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Biomedical subjects

B Hauser

Publications and source records attributed to B Hauser.

At least 55 records · Page 3Linked to original sources
PubMed1998

Accurate sequencing by hybridization for DNA diagnostics and individual genomics.

Medical DNA diagnostics will increasingly rely on an accurate and inexpensive identification of mutations that affect the function of a gene. To validate diagnostic sequencing by hybridization (SBH), a number of p53 samples were analyzed with the complete set of 8192 noncomplementary 7-mer oligonucleotides. In four repeated, blind experiments we accurately sequenced 1.1 kb per each of 12 homozygote and heterozygote samples possessing base substitutions, insertions, and deletions. This SBH variant offers a high throughput platform to inexpensively sequence individual gene or pathogen genome samples within the clinical laboratory setting.

DNA↗
PubMed1998

Field validation of laboratory tests for clinical diagnosis of sheep-associated malignant catarrhal fever.

Until recently, sheep-associated malignant catarrhal fever (SA-MCF) was diagnosed mainly on the basis of clinical presentation and histopathological changes. Using clinically diagnosed field cases, we have evaluated a seminested PCR and a competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA) and compared these assays in the diagnosis of SA-MCF in cattle with histopathology as a provisional "gold standard." Samples from 44 cattle with clinical signs suggestive of SA-MCF were examined by histopathology, PCR, and CI-ELISA. In addition, samples from healthy cattle were evaluated by PCR (n = 96) and CI-ELISA (n = 75). Based on histopathology, 38 of the 44 clinical cases were classified as SA-MCF positive, 3 were classified as inconclusive, and 3 were classified as SA-MCF negative. The sensitivity of PCR was 95 to 97%, whereas the specificity ranged between 94 and 100%. The CI-ELISA showed a sensitivity of 56 to 87% and a specificity between 91 and 100%. In the field, there is good correlation between the diagnoses of SA-MCF by histopathology, PCR, and CI-ELISA. These data also confirm the close association of ovine herpesvirus 2 with SA-MCF in Switzerland.

Animals↗
PubMed1998

[Differential diagnosis of hypercalcemia--a retrospective study of 46 dogs].

UNLABELLED: The case records of 46 dogs with hypercalcemia were studied retrospectively. The most common cause of hypercalcemia was malignancy, of which the majority were diagnosed as having lymphosarcoma (LSA, n = 23). Interestingly only 15 had palpable lymphadenopathy. Other neoplasia were apocrine adenocarcinoma of the anal sac (n = 4), mammary adenocarcinoma (n = 2), anaplastic carcinoma (n = 1), and malignant histiocytosis (n = 1). Non-neoplastic reasons for hypercalcemia were hypoadrenocorticism (n = 5), acute renal failure (n = 2), chronic renal failure (n = 2), hypervitaminosis D (n = 1), and primary hyperparathyroidism (n = 1). In 4 cases no definitive diagnosis could be obtained. Moderate to marked hyperphosphatemia and azotemia was found in all dogs with primary renal failure and in 4 of 5 dogs with hypoadrenocorticism. In contrast only 4 of 31 dogs with neoplasia showed (mild) hyperphosphatemia and 20 showed mild to moderate azotemia. Elevated PTH levels were found in dogs with primary chronic renal failure and with primary hyperparathyroidism, but also in one dog with neoplasia. Low PTH concentrations were measured in the dog with hypervitaminosis D and in 8 cases with neoplasia. Additional three cases with neoplasia had values in the reference range. CONCLUSIONS: 1. The most common cause of hypercalcemia is LSA. Absence of palpable lymphadenopathy does not exclude LSA and further diagnostic steps may be necessary 2. The combination of moderate to marked hyperphosphatemia suggests primary renal failure or hypoadrenocorticism. 3. An elevated PTH level is consistent with primary hyperparathyroidism, but does not exclude other causes of hypercalcemia.

Adrenal Insufficiency↗
PubMed1998

[Solar glossitis in sled dogs].

In a colony of sledge dogs, an increased incidence of ulcerative glossitis was diagnosed. Several facts indicate that the lesions were directly caused by UV light. The presence of signs coincided with the use of the dogs of the glacier. The lesions were localized on the first part of the tongue. The histologic changes were consistent with a phototoxic reaction and other causes of glossitis were ruled out.

Animals↗
PubMed1997

Dependence of genotoxicity of benzo[a]pyrene suspensions in Mutatox test on dissolved concentration and S9 addition.

