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Biomedical subjects

J Bohl

Publications and source records attributed to J Bohl.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Clinical, neurophysiologic and biopsy findings in neurotoxic amiodarone syndrome].

PATIENTS: Three patients complained of proximal weakness and paraesthesia of the legs and difficulties in walking during amiodarone treatment. Examination showed signs of a predominantly distal sensory neuropathy, a proximal myopathy, and a cerebellar gait disorder. All had amiodarone dosages of 600 mg per day, amiodarone serum levels above 2.7 mg/l and a total amount of amiodarone ingestion of 300 to 500 g. The clinical symptoms subsided within six to eleven months after treatment was stopped. RESULTS: The neurophysiologic investigations showed slowing of sensory and motor nerve conduction velocities with dissociation of the action potentials and delay of SEP latencies. With discontinuation of the drug these abnormalities were progressive in one patient. The biopsy (muscle, nerve and skin) in the most severely affected patient showed numerous intracellular lysosomal inclusions in cells of different tissues. It is supposed that the storage of amiodarone in muscle cells results in a predominantly proximal myopathy whereas storage in Schwann cells results in a secondary neuropathy. A similar storage in Purkinje cells may be responsible for the cerebellar gait disorder. CONCLUSION: The clinical picture should be termed a neurotoxic amiodarone syndrome rather than amiodarone neuropathy.

Amiodarone↗
PubMed1994

Adenylyl cyclase activity in Alzheimer's disease brain: stimulatory and inhibitory signal transduction pathways are differently affected.

Adenylyl cyclase (AC) activity was studied in post mortem hippocampus and cerebellum from eight patients with Alzheimer's disease/senile dementia of the Alzheimer type (AD/SDAT) and seven non-demented control patients. AC was stimulated via stimulatory guanine nucleotide binding proteins (Gs) using guanosine triphosphate (GTP) and GppNHp (both 10(-4) M) or directly with either forskolin (10(-4) M) or Mn2+ (10(-2) M). Inhibition of AC via A1-receptors was performed with N6-cyclohexyladenosine (CHA) under basal conditions and in the presence of forskolin (10(-5) M). In both brain regions AC activity was significantly reduced in AD/SDAT when compared to controls. Under basal conditions and after stimulation via Gs mean reduction in hippocampus and cerebellum was 47.7% and 58.2%, respectively. The reduction was less pronounced after direct activation of the AC, amounting to 21.8% in hippocampus and 28.1% in cerebellum. CHA inhibited basal and forskolin-stimulated AC concentration-dependently by about 20% (basal) and 30% (forskolin). Inhibition by CHA was similar in hippocampus and cerebellum and tended to be more pronounced in AD/SDAT than in controls. Since the reduction of AC activity in AD/SDAT is greater after stimulation via Gs than after direct activation of the catalytic subunit, we suggest that both Gs and the catalytic subunit seem to be impaired. The fact that CHA-mediated inhibition of AC is not significantly different in AD/SDAT and controls, indicates that in contrast to Gs-, inhibitory G-proteins (Gi) coupling to AC remains intact in Alzheimer's disease.

Adenosine↗
PubMed1994

Quantitative investigations on the human entorhinal area: left-right asymmetry and age-related changes.

The total nerve cell numbers in the right and in the left human entorhinal areas have been calculated by volume estimations with the Cavalieri principle and by cell density determinations with the optical disector. Thick gallocyanin-stained serial frozen sections through the parahippocampal gyrus of 22 human subjects (10 female, 12 male) ranging from 18 to 86 years were analysed. The laminar composition of gallocyanin (Nissl)-stained sections could easily be compared with Braak's (1972, 1980) pigmentoarchitectonic study, and Braak's nomenclature of the entorhinal laminas was adopted. Cell-sparse laminae dissecantes can more clearly be distinguished in Nissl than in aldehydefuchsin preparations. These cell-poor dissecantes, lamina dissecans externa (dis-ext), lamina dissecans 1 (dis-1) and lamina dissecans 2 (dis-2), were excluded from nerve cell number determinations. An exact delineation of the entorhinal area is indispensable for any kind of quantitative investigation. We have defined the entorhinal area by the presence of pre-alpha cell clusters and the deeper layers of lamina principalis externa (pre-beta and gamma) separated from lamina principalis interna (pri) by lamina dissecans 1 (dis-1). The human entorhinal area is quantitatively characterized by a left-sided (asymmetric) higher pre-alpha cell number and an age-related nerve cell loss in pre as well as pri layers. At variance with other CNS cortical and subcortical structures, the neuronal number of the entorhinal area appears to decrease continuously from the earliest stages analysed, although a secular trend has to be considered. The asymmetry in pre-alpha cell number is discussed in the context of higher human mental capabilities, especially language.

