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Biomedical subjects

K Otto

Publications and source records attributed to K Otto.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Evaluation of the antinociceptive effect of xylazine after epidural administration in dogs under general anesthesia with isoflurane].

Seven dogs anaesthetized with isoflurane in oxygen (1.9 Vol.-% ET) were examined before and after lumbosacral injection of xylazine (0.25 mg/kg) into the epidural space. Over a 240 minute period the dogs were first stimulated in a visceral manner (extension of the colon descendens by a balloon-catheter) every 15 minutes. In a second part, the dogs were stimulated somatically by pressure to the interdigital skin of a hindlimb. Heart rate and mean arterial pressure were used to determine the analgesic properties of epidurally injected xylazine. Furthermore, plasma xylazine concentration was controlled in both series. Before epidural anaesthesia, heart rate and mean arterial pressure increased during stimulation significantly in both groups. After epidural injection of xylazine, hemodynamic reactions were distinctly diminished, in the somatically stimulated group more than in the viscerally stimulated group. Up to 30 minutes after epidural injection, plasma xylazine concentrations of about 100 ng/ml were found in both groups. Up to 60 minutes after epidural injection, plasma xylazine concentrations of more than 60 ng/ml still were found. From the 120th minute on, xylazine concentration decreased below 30 ng/ml. From these results, it can be concluded that there is a well-suited analgesic effect of epidurally applicated xylazine for approximately 240 minutes.

Analgesia↗
PubMed1997

[Pain conditioned changes in animal behavior].

Other than in human beings, only nonverbal methods including motor reflexes, autonomic reflexes, neuroendocrine responses, and changes in overall behavior are available for pain evaluation in various animal species. Pain-like changes in most of these variables can be induced by approaching and handling conscious animals rendering increases in heart rate, blood pressure, and plasma catecholamine levels, etc. to nonspecific indicators for pain. In recent years, changes in overall behavior have been used for assessment of animal pain. Multiple Pain Discomfort Scales (MPDS) have been established for objective evaluation of behavioral changes in response to both noxious stimulation and analgesic drug therapy. These Multiple Pain Discomfort Scales include species specific behavioral patterns, making this approach a potentially more specific indicator of animal pain. This, however, needs to be confirmed by further extended studies in the near future.

Animals↗
PubMed1996

[Pharmacokinetics and effects of xylazine (Rompun) in dogs].

Six beagle dogs were treated with xylazine hydrochloride (1 mg/kg i.m.). The plasma xylazine concentration was measured by HPLC. Additionally, clinical effects were registered (cardiac rate, respiratory activity, electrocardiogram, body temperature, motoric activity, attention, analgesia). Maximum plasma concentrations were measured after 15 minutes (476 ng/ml). The plasma half-life was 24 minutes. Sedation was registered over one hour (xylazine concentration of more than 150 ng/ml). Within the first 30 minutes after treatment (xylazine concentration of more than 300 ng/ml), a low-grade analgesia was observed. In contrast, cardiac and respiratoric depression and also significantly diminished body temperature were registered over 2 to 3 hours.

Analgesia↗
PubMed1996

[Clinical investigations of an i.m. combination anesthesia with fentanylclimazolam/xylazine and postoperative i.v. antagonism with naloxone/sarmazenil/yohimbine in guinea pigs].

Aim of the study was the clinical use of a completely antagonisable anaesthesia in guinea pigs. The dosage based on experimental studies. Fentanyl, climazolam and xylazine (0.05/2.0/2.0 mg/kg) were injected i.m. for combination anaesthesia and naloxone, sarmazenil and yohimbine (0.03/0.3/2.0 mg/kg) i.v. were used for antagonisation. 18 guinea pigs (17 female, one male) with an average body weight of 1177 g aged between eight months and five years were anaesthetised for various surgical procedures. The following clinical parameters were measured: body temperature, muscle relaxation, analgesia, hyperacusia, righting-, interdigital- and palpebral reflex. After antagonisation the return of righting reflex, the appearance of muscle trembling, the first walking without ataxia and the first food uptake were observed. The investigations showed that this kind of anaesthesia is suitable for surgical procedures in the guinea pig and is very safe because of the complete antagonisation of the depressing respiratory and circulatory effects of anaesthesia.

Anesthesia, General↗
PubMed1996

A new transdermal delivery system for pilocarpine in glaucoma treatment.

