Biomedical subjects

M Bergmann

Publications and source records attributed to M Bergmann.

At least 127 records · Page 7Linked to original sources

PubMed1996

Primary non-Hodgkin lymphomas of the CNS-proliferation, oncoproteins and Epstein-Barr-virus.

Primary cerebral lymphomas (PCL's) are rare tumors which, however, occur with increasing frequency. The present study investigated 55 PCL's of B-cell type, 36 in immunocompetent and 19 in AIDS-patients and 6 cases of intravascular lymphomatosis. In immunocompetent patients, proliferative indices as evaluated by PC10 and MIB1 reflected the histologic grade. Low grade tumors had a mean PCNA and MIB-1 count of 19 and 18.8 (SD 14.7 and 13.2), respectively, and high grade neoplasias showed counts of 56.7 and 47.1 (SD 19 and 17.4), respectively. No correlation of both indices with patient survival was found. 21 cases (58.3%) displayed p53-positivity of varying degree and 19 cases (52.7%) harbored bcl-2 positive neoplastic cells. Immunocompetent cases were always negative for Epstein-Barr virus RNA and lmp-1-protein. In AIDS-cases, 13 cases (68.4%) showed up lmp-1 positivity and 15 cases (78.9%) had EBER-RNA. bcl-2 positive cells were detected in 5 cases (26.3%) and all cases were p53-negative. These results are in keeping with a role of EBV in the pathogenesis of primary cerebral lymphomas in AIDS-, but not in immunocompetent patients. None of the cases with intravascular lymphomatosis showed an expression of bcl-2 or p53 oncoproteins or lmp-1 and none had EBER-RNA.

Adult↗

PubMed1996

[Tumorous neurosarcoidosis--a rare manifestation of Boeck disease--3 cases and review of the literature].

Neurosarcoidosis mimicking CNS tumours represents a rare manifestation of Schaumann's disease. The central or peripheral nervous system is clinically involved in 5% of sarcoidosis, basal parts of the brain being mainly affected by the inflammation. This location of the process causes basal meningitis with cranial nerve paresis as well as parenchymal granulomatosis around the third ventricle and hypophysis. Solid, space-occupying lesions rarely occur, evoking problems in the differentiation from cerebral tumours. We report three cases of neurosarcoidosis presenting as intracranial tumours, where a space-occupying lesion was the first of only manifestation of sarcoidosis. The lesions in our cases were found in parietal and parieto-occipital cortex and in the fourth ventricle and vermis cerebelli, respectively. These locations are unusual, since most of the reported cases were affecting the temporal lobe. We review the literature and discuss the role of neurosarcoidosis in the differential diagnosis of intracranial tumours.

Brain↗

PubMed1995

Morphomechanics of the humero-ulnar joint: I. Joint space width and contact areas as a function of load and flexion angle.

BACKGROUND: Previous studies have shown that the trochlear notch is deeper than necessary for an exact fit with the humerus. However, humero-ulnar joint space width and contact areas have so far not been quantified for variations in the load and angle of flexion. METHODS: Six fresh cadaveric specimens were investigated at 30 degrees, 60 degrees, 90 degrees, and 120 degrees of flexion and at loads of 25 and 500 N, simulating resisted elbow extension. The joint space width and contact were determined, using polyether casting material. RESULTS: At 25 N all joints made contact in the ventral and dorsal aspects of the articular surfaces, whereas in the depth of the trochlear notch the joint space was on average between 0.3 and 2.8 mm wide, with some variation between individuals. At 500 N the joint space width was considerably reduced and the contract areas expanded towards the depth of the notch. The size of the dorsal contact areas was significantly smaller at 30 degrees and that of the ventral ones at 120 degrees, their ventro-dorsal ratio decreasing considerably from 30 degrees to 120 degrees (p < 0.01). CONCLUSION: These results indicate that the size of the contact areas depends to a slight extent on the joint position, but that at all loads and flexion angles a bicentric contact and an important central joint space width emerge because of the concave incongruity of the joint. These data may be used for numerical calculations, analysing the effects of incongruity on the joint stress and on the functional adaptation of the subarticular tissues.

Adult↗

PubMed1995

Nemaline myopathy: two autopsy reports.

