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Biomedical subjects

H Lutz

Publications and source records attributed to H Lutz.

At least 109 records · Page 6Linked to original sources

Granulocytic ehrlichiosis in two dogs in Switzerland.

This case report describes two dogs with granulocytic ehrlichiosis. Dog 1 was a male Labrador retriever with clinical signs of lymphosarcoma. Dog 2 was a female Airedale terrier, whose clinical signs included apathy, pyrexia, diarrhea, and abdominal pain. Examination of blood smears revealed Ehrlichia organisms in the neutrophils of both dogs. There was thrombocytopenia in both dogs, and dog 2 also had leukopenia. In both dogs, bands of identical length were amplified from DNA of leukocytes via nested PCR. The bands had identical nucleotide sequences, which differed from the gene sequences of Ehrlichia equi and E. phagocytophila in three and two positions, respectively. Interestingly, the nucleotide sequence of the 16S rRNA was 100% homologous to that of a human granulocytic ehrlichia.

Animals↗

Nucleotide and predicted peptide sequence of feline interleukin-12 (IL-12).

Feline Interleukin-12 (IL-12) is a heterodimeric glycoprotein consisting of two disulfide linked subunits of about 40 kD (p40) and 35 kD (p35). It is a pleiotropic cytokine mediating biological activities on T- and NK-cells. One important function is the induction of a Th1 immune response. Here we report the cloning and sequencing of feline IL-12, the expression of the p40-protein in E. coli and production of monoclonal antibodies. At the nucleotide level, feline IL-12 shows between 87-90%, on the amino acid level between 82-87% identity to the bovine and human IL-12, respectively.

Amino Acid Sequence↗

[Short evaluation of the QBC-Vet Autoread System].

The QBC-Vet Autoread-System (QBC = Quantitative Buffy Coat) is an advanced version of the OBC-Vet Haematology-System, to which an automatic reader and a printer have been added. In addition to the determination of haematocrit, haemoglobin, MCHC, white blood cell, granulocyte, lympho-/monocyte and platelet counts, measurement of eosinophils and neutrophils in dogs, and the estimation of reticulocytes and nucleated red blood cells in both dogs and cats are possible. The aim of this study was to evaluate the QBC-Vet Autoread-System with respect to its suitability in veterinary practice. Samples collected from 213 mostly ill animals were analysed and the results compared with conventionally measured values. The system was found to be easy both in handling and interpretation of results. Accuracy was found to be good for the majority of the parameters (correlation coefficients: haematocrit r > 0.96, WBC r > 0.89). The printed buffy coat profile was found to be very useful to verify accuracy of results immediately and to prevent misinterpretations. Although this is a preliminary study with a small number of samples, the QBC-Vet Autoread-System was found to be a true improvement over the older system and will be very useful in veterinary practices.

Animals↗

[Placebo-controlled double-blind study on the efficacy of a paramunity inducer in the treatment of naturally FeLV-infected cats].

The study involved 120 cats, of which 60 were treated with Baypamun HK and 60 cats received a preparation of virus free cell culture medium. Therapeutic efficacy was determined by monitoring the general status of health, body weight, skin, lymph nodes, oral cavity, the presence of the p27 antigen and the FeLV p27 antigen concentration in serum. No statistically significant differences between both groups could be demonstrated neither for clinical nor for virologic parameters. Remission of the viremia occurred in 11.7% of the cats treated with Baypamun HK and in 6.7% of the cats treated with placebo. The FeLV p27 antigen level decreased by an average of 7.2% with Baypamun HK and by an average of 5.1% with placebo.

Adjuvants, Immunologic↗

[Serologic studies on the occurrence of bovine ehrlichiosis in the cantons Zürich, Schaffhausen, Thurgau, St. Gallen and Obwalden].

The purpose of this study was to investigate the geographical distribution of bovine ehrlichiosis in the Cantons Zürich, Schaffhausen, Thurgau, St. Gallen and Obwalden. To this end, an indirect immunofluorescence assay was established. The diagnostic sensitivity and specificity was estimated to be close to 100% based on the results obtained with several reference sera from the US National Veterinary Services Laboratories and the seroconversion panels of 20 heifers and cows. Blood samples from 2557 healthy cattle were tested for antibody response against Ehrlichia phagocytophila. Ninety-three animals (3.6%) were seropositive with titers ranging from 1:20 to 1:320. Most of the positive animals were found in the area north of lake Zürich spanning to the german border, in the area between Walensee and Bad Ragaz, the Rhine valley and Klein Melchtal. All seropositive animals had grazed on pastures or alps with a favourable biotope for the tick Ixodes ricinus.

