Biomedical subjects

C H Rickert

Publications and source records attributed to C H Rickert.

At least 55 records · Page 3Linked to original sources

PubMed1998

Cell death mechanisms in multiple system atrophy.

The presence and distribution of apoptotic cell death in multiple system atrophy (MSA) and morphologically related diseases were investigated by means of a modified terminal deoxynucleotidyl transferase-mediated nick end labeling method, comparing their distribution with that of glial cytoplasmic inclusions, immunohistochemically demonstrated bcl-2 protein, bax protein, CD95, TNFalpha, and p53-protein expression, as well as activated microglia. Apoptosis occurred almost exclusively in oligodendrocytes in multiple system atrophy and its general distribution was comparable to the already known oligodendroglial pathology in this disorder. Additionally, in about a quarter of glial cytoplasmic inclusions, there was upregulation of bcl-2-protein and coexpression with ubiquitin, suggesting a final attempt of involved cells to counteract apoptotic cell death. Bax protein was also demonstrated in oligodendroglial cells. A significant neuronal apoptosis was not observed in MSA; these cells might be destroyed secondarily to oligodendroglial apoptosis by necrosis or other forms of programmed cell death. These results emphasize the central role of oligodendroglial pathology in multiple system atrophy, making this disease unique among neurodegenerative diseases.

Adult↗

PubMed1998

Shunt-related abdominal metastasis of cerebral teratocarcinoma: report of an unusual case and review of the literature.

OBJECTIVE AND IMPORTANCE: Internal drainage of cerebrospinal fluid to the abdominal cavity via a ventriculoperitoneal shunt (VPS) is a common procedure for therapy of obstructive hydrocephalus; because this condition is often caused by brain tumors blocking the natural cerebrospinal fluid pathways, the VPS as an artificial anastomosis can provide the means for the spreading of tumor cells by the cerebrospinal fluid. We report the case of a VPS-related abdominal metastasis of a teratocarcinoma and review the pertaining literature. CLINICAL PRESENTATION AND INTERVENTION: A 24-year-old man with a history of three brain tumors that were operated on when the patient was 14, 21, and 23 years of age developed an acute ileus 7 months after VPS insertion for cerebral teratocarcinoma. Intraoperatively, a massive abdominal tumor was observed, which turned out to be a peritoneal metastasis of the aforesaid brain tumor. The patient died as a result of his illness 1 month later. RESULTS: To date, 58 VPS-related metastases of brain tumors have been described. The male-to-female ratio is 1.6:1, the mean age at shunt insertion is 12.2 years, and the interval between shunt operation and diagnosis of metastases is 16.8 months. During the observation time, 69.2% of the patients died as a result of their illness or abdominal metastases. The most common sources of the metastases were germinomas (27.7%), medulloblastomas (19.1%), and endodermal sinus tumors (10.3%). CONCLUSION: The presented case is only the second VPS-related abdominal spreading of a cerebral teratocarcinoma. Metastases via VPS are rare but should be considered as a possible complication and mode of systemic spread in patients with primary intracranial malignancy.

Adolescent↗

PubMed1997

[Paraneoplastic limbic encephalitis].

We report on a 69-year old male patient who presented with vague depressive symptoms and loss of weight accompanied by lack of appetite, ageusia and anosmia. The patient died of bronchial pneumonia, and neuropathological examination revealed a so-called limbic encephalitis. The paraneoplastic origin of this case was later confirmed by discovery of a clinically inapparent, indolently growing small cell lung cancer. This case illustrates the difficult clinical diagnosis of paraneoplastic limbic encephalitis and the need for a close cooperation of pathologists and neuropathologists in the clarification of such cases.

Aged↗

PubMed1997

[Paraganglioma of the cauda equina].

