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Biomedical subjects

K Christensen

Publications and source records attributed to K Christensen.

At least 19 recordsLinked to original sources
PubMed1992

Prevention of excess neonatal morbidity associated with group B streptococci by vaginal chlorhexidine disinfection during labour. The Swedish Chlorhexidine Study Group.

Streptococcus agalactiae transmitted to infants from the vagina during birth is an important cause of invasive neonatal infection. We have done a prospective, randomised, double-blind, placebo-controlled, multi-centre study of chlorhexidine prophylaxis to prevent neonatal disease due to vaginal transmission of S agalactiae. On arrival in the delivery room, swabs were taken for culture from the vaginas of 4483 women who were expecting a full-term single birth. Vaginal flushing was then done with either 60 ml chlorhexidine diacetate (2 g/l) (2238 women) or saline placebo (2245) and this procedure was repeated every 6 h until delivery. The rate of admission of babies to special-care neonatal units within 48 h of delivery was the primary end point. For babies born to placebo-treated women, maternal carriage of S agalactiae was associated with a significant increase in the rate of admission compared with non-colonised mothers (5.4 vs 2.4%; RR 2.31, 95% CI 1.39-3.86; p = 0.002). Chlorhexidine reduced the admission rate for infants born of carrier mothers to 2.8% (RR 1.95, 95% CI 0.94-4.03), and for infants born to all mothers to 2.0% (RR 1.48, 95% CI 1.01-2.16; p = 0.04). Maternal S agalactiae colonisation is associated with excess early neonatal morbidity, apparently related to aspiration of the organism, that can be reduced with chlorhexidine disinfection of the vagina during labour.

Administration, Intravaginal↗
PubMed1992

[Study of the Danish Malformation Registry for the incidence of cleft lip and palate during 1983-1987].

The Danish Register of Congenital Malformations at the National Board of Health is used for surveillance and research. More than 10% of all patients registered have oral cleft diagnoses. This report evaluates the completeness of the Register of Congenital Malformations as regards registration of oral cleft patients born in Denmark in the period 1983-1987. The register is limited to congenital anomalies diagnosed in hospitals in the child's first year of life. The investigation shows, that the register is suitable for surveillance of clefts, because the completeness of registration was constant during the five-year period 1983-1987. The completeness was more than 90% of all known cases, and probably higher for severe clefts and cases with associated anomalies. Identical diagnosis was found in 93% of all patients registered in The Register of Congenital Malformations with at least one other source of ascertainment. In addition, the investigation disclosed misclassification of a small oral-cleft-subgroup and the need for an additional diagnosis in the coding. The register can only be used for surveillance and research in congenital anomalies, which are usually diagnosed in the child's first year of life.

Cleft Lip↗
PubMed1992

Comparison of two ibuprofen formulations in the treatment of shoulder tendonitis.

In order to compare the efficacy and tolerance of two drug formulations of ibuprofen, conventional tablets 600 mg QID (CI) and sustained-release tablets 1200 mg BID (SRI), a total of 147 patients in 7 centres in Denmark with nontraumatic shoulder pain were included in a double-blind dummy study. Initially all patients received a local injection of corticosteroid and local anaesthetic, and were randomly allocated either drug (CI or SRI) for a period of 3 weeks. Complete relief was recorded from significantly more of the patients in the CI group (21%) than in the SRI group (7%) while a similar number of patients improved viz., 67% of the SRI treated group and 77% of the CI treated group. Based on doctor's assessment improvement in the two groups was equal. 44% of the patients recorded side effects, the number and pattern being the same in the two groups. No serious side effects were recorded. It is concluded that the two treatment regimens can be rated as clinically equivalent.

Adult↗
PubMed1992

Dairy breed bull with complex chromosome translocation: fertility and linkage studies.

A chromosome study was performed on the offspring of an American Brown Swiss bull, which was carrier of a complex chromosome translocation. A total of 10 phenotypically normal calves were examined and a similar complex translocation was detected in five calves. The translocation involved identifiable parts of chromosome number one and eight. Furthermore, the terminal band of chromosome one had been translocated to an unidentified chromosome. One of the calves also carried a 1/29 centric fusion chromosome. Pedigree and chromosome analysis showed that the centric fusion originated from another American Brown Swiss bull. A linkage study was performed and an indication of linkage between the Z blood group system and the complex translocation was found. The fertility of the bull was studied, and it was found to have a severely reduced fertility mainly due to an increased rate of early embryonic mortality.

Animals↗
PubMed1992

Assignment of a porcine male-specific DNA repeat to Y-chromosomal heterochromatin.

Primers were designed to amplify by PCR a 509-bp genomic fragment from male pig DNA, using the porcine male-specific repeat sequence described by McGraw et al. (1988). This PCR product showed male-specific hybridization in Southern blots. Nonradioactive in situ hybridization localized it to the entire length of the heterochromatic portion of Yq. The assignment was confirmed using the PCR primer pDYZ1-S for primed in situ labeling.