Animals↗

Flow cytometric detection of activation-induced cell death (apoptosis) in peripheral blood lymphocyte subpopulations from healthy cats.

Human peripheral blood lymphocytes (PBLs) from healthy individuals are resistant to in vitro-induced apoptosis, but activated human lymphocytes can readily undergo apoptosis. The activation of human lymphocytes is accompanied by the upregulation of a cell surface antigen, the major histocompatibility complex (MHC) class II-antigen. Only a minority of PBLs are usually MHC class II-antigen-positive in healthy humans. In contrast, in healthy cats the majority of feline PBLs are MHC class II-antigen-positive. We have, therefore, investigated the sensitivity of feline peripheral blood lymphocytes obtained from specified pathogen free (SPF) cats to the induction of apoptosis. Feline PBLs from SPF cats (n = 16) and human PBLs from healthy donors (n = 2) were isolated. After short-term culture, cells were examined for the presence of fragmented DNA as a result of apoptosis by a DNA agarose gel electrophoresis method and for the presence of DNA double strand breaks by in situ 3' end labeling. In addition, relative DNA content per cell was flow cytometrically determined using propidium iodide (PI) or 7-actinomycin-D (7-AAD) and apoptotic cells were identified on the basis of a reduced DNA content. Cell surface antigens and cellular DNA were analyzed simultaneously by dual-color flow cytometric analyses in order to study lymphocyte subsets. Single- and dual-color analysis revealed that, in contrast to human lymphocytes, feline lymphocytes rapidly underwent apoptosis when cultured overnight in medium. Furthermore, the majority of apoptotic cells was found within the MHC II-positive cell subject.

Animals↗

A canine distemper virus epidemic in Serengeti lions (Panthera leo).

Canine distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti-Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.

Amino Acid Sequence↗

Prevalence of antibodies to feline parvovirus, calicivirus, herpesvirus, coronavirus, and immunodeficiency virus and of feline leukemia virus antigen and the interrelationship of these viral infections in free-ranging lions in east Africa.

While viral infections and their impact are well studied in domestic cats, only limited information is available on their occurrence in free-ranging lions. The goals of the present study were (i) to investigate the prevalence of antibodies to feline calicivirus (FCV), herpesvirus (FHV), coronavirus (FCoV), parvovirus (FPV), and immunodeficiency virus (FIV) and of feline leukemia virus (FeLV) antigen in 311 serum samples collected between 1984 and 1991 from lions inhabiting Tanzania's national parks and (ii) to evaluate the possible biological importance and the interrelationship of these viral infections. Antibodies to FCV, never reported previously in free-ranging lions, were detected in 70% of the sera. In addition, a much higher prevalence of antibodies to FCoV (57%) was found than was previously reported in Etosha National Park and Kruger National Park. Titers ranged from 25 to 400. FeLV antigen was not detectable in any of the serum samples. FCoV, FCV, FHV, and FIV were endemic in the Serengeti, while a transient elevation of FPV titers pointed to an outbreak of FPV infection between 1985 and 1987. Antibody titers to FPV and FCV were highly prevalent in the Serengeti (FPV, 75%; FCV, 67%) but not in Ngorongoro Crater (FPV, 27%; FCV, 2%). These differences could be explained by the different habitats and biological histories of the two populations and by the well-documented absence of immigration of lions from the Serengeti plains into Ngorongoro Crater after 1965. These observations indicate that, although the pathological potential of these viral infections seemed not to be very high in free-ranging lions, relocation of seropositive animals by humans to seronegative lion populations must be considered very carefully.

Africa, Eastern↗

[Detection of feline coronavirus using RT-PCR: basis for the study of the pathogenesis of feline infectious peritonitis (FIP)].

The aim of this study was to further investigate the pathogenesis and epidemiology of feline coronavirus (FCoV)-infections and among others to determine the prognostic value of a positive result in the RT-PCR for FCoV in serum samples collected from cats with abdominal signs. Viral RNA was isolated from 100 microl of serum and subsequently amplified by a nested RT-PCR using primers binding to a highly conserved region of the 3'-end of the FCoV-genome. Sixty-three serum samples collected from 62 cats with abdominal signs were examined by RT-PCR and the clinical outcome was followed up. Four of these cats with a positive PCR-result are healthy more than 70 months after the collection of the blood sample. It can be concluded that viremia with FCoV does not necessarily lead to FIP and death. With respect to diagnosing FIP, a positive FCoV-RT-PCR is of low prognostic and diagnostic value. It can not be recommended to use this assay as sole indication to euthanize cats. Further studies will have to be carried out to demonstrate if the prognostic and diagnostic value of this PCR-assay in other samples such as peripheral blood mononuclear cells is more reliable. However, this method was found to be an important tool to further study the pathogenesis and epidemiology of FIP.