We studied the intraocular pressure (IOP)-lowering effect and the side effects of a new transdermal delivery system (TDS) containing pilocarpine. After giving their written informed consent, patients were randomly assigned to receive a pilocarpine TDS or a placebo TDS. Two patches, each containing 30 mg of pilocarpine or placebo, were applied to the supraclavicular skin of 24 patients. The IOP was recorded before and at +12, 16, and 20 h after application. Plasma samples were analyzed for pilocarpine before treatment and 12 and 20 h later via high-performance liquid chromatography. The amount of drug remaining on the dermal patches was analyzed at 20 h. The mean IOP recorded before application was 22.7 +/- 5.8 mmHg. As compared with the placebo TDS, the pilocarpine TDS did not significantly reduce IOP at 12, 16, or 20 h after application (P = 0.42). The mean plasma concentrations were 2.9 ng/ml at 12 h and 1.3 ng/ml at 20 h. The verum TDS showed a residual mean drug concentration of 35.3 mg pilocarpine on the TDS. A substantial amount of pilocarpine was released from the TDS to the dermis, causing detectable plasma levels of pilocarpine at 12 and 20 h after administration. The pilocarpine TDS is a new nonocular pharmaceutical device that should avoid the side effects well known in glaucoma treatment when conventional eye drops are used.

Absorption↗
PubMed1996

[Hemophilia A in the dog: symptoms, blood coagulation analysis and treatment].

In our patients, haemophilia A was observed in German shepherd dogs and Siberian huskies. Frequently occurring clinical symptoms were excessive bleeding from the gums, when getting adult teeth, and haematomas in the regions of the proximal hindleg, the knee joint as well as the chest or abdominal wall, respectively. The activated partial thromboplastin time (aPTT) as a screening test of the intrinsic coagulation system reflects sensitively also a mildly reduced factor VIII:C activity which may be present for example during substitution therapy. Therefore, the aPTT is well suited for screening for haemophilia A. In haemophilic dogs suffering from hypovolaemic shock due to a considerable acute blood loss, besides the aPTT also the prothrombin time and partly the platelet number were beyond the respective reference range due to loss and consumption of coagulation factors and thrombocytes. For substitution therapy, fresh frozen plasma was used in the first line. Administered at a dose of 15 or 20 ml/kg BW, it caused an increase of factor VIII:C activity by 20 or 33%, respectively. 24 hours after the end of infusion the mean of the remaining activity increase in comparison with the value measured immediately after substitution was 27%. The fast, biphasic elimination of factor VIII:C in some cases required a repeated application until clinical recovery. Desmopressin acetate given at a dose of 1 microgram/kg KGW intravenously or subcutaneously to two dogs each did not cause a distinct increase of the factor VIII:C activity, and is, therefore, not an efficacious supplementary therapy to substitution therapy in haemophilic dogs.

Animals↗
PubMed1996

[Dorsal recumbency in dogs--a circulatory risk during surgical treatment?].

In this study, changes in hemodynamic, blood gas, and metabolic variables recorded during right lateral and dorsal recumbency in beagles anaesthetised with thiopental are presented. Other than reported in human beings, dorsal recumbency in these dogs resulted in an increase (33%) in heart rate, decrease (30%) in systolic, diastolic, and mean systemic arterial pressure, a decrease (17%) in systemic vascular resistance, and a decrease in both right (31%) and left (39%) ventricular work in comparison with lateral recumbency. Furthermore, mixed-venous PO2, oxygen saturation and respiratory quotient were lower in dorsal than in lateral recumbency while O2 consumption and lipolysis were increased in the former. The changes presented may have been caused by beta-adrenergic stimulation in dorsal recumbency. It needs to be studied if capillary perfusion can be maintained adequately during surgery in dorsal recumbency or if this predisposes to cardiovascular shock.

Anesthetics, Intravenous↗
PubMed1994

[Anesthesia in cats using tiletamine/zolazepam in minimal doses].

The object of this study was to evaluate minimal dose anesthesia with Tiletamine/Zolazepam for castration, dental treatments and other minor surgical procedures in cats. The study included 264 cats treated either at the Department of Veterinary Surgery, Ludwig-Maximilians University of Munich or under private practice conditions, in a small animal clinic in Hamburg (Germany). The drug dose needed for anesthesia for a 10 minute surgical procedure was calculated in each case using a formula. Side effects that occurred with doses recommended by the manufacturer could not be eliminated by decreasing the drug dose, but could be reduced considerably in severity and duration. Tiletamine/Zolazepam was found to be a useful drug for short anesthesia in cats at an average dose of 4.2 mg/kg.