Nemaline myopathy belongs to the group of congenital non-progressive myopathies; however, in rare cases death occurs in early infancy. We report two cases of rapidly fatal nemaline myopathy. The first patient, who died at the age of 26 months, showed atrophy of type 1 fibers containing numerous rods in biopsy sections. Biopsy of the second patient, who had died at the age of 5 months, revealed severe maturational arrest and myopathy, but rods were so rare that diagnosis could only be made at the ultrastructural level. Autopsy of both patients showed that atrophy of type 1 fibers and maturational arrest had disappeared in the very same muscles; rods had moved to a central position in the first and significantly increased in number in the second case. Diaphragma muscles contained abundant amounts of rods in both cases. The cardiac musculature showed a few rods only in the first patient, who had developed heart insufficiency 11 months prior to death. Immunohistochemical analysis showed that rods did not contain desmin or ubiquitin.

Biopsy↗

PubMed1995

Dysembryoplastic neuroepithelial tumour of the cerebellum.

A case of dysembryoplastic neuroepithelial tumour of the cerebellum occurring in a 28-year-old woman is presented. The lesion extended from the cortex of the inferior vermis upwards into the white matter. Histologically, it exhibited areas of microcystic cerebellar astrocytoma and glial regions with hamartomatous blood vessels as well as areas with oligodendrocyte-like cells (OLC) with a delicate, fibrillary stroma lying in a mucinous, often microcystic matrix. The OLC showed prominent rosette formation and immunohistochemical features suggesting neuronal, i.e. granule cell, differentiation.

Adult↗

PubMed1995

Onuf's nucleus is frequently involved in motor neuron disease/amyotrophic lateral sclerosis.

Involvement of Onuf's nucleus (ON) in 28 cases of amyotrophic lateral sclerosis/motor neuron disease (MND/ALS) with different clinical syndromes is reported. Although significant neuronal loss was absent, all cytoskeletal abnormalities typical of alpha-motor neurons in MND/ALS were found in ON. Spheroids were detected in 53.5% of cases; 0.6-4.5% of ON neurons contained Bunina bodies, which were present in 42.8% of cases. Ubiquitin-reactive inclusions (UBRI) of filamentous and hyaline type were found in 57.1% of cases and in 1.2-10.7% of ON neurons. Cases with pyramidal tract involvement (ALS) were involved by UBRI in 76.5%, whereas cases with progressive spinal muscular atrophy revealed the same inclusions in only 27.2%. No similar inclusions were present in sacral parasympathetic intermediolateral nucleus. It can be concluded, therefore, that ON belongs to the somatic motor system and is principally vulnerable to MND/ALS, albeit to a lower degree.

Adult↗

PubMed1995

Spontaneous recrudescence of spermatogenesis in the photoinhibited male Djungarian hamster, Phodopus sungorus.

Photosensitive rodents exposed to inhibitory short photoperiods become insensitive to this environmental factor after prolonged exposure. During the following process of spontaneous recrudescence, the animals that have adapted to the winter season show a return of all seasonal parameters. In the Djungarian hamster, obvious photoperiod-dependent changes are reinitiation of the reproductive organs, a 20-30% increase in body weight, and a moult from whitish fur into brown summer fur. This study was designed to analyze the morphological and endocrinological changes occurring during spontaneous testicular recrudescence in male Djungarian hamsters under prolonged short photoperiods. Two experiments were performed 1) to analyze the time-dependent changes in groups of hamsters exposed to short photoperiods and 2) to observe testicular and humoral changes in individual animals during spontaneous recrudescence. Regrowth of the testes and seminal vesicles did not begin before Week 18 in short photoperiods. While serum testosterone did not increase before Week 24, serum FSH had already returned to normal values from Week 18 onwards. Individual analysis by enzyme histochemistry revealed that 3 beta-hydroxysteroid-dehydrogenase activity in Leydig cells was not restored before testicular weights of more than 400 mg were observed and the first wave of spermatogenesis had reached the stage of elongated spermatids. This indicates that the testicular testosterone production was low until a status of testicular recrudescence had been achieved, at which point the testis showed complete qualitative spermatogenesis and a restoration of the Sertoli cell actin filaments. These data suggest that the process of early spontaneous recrudescence in male Djungarian hamsters appears to be initiated by the restoration of serum FSH rather than by testosterone.

3-Hydroxysteroid Dehydrogenases↗

PubMed1995

The relative amount of an influenza A virus segment present in the viral particle is not affected by a reduction in replication of that segment.

