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C Brunner

Publications and source records attributed to C Brunner.

At least 19 recordsLinked to original sources
PubMed1998

Intracellular metabolism of human apolipoprotein(a) in stably transfected Hep G2 cells.

Lipoprotein(a) [Lp(a)] consists of LDL and the glycoprotein apolipoprotein(a) [apo(a)], which are covalently linked via a single disulfide bridge. The formation of Lp(a) occurs extracellularly, but an intracellular assembly in human liver cells has also been claimed. The human apo(a) gene locus is highly polymorphic due to a variable number of tandemly arranged kringle IV repeats. The size of apo(a) isoforms correlates inversely with Lp(a) plasma concentrations, which is believed to reflect different synthesis rates. To examine this association at the cellular level, we analyzed the subcellular localization and fate of apo(a) in stably transfected HepG2 cells. Our results demonstrate that apo(a) is synthesized as a precursor with a lower molecular mass which is processed into the mature, secreted form. The retention times of the precursor in the ER positively correlated with the sizes of apo(a) isoforms. The mature form was observed intracellularly at low levels and only in the Golgi apparatus. No apo(a) was found to be associated with the plasma membrane. Under temperature-blocking conditions, we did not detect any apo(a)/apoB-100 complexes within cells. This finding was confirmed in HepG2 cells transiently expressing KDEL-tagged apo(a). The precursor and the mature forms of apo(a) were found in the ER and Golgi fractions, respectively, also in human liver tissue. From our data, we conclude that in HepG2 cells the apo(a) precursor, dependent on the apo(a) isoform, is retained in the ER for a prolonged period of time, possibly due to an extensive maturation process of this large protein. The assembly of Lp(a) takes place exclusively extracellularly following the separate secretion of apo(a) and apoB.

Apolipoproteins A↗
PubMed1998

Sex-lethal, the master sex-determining gene in Drosophila, is not sex-specifically regulated in Musca domestica.

Sex-lethal (Sxl) is the master switch gene for somatic sex determination in Drosophila melanogaster. In XX animals, Sxl becomes activated and imposes female development; in X(Y) animals, Sxl remains inactive and male development ensues. A switch gene for sex determination, called F, has also been identified in the housefly, Musca domestica. An active F dictates female development, while male development ensues when F is inactive. To test if the switch functions of Sxl and F are founded on a common molecular basis, we isolated the homologous Sxl gene in the housefly. Though highly conserved in sequence, Musca-Sxl is not sex-specifically regulated: the same transcripts and protein isoforms are expressed in both male and female animals throughout development. Musca-Sxl is apparently not controlled by the primary sex-determining signal and, thus, is unlikely to correspond to the F gene. Ectopic expression of Musca-SXL protein in Drosophila does not exert any noticeable effects on the known target genes of endogenous Sxl. Instead, forced overexpression of the transgene eventually results in lethality of both XY and XX animals and in developmental abnormalities in some escaper XY animals. Similar results were obtained with the Sxl homologue of Ceratitis capitata (Saccone, G., Peluso, I., Artiaco, D. , Giodano, E., Bopp, D. and Polito, L. C. (1998) Development 125, 1495-1500) suggesting that, in these non-drosophilid species, Sxl performs a function different from that in sex determination.

Amino Acid Sequence↗
PubMed1998

[Cutaneous malacoplakia. An immunohistochemical and ultrastructural case study].

The authors report a case of a 70 year-old man with a past of myelodysplasia and presenting a voluminous lesion of the thigh corresponding to a cutaneous malacoplakia. Histologic study showed a dermo-hypoderma granuloma with numerous Von Hansemann cells containing some Michaelis-Gutmann bodies. Immunohistochemical study showed a positivity of these cells with the antibodies against CD68 (KP1, Mac 387, PGM1), the lysozyme and the alpha-chemotrypsine. Ultrastructural study confirmed the histiocytic origin of this infiltration by showing some regular and voluminous inclusions with a clear center and a peripheral and dense ring, and also some bacteria measuring 3 to 5 microns. Bacteriological study isolated an Escherichia coli. The evolution was favourable after surgical excision and antibiotherapy. Cutaneous malacoplakia is a very rare disease, usually with a perineal localization, and occurring in immunodeficient host. Michaelis-Gutmann bodies are sometimes difficult to identify by light microscopy underlying the rule of the immunohistochemical and the ultrastructural studies to perform the diagnosis.

Aged↗
PubMed1997

Detection of chromosomal aneuploidy by interphase fluorescence in situ hybridization in bronchoscopically gained cells from lung cancer patients.