The Mutatox test is a novel genotoxicity test measuring the ability of a test chemical to restore the luminescent state in dark mutants of Vibrio fischeri. Chemicals can be tested with or without rat hepatic S9 enzymes for metabolic activity, so that promutagenic agents can be detected as well. In the Microbics Mutatox Manual (1993, Microbics Corp., Carlsbad, CA), benzo[a]pyrene is recommended as positive control for S9 medium at a nominal concentration of 10 mg/liter with 2% DMSO as carrier solvent. The concentration of benzo[a]pyrene dissolved in this test suspension without addition of S9 was determined by GC-MS. It was significantly lower than the nominal concentration and did not reveal a genotoxic effect in the Mutatox test with S9. The analytical concentration of benzo[a]pyrene in the supernatant of the test suspension in S9 medium was significantly higher and induced the luminescence of bacteria. Therefore, S9 microsomes seem, apart from metabolizing benzo[a]pyrene to its genotoxic epoxide, to increase transfer of benzo[a]pyrene into V. fischeri in such a way that the genotoxic effect is produced. This suggests that sparingly soluble compounds might have different ecotoxicological effects as suspensions than as solutions. Therefore, the possible uptake of suspended particles by organisms without being completely dissolved before should be considered in ecotoxicological tests.

Animals↗
PubMed1997

Comparison of acute toxicity and genotoxic concentrations of single compounds and waste elutriates using the Microtox/Mutatox test system.

The Mutatox test has been developed by Microbics Corp., U.S.A., in addition to the widely used acute toxicity test Microtox. The Mutatox test indicates the presence of any material in a test sample that causes genetic damage to dark variants of the luminescent bacteria Vibrio fischeri. As the Microtox test is less time-consuming and more cost-effective than the Mutatox test, the possibility of using the EC50 measured by Microtox for range-finding of genotoxic concentrations for the Mutatox test was examined. Both tests were applied on single compounds and several waste elutriates. The genotoxic potential of two PAH metabolites--1-hydroxypyrene and 9-fluorenone-1-carboxylic acid--was detected. According to the present results the highest concentration of a sample in the Mutatox test should in general exceed the EC50 by about 5-10 times. Elutriates were submitted to analyses of TOC, heavy metals, phenols, and PAH; additionally GC/MS screening analyses were carried out. In most cases correlations of ecotoxicological effects with single contaminants were not possible, but it can be assumed that these effects were produced by the interaction of inorganic and organic compounds present in the elutriates.

Fresh Water↗
PubMed1997

Placebo-controlled evaluation of a modified life virus vaccine against feline infectious peritonitis: safety and efficacy under field conditions.

A modified live virus vaccine against feline infectious peritonitis (FIP) was evaluated in a double blind, placebo-controlled field trial in two high-risk populations. The vaccine was found to be safe and efficacious in one population of cats that had low antibody titre against feline coronavirus (FCoV) at the time of vaccination. Although clinically healthy at the time of vaccination, retrospectively some vaccinees that later came down with FIP were found to be RT-PCR positive for FCoV in plasma and showed changes in blood parameters consistent with early stage of FIP. It is concluded that vaccination can protect cats with no or low FCoV antibody titres and that in some cats vaccine failure was probably due to pre-existing infection.

Animals↗
PubMed1997

[Sudden death of Alpine cattle in the canton Graubünden].

The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-disciplinary approach. Certain small rivers and ponds located in the affected Alpine pastures in the areas of Misox, Rheinwald and Engadin provide favourable habitats for the growth of hepatotoxic cyanobacteria, particularly during long periods of hot and dry weather. As cattle frequently take up water from these sources, the toxins produced by cyanobacteria may lead to lethal poisonings that are typically associated with hemorrhagic liver necrosis. The latest reported case of cyanobacteria poisoning of Alpine cattle occurred during the summer of 1996. Further animal losses may be avoided by the implementation of appropriate pasture management schemes. To identify sites of potential hazards to human or animal health, we have developed a sensitive screening assay for the detection of cyanobacteria hepatotoxins in algae and water samples.

Animals↗
PubMed1997

[Determination of the potential doubling time of tumors using bromodeoxyuridine and flow cytometry].