Anesthesia↗
PubMed1993

Local variations in protein structure in the human eye lens: a Raman microspectroscopic study.

Confocal Raman microspectroscopy was used to monitor local and age-related changes in protein conformation in human eye lenses. In clear human lenses of varying age (range 17-80 years) spectra were recorded along the visual axis, using laser light of 660 nm wavelength. The Raman vibrations in the 650-1750 cm-1 spectral region were analyzed. Difference spectra between central core and different positions along the visual axis were calculated after calibration for protein content using the I(1450) cm-1 CH2/CH3 vibration peak. Tryptophan content was quantified using the peak at 760 cm-1 calibrated for protein. Changes in the 'exposed' vs. 'buried' position of tryptophan were analyzed using the peak heights at I(880) and I(760) cm-1. The difference spectra revealed an excess of tryptophan, tyrosine, phenylalanine, beta-sheet conformation and molecules or molecular groups responsible for a 1425 cm-1 peak in the core region in all lenses investigated. The excess peaks disappeared at about 0.6-0.9 mm below the surface. The tryptophan content increased from superficial to deep layers, levelling off between 0.4-0.8 mm below the surface. Upon aging, the tryptophan content increases in the core not in the cortex. No changes in the 'exposed' vs. 'buried' position of tryptophan were observed. Changes in tryptophan and tyrosine probably reflect the maturational shift from cortex to core in the relative content of alpha, beta and gamma crystallines. The age-related increase in tryptophan in the core may reflect the preferential breakdown by endo- and exopeptidases of alpha-crystallins damaged upon aging. The increase in beta-sheet conformation may indicate a post-translational shift in secondary conformation upon aging. These changes in protein conformation are largely completed in a small superficial zone, i.e., in the early life span of the crystallins.

Adolescent↗
PubMed1993

[Diaphragmatic rupture in the domestic cat--pathophysiology and anesthesia complications].

The high mortality in animals with diaphragmatic hernia has been related to profound cardiopulmonary dysfunction. Shock, liver disease and renal failure are among the most common causes of death. 18 cats with traumatic diaphragmatic hernia were anaesthetized. The duration of diaphragmatic hernia ranged from a few hours to 9 months. With the exception of transient cardiac dysrhythmias or weak pulse pressures which occurred in some cats only, anaesthesia was uneventful in 14 cats. Four cats out of 18 died either during surgery (n = 2) or within the following 24 hours (n = 2). Pathophysiology and anesthetic management in cats with diaphragmatic hernia are discussed.

Acute Kidney Injury↗
PubMed1992

Ageing and changes in protein conformation in the human lens: a Raman microspectroscopic study.

Using confocal Raman microspectroscopy with laser light of 660 nm the secondary and tertiary conformation of crystallins was studied in human lenses of varying age (20-75 years). Differences in cortical and nuclear proteins in individual lenses and among lenses of different age and differences between small equatorial opacities and adjacent clear sites were analysed using a difference spectrum approach. Intensity calibration allows assessment of local variations in protein content. The main findings and conclusions are as follows. (1) Irrespective of the age of the lens nuclear proteins proved to contain more aromatic amino acids, i.e. tryptophan, tyrosine and phenylalanine. This change most probably reflects differences in crystallin composition between nucleus and cortex as described in biochemical studies. (2) Changes in the amide bands indicate a more pronounced beta-sheet conformation of the nuclear proteins. Taking into account available biochemical evidence this most probably reflects a true post-translational change in the secondary conformation of the crystallins. (3) Cortical proteins in 'old' and 'young' lenses are largely identical indicating that ageing is not accompanied by gross alterations in the transcription/translation of the crystallin genes. (4) 'Old' and 'young' nuclear proteins deviate with respect to the amount of aromatic amino acids, being more abundant in 'young' nuclear proteins. (5) Proteins in small early opacities do not exhibit alterations in conformation. (6) A pronounced peak in the difference spectra in the region 1425-1435 cm-1 for nuclear proteins especially when compared with equatorial cortical proteins may be considered as evidence for the advanced photooxidation of tryptophan and/or deamidation of asparagine from superficial to deep regions of the lens.

Adult↗
PubMed1992

[Malignant hyperthermia as a complication of anesthesia in the dog].

