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A Mathis

Publications and source records attributed to A Mathis.

At least 55 records · Page 3Linked to original sources
PubMed1997

Two Encephalitozoon cuniculi strains of human origin are infectious to rabbits.

The microsporidian Encephalitozoon cuniculi can infect a wide variety of mammals including man. In this study, E. cuniculi isolates of animal origin were compared with 6 isolates obtained from HIV-infected patients. Based on results of Western blot analysis, random amplified polymorphic DNA (RAPD) and the sequence of the rDNA internal transcribed spacer (ITS) the isolates were classified into 3 groups with the repeated element 5'GTTT-3' in the ITS being a reliable genetic marker. Five isolates from Swiss patients were found to be homologous to isolates from Swiss rabbits (strain I). The sixth isolate from a patient from Mexico differed by all methods and could be attributed to E. cuniculi strain III that has been described from 2 dogs from the USA. All of these isolates were distinguished from isolates from blue foxes from Norway (strain II). Intraspecific nucleotide divergence of the SSU rRNA gene of E. cuniculi belonging to the 3 strains was in the same low range (0.00-0.15%) as was found for the corresponding sequence of 2 E. hellem isolates. Groups of 2 rabbits were infected by oral inoculation of 10(7) E. cuniculi spores (2 isolates from strain I of human and rabbit origin, 1 from strain III) as shown by antibody responses and the re-isolation of the parasites from brain material. The results provide further evidence that per oral transmission of the parasite between various hosts is feasible.

Animals↗
PubMed1997

Simplified sample processing combined with a sensitive one-tube nested PCR assay for detection of Pneumocystis carinii in respiratory specimens.

Early diagnosis of Pneumocystis carinii pneumonia, a life-threatening complication in immunosuppressed patients, may lower morbidity and mortality. We have developed a one-tube nested PCR assay for the detection of P. carinii in respiratory specimens. Four primers were selected from the sequence of the small-subunit rRNA gene of P. carinii to amplify a 265-bp fragment, and their specificities for P. carinii were confirmed by both theoretical evaluations (by computer-assisted comparison with the sequences in GenBank) and empirical evaluations (with DNA from medically important fungi and diagnostic samples). The assay was optimized for routine diagnostic use. Processing of the clinical samples is rapid and simple (digestion with proteinase K directly in PCR buffer at room temperature in the presence of 10% Chelex 100 and no further purification steps). Bovine serum albumin (1 mg/ml) and glycerol (10%) in the amplification buffer reduced the number of samples inhibitory to the PCR, as assessed by control reactions containing a size-modified target. A total of 749 clinical specimens (312 bronchoalveolar lavage, 403 sputum or induced sputum, and 34 other specimens) from 507 patients (295 human immunodeficiency virus [HIV]-infected and 164 non-HIV-infected patients and 48 patients whose HIV status was unknown) were tested by PCR, and the results were compared with those of an indirect immunofluorescence assay (IFA). Concordant results were obtained for 732 samples (646 negative and 86 positive). There were 17 discrepant results: 12 were PCR positive and IFA negative, and 5 were PCR negative and IFA positive. After resolution of the discrepant results by review of the patients' clinical data, the sensitivity and specificity were 94.8 and 99.1%, respectively, for PCR and 93.8 and 100%, respectively, for IFA. In conclusion, the short procedure time and the technical ease of this PCR assay render it suitable for implementation in routine diagnostic laboratories.

Animals↗
PubMed1996

Isolates of Encephalitozoon cuniculi from farmed blue foxes (Alopex lagopus) from Norway differ from isolates from Swiss domestic rabbits (Oryctolagus cuniculus).

Encephalitozoon cuniculi has a wide host range among mammals, but whether it represents a homogeneous species is a subject of controversy. We have isolated, cultivated (in human MRC-5 cells) and, for the first time, characterized by immunological and molecular biological methods four isolates of E. cuniculi from Norwegian blue foxes with a history of encephalitozoonosis. The isolates were compared with nine isolates from domestic rabbits from Switzerland. Two E. cuniculi subtypes were identified according to their host species. A 5'-GTTT-3' tetranucleotide repeat was present twice in the rDNA intergenic spacer in all isolates from foxes as opposed to three times in all isolates from rabbits. Furthermore, random amplified polymorphic DNA analysis showed one polymorphic band among the subtypes, and Western-blot analysis using serum from an infected fox discriminated between the two subtypes on the basis of their banding patterns in the ranges of 31-33 and 38-40 kDa. The 5'-GTTT-3' tetranucleotide repeat is a valuable genetic marker for these two subtypes of E. cuniculi and will be of use in continued studies on the molecular epidemiology of this parasite.

AIDS-Related Opportunistic Infections↗
PubMed1996

An improved test system for PCR-based specific detection of Echinococcus multilocularis eggs.

