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J L Larsen

Publications and source records attributed to J L Larsen.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Is Vibrio cholerae serotype 0139 a potential cause of a new pandemic?].

Vibrio cholerae O139, a new V. cholerae serotype that does not react with the 138 so far known antisera, was first isolated in 1992 in Madras, India. Although a V. cholerae non-O1, it behaved quite differently from this particular group of organisms by its clinical appearance in causing epidemic cholera-like disease. The organism possessed the same register of virulence factors as V. cholerae O1. Biochemical and genetic analyses have shown that V. cholerae O139 was closely related to the El Tor biotype and it has been suggested that it might be a mutant of this biotype. Despite the fact that V. cholerae O139 isolates were very homologous in many respects, ribotyping of Thai isolates showed a certain degree of genetic diversity. From its rapid spread in populations, pattern of infection and ability to survive in aquatic environments, it may be suggested that we are dealing with a more infectious, more virulent and in an ecological sense more robust organism, whose pandemic potential appears significant. Commercial cholera vaccines offer no or only limited protection. Treatment comprises an adequate rehydration and use of effective antibiotics--at present tetracycline, ampicillin, erythromycin and ciprofloxacin. Tourism and perhaps the import of foods from Third World countries may excert a potential risk for the Danish population.

Cholera↗
PubMed1995

Prevalence of vibrio cholerae and salmonella in a major shrimp production area in Thailand.

In 1992 and 1993, a 7 months study carried out in a major shrimp-producing area in Southern Thailand to study the prevalence of Vibrio cholerae and Salmonella. A total of 158 samples were examined including water, sediment, shrimp, pelleted feed, shrimp gut, and chicken manure. Salmonella was not recovered from any sample type studied. V. cholerae O1 was isolated from 2 (2%) and V. cholerae non-O1 was isolated from 35 (33%) of 107 samples examined. The occurrence of V. cholerae was not significantly influenced by water salinity, temperature, dissolved oxygen or pH. There was no correlation between fecal coliform counts and the prevalence of V. cholerae. The results indicate that V. cholerae non-O1 is ubiquitous in aquatic environments where shrimp culture is practised under a variety of environmental conditions. The public health significance of non-O1 V. cholerae in shrimp culture remains to be determined. V. cholerae O1 and Salmonella do not appear to constitute a hygienic problem even if chicken manure was used as fertilizer.

Animals↗
PubMed1995

Ribotyping and plasmid profiling of Vibrio anguillarum serovar O2 and Vibrio ordalii.

One hundred and twenty-nine strains of Vibrio anguillarum serovar O2 and 14 strains of Vibrio ordalii were ribotyped and examined for plasmid contents. A total of 35 different ribotypes were detected. The V. anguillarum serovar O2 strains were divided into 32 different ribotypes. The V. ordalii strains showed three different ribotypes, clearly distinct from those of the V. anguillarum strains. Ribotypes were separated into seven clusters, of which one comprised the V. ordalii strains. Clustering of the strains indicated a genetic difference between North European and South European V. anguillarum O2 strains. Sero-subgroups O2a and O2b shared ribotypes; however, three of the clusters did not include O2a strains. All V. ordalii strains had a plasmid of 32 kb. This plasmid was not detected in any of the V. anguillarum strains. Seventeen different plasmid profiles with 17 different sized plasmids were detected among the V. anguillarum strains. Most of the plasmids were small (< 6 kb) and found in several strains. Except for one South European strain, plasmids were detected only in the North European strains of V. anguillarum O2.

Cluster Analysis↗
PubMed1995

Application of ribotyping for differentiating Vibrio cholerae non-O1 isolated from shrimp farms in Thailand.

A collection of 143 Vibrio cholerae non-O1 strains isolated from shrimp farms in Thailand were characterized and grouped by ribotyping. Sixty-four ribotypes were distinguished following digestion of chromosomal DNA with the restriction enzyme BglI, and the reproducibility of the method was 100%. There was no correlation between specific ribotype distributions and the locations of the shrimp farms. Ribotype similarity was examined by cluster analysis, and two main groups with 10 and 54 ribotypes, respectively, were found. Correlation between ribotype and O-antigen expression was shown to exist among those isolates tested. Ribotyping appears to be a suitable method for differentiating environmental V. cholerae non-O1 strains, and comparison of ribotype patterns showed a high degree of genetic divergence within V. cholerae non-O1.