Tumor growth-rate affects prognosis and treatment planning. The injection of bromodeoxyuridine in dogs and cats permits determination of the potential doubling time following a biopsy of neoplastic tissue and flow cytometric analysis. The essentially non-invasive method gives exact results within 24 hours. This report describes a method to measure potential tumor doubling time of different tumors, and presents results of canine and feline tumors.

Animals↗
PubMed1996

Gene-representing cDNA clusters defined by hybridization of 57,419 clones from infant brain libraries with short oligonucleotide probes.

Diverse biochemical and computational procedures and facilities have been developed to hybridize thousands of DNA clones with short oligonucleotide probes and subsequently to extract valuable genetic information. This technology has been applied to 73,536 cDNA clones from infant brain libraries. By a mutual comparison of 57,419 samples that were successfully scored by 200-320 probes, 19,726 genes have been identified and sorted by their expression levels. The data indicate that an additional 20,000 or more genes may be expressed in the infant brain. Representative clones of the found genes create a valuable resource for complete sequencing and functional studies of many novel genes. These results demonstrate the unique capacity of hybridization technology to identify weakly transcribed genes and to study gene networks involved in organismal development, aging, or tumorigenesis by monitoring the expression of every gene in related tissues, whether known or still undiscovered.

Base Sequence↗
PubMed1996

The prevalence of Helicobacter pylori positivity in asymptomatic children of different ethnic backgrounds living in the same country.

OBJECTIVE: To measure the prevalence of Helicobacter pylori seropositivity in a population of apparently healthy children of different ethnic backgrounds, matched for age and socioeconomic background, who were born and continue to reside in the same country. DESIGN: The presence of Helicobacter pylori specific IgG antibodies was determined during pre-surgery blood analysis in 883 symptom-free children, aged from 1 months to 17 years, who belong to different ethnic populations and were admitted for elective minor surgery. The different groups were matched for age and socioeconomic background. RESULTS: Seventy-two children (8.2%) had a positive titer for Helicobacter pylori. We observed a significant difference in the prevalence of Helicobacter pylori positivity between symptom-free Caucasian and non-Caucasian children (p < 0.001). However, no difference could be observed between the non-Caucasian groups (p > 0.8). CONCLUSION: We conclude that significant differences exist in the prevalence of Helicobacter pylori infection between asymptomatic children of different ethnic backgrounds, despite the fact that all investigated subjects were born in Belgium and have been living in this country ever since. Whether this difference is caused by an unknown environmental factor or an, until now, unrecognized genetic predisposition still needs to be evaluated.

Adolescent↗
PubMed1996

Symptomatology of Helicobacter pylori infection in children.

In a retrospective evaluation we reviewed the symptomatology of 143 children (age 2-15 years, mean 8.9 years) who were referred to us for upper gastrointestinal endoscopy because of recurrent abdominal pain with a duration of 6 weeks or longer. Helicobacter pylori infection was diagnosed in 36 out of 143 patients (25.2%). No statistically significant differences could be detected between the symptoms experienced by the 36 H. pylori-infected children and those experienced by the remaining 107 H. pylori-negative pediatric patients (p = 0.18-0.60). We conclude that no specific symptoms are associated with H. pylori gastritis in children. Our observations suggest that the recurrent abdominal complaints found in children with H. pylori infection seem to be caused by the secondary gastroduodenal pathology, rather than by H. pylori infection itself.

Abdominal Pain↗
PubMed1996

Uterine serosal inclusion cysts in a bitch.

A six-year-old, pluriparous German shepherd dog bitch was presented with an abnormal vaginal discharge of several weeks' duration. Clinical signs and radiographic and ultrasonographic findings supported an initial diagnosis of segmental cystic endometrial hyperplasia, and ovariohysterectomy was performed. Macroscopically, the uterus appeared normal except for one large and several smaller cysts attached to its antimesometrial side. These cysts were restricted to a small area of the left uterine horn. The histological diagnosis was serosal inclusion cysts. The clinical findings, gross pathology and histopathology are described and discussed.

Animals↗
PubMed1996

[Endocrinologic and pathologic findings in ornamental birds with polyostotic hyperostosis].

Polyostotic hyperostosis is a finding that is often seen on x-rays in companion birds. Hyperestrogenism might be a causative for polyostotic hyperostosis. The purpose of this study was to compare endocrinologic and pathologic findings in birds with polyostotic hyperostosis. Thirty-five affected and three control birds were examined. Blood samples were taken for endocrinologic statement (estrone, estradiol, testosterone and estrone sulfate) and the values were compared with the pathologic findings. In the present study the comparison of endocrinologic and pathologic findings did not reveal any significant results supporting the hypothesis that polyostotic hyperostosis was caused by hyperestrogenism.