Adolescent↗
PubMed1994

Amygdala pathology in Parkinson's disease.

The amygdala undergoes severe pathological changes during the course of Parkinson's disease (PD). Lewy bodies and Lewy neurites are distributed in a specific manner throughout the nuclear complex. The lesional pattern displays only minor interindividual variation. The most prominent changes occur in the accessory cortical and central nuclei. The cortical, accessory basal and granular nuclei show less severe alterations, while the basal and lateral nuclei, as well as the intercalated cell masses, generally remain uninvolved. The amygdala receives a broad range of afferents, allowing integration of exteroceptive information with interoceptive data. It generates major projections to the isocortex (the prefrontal cortex in particular), limbic system (hippocampus and entorhinal region) and centers regulating endocrine and autonomic functions. The specific lesional pattern seen in PD destroys part of the nuclear gray matter and its connections and, thus, may likely contribute to the development of behavioral changes and autonomic dysfunctions.

Aged↗
PubMed1994

Results of 200 intracranial stereotactic biopsies.

200 stereotactic biopsies were evaluated. The validity of the intraoperative histopathological results were compared with the final diagnosis using conventional embedding and staining techniques. Further comparison between the histology of the biopsy and the post mortem or open operative findings were possible in 41 cases. Discrepancy was found in one case regarding the tumor detection, and in three cases regarding the tumor grading. The mortality in our patients was 1% and the morbidity 3%. Stereotactical biopsy had a low risk even in deep brain regions such as basal ganglia, mesencephalon, and pons. At the same time the high histologic validity makes the CT-guided stereotactical biopsy recommendable in all lesions not operated by an open resection before any conservative or palliative therapy is started.

Adolescent↗
PubMed1994

Traumatic lesion of the extracranial vertebral artery--a note-worthy potentially lethal injury.

The autopsy findings from routine neuropathological investigations of the cervical spine after any history of trauma emphasized the vulnerability of the extracranial vertebral arteries. In 21 cases with trauma to the head and neck, normal autopsy procedures did not succeed in revealing an obvious cause of death. Traumatic lesions of the spinal cord such as contusion or neurorrhexis were seen in 10 cases. In 15 cases we observed different degrees and stages of traumatic lesions of the extracranial vertebral arteries. Sudden death due to acute brain stem ischemia might be considered as an explanation in some of these cases. Six case reports with traumatic vertebral artery (VA) lesions after severe or minor extracranial trauma are presented. A review of the literature revealed that this vascular injury has only rarely been directly established by gross pathological examination. Possible consequences of blunt trauma to the head and neck include angiorrhexis, subintimal, intramural and perivascular hemorrhage leading to a partial narrowing of the injured vessel. These processes can be complicated by thrombosis. Unilateral VA obliteration may be an occult risk of acute brain stem ischemia when associated with contralateral reduction of the posterior circulation.

Adolescent↗
PubMed1994

Image analysis of proliferating cells in tumors of the human nervous system: an immunohistological study with the monoclonal antibody Ki-67.

Obtaining growth fractions from immunohistological preparations by the commonly used cell count calculation method is time consuming. For the first time, we investigated and compared the detection of proliferating cells in immunohistologically labeled tissue from tumors of the nervous system using the monoclonal antibody Ki-67 by a new computerized image analysis system and by cell count calculation. The two methods showed a high correlation (correlation index, 0.98) in 37 gliomas (2 pilocytic astrocytomas, 10 Grade II astrocytomas, 5 Grade III astrocytomas, 20 Grade IV astrocytomas and glioblastoma multiforme) and a heterogenous group of 10 additional tumors of the nervous system, including oligodendroglioma, pineoblastoma, primary central nervous system lymphoma, and neurofibroma. Advantages of and indications for image analysis are as follows: 1) time-saving evaluation of immunohistological preparations enables their use in neuro-oncological routine diagnostics and examination of larger cell populations, thus leading to more precisely reproducible results, especially in heterogenous tumors; 2) image analysis, calculating the area of cell nuclei rather than their number, avoids difficulties with fragmented or overlapping nuclei; 3) analysis of different antibodies (for example, Ki-67 and anti-proliferating cell nuclear antigen) may be performed with the same program; 4) investigation of a larger patient group may lead, in combination with the histopathological diagnosis and clinical parameters, to better adapted therapeutic concepts.

