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Biomedical subjects

U Carlsson

Publications and source records attributed to U Carlsson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Rapid ion-exchange chromatography for preparative separation of proteins. IV. Application to bovine carbonic anhydrase III from skeletal muscle.

Bovine muscle carbonic anhydrase III was purified to homogeneity by the strategy of rapid ion-exchange chromatography. The ionic exchanger used was CM-cellulose, and this is the first application of this technique on a cation exchanger. Nitrogen gas was used to pressurize the chromatographic column to accelerate the elution. The results show that proteins with high isoelectric points can also be purified in this way. The procedure is very time-saving compared with conventional chromatography, reducing the elution time five- to ten-fold. The proteins are in addition protected against oxidation by air.

Animals↗
PubMed1991

Folding around the C-terminus of human carbonic anhydrase II. Kinetic characterization by use of a chemically reactive SH-group introduced by protein engineering.

We are characterizing the process of refolding of the enzyme human carbonic anhydrase II from the denatured state in guanidine hydrochloride. To describe the folding in defined parts of the protein we use protein engineering to introduce cysteine residues as unique chemically reactive probes. The accessibility of the cysteine SH-group to the alkylating reagent iodoacetate, at different stages during refolding, is used to give a kinetic description of the folding process. The structuration of the C-terminal part of the polypeptide chain, which is involved in a unique 'knot' topology, was investigated. Our results show that the structure around the C-terminal, composed of the outermost beta-strands in a dominating beta-structure that extends through the entire protein, is formed relatively late during refolding. In contrast, it was found that beta-strands located in the interior of the protein were structured very rapidly. The final native structure is formed in a process that is slower than those observed for formation of beta-structure.

Carbonic Anhydrases↗
PubMed1991

Border disease in sheep caused by transmission of virus from cattle persistently infected with bovine virus diarrhoea virus.

Two outbreaks of border disease occurred on farms with sheep flocks and breeding cattle. The infection of the pregnant sheep was probably caused by transmission of virus from calves persistently infected with non-cytopathic bovine virus diarrhoea virus (BVDV) which were kept in close confinement with the ewes during mid-pregnancy. Border disease was also induced experimentally in eight lambs by exposing their dams at 38 to 78 days of gestation to a heifer persistently infected with BVDV. Both the natural and the experimental infections were characterised by typical signs such as 'hairy-shaker' lambs and high lamb mortality. The diagnosis was confirmed by virus isolations from live-born lambs, seroconversion and pathology. The study supports the assertion that cattle persistently infected with BVDV and in close contact with pregnant sheep, are an important source of strains of virus capable of causing border disease.

Animals↗
PubMed1991

Protective effect of an ISCOM bovine virus diarrhoea virus (BVDV) vaccine against an experimental BVDV infection in vaccinated and non-vaccinated pregnant ewes.

Fifteen pregnant ewes were vaccinated twice with an experimental immunostimulating complex (ISCOM) subunit vaccine designed to contain the envelope proteins of a Danish cytopathic bovine virus diarrhoea virus (BVDV). The serological responses were measured in ELISA and virus neutralization (VN) tests. All ISCOM-vaccinated ewes developed high VN antibody titres to BVDV in contrast to the 14 non-vaccinated ewes. Both groups of ewes were challenged parenterally when 48-65 days pregnant with a Swedish cytopathic BVDV isolate. In the vaccinated group 26 fetuses out of 29 detected by ultrasound were liveborn, whereas only six out of 26 were liveborn in the non-vaccinated group. It is concluded that the ISCOM vaccine had the potential of eliciting high VN titres as well as protecting fetuses against transplacental infection after challenge with a virulent BVDV isolate.

Animals↗
PubMed1990

Partial amino acid sequence of erythrocyte carbonic anhydrase from tiger shark.

1. A partial primary structure (197 residues) of carbonic anhydrase from tiger shark (Galeocerdo cuvieri) erythrocytes has been determined. 2. The amino acid sequence of the enzyme is identical to those of human cytoplasmic carbonic anhydrases (CA I-III) by as much as 52-60%. 3. It is shown that tiger shark CA most closely resembles the CA II isoenzyme of amniotes. 4. Isoelectric focusing and inhibition studies on carbonic anhydrase from dogfish (Squalus acanthias) blood and muscle indicate the presence of the same isoenzyme in shark blood and muscle.