Animals↗
PubMed1992

Ligands induce conformational changes in the carboxyl-terminus of progesterone receptors which are detected by a site-directed antipeptide monoclonal antibody.

We have prepared a monoclonal antibody, C-262, to a synthetic peptide that contains the carboxy-terminal 14 amino acids from progesterone receptors (PR). This sequence is 100% conserved in all species of PRs that have been cloned to date, suggesting that this antibody will recognize all mammalian and avian PR. The C-262 antibody recognizes both native and denatured forms of the receptor. However, it does not recognize PR when they are bound to the hormone agonists progesterone or R5020. Surprisingly the antibody does recognize PR when they are bound to the steroid antagonist RU486. This suggests that progestin agonists induce a conformational change in the receptor that occludes the C-262 epitope in the carboxyl-terminus, whereas unliganded receptors and receptors bound with RU486 assume distinct conformations that leaves the C-terminal tail accessible to the C-262 antibody.

Amino Acid Sequence↗
PubMed1992

Selection bias in genetic-epidemiological studies of cleft lip and palate.

The possible impact of selection bias in genetic and epidemiological studies of cleft lip and palate was studied, using three nationwide ascertainment sources and an autopsy study in a 10% sample of the Danish population. A total of 670 cases were identified. Two national record systems, when used together, were found suitable for ascertaining facial cleft in live births. More than 95% ascertainment was obtained by means of surgical files for cleft lip (with or without cleft palate) without associated malformations/syndromes. However, surgical files could be a poor source for studying isolated cleft palate (CP) (only a 60% and biased ascertainment), and they cannot be used to study the prevalence of associated malformations or syndromes in facial cleft cases. The male:female ratio was 0.88 in surgically treated cases of CP and was 1.5 in nonoperated CP cases, making the overall sex ratio for CP 1.1 (95% confidence limits 0.86-1.4) The sex ratio for CP without associated malformation was 1.1 (95% confidence limits 0.84-1.6). One of the major test criteria in CP multifactorial threshold models (higher CP liability among male CP relatives) must be reconsidered, if other investigations confirm that a CP sex-ratio reversal to male predominance occurs when high ascertainment is achieved.

Cleft Lip↗
PubMed1991

Characterization and functional properties of the A and B forms of human progesterone receptors synthesized in a baculovirus system.

Human progesterone receptors (PR) were overexpressed in Spodoptera frugiperda (Sf9) insect cells using a recombinant baculovirus system. Recombinant viruses were constructed that produced either full-length A (94K) or B (120K) forms of human PR, and each was expressed as a functional protein. Steroid and DNA binding activities were found to be indistinguishable from that of endogenous human PR in T47D breast cancer cells. Moreover, as analyzed by gel-mobility shift, recombinant PR-A and PR-B each bound to specific progesterone response elements in a strictly hormone-dependent manner. Native receptors expressed in Sf9 cells also exhibited structural properties similar to that of endogenous PR. Cytosolic PR (PR-A or PR-B), prepared in low salt buffer, sedimented on density gradients as an 8S oligomeric complex that was converted largely to 4S by treatment with 0.4 M NaCl. Immune isolation of the 8S cytosol PR complex and analysis of protein composition revealed the presence of two specific copurifying proteins of approximately 90K and 70K. The 90-K component was identified immunologically as heat shock protein 90. The 70-K component was not identified but is likely to be the insect equivalent of heat shock protein 70. Immune isolation of PR from Sf9 cells metabolically labeled with [32Pi], revealed that expressed PR was capable of being phosphorylated in insect cells. Hormone addition to Sf9 cells, however, did not stimulate the same increase in PR phosphorylation or upshift in mobility on sodium dodecyl sulfate gels that occurs with endogenous receptors in T47D cells. Thus some, but not all, phosphorylations occur with human PR expressed in Sf9 cells. These phosphorylation data, together with the fact that expressed PR required hormone for DNA binding, indicate that the hormone-dependent phosphorylation step responsible for PR upshifts on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is not required for receptor binding to DNA. The baculovirus expression system, therefore, may prove valuable in dissecting the functional role(s) for both hormone-dependent and hormone-independent PR phosphorylation.

Animals↗
PubMed1990

Assignment of the porcine calcium release channel gene, a candidate for the malignant hyperthermia locus, to the 6p11----q21 segment of chromosome 6.

Several studies point to the possibility that malignant hyperthermia (MH) in pigs is caused by a defect in the calcium release channel (CRC) of skeletal muscle sarcoplasmic reticulum. The locus for MH is closely linked to the glucosephosphate isomerase (GPI) locus, near the centromere of chromosome 6. We demonstrate synteny of the genes for CRC and GPI using somatic cell hybrid lines, and assign the CRC gene to chromosome 6p11----q21 by in situ hybridization.

