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Biomedical subjects

M Bergmann

Publications and source records attributed to M Bergmann.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1994

Serum FSH and testicular morphology in male infertility.

OBJECTIVE: In patients with azoospermia serum FSH helps to differentiate between obstruction or spermatogenetic dysfunction as the possible cause of this condition. The role of FSH in the diagnosis of infertile men with oligoasthenoteratozoospermia is less clearly defined. In order to evaluate the diagnostic significance of serum FSH in the management of male infertility, serum FSH levels were related to testicular morphology from bilateral biopsies of infertile men. DESIGN AND PATIENTS: Testicular biopsies were obtained from 213 infertile men and evaluated in semi-thin sections. Biopsies were performed either in order to distinguish between obstructive and non-obstructive azoospermia or because of subnormal semen variables when history, clinical investigation and hormone levels failed to explain infertility. Serum FSH was measured by fluoroimmunoassay. RESULTS: Patients were divided into five groups on the basis of morphological criteria. The mean serum FSH value of patients with obstructive azoospermia and normal histology (group 1, n = 14) was normal (3.0 (2.2-4.1) IU/l) (mean (95% confidence limits)). Serum levels of FSH in non-obstructive oligo or azoospermia were as follows: group 2: mixed atrophy of tubular tissue without focal Sertoli cell only syndrome (SCO) (n = 104) (4.5 (4.0-5.1) IU/l), group 3: mixed atrophy with unilateral focal Sertoli cell only (n = 39) (7.4 (6.1-9.0) IU/l), group 4: mixed atrophy with bilateral focal SCO (n = 36) (10.7 (8.7-13.0) IU/l). Group 5: bilateral or unilateral total Sertoli cell only (n = 20) (16.0 (12.1-20.9) IU/l). Mean serum FSH levels were significantly different between all groups (P < 0.05). CONCLUSIONS: Elevation of serum FSH correlates with the appearance of Sertoli cell only tubules. Elevated FSH serum levels make testicular biopsies superfluous for diagnostic purposes, but normal FSH does not exclude severe derangement of spermatogenesis in individual cases.

Adult↗
PubMed1994

Familial pericentric inversion of chromosome 1 (p34q23) and male infertility with stage specific spermatogenic arrest.

We report on two infertile brothers presenting with severe oligozoospermia or azoospermia. Testicular biopsy was performed on one of them and showed spermatogenic arrest at the level of primary spermatocytes. Both brothers were found to be heterozygous for a pericentric inversion of chromosome 1 (46,XY,inv(1)(p34q23)). The inversion chromosome was inherited through the maternal line, with no indication of subfertility in the probands' mother.

Adult↗
PubMed1994

Regional organisational audit of district departments of public health.

Organisational audit of public health in the United Kingdom is rare. To provide a framework for a structured organisational audit in district public health departments in one region organisational factors contributing to efficient, high quality work were identified and compared between districts, enabling each department to identify its organisational strengths and weaknesses. A draft list of organisational factors, based on the King's Fund organisational audit programme, were rated by 52 public health physicians and trainees in 12 district public health departments in South East Thames region for their importance on a scale of 0 (not relevant) to 5 (vital). Factors with average ratings of > 4, judged to be "vital" and proxies for standards, were then used to compare each district's actual performance, as reported by its director of public health in a self reported questionnaire. In all, 37 responses were received to the rating questionnaire (response rate 71%) and 12 responses to the directors' questionnaire. Of the 54 factors identified as vital factors, 20(37%) were achieved in all 12 districts and 16(30%) in all but one district; 18 were not being achieved by two (33%) districts or more. Overall, vital factors were not being achieved in 9% of cases. The authors concluded that most departments are achieving most vital organisational factors most of the time, but improvement is still possible. The results have been used as a basis for planning the organisation of public health departments in several of the newly formed commissioning agencies. This was the first regional audit of public health of its kind performed in the region and it provided valuable experience for planning future regional audit activity.

Health Facilities↗
PubMed1993

Synaptophysin and synaptoporin expression in the developing rat olfactory system.

The expressions of two closely related synaptic vesicle antigens synaptophysin and synaptoporin were examined in the olfactory system of the adult rat and during pre- and postnatal development. In the adult, immunocytochemistry showed that the continuously regenerating olfactory receptor neurons (primary neurons) produce both synaptophysin and synaptoporin which were localized in the cell bodies of the receptor neurons in the olfactory epithelium, their dendrites, axonal processes in the olfactory nerve and their terminals in the olfactory bulb glomeruli. Furthermore, ultrastructural analysis revealed synaptophysin- and synaptoporin-immunoreactivities associated with synaptic vesicles in most olfactory receptor axonal terminals impinging on dendrites of the mitral and tufted neurons (secondary neurons in the olfactory bulb circuitry) in the olfactory glomeruli. In like manner, tufted neurons, granule and periglomerular neurons (interneurons in the olfactory bulb circuitry) express both synaptophysin and synaptoporin. In contrast, mitral neurons expressed only the synaptophysin antigen which was likewise associated with mitral axonal terminals in their target the olfactory cortex. The patterns of synaptophysin and synaptoporin expressions in mitral neurons (synaptophysin only) and tufted neurons (synaptophysin and synaptoporin) were similar in prenatal, postnatal and adult rats as revealed by immunocytochemistry and in situ hybridization. However, the biosynthesis of synaptophysin and synaptoporin by granule and periglomerular neurons, olfactory bulb interneurons, occurred mainly postnatally.

Animals↗
PubMed1993

Ontogeny of synaptophysin and synaptoporin in the central nervous system: differential expression in striatal neurons and their afferents during development.

The expression of the synaptic vesicle antigens synaptophysin (SY) and synaptoporin (SO) was studied in the rat striatum, which contains a nearly homogeneous population of GABAergic neurons. In situ hybridization revealed high levels of SY transcripts in the striatal anlage from embryonic day (E) 14 until birth. In contrast, SO hydridization signals were low, and no immunoreactive cell bodies were detected at these stages of development. At E 14, SY-immunoreactivity was restricted to perikarya. In later prenatal stages of development SY-immunoreactivity appeared in puncta (identified as terminals containing immunostained synaptic vesicles), fibers, thick fiber bundles and 'patches'. In postnatal and adult animals, perikarya of striatal neurons exhibited immunoreaction for SO; ultrastructurally SO antigen was found in the Golgi apparatus and in multivesicular bodies. SO-positive boutons were rare in the striatum. In the neuropil, numerous presynaptic terminals positive for SY were observed. Our data indicate that the expression of synaptic vesicle proteins in GABAergic neurons of the striatum is developmentally regulated. Whereas SY is prevalent during embryonic development, SO is the major synaptic vesicle antigen expressed postnatally by striatal neurons which project to the globus pallidus and the substantia nigra. In contrast synapses of striatal afferents (predominantly from cortex, thalamus and substantia nigra) contain SY.

Animals↗