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Biomedical subjects

C Landes

Publications and source records attributed to C Landes.

11 recordsLinked to original sources
PubMed2005

Histopathologic findings after treatment with different oxidosqualene cyclase (OSC) inhibitors in hamsters and dogs.

In order to investigate the toxicity of oxidosqualene cyclase (OSC) inhibitors, hamsters and dogs were treated up to 13 weeks with three different agents of this compound class. Subacute treatment (< or = 4 weeks) of hamsters and dogs with OSC inhibitors produced a similar spectrum of histopathologic lesions, which have previously been described for compounds of this pharmacological class. In the hamster, other lesions were produced only after subchronic treatment (13 weeks). After subacute treatment, histopathologic findings were observed in the eye, skin and forestomach. Lesions in the eye were characterized as proliferation, swelling and degeneration of lens fiber cells. This finding was considered to be an early stage in cataract development. In the skin and forestomach, squamous cell hyperplasia and hyperkeratosis accompanied by a mixed inflammation was observed. After subchronic treatment of hamsters, histopathologic findings were observed in the eye, skin, forestomach, testes, epididymides, prostate gland, seminal vesicles and long bones. Lesions in the eye were characterized as cataracts. Squamous cell hyperplasia accompanied by a diffuse hyperkeratosis and a mixed inflammation was seen in the skin and forestomach epithelium. In addition, testes lesions were characterized as testicular atrophy, generalized germ cell depletion, germ cell degeneration and tubular collapse. Atrophy, oligospermia and lumenal germ cells/cell debris were found in the epididymides. The prostate gland and seminal vesicles were decreased in size (atrophy). The bone lesions were characterized as a failure of enchondral ossification causing variable widening of the growth plate and a failure to form primary bone trabecula (lesions resemble those found in rickets). To our knowledge, this is the first study describing the toxicity of OSC inhibitors after subchronic treatment in hamsters and dogs. As all adverse effects described in this report are considered to be due to an exaggeration of the desired biochemical mechanism of action at high dose levels, a decrease of the systemic exposure by the use of more hepatoselective OSC inhibitors is expected to reduce the probability of these adverse effects in humans.

Animals↗
PubMed2000

Sonography of the temporomandibular joint from 60 examinations and comparison with MRI and axiography.

BACKGROUND AND OBJECTIVE: Establishing a diagnosis of temporomandibular joint disorder is mainly based on clinical assessment, functional examination, nuclear magnetic resonance imaging (MRI) and axiography. Sonographic examination was compared with MRI and axiography in assessing temporomandibular joint (TMJ) function in 55 patients. PATIENTS AND METHODS: Fifty-five patients with different TMJ problems were examined clinically, by means of axiography, sonography and some also by MRI. The range of motion was measured by sonography and axiography and the results compared using Student's t-test. Anatomical details diagnostic for disc-displacement were tested by sonography and MRI. RESULTS: The average time required for sonography was 2 min and for axiography 20 min. The mean measurement differences for condylar movement in maximal mouth opening was 1.7 mm, for protrusion 1.6 mm and for mediotrusion 2.5 mm. The range of condylar movement as measured by sonography and axiography coincided for opening and for protrusion (statistically significant). No significance was found for lateral excursions. The concordance in diagnosis of disc dislocation, hypermobility and impaired range of motion when comparing ultrasound with MRI was 83%. All sonographic examinations were performed by one person only. Sixty repeat examinations in patients produced no complaints and showed an absolute range of difference of 0.6 mm, with a relative range of 7%. Student's t-test was significant (p<0.05) (two repetitive measurements). CONCLUSION: Sonography proved to be a fast and reliable method for evaluating the range of movement of the TMJ. The lateral joint capsule, lateral disc, and upper condyle could be demonstrated. Pathological processes such as anterior or lateral disc displacement, disc perforation, seroma following contusion, capsular fibrosis, crystalline structures in the synovia and fracture dislocation of the condyle could be diagnosed with considerable reliability when compared with MRI. However, the medial aspect of the joint, medial disc dislocation and the angulation of the condylar slope could not be seen.

Adult↗
PubMed1995

The dorsal fascia dentata as a probe of fixation quality in the rodent brain.

In microscopic sections of the rodent brain the dorsal fascia dentata frequently shows perineuronal swelling and neuronal swelling and shrinkage. Factors influencing the occurrence of such changes, which may mimic excitotoxic effects, have been examined using various schedules of anaesthesia and perfusion fixation. Laboratory mice anaesthetized with a low dose of sodium pentobarbital manifested prolonged excitation in comparison to those anaesthetized with a high dose: the occurrence of tremor and convulsions, however, was not related to the morphological changes in the fascia dentata. The changes were diminished by increasing the perfusion pressure (from 80 to 120 mmHg), by reducing the duration of the wash-out period with buffer (from 45 to 15 seconds) and by prolonging the perfusion time (from 7 to 15 minutes). They were abolished when 5% solution of glutaraldehyde was used instead of a 2.5%. The results show that the quality of brain fixation may be best assessed according to the morphology of the dorsal fascia dentata, and that the occurrence of acute swelling and shrinkage in this area should not be mistaken for pathological changes.