We report on a case of paraganglioma of the cauda equina in a 48-year-old man. These slow-growing, mostly benign and encapsulated intradural-extramedullar tumours are clinically characterized by lumbago, paraesthesia and motor deficits as well as occasionally by incontinence. Paragangliomas of the cauda equina show monomorphous (main) cells arranged in a typical cell cluster pattern, demonstrating a lobular architecture and a fine net of connective tissue formed by so-called sustentacular cells; some tumours show focal ganglionic differentiation. Because of their morphological similarity to the more common ependymomas, paragangliomas of the cauda equina are sometimes misdiagnosed so that their incidence is likely to be higher than previously estimated. Immunohistochemistry findings are positive for neuron-specific enolase, chromogranin and other neuronal markers as well as neuropeptides (main cells) and S-100 protein (sustentacular cells) while widely lacking reactivity for GFAP. Paragangliomas of the cauda equina represent a rare entity, of which only 80 cases have been described in the literature. Because they only occur sporadically, they are often not included in the differential diagnosis of mass lesions of the region of the cauda equina.

Biomarkers↗

PubMed1997

Primary intracranial neoplasms of infancy and early childhood.

We investigated the age-related location, gender distribution, and histology of 107 brain tumors in children under 4 years of age seen in our department between 1984 and 1997. The male-to-female ratio was 1.4 (62/45 cases) with a prevalence of supratentorial tumors (60/47 = 1.3); the main histological entity was astrocytoma (33.6%), followed by ependymoma (14.0%). In the 1st year of life 22 cerebral neoplasms became clinically apparent. A higher ratio for supratentorial tumors was revealed (17/5 = 3.4), but without gender preference, and primitive neuroectodermal tumors (PNET) were the most frequent (5/22). In the 2nd year 25 tumors were found. The male-to-female ratio was 1.5 (15/10) and the supratentorial-to-infratentorial ratio, 1.1 (13/12). The two most common entities were astrocytoma and ependymoma (6 cases each). In addition, a survey of previously published investigations into this subject was performed and a compilation of data on 1960, 545 and 1084 tumors in children below the age of 1, 2 and 4 years, respectively, was prepared, which makes it the most extensive review of brain tumors of infancy and early childhood yet undertaken.

Age Factors↗

PubMed1997

Congenital immature teratoma of the fetal brain.

Congenital intracranial tumors are very rare and only account for 0.5-1.5% of all childhood brain tumors. Even rarer are those with prenatal manifestation. The most common of these present at birth are teratomas, which show divergent differentiation with 90% of them containing tissues from all three germ layers. We report a rare case of an intrauterine congenital immature teratoma in a female fetus at 23 weeks of gestation, which was sonographically diagnosed in vivo by detection of the tumor and associated craniomegaly. Because of the poor prognosis, termination of the pregnancy was induced by Rivanol instillation. The cerebral tumor was confirmed at autopsy and was not associated with any other malformations. Histological and immunohistochemical features of this tumor are presented.

Abortion, Eugenic↗

PubMed1997

Factor XIIIa expression in granulomatous lesions due to sarcoidosis or mycobacterial infection.

The a-subunit of the clotting factor XIII (FXIIIa) has previously been shown to be synthesized by cells of monocyte lineage such as macrophages and histiocytes. Thus, besides clot retraction, a possible role of FXIIIa has also been postulated in inflammation. In order to test this hypothesis, FXIIIa-expression in granulomatous lesions due to sarcoidosis and mycobacterial infection was investigated. In the 12 cases (six cases each) examined, FXIIIa-positive macrophages were consistently detected by immunohistochemistry. They were predominantly observed in the periphery of granulomas, whereas the centers were generally devoid of these cells. We did not find any difference in the distribution of FXIIIa-positive cells in both conditions; thus FXIIIa did not improve the differential diagnosis between sarcoidosis and tuberculosis. However, FXIIIa-producing macrophages seemed to contribute to the centripetal fibrosis in granuloma. These results further suggest that the basic pathogenetic mechanisms in granuloma formation are very similar, regardless of their origin from sarcoidosis or tuberculosis.

Adolescent↗

PubMed1997

Morphological and immunohistochemical characterization of granular cells in non-hypophyseal tumours of the central nervous system.

