Search PubMed⌕ Search

Biomedical subjects

D Troost

Publications and source records attributed to D Troost.

At least 91 records · Page 5Linked to original sources
PubMed1993

Distribution of metallothionein in the human central nervous system.

The distribution of metallothionein (MT), a metal-binding protein, was examined immunohistochemically in the normal human brain and spinal cord. Paraffin-embedded brain tissue from three patients who had died from a non-neurological disease and were free of histopathological central nervous system alterations were processed. The results of the present study demonstrate that MT is readily detectable in a subgroup of astrocytes in the normal human brain. MT staining is most intense on grey matter astrocytes that bear short stout processes and which probably represent protoplasmic astrocytes. Using anti-MT and anti-glial fibrillary acidic protein immunostaining, we could demonstrate two subpopulations of astrocytes that were mutually exclusive. The functional significance of MT-expression in protoplasmic astrocytes is not entirely clear. Metal detoxification is only one of the many postulated functions of MT. The finding that staining for MT permits subtyping of astrocytes may be of great importance in glia research and surgical pathology of the human brain.

Adult↗
PubMed1993

Inflammatory cells in the peripheral nervous system in motor neuron disease.

We examined post-mortem material of the peripheral nervous system of 26 cases of motor neuron disease (MND) for the presence of lymphocyte subsets and macrophages. Findings were quantified and compared with those in control nerves. Lymphocytes in chronic and acute axonal degeneration were studied in sural nerve biopsy and animal material. Signs of demyelination were studied in MND and controls with infiltrates of T cells. A few T lymphocytes were scattered diffusely within the fascicles. The numbers did not differ between MND and controls. About half of the T cells was positive for CD45RA, the other half being positive for CD45RO. T cells were negative for CD25, CD54 and major histocompatibility complex (MHC)-class II. There were hardly any B lymphocytes. The numbers of lymphocytes in nerves with and without axonal degeneration did not differ. Increased MHC class II expression was present on denervated Schwann cells and macrophages in MND and in sural nerves with axonal degeneration. Macrophages were increased in number and in size, both in MND and in control material with axonal degeneration. No signs of demyelination were present either in MND or in controls. It is concluded that a T cell-mediated process in peripheral nerves in MND is very unlikely.

Adolescent↗
PubMed1993

Tissue fixation methods alter the immunohistochemical demonstrability of neurofilament proteins, synaptophysin, and glial fibrillary acidic protein in human cerebellum.

This study has examined the effect of postmortem autolysis, type, and duration of fixation on neurofilament, synaptophysin, and glial fibrillary acidic protein (GFAP) antigen decay as demonstrated by immunohistochemistry, using a streptavidin-biotin peroxidase method. The system used consisted of 5 normal cerebellar cortices. Time intervals, temperature, mode of fixation and storage, and staining technique were well controlled. Anti-neurofilament antibodies comprised SMI-31, MNF, and BF-10 against phosphorylated epitopes, and SMI-32 against a non-phosphorylated epitope. Bouin's and B5 fixative, and Sensofix gave best results, whereas formaldehyde and paraformaldehyde fixation gave much lower immunoreactivity. Phosphorylated neurofilament epitopes were less affected by aldehydes than unphosphorylated epitopes. GFAP staining was most consistent after Bouin fixation while the monoclonal antibody was much more sensitive to the fixative used than the polyclonal one. Aspecific background staining increased considerably after a postmortem interval of 24 hours. Synaptophysin immunoreactivity, as demonstrated by SY-38, proved very sensitive to prolonged fixation and was of poor quality following formaldehyde and paraformaldehyde fixation. Knowledge of antigen decay due to postmortem artifacts is essential for the correct evaluation of immunoperoxidase studies of autolyzed tissues that have been fixed and stored in different modes and for variable time interval.

Antibodies↗
PubMed1993

Decreased number of oxytocin neurons in the paraventricular nucleus of the human hypothalamus in AIDS.

