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Biomedical subjects

A Engelhardt

Publications and source records attributed to A Engelhardt.

At least 37 records · Page 2Linked to original sources
PubMed1993

Immunohistochemical findings in vasculitic neuropathies.

Fifteen sural nerve biopsies of vasculitic neuropathies have been compared with 11 cases of different non-vasculitic neuropathies and normal nerves from brain-dead organ donors. The APAAP (alkaline phosphatase monoclonal anti-alkaline phosphatase) immunostaining method was applied to cryostat sections from unfixed snap-frozen tissue samples. Immunoglobulins IgG, IgM, IgA, complement factors and light chains were reactive in biopsies of normal nerves as well as of vasculitic and nonvasculitic neuropathies. A strong reaction against IgE in the epineurial vessel walls was only seen in cases of Churg-Strauss-vasculitis. Antibodies against MHC class II (HLA DR) were positive in most of vasculitic infiltrates. Vascular endothelial cells were positive with anti MHC class I in all biopsies. A typical finding in all vasculitic neuropathies was the infiltration of epineurial vessels with CD4 positive and, to a lesser extent, CD8 positive lymphocytes. CD22 positive lymphocytes (B cells) have only been seen in about one third of vasculitic neuropathies. CD16 positive cells (NK-cells or neutrophils) could be demonstrated only in two biopsies. CD68 positive cells (macrophages) are frequently seen in most cases of neuropathy regardless of their etiology. The results support the concept of a primary T-cell mediated process against epineurial vessels as the most important mechanism in the pathogenesis of vasculitic neuropathies. In some cases with small epineurial infiltrates the vasculitic process can only be recognized with antibodies against CD4 or CD8. Therefore, the immunohistochemical evaluation of sural nerve biopsies may be helpful for identifying cases with microvasculitis.

Adolescent↗
PubMed1993

[The development of the cestode fauna in rainbow trout (Oncorhynchus mykiss) in a newly formed surface mine residual water].

Helminthofaunistical studies on rainbow trout, wild fish and zooplankton organisms of a recently emerged rest waters from an open-cast mine have been made continuously in the period from 1980 till 1990. Three years after the beginning of the trout production larval triaenophorosis appeared as the first cestodosis. In the subsequent time changes of the cestode fauna of rainbow trout kept in net-cages could already be observed within a few years. Possible causes for the replacement of Eubothrium crassum by Proteocephalus neglectus are discussed. Since 1985 proteocephalosis is the dominating helminthosis in the stock of trout. Changes in the population dynamics of cestodes of the genus Proteocephalus are traced back to a multitude of complexly functioning ecological and anthropogenic regulation mechanisms in all links of the life-cycle.

Animals↗
PubMed1992

[Causes of disease and death in ornamental fish--frequency and importance].

Between 1986 and 1990 1068 aquarium fishes from breeders, wholesale dealers and pet shops and from private owners were examined. In 45% of the cases different non infectious causes of illness or death were detected. Infectious causes were present in 38%. 14% of the fishes showed no pathologic symptoms, whereas 3% of the samples were unfit for examination. The frequency of infectious and non infectious diseases respectively in fishes from breeders vs. dealers vs. private owners is given. From these results factors of pathogenesis in aquarium fishes are discussed and compared to those in fish breeding for food fish. Advices for prevention of diseases in fancy fishes are given.

Animals↗
PubMed1990

Effects of long-impulse electrical stimulation on atrophy and fibre type composition of chronically denervated fast rabbit muscle.

The efficacy of electrical stimulation on a chronically denervated muscle depends on stimulus parameters, which have an important influence on the development of atrophy. Stimulus frequency and/or total activity are particularly responsible for the development of some histological, biochemical and contractile features. The present study in 18 rabbits deals with a recently developed electrical stimulus, which had proved effective in maintaining muscle force following denervation. This current has (1) unusual long bidirectional rectangular impulses (20 ms) and (2) a frequency of 25 Hz, which is between the frequencies of fast- and slow-firing motor units. Electrical stimulation began 28 (in one animal 53) days after total motor and sensory denervation of the right hindleg, and was continued until the end of the experiment, up to 205 days. To mimic a therapeutic regimen, which should be agreeable to patients, daily treatment times were kept to a minimum (2 x 6 min), and surface electrodes were used. Morphometric evaluation of the fast flexor digitorum sublimis muscle showed that such electrical stimulation was able to preserve fibre diameter at a level of 72-86% of the initial values for several months, while unstimulated fibres showed the usual atrophy with a decrease of diameters below 40% of normal. The stimulation induced a "hybrid" fibre type with properties of a slow muscle (rich in mitochondria in NADH-dependent tetrazolium reductase staining and electron microscopy) as well as of a fast-twitch muscle (fibre type IIb in myofibrillar ATPase stainings).

Animals↗
PubMed1990

[Ocular changes in MELAS syndrome].

The present paper reports on the clinical findings of a 34-year-old male patient with MELAS syndrome. MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis and strokelike episodes) belongs to a group of syndromes called mitochondrial encephalomyopathies that are characterized by changes of the mitochondrial respiratory chain and the histological finding of "ragged red fibers" in muscle biopsy. In our case the diagnosis was confirmed by multiple neurologic tests including muscle biopsy and biochemical analysis of the respiratory chain. The ocular findings included reversible, homonymous hemianopic visual field loss documented six years earlier, atypical retinitis pigmentosa with marked attenuation of the scotopic ERG, myopia and nuclear cataract of the right eye. An extracapsular cataract extraction with implantation of a posterior chamber lens was performed on the rigt eye, the course was unremarkable and vision improved. In dealing with patients presenting with ocular or neurologic signs indicating mitochondrial encephalopathy, the ophthalmologist should consider MELAS syndrome or any other of the mitochondrial encephalomyopathy syndromes as a possible etiology and take the necessary steps for further medical and neurologic evaluation of the patient.

