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Biomedical subjects

J Hansen

Publications and source records attributed to J Hansen.

At least 307 records · Page 17Linked to original sources
PubMed1982

Functions of the peptide antibiotics tyrocidine and gramicidin. Induction of conformational and structural changes of superhelical DNA.

The peptide antibiotic tyrocidine which is produced by Bacillus brevis and is probably involved in sporogenesis, unwinds superhelical plasmids in vitro at low peptide: DNA ratios, as found by gel electrophoresis. At higher peptide concentrations, the DNA is packed tightly leading to apparent nuclease stability of the complex and inhibition of RNA synthesis. The addition of the linear gramicidin, another peptide antibiotic synthesized by the same bacterial strain, partially restores transcription by breaking down the tightly packed DNA X peptide complex. The complexed DNA, after nuclease digestion, is retained on a nitrocellulose filter, but loses its affinity for the filter in the presence of gramicidin. The results are discussed with respect to possible functions of the two peptides within in the cell.

Bacillus↗
PubMed1982

Urinary incontinence in old age. A controlled clinical trial of emepronium bromide.

The effect of the anticholinergic agent, emepronium bromide (Cetiprin), was studied in a double blind crossover study of a group of elderly patients with urinary incontinence and uninhibited bladder contractions during cystometry. There was no statistically significant difference between the subjective effect of emepronium bromide and that of placebo, and no change in the cystometric parameters. The overall subjective cure or improvement rate was 79%. The effect of anticholinergic drugs in the treatment of urinary incontinence in elderly patients with uninhibited bladder contractions might to some extent be due to an improvement in the patients' understanding and acceptance of the bladder disorders.

Aged↗
PubMed1982

Reaction of ampicillin with serum albumin to produce penicilloyl-protein conjugates and a piperazinedione.

Formation of penicilloyl-protein conjugates in the body by reaction of penicillins with nucleophilic groups of proteins is considered to be involved in penicillin allergy. In this study the kinetics and mechanism of reaction of ampicillin with human and bovine serum albumin in aqueous solution at 37 degrees C and pH 6.6-10.4 have been investigated and compared with the reaction of benzylpenicillin previously reported. In addition to forming penicilloyl-protein conjugates, ampicillin was found to react with the proteins to yield a free piperazine-2,5-dione derivative. This product is suggested to arise from intramolecular aminolysis of an N-(penicilloyl)imidazole intermediate at pH 6-8 and of a penicilloyl ester intermediate at higher pH values. The piperazinedione formation was found to compete effectively with formation of penicilloyl-protein conjugates at physiological pH and, along with studies of ampicillin with protein model compounds, the reaction allowed suggestions to be made abut the penicillin-reacting sites in the proteins.

Amines↗
PubMed1982

Association of cap-binding protein with eucaryotic initiation factor 3 in initiation factor preparations from uninfected and poliovirus-infected HeLa cells.

Extracts from poliovirus-infected HeLa cells are unable to translate vesicular stomatitis virus or cellular mRNAs in vitro, probably reflecting the poliovirus-induced inhibition of host cell protein synthesis which occurs in vivo. Crude initiation factors from uninfected HeLa cells are able to restore translation of vesicular stomatitis virus mRNA in infected cell lysates. This restoring activity separates into the 0 to 40% ammonium sulfate fractional precipitate of ribosomal salt wash. Restoring activity is completely lacking in the analogous fractions prepared from poliovirus-infected cells. The 0 to 40% ammonium sulfate precipitates from both uninfected and infected cells contain eucaryotic initiation factor 3 (eIF-3), eIf-4B, and the cap-binding protein (CBP), which is detected by means of a cross-linking assay, as well as other proteins. The association of eIF-3 and cap binding protein was examined. The 0 to 40% ammonium sulfate precipitate of ribosomal salt wash from uninfected and infected cells was sedimented in sucrose gradients. Each fraction was examined for the presence of eIF-3 antigens by an antibody blot technique and for the presence of the CBP by cross-linking to cap-labeled mRNAs. From uninfected cells, a major proportion of the CBP cosedimented with eIF-3; however, none of the CBP from infected cells sedimented with eIF-3. The results suggest that the association of the CBP with eIF-3 into a functional complex may have been disrupted during the course of poliovirus infection.

