Echocardiographic quantification of Dirofilaria immitis in experimentally infected cats.

The safety of heartworm preventives in heartworm-positive cats has traditionally been evaluated using adult Dirofilaria immitis removed from infected dogs and surgically implanted into the cats. An alternate study model uses infective larvae to establish adult infections in cats. Unfortunately, the number of adult worms resulting from the latter method varies widely from none to more than 30, both unacceptable for studies of natural heartworm infection and for studies evaluating product safety in heartworm-infected cats. We sought to determine infection severity in experimental infections via echocardiography to reduce the chances of enrolling uninfected and heavily infected cats into a study. Eighty adult cats were each inoculated with 60 infective D. immitis larvae and maintained for 8 months to allow for the development of adult worms. Antigen and antibody testing, as well as echocardiographic imaging, were performed to confirm and estimate adult worm burdens. Approximately 8 and 12 months post-infection, echocardiographic examination was performed to confirm and enumerate adult D. immitis populations in the cardiovascular system. Worm burdens were stratified as 0, 1-3, 4-11, and > 11 adults, with 0 being considered uninfected and more than 11 considered too heavily infected to be relevant for anthelmintic studies. Cats with clinically relevant infections (1-10 adults) subsequently received multiple treatments with the investigational drug, and worm burdens were confirmed by necropsy 30 days following the final treatment. Worm burden estimated with echocardiography correlated well, but not precisely, with post-mortem counts (p < 0.001, r2 = 0.67). Echocardiography under-, over-, and exactly estimated heartworm burden 53%, 27%, and 22% of the time, respectively. Although the correct category (0-4) was determined by echocardiography in only 54% of cats, positive cats were distinguished from negative cats 88% of the time and the heaviest infections (> 11) were correctly categorized 95% of the time. Both false negative and false positive results were observed. We conclude that echocardiography is useful for detecting mature experimental heartworm infections, identifying cats that have rejected mature infection, and detecting very heavy heartworm burdens, but it is only moderately accurate in classifying lesser burdens. While echocardiography cannot be relied upon to consistently determine the exact heartworm burden in experimentally infected cats, it is useful in stratifying worm burdens for anthelmintic safety studies.

[DIGITOS-prosthesis for the proximal interphalangeal joint--long-term results]. / DIGITOS-Fingermittelgelenkprothese--Langzeitergebnisse.

Most important methods for the surgical treatment of painful arthritis of the proximal interphalangeal joint are the joint fusion or the implantation of a prosthesis. There are a lot of different models for joint replacement. Sixteen patients received 19 middle joint replacements performed with the DIGITOS-prosthesis between 1996 and 1999. Over a period of seven years, 14 patients with 17 prostheses have been observed prospectively. In the 7-year follow-up, a minimal radiolucent line at the bone-cement junction and huge periarticular osteophytes could be found in every case. No cortical penetration, luxation, or implant fractures were recorded. The preoperative median range of motion was 50 degrees. Postoperatively, there was an improvement to 60 degrees. The range of motion decreased to 50 degrees after one year and to as little as 30 degrees after seven years. Preoperatively, eleven patients had pain with activity and three had pain without activity. During the whole follow-up period there were only two patients who had pain at work. All patients were satisfied with the results of the operation throughout the control period and would choose the same treatment again.

Renaut bodies in the sciatic nerve of beagle dogs.

182 control Beagle dogs from 23 historical studies (14 chronic, 9 subchronic) were reviewed histologically for the presence of Renaut bodies in the sciatic nerve. Renaut bodies were found in 36.1 percent of the subchronic-study dogs and in 46.4 percent of the chronic-study dogs. The Renaut bodies most often resided in the distal sections of the sciatic nerve, specifically in the tibial branch as it traversed the knee joint in situ. There was no sex predilection. Renaut bodies were located predominately in the endoneurium, in the center of the nerve sections. There was no associated axonal degeneration, reactive gliosis, or encapsulation. The Renaut bodies were characterized as large (20 to 500 microns diameter in cross section), well-demarcated elliptical structures with an onion-skin arrangement of loosely textured, filamentous strands intermixed with sparse numbers of dark spindle-shaped nuclei. Occasionally the core displayed a more dense, intensely eosinophilic arrangement of fibers. Histochemical results included: positive acidic alcian blue, Gomori's trichrome, and Verhoeff Van Gieson's; and negative Periodic-acid Schiff, Congo Red, and Luxol fast blue/cresyl violet. Immunohistochemical results included: positive vimentin and collagen (subtypes I, II, and VI); and negative NSE, S-100, GFAP, amyloid A component, desmin, alpha-sarcomeric actin, pancytokeratin, EMA, and von Willebrand factor. Transmission electron microscopy revealed loosely arrayed, circumferentially oriented collagen fibers intermixed with varying amounts of amorphous substance and finely fibrillar material. Most of the cells comprising the Renaut body were identified as fibroblasts. No nerve fibers entered or left the Renaut body, and nearby nerves appeared to be normal structurally. Based on this characterization of Renaut bodies and in conjunction with the past literature, Renaut bodies appear to have little or no pathological significance, but rather are suggestive of a physiological adaptation in response to mechanical stress imposed on nerves.