Anesthesia↗
PubMed1993

[Radiologic determination of bone screw exit site on the femoral condyle. A method of exact imaging and length determination of internal fixation devices (screws, K-wires) in metaphyses of larger tubular bones exemplified by the distal femur].

Distal femur imaging (A-P and lateral X-rays) after internal fixation often give only poor visualization of the exact position. A model with two anteriorly positioned cortex screws was used to show that an additional oblique X-ray, or fluoroscopy of the tip of the screw, allows much more exact determination of its length, so that it can be changed if necessary. This method is considered by the authors as a simple check of screw length measurement in "foyer fermée" procedures.

Adolescent↗
PubMed1991

Delayed epidural hematoma.

A case of delayed epidural hematoma is described who had an initial computerized tomography (CT) scan reported as normal. Repeat CT scan at 48 h demonstrated a right temporal epidural hematoma. A skull fracture was not observed radiographically or at surgery. The world literature is reviewed and the criteria for repeat CT scanning is discussed.

Adult↗
PubMed1990

Contribution of immunohistochemistry toward the diagnosis of tumors of laboratory rats.

A polyclonal antibody detecting S-100 protein (S-100) and a monoclonal antibody demonstrating epithelial cell (Lu-5) were used in addition to routine, hematoxylin-eosin stain to improve the identification of tumors of neural or epithelial origin diagnosed in conventionally treated tissue from rat bioassays. Among 108 lesions tested for S-100, 51 reacted positively; they included benign and malignant schwannoma, endomyocardial disease, some cases of benign and malignant thymoma, and renal tubular adenoma. S-100 protein is considered particularly useful for discriminating of neoplasms of Schwann cell origin from mesenchymal tumors. 31 of 51 lesions tested for Lu-5 reacted positively: they comprised adenoma, carcinoma, benign and malignant thymoma and atriocaval node tumor of the heart. Lu-5 was especially useful to distinguish epithelial from mesenchymal neoplasms and was capable of identifying epithelial elements in lymphocyte-rich thymomas as well as in dedifferentiated or autolytic tumors. The binding of both antibodies in neoplastic tissue was compared with a complete set of anatomically normal rat tissues.

Animals↗
PubMed1988

Rat endomyocardial disease: a neural origin?

Of 58 cardiac lesions in rats from a Sprague-Dawley-derived strain, representing different stages of endomyocardial disease including 10 cases progressing to tumors, most stained positively for S-100 protein, while duplicate sections of selected cases also reacted positively for neuron-specific enolase. The results demonstrate the probable neural origin of these lesions.

Age Factors↗
PubMed1985

[Primary neoplasms and hyperplasias of the gastric mucosa in the dog].

During the past 15 1/2 years (from 1969 to the middle of 1984) 35 canine primary gastric neoplasms (32 necropsies and 3 partial gastric resections) were examined. Brought into relation with the total number of necropsies carried out in dogs (12,494) the incidence of stomach tumours in the dogs is 0.3%. The tumours are classified as 12 benign (1 adenomatous polyp, 11 leiomyomas) and 23 malign neoplasms (20 carcinomas, 3 sarcomas). In addition a circumscribed hyperplasia of the gastric mucosa is reported. The average age of the dogs with carcinomas is 8.9 years. The tumours were most frequently located in the pyloric region and combined with ulcerations. Most of them had metastases. According to a classification of human gastric carcinomas, which also is applied to animals, 18 tumours are of the "diffuse type", two of the "intestinal type". The described cases are compared with corresponding data of the literature. The pathogenesis and the etiology of gastric carcinomas are discussed.

Adenocarcinoma↗
PubMed1984

[Causes of death and disease in cats based on 1969-1982 autopsy statistics].

The post mortem investigation of 4561 cats during 14 years is analysed according to the diagnosis. The age of the cats necropsied ranged from 1 day to 22 years, with an average of 3,3 years. The sex distribution was about 1:1. The most common disease is feline panleucopenia (16,6%) followed by traumata (11,5%), disorders of the urinary tract (7,0%), feline infectious peritonitis (6,0%), disorders of the circulatory system (5,8%), and diseases of the digestive tract (5,3%). The majority of kittens died of virus diseases, mainly feline panleucopenia. Feline leucosis is found among all groups of age. In middle aged animals (5-10 years) feline leucosis and diseases of the urinary tract are the main causes of death. Cats older than eight years show a high rate of tumor incidence, especially those of non lymphatic origin. Among siamese cats congestive cardiomyopathy is very common. A sexual disposition is notable for the feline urologic syndrome, occurring predominantly in male individuals.

Age Factors↗