Animals↗
PubMed1995

Tomato contains two differentially expressed genes encoding B-type phytochromes, neither of which can be considered an ortholog of Arabidopsis phytochrome B.

Tomato (Solanum lycopersicon L.) contains two B-type phytochrome genes (PHYB1 and PHYB2). Fragments of these two PHYB were cloned following amplification by the polymerase chain reaction of a portion of their relatively well conserved 5' coding regions. Polypeptides encoded by these gene fragments exhibit 90% sequence identity. These two PHYB are independently expressed in organ-specific fashion. In mature plants, PHYB2 mRNA is most abundant in fruit and PHYB1 mRNA in expanded leaves. A phylogenetic analysis fails to establish which tomato PHYB is orthologous to either Arabidopsis PHYB or PHYD, the latter being a second B-type phytochrome. Instead, this analysis indicates that following the divergence of the Solanaceae and Brassicaceae from one another, a PHYB gene duplicated independently in each lineage. Consequently, Arabidopsis PHYB mutants cannot be considered strictly equivalent to the tomato tri mutants, which appear to be mutated at the PHYB1 locus. Similarly, other putative PHYB mutants might not be equivalent to those described for Arabidopsis and tomato. This situation complicates efforts to determine 'PHYB function' because there might be no one answer to this question.

Amino Acid Sequence↗
PubMed1995

The long-term effect of a partial whey hydrolysate formula on the prophylaxis of atopic disease.

At the age of 5 years, the prevalence of atopic manifestations was analysed in 58 formula-fed "at risk" infants because of a history of atopic disease in at least two first degree relatives. Infants were randomly assigned to receive either a partial whey-hydrolysate formula (n: 28) or a regular cow's milk formula (n: 30) during the first 6 months of life; thereafter, feeding was unrestricted. Only non-breastfed infants were included. The groups did not differ in risk factors or in known confounding factors possibly influencing the incidence of manifestations suggestive of atopic disease. At 6 months, the prevalence of cow's milk protein (CMP) sensitivity was significantly decreased in the hydrolysate group (7% versus 43%; P: 0.002). At the age of 12 (21% versus 53%; P: 0.029), 36 (25% versus 57%; P: 0.018) and 60 months (29% versus 60%; P: 0.016) there was still a significant difference in the number of atopic manifestations, if calculated cumulatively. There was no difference between the groups if only the new cases after the age of 6 months were considered. Eczema was less frequent in the whey-hydrolysate group, but only during the 1st year of life, suggesting a decreased prevalence of CMP sensitivity. During the first 6 months, diarrhoea of non-infectious origin occurred in 8/30 infants (27%) of the adapted formula group, and in no infant in the hydrolysate group. "Colic as single manifestation" was considered of "allergic" origin in 1/28 infants in the hydrolysate group, and in 4/30 infants in the adapted formula group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The contribution of specific immunoglobulin M antibodies to the diagnosis of Helicobacter pylori infection in children.

OBJECTIVE: To evaluate the diagnostic value of specific immunoglobulins G and M in the detection of Helicobacter pylori infection. METHODS: Sera from 68 H. pylori-infected children and 35 H. pylori-negative children (aged 1-15 years) were examined using recent-generation serum enzyme-linked immunosorbent assay (ELISA) tests (Malakit Helicobacter pylori series; Biolab, Limal, Belgium). RESULTS: All of the investigated children had positive values for immunoglobulin G antibodies. However, anti-H. pylori-specific immunoglobulin M could be detected only in 19 (27.9%) of the 68 children. When compared with the 13C-urea breath test, these findings represent sensitivity, specificity and positive and negative predictive values of 27.9, 100, 100 and 41.7%, respectively, for the serum ELISA test for the detection of H. pylori-specific immunoglobulin M compared with 100.0, 97.2, 98.5 and 100.0%, respectively, for the Malakit for the detection of specific immunoglobulin G antibodies. CONCLUSION: Although H. pylori-specific immunoglobulin G has been established as a reliable indicator of active H. pylori infection, using the Malakit for the detection of H. pylori-specific immunoglobulin M does not seem to be of major value in the diagnosis of H. pylori infection in children.

Adolescent↗