For the sensitive detection of eggs of Echinococcus multilocularis in fox faeces by PCR we have evaluated a method based on the previous concentration of helminth eggs by a combination of sequential sieving of faecal samples and flotation of the eggs in zinc chloride solution. The eggs were microscopically detected in the fractions retained in 40 and 20 microns mesh sieves. DNA of the taeniid eggs retained in the 20 microns sieve was obtained after alkaline lysis and PCR was performed using E. multilocularis species-specific primers. Compared to the parasitological findings after examination of the small intestines of the foxes, the specificity of the PCR was 100% (no false-positive result with 20 foxes free of E. multilocularis) and the sensitivity was 94% (33 positive results from total 35 foxes proven to be infected with E. multilocularis). Both false-negative results were obtained with faeces from foxes harbouring immature worms. Using faecal volumes between 2 and 20 ml, no inhibition of PCR was observed as was demonstrated by the amplification of size-modified target in parallel reactions. The tests were undertaken with fresh faeces stored in 70% ethanol, but egg detection by PCR was also possible after inactivation of eggs by freezing the faeces at -80 degrees C for one week or by incubation at +70 degrees C for 2 h.

Animals↗
PubMed1996

Immunologic and molecular characteristics of Encephalitozoon-like microsporidia isolated from humans and rabbits indicate that Encephalitozoon cuniculi is a zoonotic parasite.

To assess the zoonotic potential of Encephalitozoon-like microsporidia, we isolated and cultivated spores from specimens of urine, respiratory secretions, and stool from six patients infected with human immunodeficiency virus and from nine rabbits. Because spores of Encephalitozoon-like species are indistinguishable by microscopy, we characterized the isolates by western blot analysis and by restriction enzyme analysis of the small subunit (SSU) rDNA after amplification by the polymerase chain reaction. We identified Septata intestinalis in one patient and Encephalitozoon hellem in two symptomatic patients. Encephalitozoon cuniculi was found in all rabbits and in three patients. One of these patients had clinical manifestations of infection with this parasite (severe interstitial pneumonitis). We observed abatement of symptoms and cessation of parasite excretion when these patients were treated with albendazole. Our findings suggest that E. cuniculi may be pathogenic in humans and that it is a zoonotic parasite.

AIDS-Related Opportunistic Infections↗
PubMed1996

[PCR for detection and characterization of parasites (Leishmania, Echinococcus, Microsporodia, Giardia)].

The application of PCR for the diagnosis and the characterisation of parasites is discussed using four examples. (1) A PCR assay that was developed for the detection of Leishmania was shown to be as highly sensitive as in vitro cultivation of the parasites from lymph node aspirates and bone marrow biopsies. (2) Single eggs of Echinococcus multilocularis can principally be detected and identified by PCR. However, a cumbersome sample preparation is inevitable in order to remove PCR-inhibitory substances present in fox faeces. (3) Analysis of the amplified SSU rRNA gene of Encephalitozoon-like isolates from humans, rabbits and farm foxes confirmed for the first time that E. cuniculi-isolates from humans and animals are indistinguishable and that they are of importance as opportunistic parasites in HIV-infected patients. (4) Swiss isolates of Giardia originating from humans, calves, sheep and a dog could be allocated into three distinct genetic groups by analysing several PCR-amplified genes that encode for variant-specific surface proteins. There was no evidence for the presence of host-specific genotypes.

AIDS-Related Opportunistic Infections↗
PubMed1995

Sequence of RNA 2 of a nematode-transmissible isolate of tobacco rattle virus.

Tobacco rattle virus (TRV) isolate PPK20 is transmitted by Paratrichodorus pachydermus nematodes. The factor(s) determining vector transmissibility has been shown to be located on TRV RNA 2. Sequence determination revealed that PPK20 RNA 2 contains three open reading frames encoding the coat protein (cp) and proteins with molecular masses of 29.4 and 32.8 kDa. The 29.4 and 32.8 kDa protein-coding genes showed no significant sequence similarity to any other known tobravirus gene. A full-length cDNA of PPK20 RNA 2 cloned between the 35S promoter and nos terminator infected plants when co-inoculated with PPK20 RNA 1. Deletions in the reading frames of the 29.4 and 32.8 kDa proteins revealed that these sequences are dispensable for replication of PPK20 RNA 2 in plants. Subgenomic RNAs for translation of cp and the putative 29.4 and 32.8 kDa proteins were detected in infected leaves. The possible role of PPK20 RNA 2 non-structural genes in TRV vector transmission is discussed.

Amino Acid Sequence↗
PubMed1995

PCR and in vitro cultivation for detection of Leishmania spp. in diagnostic samples from humans and dogs.

