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Biomedical subjects

C Fuchs

Publications and source records attributed to C Fuchs.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Impairment of myocardial perfusion reserve in microvascular angina (syndrome X): assessment by 99mTc-MIBI-SPECT].

AIM: In 22 patients with typical chest pain and normal coronary arteries (microvascular angina, syndrome X) 99mTc-MIBI-SPECT was examined in regard to assess impairment of myocardial perfusion reserve. METHOD: The study was performed with 99mTc-MIBI-SPECT at rest and under vasodilation with dipyridamole. The findings were compared with a normal database. A normal perfusion reserve was said to be an increase > 20% of the 99mTc-MIBI-activity. RESULTS: In 2/22 (9%) of the patients the perfusion reserve lay > 20% i.e. 37%. In 91% of the patients a diminution or even decrease of the perfusion was to be seen. From these 9/22 (41%) of the patients showed a diminution of the 99mTc-MIBI-uptake by 6%. 1/22 patients had a decrease of the perfusion under vasodilation with dipyridamole i.e. a lower activity of 99mTc-MIBI by 13% CONCLUSION: Vasodilation 99mTc-MIBI-SPECT offers good imaging quality and enables semi-quantitative assessment of myocardial perfusion reserve in patients with microvascular angina.

Blood Pressure↗
PubMed1996

[Pseudodefects in myocardial SPECT after implantation of defibrillator patches: phantom measurement with SPECT and PET].

AIM AND METHODS: In order to estimate the effect of an epicardial or subcutan defibrillator patch electrode on the imaging of myocardium with SPET and PET we performed measurements with a body phantom and two different patch electrodes. RESULTS: We found that in 201TI-SPET with epicardial placing one electrode causes significant pseudodefects, which might lead to the impression of an infarction ("pseudoinfarction"), particularly in the case of reduced myocardial wall thickness. Measurements with 99nTc show the same pseudodefects. In case of subcutaneous placing the electrodes are much less likely to cause relevant absorption effects. With PET even epicardially placed both patch electrodes do not produce pseudodefects. Therefore the risk of false-positive findings is very small with PET. CONCLUSION: In order to avoid false positive findings in cardiovascular nuclear medicine caused by defibrillator patch electrodes, patients with patch electrodes should be referred to PET, if available.

Artifacts↗
PubMed1995

Amyloid beta-protein inhibits ubiquitin-dependent protein degradation in vitro.

Intraneuronal accumulation of ubiquitin conjugates in inclusion bodies and neurofibrillary tangles is a pathological feature of neurodegenerative disorders such as Alzheimer's disease and Down's syndrome and of normal aging of the brain. Amyloid beta-protein (A beta) and its precursor are found in neurofibrillary tangle-containing neurons. A beta is the major component of extracellular plaques. We showed that A beta acts as an inhibitor of the ubiquitin-dependent protein degradation in vitro. We examined the effect of A beta on the steps of this proteolytic pathway that contribute to the level of ubiquitin conjugates in the cell. Neither conjugate formation nor conjugate deubiquitination was affected by the presence of A beta. However, A beta significantly reduced the rate of conjugate degradation. Our results indicate that A beta interacts with the proteolytic step of the ubiquitin degradative pathway. Since this step is performed by the 26 S proteasome, the effect of A beta on the catalytic core of this proteolytic complex, the 20 S proteasome, was determined. We found that A beta selectively inhibits the chymotrypsin-like activity of the 20 S proteasome. Under pathological conditions in the affected neuron, A beta could interfere with ubiquitin-dependent degradation by inhibiting the 26 S proteasome activity. This finding may explain the origin of the accumulation of ubiquitin conjugates.

Alzheimer Disease↗
PubMed1995

Social information processing by aggressive and nonaggressive men with mental retardation.

The social information-processing skills of 16 aggressive and 19 nonaggressive men with borderline to moderate mental retardation were examined in light of some of the steps described in Dodge's social information-processing model (Dodge, Pettit, McClaskey, & Brown, 1986). Contrary to expectations based on Dodge et al.'s findings with children who did not have mental retardation, aggressive and nonaggressive groups did not differ in their ability to generate multiple solutions or in their ability to provide appropriate responses. Similar to Dodge et al.'s findings, however, subjects in the aggressive group generated significantly more aggressive solutions and tended more often to give an aggressive response first than did the nonaggressive subjects. Preliminary implication for treatment were offered.

Aggression↗
PubMed1994

Plasticin, a newly identified neurofilament protein, is preferentially expressed in young retinal ganglion cells of adult goldfish.

