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Biomedical subjects

M Ganter

Publications and source records attributed to M Ganter.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Foot and mouth disease in sheep and goats].

Small ruminants play an important role in the epidemiology and transmission of Foot-and-Mouth Disease (FMD). The main reasons therefore are: FMD is difficult to diagnose as infected sheep not always show typical clinical symptoms or as the cardinal signs mimicked other diseases. Sheep and goats may be carriers. Infected herds which practice transhumance or are nomadic can spread the infection to other herds long before diagnose of the disease is established. Shipping and trade with live sheep and goats is much more common world wide than in other FMD susceptible species. Lack of registration of all sheep and goat herds (especially of small hobby herds) and lack of individual identifications signs (ear tags) may result in incomplete control measurements under FMD conditions. Basing on published experiences with the actual FMD epidemic in the UK and basing on the own experiences with the restrictions to prevent from spreading of the FMD from the UK to Germany suggestions for future disease control are made.

Animals↗
PubMed2000

Virtual reality for dermatologic surgery: virtually a reality in the 21st century.

In the 20th century, virtual reality has predominantly played a role in training pilots and in the entertainment industry. Despite much publicity, virtual reality did not live up to its perceived potential. During the past decade, it has also been applied for medical uses, particularly as training simulators, for minimally invasive surgery. Because of advances in computer technology, virtual reality is on the cusp of becoming an effective medical educational tool. At the University of Washington, we are developing a virtual reality soft tissue surgery simulator. Based on fast finite element modeling and using a personal computer, this device can simulate three-dimensional human skin deformations with real-time tactile feedback. Although there are many cutaneous biomechanical challenges to solve, it will eventually provide more realistic dermatologic surgery training for medical students and residents than the currently used models.

Computer Simulation↗
PubMed2000

Creating fast finite element models from medical images.

The procedure for creating a patient-specific virtual tissue model with finite element (FE) based haptic (force) feedback varies substantially from that which is required for generating a typical volumetric model. In addition to extracting geometrical and texture map data to provide visual realism, it is necessary to obtain information for supporting a FE model. Among many differences, FE-based VR environments require a FE model with appropriate material properties assigned. The FE equation must also be processed in a manner specific to the surgical task in order to maximize deformation and haptic computation speed. We are currently developing methodologies and support software for creating patient-specific models from medical images. The steps for creating such a model are as follows: 1) obtain medical images and texture maps of tissue structures; 2) extract tissue structure contours; 3) generate a 3D mesh from the tissue structure contours; 4) alter mesh based on simulation objectives; 5) assign material properties, boundary nodes and texture maps; 6) generate a fast (or real-time) FE model; and 7) support the tissue models with task-specific tools and training aids. This paper will elaborate on the above steps with particular reference to the creation of suturing simulation software, which will also be described.

Computer Graphics↗
PubMed2000

[Efficacy of a flock-specific pseudotuberculosis vaccine in goats].

In a flock with 33 adult goats repeated abscesses due to Pseudotuberculosis occurred. For the owners refused a sanitation program based on testing and removing, the goats were vaccinated with a flock specific, whole-cells lysate vaccine of Corynebacterium pseudotuberculosis. Partly simultaneously or 14 days later vaccinations against Clostridiosis (Covexin8) and against Erysipelas (Erysorb plus) were performed at different application sites. After a twofold basal vaccination in a 4 week interval the goats were revaccinated in half year intervals. The local (swelling at the injection site) and systemic reactions (temperature elevation, antibody activity) after vaccination and the clinical status of the flock (core body temperature, adspection, abscesses, lymph nodes) were investigated over a period of two years. Due to the vaccination program the rate of new cases of clinical pseudotuberculosis were reduced significantly. In the last 3 months of the investigation no clinical cases occurred. The vaccination with the C. pseudotuberculosis-vaccine induced a significant increase in antibody activities detected by ELISA. Due to interaction of maternal antibodies with the antigen of the vaccine lambs should be vaccinated at the earliest at an age of 9 weeks. Vaccinating the C. pseudotuberculosis-vaccine separately in time to Covexin8 and Erysorb plus induced with increasing numbers of revaccinations higher antibody activities against C. pseudotuberculosis than simultaneous vaccinations with all the 3 vaccines. But this difference does not justify the additional expense of separate vaccinations in time. Despite considerable local and systemic reaction the C. pseudotuberculosis-vaccine is recommended to support sanitation programs.

Animals↗
PubMed2000

[Blood gas values in healthy sheep and in sheep with lung diseases] .

In 24 healthy and 101 sheep with different lung diseases like catarrhalic pneumonic bronchopneumonia, lung abscesses, lung worm infections, Maedi and Sheep Pulmonary Adenomatosis (SPA) in arterial and venous samples blood gas analysis was performed. The alveolo-arterial-oxygen-difference was the most sensitive parameter to detect impaired ventilation, it was 11.40 +/- 6.39 mm Hg in healthy sheep. Global insufficiency occurred mainly in sheep with SPA and in mixed infections of SPA with Maedi.

