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Biomedical subjects

H Lutz

Publications and source records attributed to H Lutz.

At least 73 records · Page 4Linked to original sources
PubMed1999

Direct determination of selenium and other trace elements in serum samples by ICP-MS.

Selenium belongs to a group of trace elements of special interest in biological samples for clinical diagnosis. Selenium has antioxidizing functions and is essential for providing the organism with triiodothyronine produced from thyroxine. Among several analytical techniques used to determine the Se concentration in serum, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) has been used in the past because of its high sensitivity. Interference problems originating from different ions on the major Se isotopes have been described to be a limiting factor for the direct determination of Se in these matrices. Standard addition calibration or isotope dilution is often required to overcome carbon-enhanced ionisation effects in biological sample matrices. In most cases, the typical serum sample volume which is available for the analysis is limited to 0.5 ml or less, making multiple sample preparation for standard addition calibration impractical. Isotope dilution requires enriched isotopes and substantial sample preparation. Furthermore, the approximate Se concentration in every sample has to be known to adjust the appropriate amount of spike to each sample. Matrix matching with methanol has been described to overcome ionisation effects but we found limiting factors of this application when other trace elements are also determined within one sample run. This paper describes an effective sample preparation method which allows the direct determination of Se in serum without limiting the analytical capabilities for the additional determination of Al, Cu, Ni, Co, Cd, Mn and Zn in a single sample run by ICP-MS. Optimization procedures are presented and results of the analysis of reference samples are discussed, with a comparison of more than 150 serum data with those obtained by the GF-AAS method.

Animals↗
PubMed1999

The role of polymerase chain reaction and its newer developments in feline medicine.

We give a brief overview on the principles of the polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR), quantitative competitive PCR and real-time PCR (TaqMan technology). The literature dealing with PCR and its role in the diagnosis, pathogenesis and research of infectious diseases of the domestic cat is reviewed. Cross-contaminations which occasionally occur during handling of amplified DNA may be an important problem in the PCR laboratory. In many infectious diseases, PCR results are difficult to interpret as their predictive positive and negative values are not always known. Newer assays, such as TaqMan procedures, are becoming increasingly reliable and cost-effective. It can be expected that additional knowledge on how to interpret PCR results will soon be available.

Animals↗
PubMed1999

Molecular evidence of coinfection of ticks with Borrelia burgdorferi sensu lato and the human granulocytic ehrlichiosis agent in Switzerland.

Adult Ixodes ricinus ticks were collected in Switzerland and tested for the presence of coinfection with Borrelia burgdorferi sensu lato and the human granulocytic ehrlichiosis (HGE) agent by real-time PCR. Of 100 ticks, 49% were positive for B. burgdorferi and 2% were positive for the HGE agent. The two HGE agent-positive ticks were also found to be positive for B. burgdorferi.

Animals↗
PubMed1999

Quantitative evaluation of ehrlichial burden in horses after experimental transmission of human granulocytic Ehrlichia agent by intravenous inoculation with infected leukocytes and by infected ticks.

This paper describes the kinetics of the human granulocytic ehrlichiosis agent in the blood of horses experimentally infected by intravenous inoculation with infected leukocytes and by infected ticks as evaluated by using a real-time quantitative PCR assay. The data obtained indicated differences in the period of incubation, duration of rickettsemia, and initial and maximal ehrlichial loads between the two routes of infection.

Animals↗
PubMed1999

Serological evidence of infection with Ehrlichia spp. in red foxes (Vulpes vulpes) in Switzerland.

Serum samples from 1,550 red foxes in Switzerland were tested for antibodies to the agents of canine granulocytic and monocytic ehrlichiosis by an indirect immunofluorescent technique. Forty-four (2.8%) of the samples were positive for Ehrlichia phagocytophila, which is an antigen marker for granulocytic ehrlichiosis. In contrast, none of the samples had antibodies specific to Ehrlichia canis, the agent of monocytic ehrlichiosis.

Animals↗
PubMed1999

Quantitative real-time PCR for detection of members of the Ehrlichia phagocytophila genogroup in host animals and Ixodes ricinus ticks.