Animals↗

[Quantification of proviral FIV DNA using competitive PCR].

Quantification of provirus copies is important in the context of different biological questions. The most reliable approach for DNA quantification is a PCR based on coamplification of two templates of similar length, the target sequence and the reference template, sharing the same primer recognition sequences. During the amplification, the two templates compete for the same primer set (competitive PCR, or cPCR) AND consequently amplify at the same rate independently of the number of cycles. The amplified products can be distingushed by their different lengths. After densitometrical analysis, the proviral copy number of experimentally feline immunodeficiency virus infected cats could be calculated, since a known amount of reference template was used. The method described here proved to be very sensitive (10 copies for the competitor-DNA) and was used to quantitate the proviral load during several experiments in which the influence of periodical immunestimulations and the effect of vaccines on the virus load was studied.

Animals↗

[A new hereditary disease in Braunvieh cattle in Switzerland: spinal demyelinization (SDM) in calves that remain in lateral recumbency].

Clinical, laboratory and histopathological findings are described in ten Braunvieh calves with Spinal Dysmyelination (SDM). Characteristically, immediately after birth the animals were normally alert but remained in lateral recumbency with opisthotonus, spastic hind limbs, partially increased spinal reflexes and were unable to stand or support themselves. Histological examination of the spinal cord revealed a bilateral symmetrical reduction of myelin. Means of differentiating between SDM and other conditions, in particular spinal muscular atrophy (SMA) are discussed.

Animals↗

[The "activated coagulation time (ACT)": two simple screening methods for evaluating coagulation disorders in dogs].

The use of the activated coagulation time (ACT) for testing the intrinsic coagulation is well established among veterinary practitioners in the USA. The advantage of the ACT compared to other coagulation tests is its ease to be performed under practice conditions. The ACT may be measured manually or instrumentally. The reference range of our instrumental measurement is between 90 and 120 seconds (median 105 seconds), of the manual measurement at room temperature between 115 and 145 seconds (median 125 seconds). Advantages of the instrumental method are the smaller amount of blood (0.4 ml versus 2.0 ml) necessary to perform the test, and the smaller potential for errors by unexperienced examiners. The spread is comparable between the two methods. The most important cause of false results is poor venipuncture technique: traumatic venipuncture will trigger the coagulation cascade already during venipuncture causing an artificially shortened ACT.

Animals↗

[Liberation into the wild of wild felines--danger of the release of virus infections].

There are several felidae amongst the numerous endangered species. Means of aiding survival are the reintroduction to the wild of animals bred under the auspices of man and their relocation from densely populated to thinly populated areas. It is unlikely that the dangers of such reintroduction or relocation projects have been examined sufficiently in respect to the risks of virus infections confronting individuals kept in zoos or similar situations. This report presents three examples to illustrate that accidental virus infections may be expected to occur when relocating and reintroducing wild cats. The first example is the reintroduction of captive snow leopards. Zoo bred snow leopards may be infected with FIV, a virus infection that is highly unlikely to occur in the original himalayan highlands of Tibet and China. A second example is of several cases of FIP that occurred in European wild cats bred in groups in captivity. The third example mentioned is the relocation of lions from East Africa where all the commonly known feline viruses are wide-spread to the Etosha National Park. In the latter, virus infections such as FIV, FCV and FPV do not occur. The indiscriminate relocation and reintroduction of the wild cats mentioned here harbours a potential of undesirable consequences.

Animals↗

Panleukopenia-like syndrome of FeLV caused by co-infection with FeLV and feline panleukopenia virus.

To study the effect of interferon on feline leukemia virus (FeLV) infection, 30 specific pathogen free (SPF) cats were infected with the apathogenic FeLV A Glasgow. Unexpectedly, between 5 and 8 weeks after FeLV infection, all 19 cats with persistent FeLV infection but not the FeLV-negative cats died from a panleukopenia-like syndrome. No feline panleukopenia virus (FPLV) antigen was found in feces by latex agglutination, enzyme-linked immunosorbent assay (ELISA) or immunoelectron microscopy. No enteropathogenic bacteria were found. Histopathology revealed changes resembling those of FPLV infection such as destruction of crypts and pancytopenia of bone marrow. Neither clinical signs nor seroconversion to FPLV could be induced by transmitting intestinal extracts to two SPF cats. However, FPLV antigen was demonstrated by immunofluorescence assay in intestinal cryostat sections of diseased animals. FPLV could also be demonstrated in intestinal extracts by immunoelectron microscopy, by latex agglutination and ELISA after anti-FPLV antibodies were removed from immune-complexed FPLV by ultracentrifugation over a CsCl gradient at pH 2.0. From these experiments it was concluded that the panleukopenia-like syndrome of FeLV may not be caused by FeLV alone but at least in some cases by co-infection with FeLV and FPLV. In addition, some form of 'cooperation' between FeLV and FPLV must be postulated because neither virus alone induced symptoms.