Adolescent↗
PubMed1993

Beta-adrenoceptor density and subtype distribution in cerebellum and hippocampus from patients with Alzheimer's disease.

beta-Adrenoceptor density and beta 1- and beta 2-subtype distribution were examined in hippocampi and cerebella from patients with Alzheimer's disease (AD/SDAT). Tissues from age-, sex and post-mortem delay matched non-demented patients served as controls. The total beta-adrenoceptor density as evaluated in saturation experiments with the hydrophilic radioligand [3H]CGP 12177 was higher in hippocampal (36-39 fmol/mg protein) than cerebellar tissues (20-21 fmol/mg), however, no differences were found in either brain region between AD/SDAT patients and controls. Subtype distribution using the highly selective beta 1-adrenoceptor antagonist CGP 20712A revealed a slightly higher proportion of beta 1-adrenoceptors in hippocampus (26%-27%) than in cerebellum (20%-21%) with, again, no difference between AD/SDAT and controls. We recently described a 40% reduction in basal and stimulated adenylyl cyclase activity in post-mortem hippocampus of AD/SDAT patients, a brain region greatly affected by the disease, the present data now demonstrate that this disease-related effect is not mirrored by a similar change in beta-adrenoceptor density nor in subtype distribution.

Adrenergic beta-Antagonists↗
PubMed1993

Amyloidoma of the gasserian ganglion as a cause of symptomatic neuralgia of the trigeminal nerve: report of three cases.

Three cases of symptomatic neuralgia of the trigeminal nerve due to an amyloidoma in the gasserian ganglion are described. The correct diagnosis was not made prior to histological examination of the surgical biopsy specimens. Medical history and clinical observation led to the diagnosis of a malignant process of the nasal cavities in the first patient; of an inflammatory dental focus in the second patient; and of multiple sclerosis in the third patient. CT findings were normal in cases 1 and 2; in case 3, a schwannoma was suspected from the CT appearances. In case 1, MRI had not been performed; in cases 2 and 3, MRI revealed a tumour mass which was also considered to be a schwannoma. Histologically, the tumours consisted of masses of amyloid deposits which had largely replaced the pre-existing ganglionic cells and satellite cells. Electron microscopy confirmed the fibrillar structure of the deposits. Immunohistochemistry and immunocytochemistry revealed the amyloid to belong to the AL-lambda subtype.

Adult↗
PubMed1993

Staging of Alzheimer-related cortical destruction.

The gradual intraneuronal accumulation of an insoluble fibrous material which partly consists of abnormally phosphorylated tau protein (neurofibrillary change) represents an important neuropathological hallmark of Alzheimer's disease. Neurofibrillary tangles and neuropil threads formed from this material develop in only a few types of cortical pyramidal cells. The first changes are seen in the entorhinal cortex. The destructive process then spreads into the hippocampal formation and eventually encroaches upon the isocortex. This sequence of events permits the distinction of six stages with a progressive increase in the severity of cortical destruction. The entorhinal region serves as an important interface between the isocortex and hippocampus. This interface function is markedly impaired due to the early deterioration of the entorhinal cortex. Severe entorhinal involvement is considered to represent the morphological counterpart of clinically incipient Alzheimer's disease. Similar changes are found in mentally impaired individuals suffering from Parkinson's disease or progressive supranuclear palsy.

Aged↗
PubMed1992

Allocortical neurofibrillary changes in progressive supranuclear palsy.

Silver techniques for intraneuronal cytoskeleton abnormalities (neurofibrillary tangles and neuropil threads) and extracellular A4-amyloid deposits were used to examine lesions of the cerebral cortex in six cases of progressive supranuclear palsy (three were mentally unimpaired and three showed moderate degrees of dementia). Deposits of A4-amyloid protein occurred in small numbers or were absent. Neurofibrillary tangles and neuropil threads were present in all cases and were largely confined to the allocortex. A characteristic pattern of changes was found in the entorhinal cortex. The three mentally unimpaired individuals had mild cortical changes virtually confined to the transentorhinal region while all of the demented patients showed severe destruction of the superficial cellular layer in both the transentorhinal and entorhinal region. This pattern of allocortical destruction closely resembles that seen in clinically incipient Alzheimer's disease or in mentally impaired cases of Parkinson's disease. The entorhinal region receives dense input from isocortical association areas and projects via the perforant path to the hippocampal formation. The cells of origin of major portions of the perforant path are located within the superficial entorhinal cellular layer. Destruction of this layer partially or totally disconnects the hippocampus from the isocortex. The specific pattern of entorhinal destruction is considered to contribute to cognitive impairment and personality changes, frequently seen in patients with progressive supranuclear palsy.

Aged↗
PubMed1992

CT-guided stereotactic biopsy aided by Doppler ultrasonic vascular monitoring.