Abscess↗
PubMed1999

Combined ultramicrotomy for AFM and TEM using a novel sample holder.

A new sample holder that allows combined microtomy for atomic force microscopy (AFM) and transmission electron microscopy (TEM) is described. The main feature of this sample holder is a small central part holding the sample. This central part fits into the head of an atomic force microscope. AFM measurements can be performed with a sample mounted in this central part of the sample holder. This makes the alignment of a microtomed bulk sample unnecessary, and offers the opportunity of an easy and fast combined sample preparation for AFM and TEM.

Microscopy, Atomic Force↗
PubMed1999

[Investigations on manifestations of vitamin E and selenium deficiency in sheep and goats].

In a prospective study from 1991-1998 plasma concentrations of alpha-Tocopherole (VitE) and Selenium (Se) were analysed in 125 sheep and 32 goats with generalised motor disturbances or elevated plasma-activities of Creatine-Kinase (CK). VitE-values < 1.0 mg/l and Se-values < 0.08 mg/l were regarded as deficiency. Diagnosis of pathological manifestations was based on blood enzyme values. CK-values in plasma > 300 U/l or Aspatate-Amino-Transferase (ASAT) > 150 U/l were regarded as myopathy, Glutamat-Dehydrogenase-values > 25 U/l indicated a hepatopathy. 92 (74%) sheep and 10 (31%) goats showed VitE and/or Se deficiency. There were no principal differences in the frequencies of myopathies (67%) and hepatopathies (46%) between pure VitE deficiencies or pure Se deficiencies or combinations of both deficiencies. In VitE deficiency and in the combinations of VitE and Se deficiency the elevations of the enzyme activities were more pronounced than in Se deficiency. The lethality was significantly higher in combined VitE + Se deficiencies (73%) than in pure VitE or Se deficiencies (35%). Combined VitE + Se deficiencies occurred more frequent in lambs (53%) and was often accompanied by anaemia (29%) and hypoproteinaemia (32%). The diagnostic reliability of ASAT and GLDH for the detection of VitE and Se deficiency was better than CK. Diagnostic and therapeutic strategies in flock diseases are discussed.

Animals↗
PubMed1999

Fast finite element modeling for surgical simulation.

Given the geometric complexity of anatomical structures, realistic real-time deformation of graphical reconstructions is prohibitively computationally intensive. Instead, real-time deformation of virtual anatomy is roughly approximated through simpler methodologies. Since the graphical interpolations and simple spring models commonly used in these simulations are not based on the biomechanical properties of tissue structures, these "quick and dirty" methods typically do not accurately represent the complex deformations and force-feedback interactions that can take place during surgery. Finite element (FE) analysis is widely regarded as the most appropriate alternative to these methods. Extensive research has been directed toward applying the method to modeling a wide range of biological structures, and a few simple FE models have been incorporated into surgical simulations. However, because of the highly computational nature of the FE method, its direct application to real-time force-feedback and visualization of tissue deformation has not been practical for most simulations. This limitation is primarily due to the overabundance of information provided by the standard FE approaches. If the mathematics is optimized to yield only the information essential for the surgical task, computation time can be drastically reduced. Parallel computation and preprocessing of the model before the simulation begins can also reduce the size of the problem and greatly increase computation speed. Such methodologies are being developed in a combined effort between the Human Interface Technology Laboratory (HIT Lab) and the Mechanical Engineering Department of the University of Washington. We have created computer demonstrations which support real-time interaction with simple finite element soft tissue models. In collaboration with the Division of Dermatology, a real-time skin surgery simulator is being developed using these fast FE methods.

Computer Simulation↗
PubMed1999

[Investigations on the dependence of hematologic and blood chemical parameters on the age of health lambs--a contribution to the definition of reference values in sheep].

Haematological and biochemical examinations were carried out in 284 clinically healthy lambs aged from birth to nine month. The 122 male and 164 female animals belonged to the following breeds: German blackheaded mutton sheep (n = 114), Merino (n = 21), Frisian milksheep (n = 98), Texel (n = 31), Bentheimer landrace (n = 16) and Leine sheep (n = 5). The lambs were selected from a larger number of probationers by use of outlier tests. No differences were found between sexes for any of examined parameters. For the period from two to eight weeks of age breed differences could be proven for glutamate dehydrogenase and creatinin. Many parameters showed a strong dependence on the age of the lambs in a linear or polynomial function. While lymphocytes, protein, urea, creatinin, 3-hydroxybutyrate and copper increased, bilirubin, glucose, calcium, inorganic phosphate and the activities of alkaline phosphatase and gamma-glutamyl-transferase decreased with age. Body weight had no influence on any examined parameter within the age dependence. Reference values (limits) are defined for healthy lambs and for healthy ewes, summarized from former studies.