The number of immunocytochemically identified vasopressin (AVP) and oxytocin (OXT) neurons was determined morphometrically in the paraventricular nucleus of the hypothalamus of 20 acquired immunodeficiency syndrome (AIDS) patients and 10 controls. The AIDS group consisted of 14 homosexual males (age range 25-62 years), four of whom had a probable HIV-1 associated dementia complex, and six non-demented heterosexuals (four males and two females, age range 21-73 years). Ten males without a primary neurological or psychiatric disease served as a control group. The number of OXT-expressing neurons in the paraventricular nucleus of both groups of AIDS patients was approximately 40% lower than that of the controls. In contrast, the three groups showed no significant differences in the number of AVP-expressing neurons in the paraventricular nucleus. Since there were no significant differences in the number of AVP and OXT cells between the homosexual and heterosexual subjects with AIDS, the morphological difference in the paraventricular nucleus seems to be related to AIDS and not to sexual orientation. No inflammatory changes were found in the paraventricular nucleus area. The selective changes in the OXT neurons of the paraventricular nucleus may be the basis for part of the neuroendocrine, autonomic dysfunction or vegetative symptoms in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Neuronophagia in the motor cortex in amyotrophic lateral sclerosis.

This study was designed to identify which phagocytic cells in the cerebral cortex of amyotrophic lateral sclerosis (ALS) patients are involved in the process of neuronophagia. For this purpose a number of single and double immunocytochemical stains were carried out on five ALS cases which were selected on the basis of the presence of degenerative and phagocytic phenomena in the cerebral cortex. The cortical degenerative process is mainly present in the third and fifth layers and is not restricted to the fifth layer which contains the cell bodies of the Betz cells. The present study indicates that a number of cells are involved in the process of phagocytosis in ALS. Resident macrophages (from microglial or perivascular origin) and astrocytes seem to play an immunologically-mediated role in the disappearance of neurons. Some of the cells involved in the degenerative process, i.e. rounded macrophages and microglia, expressed major histocompatibility class II antigen. The phagocytic cells in neuronophagia were phenotypically identical to perivascular macrophages and not to microglia. Therefore, the process of phagocytosis of neurons appears to be primarily the task of the perivascularly located macrophage.

Adult↗
PubMed1992

Metallothionein immunoreactivity is increased in the spinal cord of patients with amyotrophic lateral sclerosis.

Sections of the spinal cord from 10 patients with classic amyotrophic lateral sclerosis and from 10 control cases were examined by immunocytochemical methods to localize metallothionein. Metallothionein immunoreactivity was seen in the nucleus and cytoplasm of a subset of astrocytes, largely confined to the gray matter. Also, diffuse gray matter staining was observed, probably representing small glial fibers. Astrocytic metallothionein immunoreactivity (P less than 0.01) and strong gray matter matrix staining (P less than 0.03) was increased in the spinal cords from patients with amyotrophic lateral sclerosis. Although compatible with induction by metals, increased metallothionein expression in the spinal cords from patients with amyotrophic lateral sclerosis may also have resulted from inflammation or gliosis.

Amyotrophic Lateral Sclerosis↗
PubMed1992

Molecular characterization of areas with low grade tumor or satellitosis in human malignant astrocytomas.

Malignant astrocytomas often display histopathological heterogeneity. In the present study, we have molecularly characterized different areas within 4 such tumors to determine whether the tissue heterogeneity can be explained by differences in DNA constitution. Two tumors contained low grade areas, and the other 2 had areas with satellitosis. The tumors were examined for loss of heterozygosity with markers from chromosomes 9p, 10, and 17p and for amplification of the epidermal growth factor receptor gene. In each case, the high grade portion of the tumor displayed at least one of these structural alterations. However, identical alterations were found in the associated low grade or satellitosis areas of each tumor. Our data suggest that: (a) genetic alterations associated with tumor progression already occur in histopathologically low grade areas of high grade astrocytoma; (b) satellitosis associated with a high grade astrocytoma has to be considered as part of that tumor; and (c) tissue heterogeneity within a high grade astrocytoma is not a consequence of differences in DNA constitution at the loci that were examined.

Astrocytoma↗
PubMed1992

Increased metallothionein in the liver and kidney of patients with amyotrophic lateral sclerosis.

