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Biomedical subjects

K Larsen

Publications and source records attributed to K Larsen.

At least 91 records · Page 5Linked to original sources
PubMed1990

Purification of nodule-specific uricase from soybean by arginine-sepharose affinity chromatography.

A method to purify uricase from soybean root nodules is described. The separation uses a single affinity chromatography step on Arginine-Sepharose, which was constructed by coupling L-Arginine to Activated CH-Sepharose 4B. Crude extracts were loaded onto small columns of Arginine-Sepharose and a significant retardation of uricase was observed. With a re-run of the fraction containing maximal uricase activity on the same column highly purified enzyme was obtained. Analysis by SDS-polyacrylamide gel electrophoresis revealed two protein bands. Analytical isoelectric focusing showed two isoforms of uricase, one dominating with pI 9.0 and a minor with pI 7.0.

Chromatography, Affinity↗
PubMed1990

Peak flow nasal patency indices and self-assessment in septoplasty.

The present study evaluates the results of septoplasty monitored by the objective peak flow nasal patency indices and the subjective patient self-assessment scores of nasal obstruction. Mini-Wright peak flow meters were used. The peak flow nasal patency index was defined as the ratio between nasal and oral peak flow rates. Uni and bi-lateral, as well as ex and in-spiratory, indices were calculated. Both peak ex and in-spiratory flow nasal patency indices were significantly increased 1 and 6 months post-operatively, indicating improved nasal patency. The most marked post-operative increase of the nasal patency indices was seen for the preoperatively worst airway and the total airway. A weak significant positive correlation was found between the peak flow nasal patency indices and the patient mean self-assessment scores of the uni and bi-lateral nasal obstruction. The change of the peak flow nasal patency indices measured 6 months post-operatively correlated well with the patient overall assessment of the operative changes of the total nasal patency. The method was found quick and easy to handle in monitoring the effect of functional septoplasty and is recommended as an alternative to rhinomanometry.

Adult↗
PubMed1989

Limb salvage in diabetics with foot ulcers.

The healing results in 491 ulcers in 272 diabetic patients are reported. Soft moulded insoles and shoe corrections were the main part of the therapy. There were 329 (67%) neuropathic, 87 (17%) traumatic, 44 (9%) ischaemic and 31 (6%) ulcers of other various pathogenesis. Thirty seven per cent of the ulcers were complicated with invasive infection. Within the period of observation of 18 months (3-39 months) healing was obtained in 79% of the patients (88% of the ulcers) and major amputation was carried out in 8% (4% of the ulcers). There were 21 major amputations, which in 18 cases was due to ischaemia. Thus in only 3 cases (1% of the patients) neuropathy as complicated by invasive infection caused major amputation. Fifty nine ulcers (12%) were classified as relapsing ulcers or ulcers with new localizations and were caused by severe deformity of the foot (58 cases) often in combination with neglect of prophylaxis (7 cases). Only one recurrent ulcer was caused by ischaemia. The series shows that shoe corrections and insoles are effective in treating diabetic neuropathic ulcers. Recurrent ulcerations are caused by severe foot deformity and neglect of therapy. Loss of limbs is caused by ischaemia and invasive infection.

Adult↗
PubMed1988

Heterologous flavivirus infection-enhancing antibodies in sera of Nigerians.

Human sera collected from Nigerians were examined for plaque reduction neutralizing and infection-enhancing antibodies against dengue 2, yellow fever, and West Nile viruses. Neutralization tests showed that 17 of 19 sera contained flavivirus neutralizing antibody; 11 were positive to all 3 viruses, 5 to dengue and yellow fever, and 1 to dengue virus only. Two sera had no detectable neutralizing antibody to any of the flaviviruses. Enhancement assays showed that 17 flavivirus neutralizing antibody-positive sera contained infection-enhancing antibodies to dengue 2, and 16 had antibody to yellow fever. Although 11 sera were positive for West Nile neutralizing antibody, 17 enhanced this virus. Heterologous infection-enhancing antibody titers were lower than the homologous ones. Broadly reacting sera and those with high neutralizing antibody titers produced the highest infection-enhancing antibody titers.