A TaqMan PCR was established for identification and quantitation of members of the Ehrlichia phagocytophila group in experimentally infected cows and in Ixodes ricinus ticks. The TaqMan PCR identified a 106-bp section of the 16S rRNA gene by use of a specific fluorogenic probe and two primers. This technique was specific for members of the E. phagocytophila group, which include E. phagocytophila, Ehrlichia equi, and the agent of human granulocytic ehrlichiosis. The TaqMan system identified 10 copies of a cloned section of the 16S rRNA gene of E. phagocytophila. The sensitivity and specificity of the TaqMan PCR were similar to those of conventional nested PCR. The numbers of ehrlichiae in leukocytes of the two cows experimentally infected with E. phagocytophila were measured daily by TaqMan PCR and had a course similar to that of the percentages of infected leukocytes determined daily by light microscopy. The prevalence of infected free-living ticks, which were collected from areas where bovine ehrlichiosis is endemic and from regions with sporadic occurrences of granulocytic ehrlichiosis in dogs and horses, was identical as determined by nested PCR and TaqMan PCR.

Animals↗
PubMed1999

Evidence of the human granulocytic ehrlichiosis agent in Ixodes ricinus ticks in Switzerland.

A total of 1,667 Ixodes ricinus ticks were collected from five regions in Switzerland where there have been sporadic occurrences of granulocytic ehrlichiosis in dogs and horses. The ticks were examined for rickettsiae of the Ehrlichia phagocytophila group via nested PCR. Twenty-one ticks (1.3%) were positive; 3 (0.5%) were nymphs, 6 (1.3%) were adult males, and 12 (1.9%) were adult females. The number of positive ticks varied with the stage of development and with the geographical origin. Nucleotide sequencing of the isolated PCR products identified these products as part of the 16S rRNA gene of Ehrlichia. In addition, these products had 100% homology with the agent of human granulocytic ehrlichiosis. The occurrence of this agent in I. ricinus in Switzerland presents a potential danger of transmission of granulocytic ehrlichiosis to dogs, horses, and humans.

Animals↗
PubMed1999

Viral infections in free-living populations of the European wildcat.

While the importance of viral infections is well studied in domestic cats, only limited information is available on their occurence and prevalence in the European wildcat (Felis silvestris silvestris). The aim of this study was to determine the prevalence of antibodies to feline coronavirus (FCoV), calicivirus (FCV), herpesvirus (FHV), parvovirus (FPV), immunodeficiency virus (FIV), leukemia virus (FeLV), and FeLV antigenemia in 51 European wildcat sera. Samples were collected between 1996 and 1997 from wildcat populations in France, Switzerland, and Germany. Antibodies to FCoV were detected in two cats (4%) and FCoV RNA was detected in feces of one of these two cats. Antibodies to FCV, FHV and FPV were found at relatively low frequencies of 16%, 4%, and 2%, respectively. Antibodies to FIV were not detected. Although antigen and antibodies to FeLV were detected in 49%, and 75%, respectively, no evidence of FeLV-associated pathology was found. From the low prevalence of FCoV, FCV, FHV and FPV infections and from the fact that the European wildcats live solitarily, it was concluded that these viral infections do not spread readily within a population. Therefore, it may be assumed that release into the wild of European wildcats bred in captivity would not bring about a high risk of introducing of these viral infections to the free-ranging wildcats. As an exception, wildcats should be tested for absence of FIV infection before release if they were at risk to acquire this infection from domestic cats.

Animals↗
PubMed1999

[Investigations on the treatment of cerebrospinal nematode infections in goats].

In 17 goats the therapeutical outcome of cerebrospinal nematodiasis, a parasitic infection in the central nervous system with the nematode Elaphostrongylus cervi, is described. The diagnosis was made on the basis of physical findings and cerebrospinal fluid eosinophilia. The therapy was based on the administration of a non-steroidal antiinflammatory drug (flunixin meglumine) and two anthelmintics (fenbendazol, ivermectin) for five days. The response to therapy was documented immediately and 30 days after therapy and by owners report up to 30 months. Eleven goats (64.7%) showed an improvement of the neurological signs directly after therapy. Three had a complete recovery. Signs of a light and middle ataxie were still present in 6 and 2 goats, respectively. Six recumbent goats (35.3%) had to be euthanasied because of a non-therapeutical response. This study has shown a clinical impression of successful use of flunixin meglumine, fenbendazole and ivermectin in goats with light to middle neurological signs. The goats could accommodate the remaining ataxia without showing a reduced production. Goats with high neurological deficits could not be successful treated based on the high degree of the neurological damage.

Animals↗
PubMed1999

[An unusual cause of gastrointestinal hemorrhage: pseudoaneurysm of the gastroduodenal artery in chronic pancreatitis].