To evaluate the putative role of metals and trace elements in the pathogenesis of classic amyotrophic lateral sclerosis, we studied the metallothionein levels in liver and kidney samples obtained at autopsy from 24 patients with amyotrophic lateral sclerosis and 18 controls. To assay metallothioneins and copper, cadmium, and zinc bound to metallothioneins, we used high-performance liquid chromatography directly coupled to flame atomic absorption spectrometry. Total cadmium, zinc, and copper concentrations were determined separately with the use of graphite furnace atomic absorption spectrometry with Zeeman background correction. The median liver metallothionein level was 60.3 mg/kg (range, 9 to 318 mg/kg) in the patients with amyotrophic lateral sclerosis and 12.6 mg/kg (range, 0 to 104.5 mg/kg) in the controls. In the kidney, median metallothionein levels were 126.9 mg/kg (range, 44 to 387 mg/kg) in the patients with amyotrophic lateral sclerosis and 64 mg/kg (range, 13.1 to 187 mg/kg) in the controls. Total zinc, cadmium, and copper concentrations, as measured by atomic absorption spectrometry, were not significantly different in patients vs controls. Our finding of elevated metallothionein levels in organs from patients with amyotrophic lateral sclerosis may indicate an increased exposure to metals.

Adolescent↗
PubMed1992

Neurofilament and glial alterations in the cerebral cortex in amyotrophic lateral sclerosis.

According to the literature, only minor nonspecific histopathological lesions are present in the motor cortex in up to 90% of the amyotrophic lateral sclerosis (ALS) patients. These observations, however, have so far been based mainly on conventional staining techniques. An exception to this is the focal glial reaction that has been reported following immunocytochemical staining for glial fibrillary protein (GFAP), which is reported to be distinctive for ALS in the cortex. Since perikarya of degenerating motor neurons in the spinal cord of ALS patients have been found to accumulate phosphorylated neurofilaments (PNF), an investigation was conducted to determine whether PNF was also a sensitive marker for alterations in the motor cortex in this condition. On large brain sections from 15 ALS patients, intense PNF immunoreactivity was found in the motor cortex from 11 patients. It was mainly localized in small pyramidal cells and basket cells, whereas only slight staining was observed in Betz cells. PNF-positive basket cells were also present in controls, but the basket cells staining for PNF were less numerous in controls than in ALS specimens. PNF-positive Betz cells were found in 47% of 15 ALS patients and in 10% of the controls. PNF accumulation was also found in swollen, probably degenerating, terminal boutons around perikarya of large pyramidal cells and Betz cells in the motor areas of ALS patients only. These observations suggest that the premotor innervation of the motor system is preferentially affected in ALS. Small brain sections, comprising the motor cortex, from 18 additional ALS patients demonstrated a similar PNF-staining pattern. However, differentiating ALS patients from controls was much easier when studying large brain sections. No ubiquitin-immunoreactive inclusions were found, except for sporadic tangles. The presence of a focal-GFAP positive astrocytosis as reported in the literature in the precentral cortex was confirmed. However, it was found to be nonspecific since it was also present outside the precentral cortex and in the cortex of normal control patients. No spatial relation was found between the distribution of the glial reaction in ALS and the areas containing neurons and boutons accumulating PNF.

Adult↗
PubMed1992

Hyperthermic injury versus crush injury in the rat sciatic nerve: a comparative functional, histopathological and morphometrical study.

Functional and morphological changes of the rat sciatic nerve after local hyperthermia (30 min, 45 degrees C) and crush treatment were compared. After hyperthermic injury nerve function loss developed in a time period of about 7 h. Nerve crush led to an immediate loss of nerve function. Nerve function loss was assessed by a motor and a sensory function test. Recovery from function loss took place in both treatment groups and was complete in 4-5 weeks. Early (within 8 h post-treatment) histopathological changes in the nerve after heating included edema, possible blood stasis and changes in the blood vessel wall, like swelling of the media. During this period some axonal changes were observed. Immediate after crushing axons were severely damaged, while many blood vessels remained normal. Within one week after both treatments, degeneration of axons and myelin was observed at the site and distal from the site of the lesion (Wallerian degeneration). Three weeks after treatment a major part of the axons had regenerated and remyelinated. Vascular changes at the site of lesion could still be observed in the heat-treated nerves. Twelve weeks after both treatments, blood vessels appeared to be normal again. Morphometrical analysis of the treated nerves confirmed the histological observations. Three and 12 weeks after treatment average axon diameters were significant smaller and average myelin sheaths were significant thinner compared to untreated nerves. These parameters did not differ significantly when the two treatment groups were compared.