The principles of influenza A virus replication and packaging are not fully understood. In order to investigate the signals required for these processes we have introduced mutations in the terminal non-coding region of an influenza A virus neuraminidase (NA) gene. Specifically, we have obtained two viruses, NA/X and NA/Y, which produced a reduced amount of NA-specific genomic RNA in infected cells but not in the viral particle. These data indicate that (i) specific signals which affect the amount of RNA in the viral particle are distinct from those required for viral replication and (ii) the amount of packaged RNA is not strictly dependent on the amount of RNA produced during replication. In addition, mutant NA/Y was shown to be effectively attenuated in mice. Thus, diminished replication of one viral segment might be a principle on which to base a live influenza virus vaccine.

Animals↗

PubMed1995

Congenital myopathy with focal loss of cross striations: a case report with morphologic and immunohistochemical study.

A case of an unusual congenital myopathy is reported. The boy presented at birth with generalized muscular hypotonia and dysmorphic features. Muscle biopsy at the age of 10 years revealed focal areas with decreased ATPase activity and variable oxidative enzyme activity. There was only one type II fiber in the whole section. 22.5% of fibers had central nuclei, sometimes with radial arrangement of the intermyofibrillary network. Focal lesions displayed strong desmin and weak vimentin immunoreactivity. On electron microscopic examination normal sarcomeres were focally disrupted and mitochondria were absent from these areas; the normal structure was replaced by numerous fragments of sarcoplasmic reticulum, filamentous material, scattered glycogen particles, and the Z-line was replaced by irregular longitudinal streaks of electron-dense fibrillar material. We classify this case as a congenital myopathy with focal loss of cross striations.

Abnormalities, Multiple↗

PubMed1995

Mitochondrial differentiation during meiosis of male germ cells.

In male germ cells mitochondria undergo dramatic morphological changes during spermatogenesis, at least three different types of mitochondrion being present. The usual cristae type of mitochondrion in spermatogonia, preleptotene and leptotene spermatocytes develops, via an intermediate form in zygotene spermatocytes, to the condensed form with almost no cristae which is typical of pachytene spermatocytes and early spermatids. In cell culture experiments in which isolated preparations of meiotic germ cells were used, it was shown that condensed mitochondria in pachytene spermatocytes cultured in Earle's minimal essential medium dedifferentiated to the intermediate type, while Sertoli cell-conditioned medium (SC-CM) was able to maintain the condensed structure. SC-CM was also able to induce conversion of the intermediate type to the condensed type in isolated zygotene spermatocytes. Preliminary biochemical characterization showed the involvement of one or several proteinaceous factors > 10 kDa (PMMF: paracrine mitochondria maturation factor) that were protease (subtilisin)- and heat-sensitive. Three mitochondrial proteins served as markers for germ cells in different phases of maturation. The chaperonin hsp60 was detectable in the orthodox-type mitochondria of spermatogonia and primary spermatocytes (leptotene and zygotene). An ATP- dependent mitochondrial matrix enzyme -- the Lon-protease -- appeared in the orthodox and intermediate forms of mitochondria in leptotene and zygotene spermatocytes. Sulphydryl oxidase is present in the condensed mitochondria of pachytene spermatocytes and early spermatids.

Animals↗

PubMed1994

Differential expression of synaptophysin and synaptoporin during pre- and postnatal development of the rat hippocampal network.

The closely related synaptic vesicle membrane proteins synaptophysin and synaptoporin are abundant in the hippocampal formation of the adult rat. But the prenatal hippocampal formation contains only synaptophysin, which is first detected at embryonic day 17 (E17) in perikarya and axons of the pyramidal neurons. At E21 synaptophysin immunoreactivity extends into the apical dendrites of these cells and in newly formed terminals contacting these dendrites. The transient presence of synaptophysin in axons and dendrites suggests a functional involvement of synaptophysin in fibre outgrowth of developing pyramidal neurons. Synaptoporin expression parallels the formation of dentate granule cell synaptic contacts with pyramidal neurons: the amount of hippocampal synaptoporin, determined in immunoblots and by synaptoporin immunostaining of developing mossy fibre terminals; increases during the first postnatal week. Moreover, in the adult, synaptoporin is found exclusively in the mossy fibre terminals present in the hilar region of the dentate gyrus and the regio inferior of the cornu ammonis. In contrast, synaptophysin is present in all synaptic fields of the hippocampal formation, including the mossy fibre terminals, where it colocalizes with synaptoporin in the same boutons. Our data indicate that granule neuron terminals differ from all other terminals of the hippocampal formation by the presence of both synaptoporin and synaptophysin. This difference, observed in the earliest synaptic contacts in the postnatal hippocampus and persisting into adult life, suggests distinct functions of synaptoporin in these nerve terminals.

