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Biomedical subjects

J Presthus

Publications and source records attributed to J Presthus.

14 recordsLinked to original sources
PubMed1989

The neuropathology in toxoplasmosis-like infection caused by a newly recognized cyst-forming sporozoon in dogs.

The pathomorphological changes in the central nervous system associated with an infection with a previously reported, Toxoplasma-like, cyst-forming sporozoon were studied by means of light microscopy, including immunohistochemistry, and transmission electron microscopy in seven dogs, aged 4 months to 2 years. Tachyzoites (endozoites) within parasitophorous vacuoles were found in neurons, astrocytes, macrophages, vascular pericytes and probably also in fibroblasts, while cyst stages were only observed in cells showing features of neurons. Proliferating tachyzoites were associated with lesions of a necrotic/granulomatous type. Perivascular accumulations of lymphocytes and plasma cells, together with an activation of astrocytes and perivascular fibroblasts resulting in marked sclerosis, were prominent features in all cases. The grey matter was most seriously affected in the brain, while the white matter was most often the site of inflammation in the spinal cord. The structural similarity to the newly reported Neospora caninum suggests that we are dealing here with the same parasite. However, the present infection and toxoplasmosis have so many features in common, including the light microscopical morphology of the organisms and host/parasite relationship, that a definite etiological diagnosis should be based on ultrastructural and/or immunohistochemical examinations.

Animals↗
PubMed1988

Immuno-histochemical and ultrastructural characteristics of a cyst-forming sporozoon associated with encephalomyelitis and myositis in dogs.

Light-microscopy, including immuno-histochemical staining, and transmission and scanning electron microscopy were applied for the characterization of a Toxoplasma-like parasite associated with encephalomyelitis and myositis in dogs of the boxer breed. Most parasites were tachyzoites, occurring in clusters, up to 60 micron in diameter, in parasitophorous vacuoles of host cells. Cyst stages with a definite cyst wall were few, but could be demonstrated in all cases. Immunostaining with antiserum against Toxoplasma gondii was negative, while both tachyzoites and bradyzoites were stained with serum from affected dogs. Ultrastructurally, the parasite was characterized by a great number of rhoptries, few amylopectin granules, lack of micropores in the tachyzoites, and the occurrence of numerous dense bodies in the bradyzoites. Numerous intravacuolar tubules were present in the space of the parasitophorous vacuole. The cyst wall resembled that of T. gondii. Until a definite host is found, the parasite may be regarded as an "orphan", cyst-forming sporozoon that is ultrastructurally different from other known protozoan parasites. It has a light-microscopical similarity to T. gondii but is antigenically different.

Animals↗
PubMed1987

Selegiline (1-deprenyl) and low-dose levodopa treatment of Parkinson's disease. A double-blind crossover trial.

Fifteen parkinsonian patients previously untreated with levodopa were treated with daily doses of 200 mg Madopar and randomized to addition of 10 mg selegiline (1-deprenyl) in a double-blind, placebo controlled, crossover trial. According to the patients own evaluations 6 reported additional therapeutic effect from selegiline to Madopar; 2 reported possible additional effect, whereas a further 6 reported no improvement; 1 did not complete the trial. Statistically significant positive therapeutic effect of selegiline could not be found on Webster's rating scale or on a sensimotoric test designed for parkinsonian disabilities. Side effects of selegiline were minimal. It is concluded that selegiline may be of some value in addition to levodopa in early treatment of parkinsonian patients, but positive therapeutic effect has to be tested individually. Even in these patients the additional therapeutic effect of selegiline to levodopa seems to be quantitatively small.

Adult↗
PubMed1985

Effects of denervation, immobilization and cachexia on fibre size in the anterior tibial muscle of the rat.

The effects of denervation, immobilization and cachexia on the size of the various histochemical fibre types were studied in the anterior tibial muscle of male Wistar rats aged 60-100 days. Denervation was induced by unilateral sectioning of the sciatic nerve, immobilization by a plaster cast on one hindlimb and cachexia by restriction of food intake. In the anterior tibial muscle of the normal rat, three fibre types can be identified by myofibrillar ATPase stain after alkaline preincubation. These fibres were called dark (D-fibres), intermediate (I-fibres) and light fibres (L-fibres), respectively. The I-fibres correspond to the fast-twitch type 2 fibres and the L-fibres to the slow-twitch type 1 fibres. The D-fibres have intermediate characteristics, but they probably belong to the type 2 group. The three fibre types reacted differently to denervation, immobilization and cachexia. Denervation caused progressive atrophy of the D- and I-fibres and almost no change of the L-fibres. Immobilization caused minor reduction in size of the D- and I-fibres during the first days and no change thereafter, whereas the L-fibres showed transitory hypertrophy. Cachexia, on the other hand, resulted in progressive atrophy of all three fibre types but a predominant affection of the D- and I-fibres. The different susceptibilities of the various fibre types suggest different mechanisms for atrophy of muscle in these three conditions.