Animals↗
PubMed1992

Neurological complications after 434 MHz microwave hyperthermia of the rat lumbar region including the spinal cord.

Hyperthermia was applied in the region of the vertebral column from the second to the fifth lumbar vertebra using a ring-shaped 434 MHz microwave radiator. In all experiments temperatures were measured at a 'reference' thermocouple which was placed against the fourth lumbar vertebra. After 60 min of heat treatment at 'reference' temperatures of 43.0 degrees C, 44.0 degrees C and 45.0 degrees C (+/- 0.05 degrees C) the average maximal temperature inside the vertebral canal were 42.6 degrees C, 43.0 degrees C and 43.8 degrees C (+/- 0.3 degrees C), respectively. At all 'reference' temperatures the maximal core temperature of the animal did not exceed 40.5 +/- 0.3 degrees C after 60 min of heat treatment. Dorsal skin and muscle temperatures in the treatment area reached 'reference' temperature, and transient skin and muscle necrosis was observed after treatment for 1 h at 'reference' temperatures at 44 degrees C and 45 degrees C. Temperatures in the peritoneal cavity approximately 1 mm ventrally of the vertebral column rose to 41.8 degrees C after 60 min at reference 43.0 degrees C. Treatment at spinal cord temperature 42.6 degrees C for 60 min did not induce any significant neurological effects. Motoric dysfunction of the hind legs, such as difficulties with walking, was observed after 60 min treatment at spinal cord temperatures of 43.0 degrees C or 43.8 degrees C. In addition, 24 h after treatment at 43.8 degrees C for 60 min loss of tail tonus was observed, as well as loss of sensory function in the hind limbs. Recovery from the neurological disorders, except for the loss of tail tonus, occurred within 2 weeks after treatment. Histopathological examination revealed necrosis in the central areas of the spinal cord at 3 days and complete necrosis at 7 days after treatment at 43.8 degrees C for 60 min.

Animals↗
PubMed1992

Pyrimethamine alone as maintenance therapy for central nervous system toxoplasmosis in 38 patients with AIDS.

We retrospectively assessed the efficacy of maintenance therapy with pyrimethamine alone in 38 patients with AIDS and central nervous system (CNS) toxoplasmosis. The diagnosis was based on clinical presentation and compatible CT scan abnormalities with subsequent response to therapy. Survival analysis was performed by the product limit method of Kaplan-Meier. Fourteen patients received maintenance therapy with 25 mg pyrimethamine per day (group 1), and 24 patients were treated with 50 mg per day (group 2). The median survival from initiation of maintenance therapy until death or end of the study for the entire study population was 32 weeks. Median survival in group 1 was 28 weeks, as compared with 36 weeks in group 2 (p = 0.34). Relapses occurred in 12 patients, six in group 1 and six in group 2. There was no significant difference in failure-free survival between the two treatment groups (p = 0.09). One patient in group 1 and two patients in group 2 experienced severe toxicity, requiring discontinuation of therapy. All three patients relapsed and died. Two patients in group 2 who stopped treatment on their own initiative also had relapses. Thus, all five patients who discontinued therapy had relapses. Five of 13 patients in group 1 and two of 20 patients in group 2 relapsed during continuous therapy with pyrimethamine (p = 0.13); these seven patients responded to reintroduction of combination therapy (n = 6) or treatment with 50 mg pyrimethamine per day (n = 1). The results of our retrospective analysis suggest that maintenance therapy with oral pyrimethamine, 50 mg per day, in AIDS patients with CNS toxoplasmosis is effective.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Nerve growth factor receptor immunostaining in the spinal cord and peripheral nerves in amyotrophic lateral sclerosis.