We report 14 biopsy cases of granular cell tumours (GCT) of the central nervous system (CNS) outside the pituitary gland. In six cases the granular cells determined the morphology (actual GCT), the other eight consisted of different CNS tumours with a varying granular cell component. Pronounced immunoreactivity for ubiquitin and alpha-1-antichymotrypsin could be found in all investigated tumours, while GFAP, neuron specific enolase, von Willebrand factor, vimentin, S-100 protein, alpha-1-antitrypsin, actin, and the neurofilaments 68 kDa and 160 kDa showed mostly weak positivity in some cases. Four out of eight GCT showed no immunoreactivity for MIB1; the other four cases had a proliferation index between 0.5% and 15%. Six out of nine cases were positive for p53. We consider granular cells to originate from different cell types. Thus, although morphologically identical, GCT are actually biologically heterogeneous. GCT of the CNS may represent gliomas of mostly astrocytic origin with a metabolically induced transformation of some tumour cells into granular cells.

Adult↗

PubMed1997

Three-dimensional reconstruction of senile plaques in Alzheimer's disease.

So far, the three-dimensional approach to senile plaques, one of the principal histopathological hallmarks in Alzheimer's disease besides neurofibrillary tangles, has been scarce. Two main problems in three-dimensional reconstruction of histological specimens are the horizontal distortion during the preparation of serial thin tissue-slides and the need for consecutive vertical readjustment. This is greatly facilitated by the reflection contrast microscope (Leica, Germany) which is a light microscopical instrument causing interference patterns and reflections along interfaces by means of circularly polarized epi-illumination. Using this technique, one can obtain distinct optical sections of a depth of 1.5 microns within specimens up to 30 microns in thickness, thus preserving the integrity of the observed object and rendering a manual alignment superfluous. We applied the reflection contrast microscope (RCM) on thick tissue-slides of the cerebral cortex of a patient suffering from Alzheimer's disease which had been dyed according to Campbell. This is a silver-based staining method detecting beta A4-amyloid, the main component of senile plaques. Under the RCM, these silver-stained extracellular amyloid deposits cause reflections which allow the assessment of their three-dimensional distribution by focusing through the specimen. The optical sections obtained in this way were digitized, and the identified senile plaques reconstructed by the grey-scale image analysis system VIDAS 2.5 (Zeiss/Kontron, Germany).

Aged↗

PubMed1996

Different adhesion types and active sensitivity of platelet subpopulations.

Two different adhesion patterns of blood platelets with different sensitivity to adenosine were demonstrated by means of reflection contrast microscopy with consecutive image analysis and cell affinity chromatography. High-performance liquid chromatography revealed that thrombin-induced serotonin release of adenosine-sensitive platelets was lower than that of adenosine-resistant cells. Our results indicate platelet heterogeneity and suggest that the platelets with lower adenosine sensitivity may be actively involved in the early interaction between platelets and injured endothelium.

Adenosine↗

PubMed1996

Qualitative investigations on vital blood platelets by reflection contrast microscopy.

Light-microscopic visualization of vital human blood platelets is improved by reflection contrast microscopy. The light reflected from the specimen causes interference patterns which are used for the assessment of surfaces or adhesion areas. By means of this technique we studied the activation process of unstimulated platelets. During the observation the following two features were assessed: (1) Platelet adhesion areas and their shape change: two main types of adhesion patterns were found for activated platelets. Type A was characterized by flat spreading and extensive adhesion zones, whereas type B showed only focal contacts in the center and long and sometimes dichotomously split pseudopodia. Both adhesion types coexisted in each sample but did not change into one another during the observation period of 25 min. (2) Pseudopodia formation: initially, a rapid evagination of mobile pseudopodia could be observed which lasted for approximately 2 min. After reaching their final individual length, the pseudopodia adhered to the glass and remained stationary.

Blood Platelets↗

PubMed1996

[Adhesions and interference images of unfixed erythrocytes].