Antibodies, Viral↗
PubMed1988

Spirometric forced volume measurements in the assessment of nasal patency after septoplasty. A prospective clinical study.

Methods for assessing the nasal patency are needed in the evaluation of patients with symptoms of nasal stenosis. Apart from the commonly used rhinomanometric method spirometric forced volume measurements as well as nasal peak flow rate have gained interest especially in studies concerning allergic rhinitis and nasal hyperreactivity. We have measured the expiratory and inspiratory forced volume in 0.5 second through the mouth and nose in 12 patients before and after septoplasty and in ten controls. A nasal patency index (NPI) was calculated from the ratio between nasal and oral measurements. The expiratory and inspiratory NPI for the preoperative worst cavity and the expiratory NPI for the total nose showed significant improvement. These indices from the patients preoperative measurements also differed significantly from controls. We found the method easy to handle and sensitive enough to detect changes of the nasal patency after septoplasty.

Adolescent↗
PubMed1987

The immunization of children with combined diphtheria and tetanus vaccine in Sweden.

Two groups derived from 97 children three-four months of age were vaccinated with diphtheria and tetanus vaccines containing either a routinely prepared diphtheria toxoid or a more purified preparation. Two injections were given with an interval of one month and a third injection was given one year after the first. Prior to the third injection no child was without protection against diphtheria, i.e. had an antitoxin titre less than 0.01 IU ml-1. After the third injection 95 and 94% of the children vaccinated with the routinely and more purified diphtheria toxoids, respectively, had diphtheria antitoxin titres greater than 1 IU ml-1 (estimated to provide protection for at least ten years). Systemic reactions such as fever and malaise occurred in five children. Local reactions greater than 10 cm were observed in three children and reactions greater than 5 but less than or equal to 10 cm were seen in 14% of the children. The routinely prepared combined diphtheria and tetanus vaccine, DT, produced very good immunity against diphtheria with moderate side effects. The use of a more purified diphtheria toxoid in the combined vaccine produced the same immunity and side effects.

Diphtheria Antitoxin↗
PubMed1987

The immunization of adults against diphtheria in Sweden.

Two hundred and three women who disclaimed vaccination against diphtheria were divided into four groups and injected with either 2.0 or 6.25 Lf of a routine diphtheria toxoid or of a more purified preparation. One hundred and twenty-six of these women who did not show a secondary antibody response were given a second and a third injection one month and one year, respectively, after the first injection. Prebooster (third injection) antitoxin titres of greater than or equal to 0.01 IU ml-1 (the minimum level for protection) were found in 22 and 37% of those who received 2.0 and 6.25 Lf, respectively. Postbooster titres of greater than or equal to 1.0 IU ml-1 (calculated to give a protection of at least ten years of duration) were found in 23 and 58% of those who received 2.0 and 6.25 Lf, respectively. The rate of untoward reactions was low. Fever of short duration occurred in five women. Four out of the five women received 6.25 Lf of the more purified diphtheria toxoid and one 2 Lf of the routine toxoid. Local reactions greater than 10 cm were observed in three women. All received the higher dose, 6.25 Lf of diphtheria toxoid. Local reactions greater than 5 but less than or equal to 10 cm occurred in up to 13% (6.25 Lf of diphtheria toxoid). No significant difference between the groups of women vaccinated with routine or more purified toxoid was found. It was concluded that the diphtheria toxoids in the two doses of 2 Lf and 6.25 Lf did not induce a satisfactory immune response. To induce adequate protection the dose of diphtheria vaccine needs to be the same for adults and children, i.e. 12.5 Lf.

Adult↗
PubMed1987

Appearance of purine-catabolizing enzymes in fix and fix root nodules on soybean and effect of oxygen on the expression of the enzymes in callus tissue.