In animal experiments, nerve transection is followed by expression of nerve growth factor receptors (NGFR) on Schwann cells of both motor and sensory nerve fibres distally to the site of the lesion. To determine whether denervated Schwann cells in amyotrophic lateral sclerosis (ALS) similarly express NGFR, a study was made of post-mortem material of peripheral nerves and ventral roots from ALS cases and age-matched controls, using immunolabelling methods. Dorsal roots and spinal cords were also examined for the presence of NGFR. In all the ALS cases and controls, NGFR immunostaining was seen in the outer layer of vessel walls, perineurial sheaths, connective tissue surrounding fascicles in nerve roots and in the substantia gelatinosa of the spinal cord. In ALS, NGFR staining was also present in the Schwann cells of degenerated nerve fibres in mixed peripheral nerves, in ventral roots and, to a lesser extent, in dorsal roots. NGFR immunoreactivity was also seen in elongated cells extending from the perifascicular connective tissue into the nerve fascicles. It is concluded that denervated Schwann cells in ALS express NGFR and that NGFR immunostaining on Schwann cells may be used as an indicator of axonal degeneration. The NGFR labelling in the dorsal roots supports the notion that ALS is not a pure motor syndrome.

Amyotrophic Lateral Sclerosis↗
PubMed1991

Muscular changes in the guinea pig caused by chronic ascorbic acid deficiency.

The present study was undertaken in order to decide whether chronic ascorbic acid (AA) deficiency only causes myopathy in the guinea pig or whether it also causes central nervous system pathology. Juvenile male animals, fed an optimally balanced, purified diet with minimal amounts of AA, developed a nutritional myopathy complicated by trauma, arthrogenic factors and defective repair. The absence of changes in the spinal pyramidal tracts, the anterior horn cells and peripheral nerve agrees with the absence of neurogenic changes in muscle specimens as target, targetoid, or small angulated fibers, group atrophy, type grouping, or changes in the distribution pattern of fibers. We conclude that chronic AA deficiency in the guinea pig cannot serve as an animal model of human amyotrophic lateral sclerosis.

Amyotrophic Lateral Sclerosis↗
PubMed1990

Accuracy and interobserver variation in the interpretation of computed tomography in solitary brain lesions.

The clinical data and computed tomographic findings of 64 patients with solitary supratentorial brain lesions were presented to two panels of six experienced clinicians. The diagnoses predicted by these clinicians were compared with each other (interobserver variation) and with the definite diagnosis, which in almost all cases was based on histologic examination of the involved tissue (validity of predicted diagnosis). The interobserver agreement was only moderate. The predicted diagnoses agreed with the definite diagnoses in only 57% of cases. A high number of errors were made in distinguishing between high-grade and low-grade glioma and between high-grade glioma and cerebral metastasis, and in the detection of primary cerebral lymphoma. Possible implications of these findings for clinical practice are discussed.

Adult↗
PubMed1990

Progressive fatal dementia (Creutzfeldt-Jakob disease) in a patient who received homograft tissue for tympanic membrane closure.

We report the case history of a 54-year-old man who developed a fatal neurological disorder 4 years after a successful tympanoplasty with homograft pericardium. The final diagnosis of this case was Creutzfeldt-Jakob disease. This infectious spongiform encephalopathy is probably caused by a slow virus that can be transmitted by transplantation materials. The possible accidental transmission of Creutzfeldt-Jacob disease by the use of homograft materials in otologic surgery is discussed.

Cerebral Cortex↗
PubMed1990

Cerebral medulloepithelioma--electron microscopy and immunohistochemistry.

A case is reported of a boy, 3 years of age, with a large medulloepithelioma in the left cerebral hemisphere. Medulloepitheliomas are rare tumors of the primitive medullar epithelium. Histological, immunohistochemical and electron microscopical findings are presented. We discuss previously reported cases, the ontogeny of this type of tumor and the relation to the so-called primitive neuro-ectodermal tumors (PNET).

Brain Neoplasms↗