For the analysis of deformability in microcirculatory investigations an exact understanding of red blood cell (RBC) geometry is required. To extend knowledge we introduce a new morphological feature of resting unfixed erythrocytes by means of an inverted reflection contrast microscope (RCM). By assessing the interference patterns caused by RCM erythrocytes can be classified according to the depth of their central concavity which depends on the flexibility of the RBC. Moreover, the RBC adhesion can be directly observed. We found out that: 1. Five types of normocytes can be distinguished in RCM. 2. In phase contrast the size distribution of RBC without central concavity (type 5, 11.53% of all normocytes) shows peaks at 48 microns2 and 52 microns2. 3. Image analysis reveals two size categories of relative adhesion areas. One category consists of type 1 and 2 (relative adhesion area 25.63%), the other of the types 3 to 5 (relative adhesion area 39.91%). Besides, RCM allows the reliable identification of pathologic erythrocytes in unstained specimens.

Cell Adhesion↗

PubMed1995

Adhesion of washed blood platelets in vitro is advanced, accelerated, and enlarged by oxidized low-density lipoprotein.

In order to study the influence of oxidized low-density lipoprotein (Ox-LDL) on platelet functional morphology at an early activation stage, washed human blood platelets were stimulated by 100 micrograms/ml Ox-LDL at 37 degrees C. The settling and spreading process of stimulated and unstimulated platelets on Formvar-coated glass was observed for approximately 20 min by reflection contrast microscopy (RCM) and quantified by image analysis. Each group consisted of at least 250 platelets. The results show that incubation with Ox-LDL causes platelet shape change and pseudopodia formation. The sedimentation of stimulated platelets precedes that of unstimulated platelets by approximately 3 min. The increase of the total adhesion area of all Ox-LDL treated platelets is significantly accelerated in comparison to normal platelets (20.45 microns2/min vs. 15.45 microns2/min; P < 0.01). The mean total adhesion area of Ox-LDL-treated platelets was generally larger than that of untreated platelets (189.7 microns2 vs. 144.7 microns2; P < 0.01). The disappearance of intracellular granules after platelet activation, observed by RCM, is supported by transmission electron microscopy. Our results suggest that Ox-LDL activates platelets and advances and accelerates their adhesion and thereby may contribute to pathological thrombosis and arteriosclerosis.

Blood Platelets↗

PubMed1995

Decreased adhesion of oxidized LDL-stimulated platelets caused by cytochalasin D.

The adhesion of human blood platelets is studied with an in vitro model using reflection contrast microscopy and an image analysis system. The adhesive feature is promoted by oxidatively modified low density lipoprotein, which also induces functional morphological changes of platelets. However, when washed platelets are pretreated with 0.05 mM cytochalasin D, oxidized low density lipoprotein (100 micrograms/ml) causes a slower increase of the adhesion area (11.6 microns 2/min) compared to untreated platelets (15.7 microns 2/min) or platelets treated by oxidized low density lipoprotein alone (20.5 microns 2/min, P < 0.01). These results are supported by light transmission analysis and by transmission electron microscopy. Our experiments suggest that cytochalasin D inhibits the change of platelets in shape induced by oxidized low density lipoprotein, hinders the adhesion, but does not prevent the adhesion entirely.

Blood Platelets↗

PubMed1995

Evaluation on blood platelets by the image analysis system VIDAS 2.5.

This paper introduces a program written on the image analysis system VIDAS 2.5. It enables the automatic quantification of high numbers of adhesion areas of vital human platelets, thus allowing statistical analysis. These adhesion areas were observed by reflection contrast microscopy (RCM), which generates images of an intense contrast and serves as a prerequisite for an evaluation by image analysis. However, RCM-photographs of the observed platelets have highly varying mean greyvalues and greyranges. These common problems for self-operating identification are excluded by two procedures within the program: 1. calibration of the scanning process for an optimal use of the available greyvalues provided by the negative, camera, and the image analysis system; and 2. relation of the threshold for discrimination of adhesion areas to the statistic parameters of the histogram within each individual digitized image. Images processed according to these prerequisites were transferred to the VIDAS implemented routines for identification and measurement of areas. Thus, image analysis combined with RCM offers a tool for basic and clinical platelet research, which is shown by an example of stimulation and inhibited stimulation of platelet activation.