Aging↗
PubMed1998

Detection of Mycoplasma hyopneumoniae in bronchoalveolar lavage fluids of pigs by PCR.

In the present investigation we developed a method for the detection of Mycoplasma hyopneumoniae in bronchoalveolar lavage fluid (BALF) of pigs by PCR with a primer pair flanking a DNA fragment of 853 bp specific for M. hyopneumoniae. Several methods were tested to eliminate the amplification inhibitors present in BALFs. The best results were obtained by the extraction of the DNA from the BALFs. By the PCR performed with the extracted DNA, 10(2) CFU of M. hyopneumoniae could be detected in 1 ml of BALF from specific-pathogen-free swine experimentally inoculated with M. hyopneumoniae. DNA from 11 other mycoplasma species and 17 cell-walled bacterial species colonizing the respiratory tracts of pigs was not amplified. In a field study BALFs from 40 pigs from farms with a history of chronic pneumonia were tested for M. hyopneumoniae by cultivation and by PCR (i) with BALFs incubated in Friis medium and (ii) with DNA extracted from the BALFs. In addition, PCR was performed with postmortem lung washings from 19 of the 40 pigs, and immunofluorescence tests were carried out with sections of lungs from 18 of the 40 pigs. M. hyopneumoniae could not be detected in 18 of the 40 pigs by any of the five methods tested. The remaining 22 pigs showed a positive reaction by the PCR with DNA extracted from the BALFs and variable positive reactions by the other tests. A complete correspondence could be observed between the immunofluorescence test result and the result of PCR with DNA. The investigation shows that the PCR with DNA extracted from BALFs is a suitable technique for the sensitive and specific in vivo detection of M. hyopneumoniae.

Animals↗
PubMed1998

[Clinical and laboratory diagnostic findings in chronic pleuropneumonia of swine].

In the course of an experimental study 12 pigs were infected intrabronchially with the pathogen of infectious porcine pleuropneumonia, Actinobacillus pleuropneumoniae. All animals survived the acute stage of infection due to the application of subtherapeutic doses of antibiotics. After infection all of the animals showed clinical signs of acute pneumonia with an elevation of body temperature to about 41 degrees C. Bronchoalveolar lavage fluid (BALF) was taken every week endoscopically. An increase of neutrophil granulocytes could be observed at day 7 and 14 after infection. In parallel, a clear granulocytosis and a shift to the left of the nuclei was observed at day 7. Comparing the methods for detection of Actinobacillus pleuropneumoniae serological assays like the complement-fixation assay (CFA) and enzyme-linked immunosorbent assay (ELISA) as well as immunofluorescence in lung tissue and BALF were more sensitive than cultural isolation from lung tissue, tonsils and BALF.

Actinobacillus Infections↗
PubMed1998

[Clinical findings and differential diagnosis in ketosis and hypocalcemia in sheep].

Clinical and laboratory examinations were carried out in a prospective study from 1978 to 1998 on 454 spontaneously diseased sheep of different breeds aged 2-8 years. Three groups of sheep were defined by plasma concentrations of 3-hydroxybutyrate (3-OHB) and calcium. 214 ewes suffered from ketosis (pregnancy toxaemia, 3-OHB > 1.6 mmol/l), 195 ewes and 5 rams suffered from hypocalcaemia (Ca < 2.0 mmol/l), and 40 ewes were sick with booth diseases simultaneously. Clinical findings differ only slightly in all three groups. In ketosis the time until the onset of clinical signs and the duration of the disease is somewhat longer, while locomotion disturbances are less severe than in hypocalcaemia and in the combination of both. In individual cases a differential diagnosis is not possible on the basis of clinical findings, and also acetonuria is not a reliable criterion. Therefore, a therapy is suggested to treat all three possible forms of disease: daily oral application of Na-propionate, Ca-lactate and K-chloride, and additional subcutanous injection of Ca-borogluconate, vitamin D3, alpha-Tocopherol and selenium at the beginning of the disease. Pathogenesis of both diseases are discussed, recommendations for feeding management are given.

Animals↗
PubMed1997

[Clinical lung function investigations in sheep].