Alkylation↗
PubMed1989

The role of the metal ion in the refolding of denatured bovine Co(II)-carbonic anhydrase II.

Conditions for reactivation of guanidine-HCl-denatured bovine Co(II)-carbonic anhydrase II are given. The renaturation is accompanied by recovery of the native Co(II)-spectrum of the enzyme. After studying the kinetics of the renaturation process, the metal ion involvement in the refolding pathway can be summarized as follows: (1) Formation of an inactive Co(II)-intermediate with the metal ion firmly bound. No native Co(II)-spectrum is observed in this state, probably due to octahedral coordination of the metal ion in this intermediate. (2) Formation of an inactive Co(II)-intermediate with a native Co(II)-spectrum. The final tetrahedral coordination of the metal ion seems to have been formed in this state. (3) Formation of the active conformation of the enzyme. A functioning active-site is formed after some rearrangements of the polypeptide chain. This isomerisation step does not need to be preceded by formation of the intermediate with a native Co(II)-spectrum. Coordination of Co2+ in a native-like manner is, however, a prerequisite for enzymic activity. It is tentatively suggested that the metal ion is involved in stabilizing a nucleation structure formed at the bottom of the active centre. This probably occurs through binding of Co2+ to some or all of its histidyl ligands in this region after an early structuration of the metal ion binding site. The mechanisms of Co2+ appear to be similar for the refolding enzyme and the native apoenzyme, inferring that the binding site formed as a result of the nucleation process probably has the same structure as in the native conformation.

Animals↗
PubMed1989

Comparison of dose-response effects of inhaled beclomethasone dipropionate and budesonide in the management of asthma.

The dose-response effects of inhaled beclomethasone dipropionate (BDP) and budesonide (BUD) administered b.i.d. with the aid of metered dose aerosols were studied in 128 patients (67 men and 61 women, mean age 53 years) suffering from asthma bronchiale. The study was designed as a multi-centre, double-blind, four-period cross-over study, followed by a single-blind double placebo period. BDP was administered in doses of 400 and 1000 micrograms, and BUD in doses of 400 and 800 micrograms. The results in terms of peak expiratory flow (PEF) in the morning and evening, daily symptoms score and use of inhaled beta 2-agonists did not reveal any clinically significant differences between the drugs or between high (800 micrograms BUD, 1000 micrograms BDP) and low (400 micrograms BUD/BDP) doses. However, statistically significant differences were recorded for the corresponding parameters when comparing the placebo with preceding steroid periods. Adverse effects consisting mainly of oropharyngeal candidiasis, hoarseness and cough occurred in 54 of 468 treatment months (12%). The carry-over effects of inhaled steroids are longer lasting than was previously assumed.

Administration, Inhalation↗
PubMed1989

Evidence for an initial fast nucleation process in the folding of human carbonic anhydrase I.

Kinetic studies of the folding of carbonic anhydrase have indicated the occurrence of various conformational intermediates. Human carbonic anhydrase I contains a single cysteine residue, Cys-212, which in the native state is unavailable for alkylation. In the unfolded state, it can be specifically modified with iodoacetate. In this study the accessibility of Cys-212 in human carbonic anhydrase I to iodo[2-14C]acetate during the refolding process has been investigated. It is shown that Cys-212 is hidden to the alkylating agent as soon as the refolding is initiated. Since Cys-212 is located in the extensive beta-structure passing through the enzyme, it appears that the Cys-containing beta-strand is part of a rapidly formed nucleation center created during the folding process. This beta-strand (No. 7) together with its neighboring beta-strand (No. 6) constitute the most hydrophobic regions of the enzyme. Because hydrophobic contacts are considered to be important in predicting nucleation sites, these beta-strands probably partake in the formation of the nucleation center. These beta-strands are also partly involved in the bottom region of the active site cavity, indicating that this region is formed during the initial folding events. As a result of this study it was also observed that 2-mercaptoethanol is a potent inhibitor of the enzyme with a K1 = 26 microM at pH 8.0.

