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Biomedical subjects

M Tvede

Publications and source records attributed to M Tvede.

54 records · Page 3Linked to original sources

A rapid method for purification of homogeneous Legionella pneumophila cytotoxic protease using fast protein liquid chromatography.

A purification method was developed to isolate Legionella pneumophila cytotoxic protease in a form suitable for biological assays. Culture supernatant of a clinical isolate of L. pneumophila, Knoxville 1 strain, was used as the starting material. The protease was purified by FPLC on a Mono Q column followed by ultrafiltration. The isolated proteolytic enzyme has a specific activity of 90 azocasein units/mg protein and is a 42 kDa monomeric protein as determined by SDS-PAGE and gel filtration chromatography. It is heat-labile and toxic to a variety of cells e.g. McCoy, SIRC, HeLa, and rhabdomyosarcoma cells, baby hamster and green monkey kidney cells, and human embryonic lung fibroblasts.

Cell Line↗

Haemophilus segnis endocarditis.

Haemophilus segnis is a rarely recognised commensal in the oropharynx. We wish to report the first published case of endocarditis caused by H. segnis. The patient, a 76-year-old female did not recover until after 2 courses of ampicillin given for a total of 57 days. In the second course of treatment, ampicillin was combined with 10 days of netilmicin therapy.

Aged↗

Acute gastroenteritis in children attending day-care centres with special reference to rotavirus infections. I. Aetiology and epidemiologic aspects.

Acute gastroenteritis (GE) among 214 children (aged 6 months-7 years) attending day-care centres (DDCs) in the Copenhagen County was studied during a 12-month period. A total of 197 cases of GE was observed in 109 children (i.e. 51% of the participants). The aetiology was as follows: rotavirus (n = 48) (24%), pathogenic bacteria (n = 11) (6%), Giardia lamblia (n = 3) (2%), while the aetiology of 68% remains unknown. The pathogenic bacteria included Yersinia enterocolitica, thermophilic Campylobacter, Clostridium difficile (+/- toxin) and enteropathogenic E. coli. In 4% of the GE the infections were multiple and Cryptosporidium was seen in one of these cases. The rate of GE declined with age from 1.35 GE per child per year (age group 1.0- less than 2.0 years) to 0.36 (6.0- less than 8.0 years). Serum sampled at the start of the study period showed that the frequency of detectable rotavirus IgG increased with age from 48% in the 6 months- less than 1.0 year group to 96% in the 4.0- less than 7.0 year group. The highest rates of rotavirus GE occurred from January to April (i.e. the rotavirus season). Moreover, rotavirus GE was almost absent after the age of 4. Hence, the rates of rotavirus GE per rotavirus season per child were 0.80 (age group 6 months-less than 1.0 year), 0.32 (1.0-less than 2.0), 0.14 (2.0-less than 3.0), 0.16 (3.0-less than 4.0), 0.06 (4.0-less than 5.0) and 0.04 (5.0-less than 6.0). Only 2 out of the 48 rotavirus GE were reinfections.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Excessive hypercalcaemia and mixed connective tissue disease.

A 23-year-old female with extreme hypercalcaemia was treated with calcitonin, mitramycin and parathyroidectomy and normocalcaemia was achieved after 4 weeks. Nevertheless, the patient later died of cutaneous necrosis, impaired circulation and multiple organ failure. Serum immunoreactive parathyroid hormone was in the normal range and parathyroid tissue normal. Mixed connective tissue disease was diagnosed on the basis of high titers of antibody to extractable nuclear antigen, moderately elevated levels of antibody to nuclear antigen and only marginal elevation of anti-double standed DNA. The role of Cl. difficile toxin in the blood and an acinic cell tumour is unclear.

Adult↗

Catheter-related septicaemia in patients receiving home parenteral nutrition.