The adult goldfish retina and optic nerve display continuous growth, plasticity, and the capacity to regenerate throughout the animal's life. The intermediate filament proteins in this pathway are different from those in adult mammalian nerves, which do not continuously grow or normally regenerate. One novel intermediate filament protein of the goldfish visual pathway is plasticin, which is synthesized in ganglion cells and transported into the optic nerve. Using specific polyclonal antibodies raised against a plasticin fusion protein, we investigated the distribution of this protein in the normal retina and nerve and in the retina and nerve following optic nerve crush. In the normal pathway, plasticin was localized predominantly to the axons of very young ganglion cells; however, there was considerable immunoreactivity in older axons as they approach the chiasm. In addition, following optic nerve crush, all ganglion cell somata and their axons proximal to the crush site became equally immunoreactive. The results suggest that plasticin may contribute to axonal growth, plasticity, and regeneration.

Amino Acid Sequence↗
PubMed1994

Differential expression of keratins in goldfish optic nerve during regeneration.

The goldfish visual pathway, unlike the visual pathway of higher vertebrates, retains continuous growth and development throughout life and is capable of functional regeneration. The structure and expression of proteins that support the physiological attributes of this system are of interest. Glial cells in this pathway express keratins as the predominant intermediate filament proteins rather than the expected glial fibrillary acidic protein. Previously we identified and characterized cDNA clones representing two type I keratins from the goldfish optic nerve, GK48 and GK49. The GK48 protein is the type I keratin partner to the type II keratin ON3, while the GK49 protein is expressed in a different cell type. Here, we extend our studies on the expression of mRNA for the GK48, GK49, and ON3 proteins at the early stages of optic nerve regeneration. RNase protection assays show that at 10 days post-crush, there is no overall change in levels of mRNA for these proteins as compared to uncrushed control nerves and nerves from unoperated fish. In addition, we show by in situ hybridization that the GK49 protein shows no changes in its distribution of mRNA in the optic nerve after crush. In contrast, the levels of GK48 and ON3 mRNA are greatly reduced within the crush zone. However, these two mRNAs are differentially expressed at different time points during regeneration, with GK48 mRNA appearing in the crush zone before ON3. These results indicate that the mRNA for the GK48 and ON3 proteins are differentially regulated during regeneration and that these two proteins are expressed in a different cell type from the GK49 protein.

Animals↗
PubMed1994

Complex expression of keratins in goldfish optic nerve.

Keratins are the predominant intermediate filament proteins in the nonneuronal cells of the goldfish optic nerve. At least three different keratin pairs are expressed in this tissue, indicating an unexpected complexity. Expression of the type II keratin ON3 in goldfish optic nerve astrocytes predicts the expression of a type I keratin partner. Here we report the cDNA sequence and predicted amino acid sequence of two type I keratins from the goldfish optic nerve, designated GK48 and GK49. The GK48 protein is the goldfish equivalent of mammalian keratin 18 (K18) and is the most likely type I keratin partner to the ON3 protein. The GK49 protein is similar to the GK50 protein, a type I keratin characterized previously from the goldfish optic nerve. The GK48 and ON3 mRNAs are expressed in a variety of goldfish tissues, whereas the expression of GK49 mRNA has a more limited expression. In addition, in situ hybridization experiments show that the expression of the GK48 and ON3 mRNAs are evenly distributed throughout the optic nerve, while the GK49 mRNA is expressed along longitudinal lines. These results show that there is a diversity of keratin expression within different cell types in the goldfish optic nerve.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of gefiltin (ON1): serial expression of two new neurofilament mRNAs during optic nerve regeneration.

The goldfish visual pathway displays a remarkable capacity for continued development and plasticity. The intermediate filament proteins of this pathway do not match the intermediate filament protein composition of adult higher vertebrate neurons, which lack the capacity for growth and development. Using a goldfish retina lambda gt10 library we isolated cDNA clones representing the predominant goldfish optic nerve neurofilament protein, ON1. The mRNA for this protein is abundant in retinal ganglion cells, and its level increases slowly during optic nerve regeneration. The rate of ON1 mRNA accumulation after optic nerve crush was compared with that of plasticin, a previously described novel type III neurofilament from goldfish retinal ganglion cells. Plasticin mRNA is normally expressed at low steady state levels, but accumulates dramatically and rapidly, preceding gefiltin mRNA, in response to optic nerve crush. The predicted amino acid sequence for ON1 indicates that it is a novel intermediate filament protein. We have named it gefiltin, for goldfish eye intermediate filament protein. The serial expression of plasticin and gefiltin is discussed with respect to the diversity of neurofilament proteins during neurogenesis.

Amino Acid Sequence↗
PubMed1994

A comparison of mastoid pneumatization in adults and children with cholesteatoma.