Animals↗

Serological diagnosis of feline immunodeficiency virus infection using recombinant transmembrane glycoprotein.

We developed an antibody detection enzyme-linked immunosorbent assay (ELISA) using recombinant surface (SU), transmembrane (TM) and capsid (CA) antigens of feline immunodeficiency virus (FIV) expressed in Escherichia coli. The three antigens were tested with sera collected from experimentally infected cats in order to follow the course of seroconversion and of the antibody levels throughout the infection. An early and marked increase of TM antibodies was observed. Antibodies to TM were demonstrated at high levels throughout the observation period. The immune response to SU and to CA was less pronounced and in some cats the level of antibodies to SU and CA tended to decline 6 months after infection. In addition, 413 FIV negative and positive cat sera were tested in order to define for each antigen the diagnostic sensitivity, specificity and efficiency. TM showed the highest diagnostic sensitivity (98%) while its specificity was 97%. Its diagnostic efficiency of 97% was better than that of SU and CA and exceeded that of tests utilizing conventionally grown and gradient purified FIV. Therefore, recombinant TM can be considered a very important antigen for FIV ELISA testing. An interesting perspective is offered in the combination of TM with other recombinant antigens in a dot assay form.

Animals↗

FIV vaccine studies. I. Immune response to recombinant FIV env gene products and outcome after challenge infection.

We have vaccinated five groups of cats (n = 25) four times with five preparations of recombinant feline immunodeficiency virus (FIV) env gene products; one group (n = 7) served as control. The vaccine formulations were as follows: (1) envelope glycoprotein of FIV Zurich 2 (FIV Z2) expressed in a Baculovirus system and isolated by gel electroelution (denatured form); (2) insect cells expressing FIV Z2 glycoprotein; (3) envelope glycoprotein of a Boston strain (FIV Bangston) expressed in insect cells and isolated by gel electroelution (denatured form); (4) glycosylated Bangston envelope protein made in insect cells and isolated in a native form; (5) non-glycosylated Bangston envelope protein made in Escherichia coli. All cats were challenged with 20 50% cat infective doses (CID50) of FIV Z2 previously titrated in cats. All vaccinated cats developed high enzyme-linked immunosorbent assay (ELISA) antibodies to the homologous antigen; crossreactivity to heterologous antigens was seen at a lower level. Virus neutralizing antibodies (tested with Petaluma virus) reached titers up to 32. After challenge, all cats seroconverted (as judged by anti gag antibodies in Western blot) and became infected (as judged by virus isolation and/or polymerase chain reaction) between 4 and 11 weeks with the exception of one cat. It is concluded that it is relatively easy to induce high ELISA antibody titers using recombinant env gene products, ELISA antibody titers do not correlate with virus neutralization or with protection.

Animals↗

FIV vaccine studies. II. Clinical findings, hematological changes and kinetics of blood lymphocyte subsets.

Five groups of cats were vaccinated with different recombinant feline immunodeficiency virus (FIV) SU vaccines expressed either in Escherichia coli or in the Baculovirus system. In Part I of this series, we described the humoral immune response and outcome of intraperitoneal FIV challenge exposure. Additionally, all cats were monitored for clinical and hematological changes and the course of blood lymphocyte subsets. These results are described in this present paper. A great increase of antibodies was found after vaccination with different recombinant FIV antigens, which did not protect the cats from intraperitoneal FIV challenge infection. This observation was paralleled by an increase of eosinophils during vaccination which was even more pronounced after challenge infection. After FIV challenge, infection lymphadenopathy, gingivitis, pharyngitis, changes in total leukocytes and neutrophils and a decrease in the CD4+:CD8+ ratio were found in cats of all groups and were considered as a sign of the FIV infection taking place, independent of vaccination. The following observations suggest that in these cats a TH2-like immune response was elicited: the high counts of eosinophils, the nature of antigen and adjuvant (aluminium hydroxide) and the high amounts of antigens used for immunization. Clearly, this type of immune response did not protect the animals from intraperitoneal FIV challenge infection.

Animals↗