Animals↗
PubMed1995

Comparison of Pulsed-Field Gel Electrophoresis, Ribotyping, and Plasmid Profiling for Typing of Vibrio anguillarum Serovar O1.

A total of 75 Vibrio anguillarum serogroup O1 strains were studied with respect to their plasmid contents, ribotypes, and pulsed-field gel electrophoresis (PFGE) patterns. Eight plasmid profiles and six ribotypes were demonstrated, and one profile was dominant by both typing methods. In contrast, PFGE had very high discriminatory power, demonstrating 35 profiles. On the basis of PFGE patterns, a similarity matrix and a dendrogram were constructed. The results indicated that Scandinavian strains and southern European isolates (with some exceptions) belong to two different clonal lineages. A few strains from the United States and United Kingdom deviated considerably from each other and from Scandinavian and southern European strains.

Journal Article↗
PubMed1995

Evidence for the existence of distinct populations of Vibrio anguillarum serogroup O1 based on plasmid contents and ribotypes.

A total of 103 Vibrio anguillarum serogroup O1 strains displaying 15 different plasmid profiles were characterized with respect to biochemical properties and ribotypes. The results confirmed that V. anguillarum O1 is a biochemically homogeneous group. The 103 strains could be allocated to three main clusters with high similarity coefficients. None of the biochemical properties were connected with the presence of plasmids. In total, 12 different ribotypes were demonstrated, with HindIII being used as the restriction enzyme. Forty of the strains were isolated from the same Danish fish farm, some from the kidneys of diseased fish and some from the environment, and some strains were isolated from the mucus, gills, and feces of healthy fish. Nineteen of these isolates possessed the 67-kb virulence plasmid alone or in combination with other plasmids, while 21 had no plasmids. All strains isolated from the kidneys of diseased fish on this farm had plasmids. Irrespective of their origin (kidneys, gills, or mucus), all 19 strains carrying the 67-kb virulence plasmid had the same ribotype, profile 1, while isolates without plasmids belonged to five different profiles, all different from profile 1. These results suggest that pathogenic V. anguillarum O1 strains possessing a virulence plasmid and nonpathogenic strains without plasmids from a small geographical area and even from the same fish may constitute two essentially distinct populations. Thus, it may be suggested that an exchange of virulence plasmids among strains is unlikely to occur in vivo.

Bacterial Typing Techniques↗
PubMed1995

Pancreas transplantation for diabetes mellitus.

Vascularized pancreas transplantation has assumed an increasing role in the treatment of diabetes mellitus. Through 1993, over 5500 pancreas transplants have been performed worldwide, with over 80% being combined pancreas-kidney transplants. Overall one-year patient survival exceeds 90% and graft survival (complete insulin independence) exceeds 70%. Although successful pancreas transplantation achieves euglycemia and complete insulin independence, this occurs at the expense of hyperinsulinemia and chronic immunosuppression. The net result of these changes on diabetic complications in the long term remains to be determined. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients.

Blood Glucose↗
PubMed1995

Pancreas transplantation.

Vascularized pancreas transplantation has assumed an increasing role in the treatment of diabetes mellitus. Through 1994, over 6000 pancreas transplants had been performed worldwide, with over 80% being combined pancreas-kidney transplants. Overall 1-year patient survival exceeds 90% and graft survival (complete insulin independence) exceeds 70%. Although successful pancreas transplantation achieves euglycemia and complete insulin independence, this occurs at the expense of hyperinsulinemia and chronic immunosuppression. The net effect of these changes on diabetic complications in the long term remains to be determined. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients.

Diabetes Mellitus, Type 1↗
PubMed1995

Antibiotic resistance of Vibrio anguillarum, in relation to serovar and plasmid contents.