Animals↗

PubMed1994

The adult human cerebellum is a target of the neuroendocrine system involved in the circadian timing.

In an investigation aimed at comprehensive mapping of the adult human brain with respect to receptor sites for the pineal hormone melatonin, we consistently observed specific binding in the cerebellum. Autoradiography and in vitro binding analysis with 125I-labeled melatonin were used to examine the location and the properties of these binding sites. In all cerebellar lobes, highest-density specific binding was localized to the external zone of the molecular layer. The binding was rapid, saturable, displaceable, specific and of high affinity. Physiological concentrations of NaCl decreased the affinity, while presence of calcium ions promoted it. The non-hydrolyzable GTP analog, GTP gamma S, inhibited binding in a dose-dependent manner and provoked a shift towards low affinity. The results strongly suggest that these binding sites may be functional melatonin receptors, and indicate that the adult human cerebellum is a target of melatonin, the pineal hormone involved in the control of the circadian timing.

Adult↗

PubMed1994

Expression of the NMDA R1 receptor in selected human brain regions.

The distribution of the N-methyl-D-aspartate R1 receptor was investigated in human hippocampus, cerebellum and frontal cortex by means of in situ hybridization and immunocytochemistry. Expression of N-methyl-D-aspartate R1 receptors was observed in layers II-VI of the frontal cortex with the highest density of positive neurones in layer IV, V and VIa. The entire human hippocampus was labelled, with marked differences in intensity between the CA 1 and CA 2/3 region. Furthermore we found marked differences in the intracellular localization of the protein between granule and pyramidal cells. In the cerebellum granule and Purkinje cells stained positive, as revealed by both in situ hybridization and immunocytochemistry. These findings suggest that the receptor has a less restricted cell specific expression than previously thought, although the distribution is largely in accordance with the expression of N-methyl-D-aspartate R1 mRNA in the rat.

Adult↗

PubMed1994

The distribution pattern of cytokeratin and vimentin immunoreactivity in testicular biopsies of infertile men.

Testicular biopsies of infertile patients are often characterized by a mixed atrophy, in which different types of spermatogenic lesions are found in adjacent tubules. In order to evaluate a possible involvement of the state of differentiation of the Sertoli cells, the distribution pattern of cytokeratin and vimentin intermediate filaments within the seminiferous epithelium of 228 biopsy specimens with normal spermatogenesis (n = 10), mixed atrophy (n = 206) or Sertoli Cell Only Syndrome (n = 12) were investigated by means of immunohistochemical techniques. Sertoli cells were regularly found to show vimentin expression in tubules with normal spermatogenesis as well as in tubules with any kind of spermatogenic impairment including SCO. Cytokeratin expression as a marker showing lack of differentiation was common in Sertoli cells of tubules with arrest of spermatogenesis at the level of spermatogonia, and was occasionally associated with arrest at the level of primary spermatocytes or with SCO. Ultrastructural examination of tubules with spermatogonial arrest revealed Sertoli cells with features of typical fetal or prepubertal Sertoli cells, such as round to ovoid nuclei without indentations, stacks of rough ER and spot desmosomes. These data suggest that spermatogenic arrest at the level of spermatogonia might be due to functional impairment of the associated Sertoli cells, which have maintained or regained an undifferentiated state and are not able to initiate or trigger the process of spermatogonial differentiation.

Biopsy↗

PubMed1994

Infantile multiple system atrophy with cytoplasmic and intranuclear glioneuronal inclusions.