Pseudoaneurysm of the peripancreatic arteries is a typical cause of gastrointestinal bleeding (GIB) in patients with chronic pancreatitis. 1-10% of chronic pancreatitis are associated with an a pseudoaneurysm, especially of the splenic or gastroduodenal artery. Endoscopy often is not successful in finding the cause of bleeding. Sonography, especially color Doppler ultrasound, is the best diagnostic tool, indicating the need for celiac angiography. We report on a 59-year-old woman with recurrent severe GIB since 1995. In 1998 another bleeding occurred and sonography showed a pseudoaneurysm of the gastroduodenal artery. Typical criteria are an echo-free, pulsatile lesion with an ring-like border. Color Doppler proves a turbulent perfusion inside and shows the feeding vessel. A transcatheter embolization with stainless steel coils was successful, six months later the pseudoaneurysm was mainly obliterated.

Aneurysm↗
PubMed1998

Female cats have lower rates of apoptosis in peripheral blood lymphocytes than male cats: correlation with estradiol-17beta, but not with progesterone blood levels.

During earlier study, we quantified by flow cytometry the rate of apoptotic feline lymphocytes after overnight culture. We found evidence that the sex of the animals influences the rate of apoptosis, intact females showed lower rates of apoptosis in lymphocytes cultured overnight than castrated male cats. This observation was also confirmed for cats that were previously experimentally infected with the feline immunodeficiency virus (FIV). In an attempt to find an explanation for these sexually determined differences, plasma estradiol-17beta and progesterone levels were measured by radio-immuno assay in the blood of these cats. The hormone levels were analyzed with respect to the rate of lymphocyte apoptosis. As expected, castrated males had lower blood levels of estradiol and progesterone than females. However, no overall correlation was found between hormone blood levels and rate of apoptosis under non-stimulating conditions. Interestingly, the rate of apoptosis found in lymphocytes collected from females and stimulated overnight in phytohaemaglutinin-containing medium, showed a strong negative correlation with the estradiol levels in the blood of these cats. To our knowledge, this is the first confirmation that estradiol in physiological concentrations may protect peripheral lymphocytes from apoptosis after stimulation. No correlation was found in male cats. In conclusion, these observations broaden the list of sexually determined differences of the immune system, sex and sex hormones predispose males and females for certain immune responses and dysfunctions. The present observations have to be taken into account when designing or interpreting experiments on apoptosis and, for example, evaluating the influence of a preexisting FIV infection on the rate of apoptosis. It would be highly advisable to include only spayed cats in studies on the immune system so as to minimize the influence of sex hormones.

Animals↗
PubMed1998

Treatment of feline leukemia virus-infected cats with paramunity inducer.

Two placebo-controlled double-blind trials were performed to determine the therapeutic efficacy of the paramunity inducer, Baypamun in feline leukemia virus (FeLV)-infected cats under controlled conditions. In the first study, 120 cats were involved; 60 cats were treated with Baypamun and 60 with a placebo preparation of virus-free cell culture medium. Dosage and administration of the drug over a 7-week period were performed according to the instructions given by the company. Remission of viremia occurred in 12% and 7% of the cats treated with Baypamun and placebo, respectively. This difference was not statistically significant. In the second study, 30 naturally infected cats were treated in a placebo-controlled double-blind trial. In total, 20 immunological, clinical, laboratory, and virological parameters were examined. No statistically significant differences could be demonstrated between Baypamun and placebo application. Therefore, FeLV infection was not influenced by Baypamun treatment.

Adjuvants, Immunologic↗
PubMed1998

Feline immunodeficiency virus (FIV) infection leads to increased incidence of feline odontoclastic resorptive lesions (FORL).

Feline odontoclastic resorptive lesions (FORL), previously known as 'neck lesions,' are commonly known in domestic, but also in non-domestic cats. They are characterized by odontoclastic resorptive processes, which take place at the dental root and at the periodontium. Chronic inflammation of gingiva and periodontium is believed to be an important etiological factor in the development of FORL. In this context, various feline viruses have been discussed to play a relevant role in the pathogenesis of these lesions. The aim of this project was to determine in a blinded study the incidence of FORL in 10 cats which were infected for several years with feline immunodeficiency virus (FIV), but were otherwise free of feline viral infections (feline leukemia virus, feline calicivirus, feline herpesvirus, feline parvovirus, feline coronavirus, feline syncytium-forming virus). Nine age-matched controls were kept under identical conditions, but free of FIV. Subgingival resorptive lesions were found in six of 10 FIV-positive cats, but in three of nine controls only. FIV-positive cats had significantly more often gingivae with an increased tendency for bleeding upon probing than FIV-negative cats (p=0.0055), and they had slightly more often hyperplastic gingivae (p=0.0867). In conclusion, signs characteristic of FORL such as subgingival lesions, granulomatous or hyperplastic gingivae with a tendency for bleeding, were found significantly more often in FIV-positive cats than in the controls (p=0.0198). Therefore, it was concluded that FIV infection is an important factor for the occurrence of FORL, possibly through immune suppression or changes of the (sub)gingival micro-environment. However, non-infected control cats also showed some evidence of FORL in the absence of all tested viral infections. Therefore, factors other than viral infections must also play a role in the development of FORL in cats.