Carrier Proteins↗
PubMed1982

Normal gait of young and old men and women. Ground reaction force measurement on a treadmill.

Forty normal persons had their gait tested using an instrumented treadmill. All were tested at the same speed of gait. The temporal factors of gait, the ataxia, and the external work of the gait were all calculated from the ground reaction forces. Ten women and ten men 20-29 years and ten women and ten men aged 60-69 were tested. The study demonstrated a constant pattern of gait independent of age and sex.

Adult↗
PubMed1982

[Effects of tramadol on haemodynamics and blood gases in the early postoperative period].

A variety of opioids is available for treatment of acute pain. Sometimes administration is limited due to typical side effects such as respiratory depression or pressure increase in the pulmonary circulation. Tramadol, a synthetic opioid, was investigated in a dosage of 1.5 mg/kg body weight i.v. with regard to changes in haemodynamic parameters and in blood gases. The haemodynamic parameters generally remained stable; all changes were statistically non significant. There were no signs of respiratory depression. The risk of pain therapy with opioids seems to be reduced further by the introduction of this agent.

Adolescent↗
PubMed1982

Thiamin Metabolism in the rat during long-term alcohol administration. 1. Communication: ethanol induced changes at optimal thiamin supply.

The effect of ethanol administration on the phosphorylation of thiamin, and on the transketolase activity (TKA) in erythrocytes, heart and liver, and on the thiamin excretion in urine was investigated in rats optimally supplied with thiamin over a period of 16 weeks. Ethanol ingestion resulted in a diminished concentration of thiamin (T), thiaminmonophosphate (TMP), thiamindiphosphate (TDP) and thiamintriphosphate (TTP) in blood and organs and in a reduced excretion rate of T in urine due to an impaired intestinal absorption. An ethanol induced alteration of the degree of thiamin phosphorylation became evident only after 16 weeks resulting in a decline of T and TMP in blood and of T in heart to undetectable amounts and in an enhancement of the TDP- and TTP-pool. Despite an increasing content of TDP in erythrocytes the TKA was lowered and the alpha-TK was enhanced during the test period suggesting a partially inhibited formation of the active holoenzyme by alcohol in vivo. However, the lowered TKA and the normal alpha-TK in liver are primarily suggestive of an apo-enzyme degeneration influenced by ethanol.

Alcoholism↗
PubMed1982

Thiamin metabolism in the rat during long term alcohol administration.

In order to test the effect of a long term alcohol administration on the thiamin metabolism in blood, heart and liver under suboptimal supply, an experiment with rats was carried out over a period of 16 weeks. The suboptimal thiamin supply became visible mainly in the liver stores which were lowered during the whole test period. The unphosphorylated thiamin (T) of liver and heart was not detectable after 4 weeks up to the end of experiment. On the other hand the total thiamin concentration in the erythrocytes increased from the beginning due to an enhanced thiamin-diphosphate (TDP) and thiamintriphosphate (TTP) pool and T was lowered to undetectable amounts only after 16 weeks. In contrast, the alpha-TK in blood and liver was enhanced only after 2 and 4 weeks and tended to become normal by the end of the test period indicating an apoenzyme degeneration. Alcohol ingestion resulted in a general diminution of the total thiamin and the thiamin phosphates in blood, heart and liver and a reduced thiamin excretion in urine. An alcohol induced shift of the phosphorylation status could be observed only in the liver, but not in the heart and the erythrocytes, leading to a lowered concentration of T and TMP. The results demonstrate that the level of thiamin and thiamin phosphates in blood and organs under suboptimal thiamin supply seems to be more sensitive to chronic alcohol administration than the transketolase activity and the alpha-TK value.

Animals↗
PubMed1981

Activation of progesterone receptor by ATP.