In 144 clinical healthy and 97 sick sheep pneumotachographic investigations were performed. In 119 sheep the diagnoses "healthy" based on adspection, auscultation and palpatory percussion. In 25 additional healthy and in the sick animals the diagnoses based on clinical, endoscopical, serological, parasitological, and in 82 animals also pathomorphological findings. According to these diagnoses the animals were divided into the following groups: G = healthy, K = catarrhal purulent bronchopneumonia, E = suppurative pneumonia, W = verminous pneumonia, M = Maedi, MKE = Maedi + catarrhal purulent or suppurative pneumonia, MAKE = Maedi + Adenomatosis + catarrhal purulent or suppurative pneumonia, AKE = Adenomatosis + catarrhal purulent or suppurative pneumonia, and FAKE = animals of the AKE group at an earlier date of investigation. In all sheep respiration rate, tidal and minute volumes, forced tidal volume, peak flow and resistance were measured with the portable pneumotachograph Flowscreen. Tidal and minute volumes and flow rates depended at rest as well as after forced ventilation essentially from the respiratory rate and from the body weight of the animals. The average individual coefficients of variation of repeated measurements of healthy animals were between 21% and 36%. Only in tidal volume after forced ventilation (10%) and in the resistance (18%) the individual coefficients of variations were lower. In 57% of the animals with Lung Adenomatosis resistance-values over 0.4 kPa*s/l were measured, but in 94% of the sheep without adenomatosis resistance-values remained under this limit.

Animals↗
PubMed1997

[Bronchoalveolar lavage on pig breeding farms].

In 182 pigs lung lavage was performed using a endotracheal tube and a catheter. The collected bronchoalveolar lavage fluid (BALF) was examined microbiologically. With decreasing numbers alpha-hämolytic Streptococci, Bordetella bronchiseptica, Haemophilus parasuis, Pasteurella multocida were cultured. Actinobacillus pleuropneumoniae was isolated from 3 BALFs. In one farm piglets were lavaged routinely for monitoring of the lung health status.

Actinobacillus pleuropneumoniae↗
PubMed1996

Induction of protective immunity by aerosol or oral application of candidate vaccines in a dose-controlled pig aerosol infection model.

In order to outline basic concepts for the design of a bacterial aerosol infection model, the development of a pig model with Actinobacillus pleuropneumoniae is described. First, reproducibility of aerosol parameters should be maintained by optimizing generating and sampling conditions. Survival rates of the chosen strain must be predictable. Secondly, inhalation conditions for the recipients have to be standardized to enable the determination of deposition sites and the dose administered. Subsequently, dose-response relationship should be evaluated to find a suitable challenge dose. Furthermore, it seems necessary to establish methods to obtain local specimens for determination of the local immune responses. The present study demonstrates that after aerosol challenge pigs were completely protected after inhalation and partially protected after oral application of A. pleuropneumoniae vaccines and describes techniques to administer bacteria in a dose-dependent, viable way. Using the infection model several stages of the disease from acute pleuropneumonia to chronic infection can be induced for research purposes.

Actinobacillus Infections↗
PubMed1996

Ketamine and its use in the pig. Recommendations of the Consensus meeting on Ketamine Anaesthesia in Pigs, Bergen 1994. Ketamine Consensus Working Group.

Ketamine, when used as a mono-anaesthetic, does not appear to induce surgical anaesthesia in the pig. The addition of other drugs such as opioids, benzodiazepines and alpha 2-adrenergic agonists deepens anaesthesia and enables major surgery to be performed. A decision-tree for the rational use of ketamine for both short and long-term anaesthesia in the pig under three different levels of procedure severity is presented.

Anesthesia↗
PubMed1996

[Demonstration of pneumonia in swine as a constant problem: culture and immunofluorescence microscopic studies of bronchioalveolar lavage (BAL) and serological findings].

Bronchoalveolar lavage was performed in 128 pigs from five fattening units showing acute pneumonia (48 animals), subclinical purulent pneumonia (17 animals), and chronic purulent pneumonia (63 animals). These samples were investigated for bacteria. Additionally immunofluorescence microscopy as well as serological investigations were performed to detect antibodies against several bacteria and viruses. Pasteurella multocida could be detected in more than a half of the samples of pigs with acute pneumonia. Bordetella bronchiseptica and mycoplasmas were isolated in a lower amount. Probably these bacteria infected the pigs of at least one herd after a primary infection with influenza virus because (i) influenza virus could be detected in three of four animals investigated for influenza virus by culture methods, (ii) the virus could be detected in one third of the animals investigated for by immunofluorescence microscopy, and (iii) antibodies against influenza virus could be detected in almost all animals. From pigs with subclinical purulent pneumonia Bordetella bronchiseptica as the only bacterial lung pathogen could be isolated exclusively from nearly each sample. From the samples of pig suffering from chronic purulent pneumonia first of all Bordetella bronchiseptica, Pasteurella multocida and different mycoplasma species could be detected. Using cultural methods Actinobacillus pleuropneumoniae could be isolated from six samples only, in contrast to frequent positive reactions against Actinobacillus pleuropneumoniae antigens obtained by immunofluorescence microscopy and CFT.

Actinobacillus Infections↗