[Problems of malunited fractures of the distal radius]. / Problematik der in Fehlstellung ausgeheilten distalen Radiusfraktur.

The essential problematic of the distal fracture of the radius lies in the quality of its reduction and retention. 35 patients with distal fractures of the radius and strain fractures of the styloid process of the ulna were followed up with regard to their functional and radiological results and their subjective symptoms. Patients with intra-articular fractures were found to have significantly poorer functional results compared to those with extra-articular fractures. 29 out of 35 patients developed a nonunion of the styloid process of the ulna in the form of a compensatory false position with a significant dorsal tilt of the articular surface of the radius. Their functional results were also significantly poorer than those of the other 6 patients. The patients whose radii were shortened by more than 2 mm also had significantly poorer functional results and a median dorsal tilt of 5 degrees of the articular surface. Where the dorsal inclination of the articular surface of the radius exceeded 5 degrees, a significant increase in the scapholunar angle, which averaged 62 degrees, was found. On the basis of these figures, we conclude that in the reduction of the distal fracture of the radius, shortening by not more than 2 mm and a dorsal inclination of the articular surface of the radius, taken laterally, of not more than 5 degrees should be tolerated in order to minimise functional impairments of the wrist.

Tumors in long-term rat studies associated with microchip animal identification devices.

Tumors surrounding implanted microchip animal identification devices were noted in two separate chronic toxicity/oncogenicity studies using F344 rats. The tumors occurred at a low incidence rate (approximately 1 percent), but did result in the early sacrifice of most affected animals, due to tumor size and occasional metastases. No sex-related trends were noted. All tumors occurred during the second year of the studies, were located in the subcutaneous dorsal thoracic area (the site of microchip implantation) and contained embedded microchip devices. All were mesenchymal in origin and consisted of the following types, listed in order of frequency: malignant schwannoma, fibrosarcoma, anaplastic sarcoma, and histiocytic sarcoma. The following diagnostic techniques were employed: light microscopy, scanning electron microscopy, and immunohistochemistry. The mechanism of carcinogenicity appeared to be that of foreign-body induced tumorigenesis.

[Soft tissue reconstruction after scalping injury caused by a dog bite]. / Weichteilrekonstruktion nach Skalpierungsverletzung durch Hundebiss.

The reconstruction of soft-tissue damage on the part of the head which is covered with hair is aimed not only at repairing the damage in such a way that it will withstand mechanical strain but also at the restoring the hair on the scalp. In a 5-year-old boy with a scalping injury involving second- and third-degree soft-tissue damage over an area of 20 x 12 cm after a dog bite, surgery was initially performed to transform the damage into purely second-degree damage, which was then repaired with a split skin graft. One year later, the scalp containing the hair was stretched with the aid of two skin expanders over a period of 3 months, so that the split skin graft area could be removed and the hair on the scalp restored.

The effectiveness of ADCON-T/N, a new anti-adhesion barrier gel, in fresh divisions of the flexor tendons in Zone II.

In a prospective randomized clinical trial, ADCON-T/N was investigated with regard to its effectiveness in fresh traumatic injuries of the flexor tendons in Zone II of the hand. Thirty patients participated in the trial. Following a standardized technique of tendon repair, the total active motion (TAM) and total extension lag (TEL) were determined after 12 weeks and evaluated according to the Buck-Gramcko score. Excellent results were achieved in 15 out of 16 patients in the ADCON-T/N group and 12 out of 14 in the control group. However, no statistically significant difference was found between the mean TAM and TEL in the two groups.

[DIGITOS-prosthesis for the proximal interphalangeal joint. A 2-year follow-up]. / DIGITOS-Fingermittelgelenkprothesen--Zweijahresergebnisse.

The treatment of osteoarthrosis of the proximal interphalangeal joint by prosthesis bears several specific problems. With the DIGITOS-prosthesis a new implant is now available. It is a cemented modular hinged prosthesis. We report our experiences with this implant from a prospective clinical trial. Seven patients with osteoarthrosis of the proximal interphalangeal joint had ten prosthetic middle joint replacements performed with DIGITOS-prostheses. Over an observation period of two years, the functional results were found to be good. The mean preoperative range of motion in the affected joints was 51.5 degrees. Three months after surgery, this had improved to 60.5 degrees, but then decreased to 53.0 degrees after one year and to 49.5 degrees, i.e. the original range of motion, by the end of the second postoperative year. No implant became loose. Nearly all patients were free from pain. The only serious complication was an iatrogenic lesion of the middle slip of the extensor aponeurosis resulting in a buttonhole deformity. In spite of these encouraging two-year results, the further follow-up has to be observed carefully.

An electroretinogram protocol for toxicological screening in the canine model.

A five-step electroretinogram protocol was developed for the dog to be used as a painless screening test for ocular effects of drugs or pesticides. Standard conditions of frequency band width, stimulus intensity, dark adaptation time and non-confounding anesthesia method were selected to allow analysis of wave components. The protocol demonstrated an acceptable level of inter-subject variability for compiling an age appropriate database, and for the detection of possible retinal component toxicities in chronic dog studies. This electrophysiologic procedure may serve to corroborate biochemical, clinical and pathology data, in establishing a compound's no-observable-effect-level (NOEL).