Amino Acid Sequence↗
PubMed1990

An epidemiological study of congenital anorectal malformations: 15 Danish birth cohorts followed for 7 years.

In the county of Fyn (about 500,000 inhabitants) which is a well defined and representative 10% sample of the total Danish population, 15 total birth cohorts were scrutinized for the occurrence of anorectal malformations (ARM). All the patients were followed until the age of 7 or death. In a total of 96,073 births, 29 cases were observed; one concordant monozygotic pair was counted as one case. The study showed the point prevalence at birth to be 3.0 per 10,000; almost the same frequency has been found in Sweden whereas other figures from Europe and North America are lower. Children with ARM have in general a poor prognosis, largely due to the many associated anomalies. In this material, 11 of 12 isolated ARM cases survived until age 7, but five of these had significant handicaps. Out of 17 probands with associated anomalies, only seven survived until age 7, all of them having some handicap. This group of patients spent at least 15 times more days in hospital than an age-matched group from the same region until age 7, and they underwent a considerable number of operations. The study showed an increased frequency of chromosome anomalies among children with ARM.

Abnormalities, Multiple↗
PubMed1990

Chromosome C-band polymorphism in relation to fertility in boars of the Duroc breed.

In a study of the variation of fertility in boars of the Duroc breed from Danish AI stations, chromosome investigation has been conducted on 11 boars with high and 11 with low fertility, respectively, out of a total of 98 boars having normal semen quality according to AI standards. All 22 boars had the normal chromosome number. C-band polymorphism at chromosome 16 and 17 was more frequent in the low fertility boars compared with high fertile ones (P less than 0.01), and on average a C-band polymorphic boar sired 0.99 piglet less per litter than a non-polymorphic. More investigations are warranted before application of the results can be brought into practical swine breeding.

Animals↗
PubMed1990

Fractional processing of sequential bronchoalveolar lavage to separate bronchial and alveolar samples.

Bronchoalveolar lavage has been widely used to sample the lower respiratory tract. Most of the material recovered with this technique represents alveolar contents. A number of modifications have been suggested in order to obtain samples relatively enriched for bronchial material. In order to be able to use a standard technique for bronchoalveolar lavage to sample both airways and "routine" alveolar material, a simple modification of the technique as described by Reynolds and Newball was used: five sequential 20-ml aliquots were infused into the lower respiratory tract, and each aliquot was immediately aspirated. The return from the first aliquot was processed separately from the return from the subsequent four aliquots. These last four aliquots were pooled. Analysis of the first aliquot revealed it to be enriched for ciliated epithelial cells when compared with the subsequent aliquots. There were also differences in inflammatory cell composition with the bronchial sample containing relatively more neutrophils and relatively less lymphocytes. Aspiration during transoral bronchoscopy was documented by quantifying salivary amylase in the bronchial and alveolar lavage fluids. It was estimated, however, that the aspiration was not of quantitative significance in the vast majority of subjects studied. Finally, with the technique of fractional processing of bronchoalveolar lavage samples, it was possible to compare the protein concentrations in bronchial and alveolar lavages. Most prominent among the differences was a marked relative enrichment in the bronchial samples for immunoglobulin A. The technique of fractional processing of bronchoalveolar lavage samples provides a simple means to obtain samples enriched for bronchial and alveolar components. This should facilitate analysis of lower respiratory tract specimens in airway disease.

Adult↗
PubMed1990

Intestinal calcium transport in systemic disease. Studies with brush-border membrane vesicles.

Recent experiments utilizing brush-border membrane vesicles (BBMV) from small intestine to examine calcium uptake processes by the enterocyte are reviewed. Results demonstrate that (a) uptake must be examined in the time frame approaching initial rate, and (b) kinetics of saturable and nonsaturable processes be defined. Saturable uptake of calcium is carrier mediated, since it is inhibited competitively by strontium and noncompetitively by magnesium. Intravesicular strontium (but not magnesium), doubles Vmax for saturable uptake of calcium from the medium (countertransport), consistent with a mobile carrier. Since membrane lipid composition is expected to be an important determinant of function of a mobile carrier in a lipid bilayer, BBMV were treated with liposomes to change phospholipid and cholesterol content. Any change from native lipid composition decreased Vmax, but in treated BBMV, Vmax correlated with BBMV cholesterol content and fluidity. Since nonsaturable calcium uptake is extensively inhibited by both strontium and magnesium, electrostatic binding of calcium to the membrane is a major component of nonsaturable uptake. The remaining uninhibitable component of nonsaturable uptake is diffusion down the calcium concentration gradient. These concepts are applied to considering calcium uptake in disease and to the relationship of uptake to transenterocyte calcium movement.

Animals↗