The use of a 20 MHz pulsed Doppler technique during stereotactic brain tumour biopsies is described. By means of a miniaturized ultrasonic probe the tissue planned for biopsy was investigated for vessel signals. Out of 41 patients, with this technique a flow-pulse curve in front of the biopsy cannula was registered in 14 cases. In 9 cases one pulse curve was determined and in 5 cases two or more flow curves were found, indicating the presence of arterial vessels. The depth of the vessels signal could be localized and this area avoided for biopsy sampling. In a series of 41 stereotactic biopsies carried out in this way there was no intra-operative haemorrhage or postoperative haematoma.

Adolescent↗
PubMed1992

Ultrastructural study of the retina in late infantile metachromatic leukodystrophy.

The autopsy of a 2-year-old girl revealed a clinically unrecognized metachromatic leukodystrophy (MLD) due to an aryl-sulfatase A deficiency, characteristically affecting the central and peripheral nervous system by demyelination and by accumulation of metachromatic material. The retina though reported clinically as normal, showed the same demyelinating process in the optic nerve including the papilla but an additional intraneuronal storage of MLD-typical lysosomal residual bodies in ganglion cell perikarya of the retina. Cells of the bipolar and photoreceptor layers as well as pigment epithelial cells were not affected by MLD-specific lysosomal storage. Thus, sulfatides seem to play a particular metabolic role in ganglion cells but not in other neuronal cells of the retina in MLD.

Brain↗
PubMed1991

Reduced basal and stimulated (isoprenaline, Gpp(NH)p, forskolin) adenylate cyclase activity in Alzheimer's disease correlated with histopathological changes.

Cyclic adenosine monophosphate (cAMP) is an adenylate cyclase borne second messenger involved in basic metabolic events. The beta-adrenoceptor sensitive adenylate cyclase was studied in post-mortem hippocampi of controls and Alzheimer patients. Virtually identical subsets of each hippocampus homogenate were stimulated by 100 mumol isoprenaline, Gpp(NH)p and forskolin, respectively, in presence of an ATP-regenerating system. The determination of cAMP formed was carried out by means of a radioassay. The observed significant 50% reduction in basal as well as in stimulated adenylate cyclase activity in Alzheimer's disease is negatively correlated with semiquantitative evaluations of amyloid plaques (P less than 0.05) but not with neuritic plaques, neurofibrillary tangles or neuropil threads. This reduction in enzyme activity is obviously not due to simple cell loss alone. It is likely that the crucial point of the observed functional disturbance is at the level of the catalytic unit of the adenylate cyclase, since the same degree of reduction is maintained at all steps of the signal cascade.

Adenylyl Cyclases↗
PubMed1991

Age-related accumulation of congophilic fibrillar inclusions in endocrine cells.

Intracellular fibrillar congophilic inclusions are well known as neurofibrillary tangles in neurons and as Biondi bodies in choroid plexus epithelial cells. Recently similar amyloid-like inclusions in adrenal cortical cells were described (Eriksson and Westermark 1990). This study on 150 adrenal glands confirms these observations. In our material the age-related accumulation of congophilic inclusions starts earlier (in the sixth decade) and reaches a higher incidence (42.7%). We found similar intracellular inclusions in other endocrine organs, for example in the anterior lobe of the pituitary, in the cells of parathyroid glands and in Sertoli cells. The age-related incidence of these fibrillar inclusions in the pituitary was 68%: the co-incidence with interstitial amyloid deposits was 49.5%. Thus the intracellular accumulation of congophilic fibrils in old age is a wide-spread phenomenon and occurs not only in neurons but also in endocrine cells (adrenal, pituitary and parathyroid glands) and in active secretory cells (choroid plexus and Sertoli cells).

Adrenal Glands↗
PubMed1990

Possible involvement of the retinoblastoma gene in undifferentiated sinonasal carcinoma.

Retinoblastoma tumor formation is initiated by the loss of function of both alleles of the RB-1 gene on chromosome 13. Patients with the hereditary form of retinoblastoma carry a germ line mutation at one of the two homologous gene loci in all cells and have an increased risk for nonocular tumors (mainly osteosarcoma and other mesenchymal tumors) in later life. The authors studied a 38-year-old patient with sinonasal undifferentiated carcinoma (SNUC) who had been treated for bilateral retinoblastoma by enucleation (left eye) and irradiation (right eye), respectively. Using molecular probes for the RB-1 gene and other loci on chromosome 13, the authors detected a deletion at the RB-1 locus in metastatic SNUC cells that was not present in normal tissue. These findings indicate that somatic mutations at RB-1 locus may be involved in the formation or progression of ectodermal tumors.

Adolescent↗
PubMed1990

Diseases of the vertebral arteries.

Case reports and postmortem neuropathological findings of a wide spectrum of diseases affecting the vertebral arteries, in particular vasculitis, traumatic lesions, degenerative changes and congenital abnormalities, are discussed.

Adult↗