Progesterone-receptor complex from freshly prepared hen oviduct cytosol acquired the ability to bind to isolated nuclei, DNA-cellulose and ATP-Sepharose when incubated with 5-10 mM ATP at 4 degrees C. The extent of this ATP-dependent activation was higher when compared with heat-activation achieved by warming the progesterone-receptor complex at 23 degrees C. The transformation of progesterone-receptor complex which occurred in a time-dependent manner was only partially dependent on hormone presence. The ATP effect was selective in causing this transformation whereas ADP, AMP and cAMP failed to show any such effect. The non-hydrolyzable analogs of ATP, adenosine 5'-[alpha, beta-methylene]triphosphate and adenosine 5-[beta, gamma-imido]triphosphate were also found to be ineffective. Presence of 10 mM sodium molybdate blocked both the ATP and the heat-activation of progesterone-receptor complex. Mn2+ and Mg2+ had no detectable effect on the receptor activation but the presence of Ca2+ increased the extent of ATP-activation slightly. EDTA presence (greater than 5 mM) decreased the extent of receptor activation by about 40% and was, therefore, not included in the buffers used for activation studies. Divalent cations were also ineffective when tested in the presence of 1-5 mM EDTA. The steroid-binding properties of progesterone-receptor complex remained intact under the above conditions when analyzed for steroid-binding specificity and Scatchard analysis. However, the ATP-activated progesterone-receptor complex lost the ability to aggregate when tested on low-salt sucrose gradients. ATP was equally effective in activating the rat-uterine-estradiol-receptor complex at 4 degrees C and influenced the transformation of 4-S receptor form into a 5-S form when analyzed on sucrose gradients containing 0.3 M KCl. The presence of ATP also increased the rate of activation of progesterone-receptor complex at 23 degrees C. These findings suggest a role for ATP in receptor function and offer a convenient method of studying the process of receptor activation at low temperature and mild assay conditions.

Adenosine Triphosphate↗
PubMed1981

Patient-controlled dose regimen of methadone for chronic cancer pain.

Fourteen patients with severe cancer pain participated in a trial of methadone given in a fixed dose (10 mg) but at intervals selected by the patients themselves during the loading phase. The aim was to achieve rapid pain relief while avoiding the risk of toxicity from accumulation of methadone. As expected, the dosage intervals increased gradually over the first few days of treatment, the daily dose decreasing from 30-80 mg on the first day to 10-40 mg at the end of the week. Plasma concentrations of methadone varied sevenfold after four to five days (0.24 to 1.75 mumol/1; 7.4 to 54.2 microgram/100 ml). Eleven patients reported complete or almost complete pain relief and elected to continue with methadone after the study. In no case was treatment withdrawn because of intoxication. From these findings a patient-controlled dosage regimen of oral methadone may be an effective and safe alternative to parenteral narcotic medication, adjusting both for individual variation in pain intensity and for pharmacokinetics.

Adult↗
PubMed1981

Presence of the cap-binding protein in initiation factor preparations from poliovirus-infected HeLa cells.

Crude preparations of initiation factors from mock-infected and poliovirus-infected HeLa cells were analyzed for the presence of proteins which could be cross-linked to the 5' cap group of mRNA. A protein having an apparent molecular weight of 26,000, similar to the cap-binding protein in rabbit reticulocytes described by Sonenberg and Shatkin (Proc. Natl. Acad. Sci. U.S.A. 75:4843-4847, 1978), was found in the ribosomal salt wash from both uninfected and infected cells. Cross-linking of this polypeptide was inhibited by the cap analog m7GMP. In addition, cross-linking of a protein having an approximate molecular weight of 60,000 was similarly inhibited by cap analog. The smaller cap-binding protein fractionated in a 0 to 40% ammonium sulfate precipitate of ribosomal salt wash; the larger protein was found in the 40 to 70% ammonium sulfate fraction. Although the cap-binding proteins were present in both mock-infected and poliovirus-infected ribosomal salt wash, only preparations from uninfected HeLa cells were able to restore translation of capped vesicular stomatitis virus mRNA by extracts prepared from poliovirus-infected cells.

Carrier Proteins↗
PubMed1981

Bilateral carcinoma of the breast. Epidemiology and histopathology.

A history of previous carcinoma in the contralateral breast was found in 66 of 1351 women (5%) consecutively diagnosed as having breast carcinoma. The mean time interval between the diagnosis of the first and second tumour was 10.0 years (range 0-37 years); 63 of the tumours were metachronous. No significant differences were found between the first and the second carcinoma with respect to the Ackerman malignancy grading or the frequency of axillary node involvement. High risk groups for bilateral disease could not be defined on the basis of information about familial occurrence, parity, age at first birth, or malignancy grade.

Adult↗