A PCR assay for the diagnosis of leishmaniosis was developed by using primers that were selected from the sequence of the small-subunit rRNA gene. The assay was optimized for routine diagnostic use. Processing of the clinical samples is rapid and simple (lysis of erythrocytes in Tris-EDTA buffer, digestion with proteinase K directly in PCR buffer, and no further purification steps). Furthermore, an internal control is included in every specimen in order to detect the presence of PCR inhibitors. The PCR was compared with diagnostic in vitro cultivation of promastigote stages for the detection of Leishmania spp. in clinical specimens from humans and dogs with a tentative diagnosis of leishmaniosis. PCR and cultivation gave identical results with all but 1 of the 95 specimens from humans. The PCR result in this case was false negative, possibly because of unequal apportionment of this sample. With 10 skin biopsies from six patients with cutaneous leishmaniosis, the sensitivity was 60%. For six human immunodeficiency virus-positive patients with visceral leishmaniosis, all bone marrow biopsies and 7 of 11 whole blood samples (after isolation of leukocytes by Ficoll-Paque) were positive in both tests. PCR detected one more case with the use of 500 microliters of whole blood with direct lysis of the erythrocytes in Tris-EDTA buffer. With dog lymph node aspirates, the sensitivity was 100% (16 of 16 samples) for both methods; furthermore, PCR was positive for 5 of 13 whole blood samples from dogs with leishmaniosis. The specificity of the PCR was 100% (70 specimens from patients without leishmaniosis). This PCR assay proved to be feasible as a routine diagnostic test, being reliable and faster than in vitro cultivation.

Animals↗
PubMed1994

Detection of vascular endothelial growth factor messenger RNA and vascular endothelial growth factor-like activity in proliferative diabetic retinopathy.

OBJECTIVE: To study the involvement of eight angiogenic growth factors that have been identified so far in the literature, especially vascular endothelial growth factor, in proliferative diabetic retinopathy. METHODS: Samples of neovascular membranes were obtained from diabetic patients; these samples, excised at vitrectomy, were used to study the expression of messenger RNA of the angiogenic factors by using the method of the reverse transcription-polymerase chain reaction. Vitreous aspirates that were taken from diabetic and control patients were used to quantify vascular endothelial growth factor-like activity with a competitive radioreceptor assay. RESULTS: Of the eight angiogenic factors studied, vascular endothelial growth factor was the only one that was always expressed in the samples of neovascular membranes. Furthermore, vascular endothelial growth factor receptor-binding activity was greater in vitreous aspirates that were obtained from diabetic patients than in samples that were taken from control patients (P < .01). CONCLUSION: Vascular endothelial growth factor seems to be an appropriate candidate for mediating retinal diabetic neovascularization.

Adolescent↗
PubMed1994

Improving clinical documentation quality.

A multidisciplinary documentation quality team was appointed four years ago with the charter to revise the admission nursing assessment form, eliminate the traditional handwritten nursing care plan, establish a method to utilize standards of care and standards of practice as the basis for individualizing the patient plan of care, establish flexible charting systems for specialty sections, and develop clear and concise guidelines to accompany specialty area documentation systems. This article provides an overview of the project and the outcomes realized through commitment, collaboration, and cooperation.

Data Collection↗
PubMed1994

Heterologous encapsidation of recombinant pea early browning virus.

The coat protein gene of pea early browning virus (PEBV) was replaced with that of another tobravirus, tobacco rattle virus (TRV strain PPK20). The recombinant virus multiplied efficiently in the systemic host Nicotiana benthamiana and, on the local lesion host Phaseolus vulgaris, produced symptoms typical of PEBV rather than TRV showing that viral coat protein is not a determinant for lesion morphology. Both viral RNAs were encapsidated by TRV coat protein although the shorter particles (encapsidated RNA-2) did not form a discrete population. Evidence is presented to suggest involvement of nucleotide sequences upstream of the coat protein gene in virus particle assembly.

Antigens, Viral↗
PubMed1993

Susceptibility of transgenic tobacco plants expressing tobacco rattle virus coat protein to nematode-transmitted and mechanically inoculated tobacco rattle virus.

Transgenic Samsun NN tobacco plants expressing the coat protein of tobacco rattle virus were exposed to mechanical leaf inoculation with tobacco rattle virus and to viruliferous trichodorid vector nematodes. Whereas plants were resistant to mechanical inoculation the vector nematodes successfully transmitted tobacco rattle virus to the roots as well as to the leaves of these plants. It is suggested that transgenic resistance is overcome either because vector nematodes inject relatively large numbers of virus particles into a cell or because they inject destabilized particles. The results indicate that coat protein-mediated resistance is unlikely to be of value for controlling tobacco rattle virus in field crops.

Animals↗