Animals↗
PubMed1998

Experimental infection of four horses with Ehrlichia phagocytophila.

Four clinically healthy horses which were negative for antibodies to Ehrlichia phagocytophila, the agent of bovine ehrlichiosis, were infected experimentally with E phagocytophila-containing bovine leucocytes, administered intravenously. The horses were examined daily for four weeks, and blood samples were collected daily for cytological, haematological and biochemical examination and for a nested polymerase chain reaction (PCR). An indirect immunofluorescence test was used to determine when the horses seroconverted and the duration of positive titres. There were no abnormal clinical, haematological or biochemical findings in any of the four horses and all the PCRs yielded negative results. However, all the horses seroconverted with reciprocal titres of up to 1280, and the positive titres persisted for up to five months.

Animals↗
PubMed1998

Experimental oral transmission of Ehrlichia phagocytophila to calves.

Three groups of four calves were used to determine whether Ehrlichia phagocytophila could be transmitted orally to calves via infected milk. Groups 1 and 2 consisted of four-week-old calves and group 3 of newborn calves. The calves in group 1 were fed for several days with milk from cows infected experimentally with E phagocytophila. The calves in groups 2 and 3 were fed 200 ml of whole blood containing E phagocytophila organisms; for group 2 the blood was added to milk before being fed, and for group 3 the blood was added to colostrum before being fed within three hours after birth. Blood samples for haematological, serological and cytological examination, and for polymerase chain reaction (PCR) were collected from all the calves, starting on the first or only day of administration and then every four days for four weeks. The calves of groups 1 and 2 showed no clinical, haematological or serological changes, and there was no direct or indirect evidence of the agent. In contrast, all the calves in group 3 had mild pyrexia and seroconverted on day 8, and in one of them E phagocytophila organisms were visible in leucocytes, and the PCR on the buffy coat was positive on day 8.

Animals↗
PubMed1998

Partial protection by vaccination with recombinant feline immunodeficiency virus surface glycoproteins.

In an effort to induce a strong immune response that might protect against feline immunodeficiency virus (FIV) challenge infection, three groups of five specified pathogen-free (spf) cats each were immunized subcutaneously with different FIV antigen preparations. Immunizations were done at weeks 0, 2, and 4 with 100 microg of recombinant SU from an FIV Zurich 2 (FIV Z2) strain expressed by E. coli (group 1) or the baculovirus expression system (groups 2 and 3) adsorbed on aluminum hydroxyde and administered with QS-21 (groups 1 and 2) or Freund's adjuvant together with the recombinant nucleocapsid protein (protein NC) of rabies virus (group 3). Protein NC was described to act as an exogenous superantigen. Group 3 cats demonstrated the highest detectable antibody response to the vaccine antigen as determined by ELISA and Western blot analysis. All immunized cats together with seven control animals were challenged with 20 CID50 of cat lymphocyte-grown FIV Z2 3 weeks following the last immunization. Whereas virus was readily recovered from peripheral blood lymphocytes of seven of seven nonvaccinated control cats following this challenge dose, virus was not recovered from two cats of groups 1 and 2. All cats in groups 2 and 3 showed a provirus load significantly decreased to 3% of that of controls up to week 8 after challenge infection. Eleven of 15 vaccinated cats and 5 of 7 control cats developed virus-neutralizing antibodies by week 8 after challenge infection. The two cats negative on virus isolation remained seronegative, developed no detectable virus-neutralizing activities, but were repeatedly positive in provirus PCR. Moreover, starting at week 1 after challenge, both cats showed the lowest provirus load in their respective groups. These results indicate that immunization with recombinant FIV SU in conjunction with appropriate adjuvants may lead to partial protection against FIV challenge infection.

Adjuvants, Immunologic↗
PubMed1998

Serological evidence of human granulocytic ehrlichiosis in Switzerland.

To investigate whether human granulocytic ehrlichiosis (HGE) is prevalent in Switzerland, 1515 human serum samples from individuals with different risks for tick exposure were tested for antibodies to Ehrlichia phagocytophila, a surrogate marker of the agent of HGE. The distribution of titres showed marked differences between sera of individuals with no or low risk for tick exposure and those with a high risk. The results of serological testing provided evidence of HGE in Switzerland as well as evidence of two types of coinfections: those with the agent of HGE and Borrelia burgdorferi, and those with the agent of HGE and the central European tickborne encephalitis virus.

Antibodies, Bacterial↗