Blood Platelets↗

PubMed1995

Morphologic quantification of blood platelets by image analysis.

OBJECTIVE: For morphologic and functional investigations on the physiology and pathology of human blood platelets, their adhesion plays an important role. This feature is normally assessed concerning qualitative aspects, but there is a lack of quantitative investigations. STUDY DESIGN: We developed a model to quantify in vitro manipulations on thrombocytes by measuring their adhesion areas automatically. This was achieved by combining the VIDAS 2.5 image analysis system with reflection contrast microscopy (RCM). The evaluation was performed independent of the position of the grey value histogram by analyzing each digitized image corresponding to its individual mean grey value. RESULTS: The applicability and validity were verified from the example of a pharmacologic experiment administering the platelet stimulant oxidized low density lipoprotein (ox-LDL) to thrombocyte suspensions and confirming it by aggregometry. We assessed the temporal increase in adhesion area and mean total adhesion area of activated platelets, comparing unstimulated to stimulated ones. Ox-LDL accelerated the adhesion process and increased the adhesion area. CONCLUSION: The combination of RCM with consecutive image analysis provides useful parameters for in vitro examination on vital human platelets. Large amounts of data can be accumulated in a short time for an evaluation of influences of and on blood platelets.

Blood Platelets↗

PubMed1994

Reflection contrast microscopy within chrome-alum haematoxylin stained thick tissue-sections.

This paper introduces two innovations in reflection contrast microscopy (RCM): (1) an extended application for qualitative light microscopic investigations; and (2) a novel method for quantification in cytochemistry. (1) We found out that RCM cannot only be used for surface characterizations and in thin sections but also within thick tissue-sections. The use of the RCM technique is demonstrated on slides of the supraoptic nucleus (SON) of the rat stained with chrome-alum haematoxylin: Among all the stained structures only neurosecretory granules are found to cause reflections. The visualization of the neurosecretion and its distribution is more distinct and of sharper contrast than in bright field microscopy. (2) The improved differentiation allows the quantification of neurosecretion in tissue-sections by combining RCM with grey-scale image analysis.

Animals↗

PubMedDate not supplied

Abdominal metastases of pediatric brain tumors via ventriculo-peritoneal shunts.

Internal drainage of cerebrospinal fluid (CSF) to the abdominal cavity via a ventriculo-peritoneal shunt (VPS) is a procedure that is commonly used for the treatment of obstructive hydrocephalus. As this condition is often caused by brain tumors blocking the natural CSF pathways, a VPS, as an artificial anastomosis, can provide the means for tumor cells to be spread with the CSF. A review of the literature reveals 35 VPS-related abdominal metastases from pediatric brain tumors; 17 in patients aged 0-9 (group A) and 18 in patients aged 10-18 years (group B); the mean age of male patients was 10.5, and that of female patients, 7 years. The male-to-female ratio was 1.9 (group A 1.1, group B 3.5), and the mean interval between shunt operation and diagnosis of metastases, 16.7 months (group A 11.6, group B 22.6 months; boys 21.6, girls 7.5 months). During the observation period, 22/30=73.3% of the patients died (group A 13/15=86.7%, group B 9/15=60%; boys 13/21=61.9%, girls 9/9=100%); their mean survival time after shunting was 18.7 months (group A 15.7, group B 23.1 months; boys 25.5, girls 9 months). The four most common sources of metastases were germinomas (9 cases=25.7%; group A none, group B 9), medulloblastomas (8 cases=22.9%, group A 7, group B 1), endodermal sinus tumors (5 cases=14.3%, group A 1, group B 4), and astrocytomas (4 cases=11.4%, group A 4, group B none). Metastases via VPS are rare, but should be considered as a possible complication and mode of systemic spread in children with primary intracranial malignancy. They have a more favorable prognosis in boys and in the second decade of life.

Adolescent↗