery and those with persisting incontinence offered sphincter repair.

Adolescent↗
PubMed1993

Flow cytometric measurement of RNA synthesis using bromouridine labelling and bromodeoxyuridine antibodies.

Nuclear RNA synthesis can be analysed by flow cytometry of cells labelled with 5-bromouridine (BrUrd) and stained with anti-bromodeoxyuridine (BrdUrd) antibody and FITC-conjugated secondary antibody. A panel of 5 different commercially available anti-BrdUrd antibodies was tested on cells of a HL-60 human leukemia cell line, stained as a methanol-fixed nuclear suspension. The BrUrd-induced fluorescence signals were highest with the antibody ABDM (Partec), moderate but reproducible with B-44 (Becton Dickinson), variable or low with BR-3 and IU-4 (Caltag), and not detectable with Bu20a (DAKO). Treatment of BrUrd-labelled nuclei with ribonuclease before staining with antibodies indicated that ABDM and B-44 antibodies specifically recognized BrUrd-substituted RNA, whereas BR-3 and IU-4 antibodies also bound to BrUrd-unlabelled RNA. Combined analysis of BrUrd and DNA contents demonstrated the variation of RNA synthesis during the cell cycle. The BrUrd incorporation was high in the S and G2 phase, variable in G1, and negligible in mitosis. Similar results were obtained using other cell types.

Antibodies, Monoclonal↗