The appearance of enzymes involved in the formation of ureides, allantoin, and allantoic acid, from inosine 5'-monophosphate was analyzed in developing root nodules of soybean (Glycine max). Concomitant with development of effective nodules, a substantial increase in specific activities of the enzymes 5'-nucleotidase (35-fold), purine nucleosidase (10-fold), xanthine dehydrogenase (25-fold), and uricase (200-fold), over root levels was observed. The specific activity of allantoinase remained constant during nodule development. With ineffective nodules the activities were generally lower than in effective nodules; however, the activities of 5'-nucleotidase and allantoinase were 2-fold higher in ineffective nodules unable to synthesize leghemoglobin than in effective nodules. Since the expression of uricase has been shown to be regulated by oxygen (K Larsen, BU Jochimsen 1986 EMBO J 5: 15-19), the expression of the remaining enzymes in the purine catabolic pathway were tested in response to variations in O(2) concentration in sterile soybean callus tissue. Purine nucleosidase responded to this treatment, exhibiting a 4-fold increase in activity around 2% O(2). 5'-Nucleotidase, xanthine dehydrogenase, and allantoinase remained unaffected by variations in the O(2) concentration. Hence, the expression of two enzymes involved in ureide formation, purine nucleosidase and uricase, has been demonstrated to be influenced by O(2) concentration.

Journal Article↗
PubMed1987

Abnormal extension of the big toe as a cause of ulceration in diabetic feet.

Relief from external pressure and repetitive stress is a main concept in treating diabetic neuropathic ulcers. Ulcers on the tip of the big toe may be caused by abnormal extension of the big toe, which can be diagnosed only by observing the patient during barefoot walking. A flexor pad underneath the big toe eliminates the phenomenon, but in case of rigidity of the toe, extremely roomy toe boxes must be prescribed. Out of a series of 272 diabetic patients with skin lesions on the feet 18 suffered this phenomenon, in one case with bilateral ulcerations. Fifteen ulcers healed and below the knee amputation had to be carried out in 4 legs due to ischaemia.

Diabetic Neuropathies↗
PubMed1987

Potiskum virus: enhancement of replication in a macrophage-like cell line.

Replication of Potiskum virus was studied in P388D1 macrophage-like cell line in the presence and absence of subneutralizing concentrations of specific antiviral antibody. The cultures were infected at multiplicities of infection (MOI) ranging from 0.4 to 0.0004. The virus replicated to high titres at all MOI tested, but there was an enhancement of virus replication in cultures supplemented with the antibody. Enhancement of replication was MOI dependent, the highest ratios being obtained in cultures infected at lowest MOI. In enhancement assays using various dilutions of immune mouse ascitic fluid (IMAF), the highest enhancement ratio was observed at dilution 1 : 500; the enhancing antibody titre was 5,000.

Animals↗
PubMed1987

Cross-infection enhancement among African flaviviruses by immune mouse ascitic fluids.

Cross-infection enhancement of seven African flaviviruses by subneutralising concentrations of antibody in immune ascitic fluids was investigated in P388D1 cell culture. Infection by all the seven flaviviruses tested was enhanced by homologous and at least one of six heterologous immune mouse ascitic fluids (IMAF) tested. Enhancement ratios and enhancing antibody titres were higher in homologous than in heterologous enhancement. Zika, Wesselsbron, Uganda S and West Nile viruses were enhanced in culture by all the IMAF tested. Enhancement of Dakar bat and Yellow fever viruses was produced by five heterologous IMAF, but Potiskum virus was enhanced by one heterologous flavivirus antibody. The antibody to Potiskum virus was the most potent mediator of heterologous infection enhancement; all six heterologous flaviviruses were markedly enhanced by this antibody.

Animals↗
PubMed1986

Characterization of a glucoamylase G2 from Aspergillus niger.

Peptide fragments were generated by enzymic or chemical degradation of the small form, G2, and the large form, G1, of Aspergillus niger glucoamylase (EC 3.1.2.3). The G2 form was either identical to residues Ala1-Pro512 or to Ala1-Ala514 of the G1 polypeptide chain containing 616 amino acid residues. Structural analysis of the O-linked carbohydrates from the 70-amino-acid-residues long extensively glycosylated segment of G2 revealed no significant differences in the contents of single mannose and oligosaccharide units in comparison to the corresponding region of G1. The results suggest that the present G2 form has been generated by limited proteolysis of the larger G1. In contradistinction to this, a recently reported splicing out of an intervening sequence from G1 mRNA leads to a smaller mRNA coding for a G2 protein product with a different COOH-terminal sequence than the G2 form described in the present work [Boel et al. (1984) EMBO J. 3, 1097-1102].

Amino Acid Sequence↗