A moderate malignant hyperthermia developed in a Labrador Retriever anaesthetized with isoflurane for a femoral shaft fracture repair. Signs of malignant hyperthermia included progressive increases in PETCO2 and rectal temperature up to 39.8 degrees C, tachycardia, cyanosis, and elevated serum levels of potassium, inorganic phosphorus, AST, CK and alkaline phosphatase. Treatment initiated in the early recovery period consisted of hyperventilation with 100% oxygen, stomach lavage with iced water, body surface cooling, and intravenous administration of cold isotonic saline solution. Cooling was continued until the rectal temperature had dropped to 37.3 degrees C. After treatment the dog recovered uneventfully. Clinical signs, pathophysiology, therapy, prevention of malignant hyperthermia and its association with other disorders are discussed.

Anesthesia↗
PubMed1992

Comparison of neurologic responses to the use of medetomidine as a sole agent or preanesthetic in laboratory beagles.

Different dose regimens of medetomidine (a potent alpha 2-adrenergic agonist), adding up to a combined dose of 80 micrograms/kg, were administered to laboratory beagles to determine physiologic responses including neurologic. The study was intended to determine EEG responses where sufficient sedative and analgesic effects are reached with medetomidine and in contrast its effects when used with ketamine or halothane. Cardiopulmonary responses were very similar in each dose regimen, showing the characteristic properties of single doses of 80 micrograms/kg of medetomidine. Effective sedative and analgesic duration seemed to be a function of when the largest dose was administered. Adequate additional sedative and analgesic could be gained from injections at doses of half of the initial one. The potent sedative and analgesic effects of medetomidine confirmed by neurologic evaluation supports its potential use as a premedication to general anesthesia in dogs. In this study, 2 different doses of medetomidine were also tested as premedication to both ketamine HCI and halothane anesthesia. Neorologic responses were determined at the same time cardiopulmonary parameters, anesthetic quality, and dose requirements were recorded. Medetomidine was found to have favorable qualities in conjunction with these anesthetics. Cardiopulmonary parameters remained satisfactory in both groups as preanesthetic medication prior to halothane, but no additional benefits could be seen from doses of 40 micrograms/kg medetomidine compared to 20 micrograms/kg, except a significant 30% reduction in halothane requirement. The positive chronotropic and inotropic properties of ketamine restored the medetomidine-induced bradycardia and produced a short anesthetic period of 15 to 30 min depending on the dose of medetomidine. The quality of anesthesia was better when 40 micrograms/kg medetomidine was used, but recovery was quicker with 20 micrograms/kg medetomidine. Medetomidine significantly reduced cerebral activity as demonstrated by recordings of total amplitude and frequency evaluation of the EEG with compressed spectral analysis. This analytical method was effective in confirming clinical signs of sedation, analgesia, and anesthesia in canine subjects.

Analgesia↗
PubMed1987

[Pelvic bone defects in alloarthroplasty].

Loss of acetabular bone renders secure fixation of an artificial cup difficult. Loss of pelvic bone mainly results from repeated revision of failed THR, tumor resection within the acetabular region and trauma. The main criteria for the method of treatment to be applied are the biomechanical condition of acetabular defects, the bacteriological situation, and the patient himself. In aseptic cases we regard bony reconstruction with homografts as the method of choice. From 1982 to 1986 about 1000 bony reconstructions were performed using more or less extensive facilities for support, i.e. screws, baskets, plates. In septic cases defects are closed using antibiotic-loaded acrylic cement in combination with screws. In the extreme case of bone destruction we recommend the saddle prosthesis as an alternative measure. This type of prosthesis was used in 76 cases from 1979 to 1984. Other methods of treatment, such as resection arthroplasty, arthrodesis, and partial pelvic replacement may be considered.

Acetabulum↗
PubMed1987

Immunological safety evaluation of a haemostatic agent and wound dressing made of horse collagen fibrils.

A haemostatic agent and wound dressing made of horse collagen (Tachotop) was applied to guinea-pigs in such a way that the intended use of this material in humans was simulated, and cell-mediated and humoral immune responses of the animals were investigated. In addition, immune reactions were forcefully induced in guinea-pigs in order to validate the methodical approach and quantitate the observed reactions. Cell-mediated immunity was measured as delayed-type hypersensitivity skin reactions, and antibodies were detected by an enzyme-linked immunosorbent assay (ELISA). Simulation of the intended application of this haemostyptic material did not induce immune reactions in guinea-pigs even under critical conditions. The animals could only be immunized when the antigen was administered in solution or finely dispersed and together with adjuvant. Immune reactions thus induced were specific for collagen, no reaction was obtained against possible impurities such as albumin, immunoglobulin or fibronectin. It is concluded--in accordance with clinical experience--that this material is very unlikely to induce immune reactions upon clinical application to humans.

Animals↗