A total of 520 Vibrio anguillarum strains, isolated from fish and the environment, were tested for their sensitivity to 20 different antibiotics. Most isolates were of European origin. The results were compared with data on the O-serogroup and plasmid contents. All strains were sensitive to neomycin, spectinomycin, nitrofurantoin, flumequine and oxolinic acid, while most strains were sensitive to streptomycin, oxytetracycline, chloramphenicol, sulphonamides, trimethoprim, sulphonamides with trimethoprim, nalidixan, rifampicin, novobiocin and O/129. A major part of the strains were resistant to the macrolides, spiramycin and lincomycin. For ampicillin, cephalothin, and colistin marked differences were recorded with respect to O-serogroup. Most O1 strains were resistant to colistin and sensitive to ampicillin and cephalothin, while most O2 strains were sensitive to colistin but resistant to ampicillin and cephalothin. Some antibiotic resistant strains carried plasmids but no conjugation experiments were carried out to detect possible R factors.

DNA↗
PubMed1995

Contrast media leakage to the cerebrospinal fluid after intravenous injection. Comparison of stroke patients and controls.

We have tested a method to evaluate leakage of i.v. injected contrast media (CM) through the 3 partitions between blood and cerebrospinal fluid (CSF) in controls and in patients with acute cerebrovascular disease (ACBVD) to detect differences between normal brains and brains with ischemic lesions. High-osmolar (HOCM) and low-osmolar (LOCM) CM were used. In 55 patients and in 41 controls who underwent CT after i.v. contrast administration, lumbar CSF was collected 1 hour after injection and the iodine content in the CSF was measured. The concentration of iodine in CSF was very low, between 0.57 and 11.20 ng/l, and no significant difference could be found between patients and controls or between HOCM and LOCM. We conclude that under the conditions mentioned above, iodine detected in the human lumbar CSF does not reflect the true leakage of contrast agent through the blood-brain barrier.

Acute Disease↗
PubMed1994

Pravastatin reduces serum cholesterol and low density lipoprotein concentrations following pancreas transplantation.

Hyperlipidemia is a significant risk factor for atherosclerotic vascular disease. We have shown previously that pancreas transplantation (PTX) improves but does not normalize lipids in most PTX recipients. We studied whether pravastatin was effective in treating 10 patients with elevated low density lipoprotein (LDL)-cholesterol (LDL-C) following PTX. Seven men and 3 women were studied. Six received combined kidney-pancreas transplantations, while 4 received PTX alone. Age at time of PTX was 37.2 +/- 2.2 years (mean +/- SEM), and 4 had established coronary artery disease before PTX. Mean cholesterol (C), LDL-C, triglycerides (TG), and high density lipoprotein (HDL)-cholesterol (HDL-C) were 236 +/- 12, 142 +/- 6, 222 +/- 50, and 49 +/- 4 mg/dl before PTX. The LDL to HDL ratio was 3.0 +/- 0.3. After PTX, excluding the first 45 days, mean C, LDL-C, and HDL-C increased to 278 +/- 10, 178 +/- 7, and 63 +/- 6 mg/dl (all P < or = 0.05), respectively. TG, LDL to HDL ratio, and weight were unchanged. Pravastatin (11.7 +/- 0.8 mg/day, mean +/- SEM) was initiated 250 +/- 53 days after PTX. During therapy, C and LDL-C decreased on average to 231 +/- 10 and 134 +/- 8 mg/dl, respectively (both P < 0.01), while HDL did not change. The decreases in C and LDL-C were unexplained by a decrease in weight, cyclosporine dose or concentration, or increase in serum creatinine. However, prednisone dose decreased over the same interval, so a contribution from this variable cannot be excluded. No evidence of toxicity was identified during therapy. This is one of the first reports demonstrating that pravastatin is a safe and effective treatment for elevated C and LDL-C in patients following PTX. However, pravastatin did not increase HDL or decrease TG, as observed in the nontransplantation setting. Whether pravastatin or any hypolipidemia therapy can prevent cardiovascular events or mortality following PTX remains to be established.

Adult↗