Acidosis, Lactic↗
PubMed1990

Postoperative effects and value of sural nerve biopsies: a retrospective study.

In order to compare the adverse effects with the benefits for the characterization of neuropathies after complete sural nerve biopsy, 56 out of 80 patients were examined postoperatively. Preoperatively, sensory deficits were reported by 30 patients (53%), paresthesia and dysesthesia by 18 (32%), and pain by 16 (28%). Twenty-one months after biopsy on the average, persistent loss of sensation was found in 52 patients (93%), persistent paresthesia and dysesthesia in 17 (30%) patients each, and persistent pain in 14 (25%) patients. Pain and paresthesia showed better postoperative improvement than the other sensory symptoms. 15 cases (27%) were diagnosed by histology alone. In 21 cases (37%), nonspecific histological findings contributed valuable diagnostic information. The remaining 20 cases (36%) continued to be unclear despite histology. Demyelinating or mixed-type neuropathies did not yield better results than purely axonal forms. We conclude that sural nerve biopsy is a valuable diagnostic tool, but its side-effects require careful selection of fully informed patients.

Adolescent↗
PubMed1989

[Polyneuropathy in Churg-Strauss syndrome].

An acute polyneuropathy with fever and blood eosinophilia (69%) developed in a 72-year-old woman with chronic bronchial asthma and weight loss for a few months. A muscle biopsy revealed necrotizing vasculitis with numerous eosinophilic granulocytes and neurogenic atrophy. The vasculitic changes were only minor in the sural nerve and limited to the epineurium. Signs of acute nerve-fibre disintegration were marked, while some fascicles were only affected in some sectors. The clinical and histological diagnosis suggested Churg-Strauss syndrome. The polyneuropathy, eosinophilia and abnormal erythrocyte sedimentation rate quickly disappeared on administration of initially 80 mg prednisolone and 100 mg azathioprine.

Aged↗
PubMed1989

Peripheral nerve disorders in Lyme-Borreliosis. Nerve biopsy studies from eight cases.

Clinical, cerebrospinal fluid and nerve biopsy findings from eight patients with peripheral nervous system complications of Lyme-Borreliosis are reported. Five cases showed the typical features of the Garin-Bujadoux-Bannwarth syndrome (meningoradiculoneuritis), one patient had a multiple mononeuritis associated with acrodermatitis chronica atrophicans Herxheimer. Two cases could not be classified under these diagnostic categories. In all patients we observed a prompt relief of signs and symptoms after antibiotic treatment. Nerve biopsy studies showed gross infiltrations of epineurial vasa nervorum and small infiltrations around endoneurial capillaries. The infiltrations consisted of lymphocytes, histiocytes and plasma cells. We did not find necrotizing changes of the vessel walls, but thrombosis and recanalization was observed in some epineurial vessels. Seven biopsies showed a significant loss of myelinated axons due to axonal degeneration. Only in one biopsy did we observe segmental demyelination next to axonal degeneration. We conclude that the PNS complications of Lyme-Borreliosis in early and late stages of the disease are angiopathic due to vasculitis of the vasa nervorum and primarily caused by axonal degeneration.

Acrodermatitis↗
PubMed1989

[Polyneuropathies in HIV infection].

In approximately 10-16% of the cases, diseases of the peripheral nerves occur in the fully developed stage of AIDS, more seldom, however, in the stage of ARC. Some cases have been described in the stage of seroconversion or lymphadenopathy. At this stage cranial neuropathies can show up in connection with aseptic meningitis. The peripheral nerve diseases are present as distal symmetric sensomotory neuropathy, as chronic demyelinating polyradiculoneuropathy, as acute polyradiculoneuritis and as mononeuropathy multiplex. Frequently Varicella-zoster-radiculitis is observed. Cranial neuropathies are noted especially together with atypical aseptic meningitis, as a syndrome of the above mentioned polyneuropathies, with intracranial lymphomas and meningitides and meningoencephalitides caused by opportunistic infections. The morphological findings of the roots and nerves are variable: axonal degeneration and/or demyelination, infiltration of lymphocytes and microvasculitis. The pathogenesis varies: amongst others, direct infection by HIV, immunopathological changes and opportunistic infections are considered. The spontaneous development frequently leads to a remission. Treatment with corticosteroids and/or plasma exchange is only partially successful.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Diastematomyelia in adulthood].

A case of a 43-year-old female patient with a diastematomyelia from T11 to L4 is reported. The correct diagnosis was only made in adulthood, although clinical symptoms had been present since childhood. This case is compared with the few other cases known in the literature. The combination of myelography, CT and NMR proved to be most valuable for making this diagnosis.

Female↗
PubMed1987

[Congenital toxoplasmosis with delayed immune response in children. Diagnostic problems].

A newborn, delivered at term, developed a rapidly increasing hydrocephalus with intracranial calcifications and seizures during the first week of life. Clinical suspicion of congenital toxoplasmosis was at first not confirmed serologically (serum titer in the immunofluorescence test [IFT] of 1:1024 and complement-fixation reaction [CFR] of 1:40 equalling those of the mother; IgM-IFT being negative and the IFT and CFR titers significantly falling within two weeks). But in the further course of the disease the diagnosis of congenital toxoplasmosis was confirmed: 1. Microscopic tachyzoits in CSF when aged six weeks; 2. positive IgM-IFT in serum and CSF from the seventh weeks onwards; 3. steep IFT titer rise in serum and CSF from the 16th week onwards. This case demonstrates that with delayed immune response in the infected child only serial serological tests will exclude or confirm the diagnosis of congenital toxoplasmosis.

Antibodies, Bacterial↗