Forty-three patients received home parenteral nutrition (HPN) for 4 to 13 months (median, 30 months) with a total treatment period of 153 patient-years. All patients had central venous catheters; 71 PVC subclavian catheters, 138 Broviac catheters, and 16 other catheters were used. Broviac catheters were introduced into the central veins via a tunnel on the chest (94 catheters) or on the thigh (44 catheters). Eighty-two episodes of catheter septicaemia occurred in 28 (65%) of the patients, corresponding to an incidence of catheter septicaemia of 1 in 1.9 patient-years. The commonest microorganisms grown from the blood were coagulase-negative staphylococci, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Candida species. Septicaemia incidence was 1 in 2.6 catheter-years with the Broviac catheter on the chest and 1 in 1.6 catheter-years with the Broviac catheter on the thigh. In 49 cases the patient was treated with both antibiotics and change of the catheters, in 26 cases with antibiotics alone, and in 5 cases with change of the catheter alone. The antibiotic therapy was given for 3 to 15 days (median, 7 days). No patient died of catheter septicaemia. The relapse rate was low (less than 10%) and did not differ significantly between the three treatment groups. It is concluded that catheter septicaemia is a common complication of HPN. In most cases it runs a mild course. Bacteriaemia can often be eradicated by a brief antibiotic therapy without catheter exchange.

Adolescent↗

Actinomycotic infections of the central nervous system. Two case reports.

Two cases of CNS infections caused by Actinomyces israelii one a fatal case of brain abscess and the other a case of subdural empyema with complete recovery, are reported. One of the patients suffered from a congenital ventricular septal defect, and in both patients a pulmonary focus was found. When slow-growing bacteria such as Actinomyces may be suspected, it is important to cultivate anaerobically for at least five days.

Actinomyces↗

Serum antibodies to Bacteroides species in chronic inflammatory bowel disease.

It has been proposed that the presence of elevated serum titres against various Bacteroides species among patients with chronic inflammatory bowel disease (CIBD) may yield aetiological, pathogenic, or prognostic information. Using a crossed immunoelectrophoretic method, we investigated circulating antibodies against four Bacteroides species in 122 patients with CIBD (80 with ulcerative colitis (UC) and 42 with Crohn's disease (CD)) and in 32 patients with the irritable colon syndrome. In this cross-sectional study we found raised titre scores (greater than 0) among 26% of the patients with CD, among 46% of the patients with UC, and among 34% of the patients with the irritable colon syndrome. These differences are not significant. There were no correlations between the antibody titres and the duration of the disease, the clinical disease activity, or the site of the disease. Furthermore, the antibody titres yielded no prognostic information as to the necessity of surgery--that is, colectomy and/or small-bowel resection.

Adolescent↗

A rapid method to produce a sensitive Limulus amoebocyte lysate (LAL). I. Evaluation of inter and intra batch differences in LAL and hemolymph from Limulus polyphemus.

An improved method for preparing Limulus amoebocyte lysate (LAL) is described and compared with two other well-known procedures. In five Limuli, three different bleeding procedures and three different cell rupture methods were studied. Increased sensitivity of LAL was accomplished by avoidance of the anticoagulant N-ethylmaleimid (NEM) in the bleeding procedure, optimal methods for mechanical cell rupture and use of pyrogen free conditions. Reaction of LAL with as little as 10(-15) gram Lipopolysaccharide (LPS) per ml was generally obtained. To evaluate a possible explanation for the differences in reactivity of LAL between different Limuli, found in one experiment, six Limuli were bled, and the pH and the concentration of protein, Ca2+, Mg2+, Cu2+, Na+ and K+ were determined in LAL and cell-free hemolymph. Inter and intra batch variations were found in LAL, but there was no correlation between the sensitivity of LAL and the content of the above mentioned constituents in LAL and cell-free hemolymph. Experiments with use of NEM in the bleeding procedure and addition of NEM to homogenized cells in different concentrations, showed that NEM inhibits the reactivity of LAL to LPS. It is concluded that the modified method of producing LAL by bleeding without NEM and by using optimal methods for mechanical cell rupture is quick, simple and produces a very sensitive reagent for the Limulus test.

Animals↗