Carbonic Anhydrases↗
PubMed1989

Bovine virus diarrhoea virus, a cause of early pregnancy failure in the cow.

In the present report attention is drawn to clinical and hormonal changes in heifers following experimental or natural infection with bovine virus diarrhoea virus in early pregnancy. Three heifers were infected experimentally and one naturally at pregnancy stages from 29-41 days. A leukopenia was seen 5-7 days after infection. All four animals experienced foetal death. Two of them aborted and in two the foetus was resorbed. Oestrus was observed at the expulsion of the foetus or in connection with vaginal discharge. Peripheral blood plasma levels of progesterone and the main blood plasma metabolite of prostaglandin F2 alpha (15-keto-13,14-dihydro-PGF2 alpha) were analysed. Diagnosis of pregnancy and embryonic/foetal viability were monitored by ultrasound. The interrelationship between infection and reproductive endocrinology is discussed and the importance of avoiding infection in early gestation is pointed out. It may easily pass unobserved and can thereby cause serious economic loss.

Abortion, Veterinary↗
PubMed1988

The adenoma-carcinoma sequence in rectal adenomas. Support by the expression of blood group substances and carcinoma antigens.

The reaction patterns of eight antibodies directed against blood group substances A, B, and H and against Lewis B antigen, difucosylated carbohydrate antigens (DFCA), gastrointestinal cancer antigen (GICA) CA 19-9, carcinoma-associated antigen CA-50, and carcinoembryonic antigen (CEA) were studied in mucosa and adenomas of the rectum. Antigenic heterogeneity was a common feature of rectal mucosa and was observed to a considerable degree in adenomas. In general, the rectal mucosa expressed only a few antigens and to a limited extent. The adenomas were more extensively stained than the rectal mucosa. The proportion of positive cells increased with the grade of dysplasia but was relatively unrelated to the histologic type. The proportion of individual antigens expressed and the number of antigens extensively expressed increased between rectal mucosa, benign adenomas, and adenomas with early invasive carcinoma. These findings support the concept of an adenoma (dysplasia)-carcinoma sequence.

ABO Blood-Group System↗
PubMed1987

Recurrence rates after curative surgery for rectal carcinoma, with special reference to their accuracy.

Is the observed recurrence rate after curative surgery for rectal cancer always a good measure of therapeutic improvements? In an attempt to answer this question, the rates of local and distant recurrences were studied in two complete series of patients operated on for cure for rectal carcinoma. One hundred one consecutive patients were followed for five years in one series and 231 were followed for at least 18 years in the other series. The recurrence rate in the first series was 39 percent and in the second, with the longer observation time, 54 percent. The local recurrence rates were 24 and 38 percent, respectively. Both local and total recurrence rates increased with the length of the follow-up period. This was especially true for patients with combined local and distant disease. Autopsy sometimes demonstrated recurrences, clinically undiscovered. It is concluded that completeness, long follow-up, and intensive search for recurrence, including a high autopsy rate, are factors that raise both total and local recurrence rates. All these factors are important to consider when comparing results of different treatment modalities.

Adenocarcinoma↗
PubMed1987

Effect of bovine virus diarrhoea virus on pregnancy in the ewe monitored by ultrasound scanning and levels of 15-keto-13,14-dihydro-PGF2 alpha and progesterone.

Fourteen unvaccinated and seronegative ewes were experimentally infected with bovine virus diarrhoea virus around day 60 of pregnancy. Two other groups of pregnant ewes served as control animals. The animals were followed with ultrasound scanning to study the status of the fetus and with frequent blood sampling for analysis of progesterone and 15-keto-13,14-dihydro-PGF2 alpha, two hormones that could reflect the propagation of the infection. The unvaccinated ewes responded to the infection with abortion, resorption of the fetus, mummification or no changes at all. The endocrinological changes reflected in a most adequate way the pathological changes in the uterus. Detailed endocrinological studies can contribute to the understanding of the pathogenesis of some infectious diseases that affect reproduction.

Abortion, Veterinary↗