Adenosine Triphosphatases↗
PubMed1978

Dopaminergic agonist Ro 8-4650 in Parkinson's disease. II. Patients not treated with dopa.

An isoquinolone derivative Ro 8-4650 (rac-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-7-methoxy-2-methylisoquinoline hydrochloride) with dopaminergic properties was studied in a randomized crossover trial. The group studied comprised 37 patients with idiopathic parkinsonism, not previously treated with levodopa or dopamin agonists. The trial drug was significantly more effectve than placebo, but the clinical improvement, according to the Webster rating scale, was small. No significant difference was observed as regards involuntary movements, but the trial drug led to more frequent minor side effects. It can be concluded that the trial drug, despite its proven effect in Parkinson's disease, has only limited clinical value.

Aged↗
PubMed1978

Diagnostic problems in extrapyramidal disorders.

The diagnostic problems of extrapyramidal disorders (ED) are reviewed. Many of the wide range of ED occur rarely, and clinical experience is difficult to obtain. Despite great advances in pathophysiology and pathological anatomy the diagnosis of ED is still mainly a clinical diagnosis, and the diagnostic problems are discussed principally in relation to the involuntary movements and partly with regard to muscle tone. Except in a few diseases, biochemical and microbiological analyses, EEG, EMG and X-ray examinations offer little contribution to the solution of diagnostic problems in these disorders.

Adult↗
PubMed1976

Parkinson's disease treated with Sinemet or Madopar. A controlled multicenter trial.

92 patients with Parkinson's disease not previously treated with levodopa were considered as eligible for this triple-blind trial. Patients were allocated at random to treatment with either levodopa + benserazide ratio 4:1 (Madopar) or levodopa + carbidopa ratio 10:1 (Sinemet) using dosage schedules recommended by the manufacturers which they had to adhere to for 6 months. Unless prohibitive side-effects occurred daily maximum dosage of 800 mg levodopa + 200 mg benserazide respectively 1,500 mg levodopa + 150 mg carbidopa were obtained after 6 weeks and 3 weeks, respectively. The effect of the two schedules on the Parkinsonian symptoms were equal and appeared equally fast. The frequency of gastrointestinal side-effects and involuntary movements were significantly higher and more severe for Sinemet than for Madopar. These side effects are usually symptoms of levodopa overdosing, but whether or not a different dosage schedule with Sinemet would have given fewer side-effects without concurrent lower efficacy remains open to speculation. The treatment schedules did not differ with regard to other side-effects and influence on blood pressure. Neither treatment seemed to influence liver function, renal function and hematological parameters in a statistically way.

Aged↗
PubMed1975

Levodopa alone and in combination with a peripheral decarboxylase inhibitor benserazide (Madopar) in the treatment of Parkinson's disease: A controlled clinical trial.

A combination of levodopa and the extracerebrally acting decarboxylase inhibitor benserazide (ratio 4:1) (Madopar), was compared with levodopa alone in a controlled double-blind clinical multicenter trial on 94 patients with Parkinson's disease. During 4 months of therapy levodopa + benserazide proved superior to levodopa on several accounts. Nausea and vomiting occurred with statistically significant less severity and frequency. Clinical improvement expressed through improvement in Webster rating occurred sooner and was all together greater. The treatment schedules did not differ with regard to other side effects, in particular involuntary movements and reduction in supine blood pressure. Neither treatment seemed to influence liver function, renal function and hematological parameters.

Adult↗
PubMed1975

Treatment of parkinsonism with l-dopa and a decarboxylase inhibitor. An electrophysiological and clinical study.

Twelve parkinsonian patients with an unsatisfactory therapeutic result on L-Dopa alone due to nausea, vomiting and involuntary movements were treated WITH L-Dopa and decarboxylase inhibitor. The daily dose reached 800mg L-Dopa and 200 mg decarboxylase inhibitor. Single doses of each of the components were also given. Electrophysiological examination of hypokinesia, tremor and rigidity, and clinical observation revealed clear evidence of rapid improvement on small doses of L-Dopa combined with decarboxylase inhibitor. Most of the improvement occurred during the 1st week before the maximal dose was reached. A single oral dose of decarboxylase inhibitor resulted in an improvement, suggesting the presence in the organism of a small AMOUNT OF L-Dopa. This work also shows the absence of liver toxicity of the drug used. Elimination of the extracerebral side effects nausea and vomiting in our opinion is a principle advantage of the compound compared to L-Dopa alone, wheras abnormal involuntary movements, which were found in all patients, remain the limiting adverse side effect.

Aged↗