The records of 190 adults who presented over a 10-year period with previously untreated aural cholesteatomas were analyzed with respect to age, mode of presentation at the level of the tympanic membrane, and pneumatization of the mastoid. The findings were compared with those obtained in an earlier study of 109 children (aged 13 years and younger) seen over the same period of time. Two main types of cholesteatomas were found in both adults and children, most of them (82.3%) associated with sclerotic or diploic mastoids (i.e., poorly pneumatized mastoids) and the rest (17.3%) with pneumatized mastoids. The former type was found more often in adults (96.3%) than in children (57.8%), while the latter was more frequent in children (42.2% as compared to 3.7% in adults). In both adults and children, cholesteatomas associated with poorly pneumatized mastoids showed mainly an attic and mastoid distribution communicating with a pars tensa or pars flaccida retraction or marginal perforation. Cholesteatomas associated with pneumatized mastoids appeared most often behind an intact drug (the so-called congenital cholesteatomas) and were distributed mainly in the tympanic cavity.

Adolescent↗
PubMed1994

Cholesteatoma: ossicular destruction in adults and children.

The records of 148 adults (aged 14 years and older) presenting previously untreated aural cholesteatomas are analysed with particular emphasis on ossicular destruction and other bony lesions in the middle ear. The findings are compared with those obtained in an earlier study of 63 children (aged 13 years and younger), also with untreated cholesteatomas. The rate of stapes and malleus destruction was similar in adults and children. The rate of incus destruction was significantly higher in adults. Semicircular fistulas as well as facial paralysis were also more prevalent amongst adults. Therefore, the notion of childhood cholesteatoma aggressiveness cannot be related to its effect on these bony structures. It may stem from its higher recurrence rate and from the more troublesome post-operative mastoid cavities, which are often larger in children than in adults.

Adolescent↗
PubMed1994

Cloning of multiple forms of goldfish vimentin: differential expression in CNS.

In efforts to determine the primary structure of intermediate filament proteins in the goldfish visual pathway, we isolated clones from a retinal lambda gt11 cDNA expression library that represent goldfish vimentin. We show that there are at least two forms of goldfish vimentin, designated as vimentin alpha and vimentin beta. RNase protection assays indicate that vimentin alpha mRNA is expressed in low amounts in retina, optic nerve, and brain and in higher amounts in spinal cord. In contrast, vimentin beta mRNA is expressed in low amounts in retina, optic nerve, brain, and spinal cord and in very high amounts in eye lens. Immunohistochemical studies show that in the optic nerve, vimentin alpha is mainly restricted to blood vessels, meninges, and septa. Light staining is observed with this antibody in an astrocytic glial pattern throughout the optic nerve. Two-dimensional gel analysis shows that all of these goldfish vimentins are low abundant components of optic nerve cytoskeletal preparations.

Amino Acid Sequence↗
PubMed1994

Transvaginal aspiration of ovarian cysts: prognosis based on outcome over a 12-month period.

The success of transvaginal aspiration of ovarian cysts in terms of cyst dimensions, location, and content and the age of the women was evaluated in 35 women aged 17 to 76 years old. Three parameters proved important in predicting the outcome of aspiration: age of the woman (higher age = poorer prognosis for cure), maximum diameter of the cyst (larger diameter = poorer prognosis), and location (left-sided cysts have a poorer prognosis). Prognosis based on outcome indicates aspiration of large cysts should be avoided in older women.

Adult↗
PubMed1992

Chronic rhinitis in children.

One hundred and fifty-one children aged 2-6 years old suffering from chronic rhinitis were followed and treated for periods of 3-6 months. Seventy-five children were treated with antihistamines (AH) and 76 with antibiotics (AB). Significant statistic difference was found between pre-school children and school children. The differences were both with the nature of the symptoms, and reaction to treatment. While 49% of the school children recovered with AH treatment, only 14% of the pre-school children did. On the other hand, 58% of the pre-school children recovered with AB treatment while only 35% of the older children did. From our results it is clear that in many children bacterial infection is the cause for chronic rhinitis. In pre-school children it is the main cause, while in older children it is the cause in about a third of the cases. It is also important to remember that although allergy might be the basic reason for rhinitis, in certain age groups a secondary bacterial infection might interfere with the efficiency of antiallergic treatment.

Age Factors↗
PubMed1992

Plasticin, a novel type III neurofilament protein from goldfish retina: increased expression during optic nerve regeneration.

The goldfish visual pathway displays a remarkable capacity for continued development and plasticity. The intermediate filament proteins in this pathway are unexpected and atypical, suggesting these proteins provide a structure that supports growth and plasticity. Using a goldfish retina lambda gt10 library, we have isolated a full-length cDNA clone that encodes a novel type III intermediate filament protein. The mRNA for this protein is located in retinal ganglion cells, and its level dramatically increases during optic nerve regeneration. The protein is transported into the optic nerve within the slow phase of axonal transport. We have named this protein plasticin because it was isolated from a neuronal pathway well known for its plasticity.

Amino Acid Sequence↗