This report presents a case of infantile multiple system atrophy with probably autosomal recessive inheritance. The female patient developed generalized muscular hypotonia, myoclonias and tonic-clonic seizures at the age of 8 months, followed by gradual development of choreoathetotic hyperkinesia and increasing psychomotor retardation. Metabolic disease was ruled out and the child died of aspiration pneumonia at the age of 5 years. General autopsy was unremarkable, but neuropathological examination showed degeneration of cerebellum, inferior olives, medial thalamus, Clarke's nucleus, anterior horn cells, corticospinal, spinocerebellar tracts, and posterior columns. Immunohistochemically many neurons contained intranuclear and intracytoplasmic ubiquitin-positive inclusions, which did not contain neurofilament or tau epitopes and ultra-structurally consisted of granulofilamentous material. We tentatively classify this case as a form of infantile multiple system atrophy linked to neuronal intranuclear hyaline inclusion disease.

Cell Nucleus↗

PubMed1994

Localization of follicle-stimulating hormone (FSH) immunoreactivity and hormone receptor mRNA in testicular tissue of infertile men.

Testicular biopsies from 82 oligo- or azoo-spermic male patients were subjected to immunostaining using anti-human FSH antibodies. Histological evaluation showed normal spermatogenesis (nspg) in 7 (FSH: (2.7 +/- 0.7), mixed atrophy (ma) in 63 (FSH:L 5.3 +/- 0.5), and bilateral or unilateral Sertoli Cell Only syndrome (SCO) in 12 (FSH: 21.7 +/- 3.5) patients. For the relationship between FSH values and testicular histology, see Bergmann et al. (1994). FSH immunoreactivity was found exclusively in Sertoli cells and in some interstitial cells. Seminiferous epithelium showing normal or impaired spermatogenesis displayed only weak immunoreactivity compared to intense immunoreaction, i.e. large and numerous vesicles in Sertoli cells of SCO tubules in biopsies showing mixed atrophy or SCO. In addition, h-FSH receptor mRNA was demonstrated by in situ hybridization using biotinylated cDNA antisense oligonucleotides. Hybridization signals were found within the seminiferous epithelium exclusively in Sertoli cell cytoplasm associated with normal spermatogenesis and in epithelia showing different signs of impairment, including SCO. It is concluded that: (1) Sertoli cells are the only cells within the seminiferous epithelium expressing FSH receptors; (2) the accumulation of FSH immunoreactivity in Sertoli cells of SCO tubules appears to be a sign of impaired Sertoli cell function.

Adult↗

PubMed1994

Pleomorphic pineocytoma with extensive neuronal differentiation: report of two cases.

Two pineal parenchymal tumors are presented, arising in a 54-year-old man and a 72-year-old woman; respectively. They showed isomorphic, cellular areas of small cells, often with characteristic pineocytomatous rosettes, and of medium-sized cells, as well as less cellular regions with highly pleomorphic, often ganglioid large cells. Immunohistochemistry disclosed extensive neuronal differentiation. There was intense positivity for neurofilament protein and microtubule-associated protein 2 in the pleomorphic areas and more variable expression in the isomorphic regions. Diffuse synaptophysin positivity was seen, accentuated along the borders of pleomorphic cells and in the rosettes, as well as diffuse interstitial and/or cytoplasmic expression of neuron-specific enolase, PGP 9.5 and tau. beta-Tubulin III was detected in most cells and slight positivity was found in the rosettes. Expression of glial fibrillary acidic protein, however, was restricted to resident astrocytes and an interstitial network of processes. These neuronally differentiated pleomorphic pineocytomas underline the broad histomorphological spectrum of pineal parenchymal tumors.

Aged↗

PubMed1994

Intravascular lymphomatosis of the CNS: clinicopathologic study and search for expression of oncoproteins and Epstein-Barr virus.

Five cases of intravascular lymphomatosis (IVL) are reported. Diffuse or focal cerebral signs suggestive of vascular disease occurred in four cases, but case 5 presented with symptoms similar to Creutzfeld-Jakob disease. Clinical course ranged from two to eight months and diagnosis was made in all cases by autopsy. Neoplastic lymphoid cells mainly lodged in lumina of small vessels in many organs, but infarction was confined to the CNS. Some extravascular tumor cells were regularly seen. All cases corresponded to high-grade Non-Hodgkin lymphomas of B-cell type and displayed high proliferation indices. Different from findings in primary cerebral and nodal lymphomas, neither p53 nor bcl-2 oncoproteins were detectable. Absence of EBV genome and EBV latent membrane protein from IVL was demonstrated for the first time.

Aged↗