BACKGROUND: Development and progression of human malignancies involve multiple genetic changes. New techniques to distinguish neoplastic from benign diseases unequivocally with small amounts of cells as gained by bronchoscopy are needed to come closer to the goal of an early diagnosis in lung cancer. STUDY OBJECTIVE: The aim of this study was to determine whether interphase fluorescence in situ hybridization (FISH) can be used to visualize chromosomal aberrations in bronchoscopically gained cells from lung cancer patients and could eventually become a complementary technique to conventional cytology. METHODS: We examined 20 cancerous specimens (10 primary tumors, 10 malignant effusions) of 18 lung cancer patients by FISH with DNA probes specific for chromosomes 3, 8, 11, 12, 17, and 18. From five additional patients, endobronchial brushings and/or forceps biopsy specimens were subjected to interphase FISH analysis. RESULTS: In all primary tumors and malignant effusions, highly aneuploid cells were detectable by FISH. Chromosomal aberrations always consisted of gains of chromosomal signal numbers, and all chromosomes were found to be aneuploid to a similar extent. Using chromosomal aneuploidy as a marker of malignancy, material obtained by bronchoscopy was then examined for the presence of malignant cells. In all specimens, evidence for malignancy was obtained by FISH, including three specimens in which cells appeared to be normal or reactively changed by cytologic criteria. CONCLUSION: We conclude that interphase FISH is useful in detecting aneuploidy associated with malignancy in bronchoscopically gained cells that do not clearly meet the criteria of malignancy by conventional cytologic study.

Adenocarcinoma↗
PubMed1996

The number of identical kringle IV repeats in apolipoprotein(a) affects its processing and secretion by HepG2 cells.

A variable number of 5.6-kilobase kringle IV repeats in the human apolipoprotein(a) (apo(a)) gene results in a size polymorphism of the protein and correlates inversely with the plasma levels of the atherogenic lipoprotein(a) (Lp(a)). In order to analyze whether this association reflects a direct effect of kringle IV repeat number on Lp(a) plasma concentration, we have studied the expression of recombinant apo(a) (r-apo(a)) isoforms in the human hepatocarcinoma cell line HepG2. Following transient transfection of apo(a) cDNA expression plasmids that differed only in the number of kringle IV repeats, we observed a gradual decrease of Lp(a) in the medium of the cells with an increasing number of kringle IV repeats, mimicking the relationship present in humans in vivo. The analysis of apo(a) protein in the lysate and in the medium of cells that were transfected with a plasmid encoding an apo(a) isoform with 22 kringles revealed a predominant intracellular precursor with little secretion of the mature apo(a) protein. In contrast, transfection of a plasmid encoding an isoform with 11 kringles led to effective secretion of the mature peptide into the medium, indicating differential processing rates of apo(a) isoforms in the secretory path way. The intracellular accumulation of an apo(a) precursor in the endoplasmic reticulum was demonstrated by cell fractionation and [35S]Met metabolic labeling/temperature block experiments using HepG2 cells stably transfected with recombinant apo(a). The direct and causal effect of kringle IV repeat number on the expression of recombinant apo(a) in HepG2 cells, and presumably liver cells, provides a novel mechanism for the genetic regulation of the concentration of a protein.

Apolipoproteins A↗
PubMed1996

The management of pneumothorax with the thoracic vent versus conventional intercostal tube drainage.

The thoracic vent is a new minimally invasive device for the treatment of spontaneous and iatrogenic pneumothorax. It consists of a polyurethane catheter connected to a plastic chamber containing a one-way valve. As there is no need to connect the thoracic vent to an underwater seal device, immobilization and hospitalization can be avoided. So far the performance of the thoracic vent has been evaluated only in patients without pleural effusions and without signs of tension pneumothorax. Hence, we have performed a randomized study comparing the treatment of pneumothorax by means of the thoracic vent versus conventional intercostal tube drainage in 30 patients, including some with tension pneumothorax. 17 patients were treated with the thoracic vent, 13 with conventional intercostal tube drainage. We found no significant differences in the rate of reexpansion and rate of complications between the group treated with the thoracic vent and the group treated with intercostal tube drainage, but the patients treated with the thoracic vent needed significantly less analgesics. 70% of the patients treated with the thoracic vent were successfully managed on an outpatient basis. All patients treated with intercostal tube drainage were hospitalised; duration of inpatient-therapy was 8 +/- 6.2 days (mean +/- SD).

Adolescent↗
PubMed1995

Determination and regional assignment of grouped sets of microclones in chromosome 1pter-p35.

In an approach to mapping physically the most distal 30 Mb of human chromosome 1p, region-specific clone libraries were generated by microdissection and microcloning. PFGE blot hybridization of single or low-copy microclones against rare-cutter digests of genomic DNA revealed physical linkage for groups of markers. Supplementary PFGE analysis of 31 1p36-p35-specific probes for genetically mapped loci established a total of 15 grouped sets, consisting of altogether 69 markers. Twelve of the grouped sets were located in 1pter-p36.12, as revealed by microcell hybrid mapping; the remaining three were localized proximal to 1p36.12. Regional assignment and ordering of most grouped sets was achieved either by evaluating the included genetic markers or by fluorescence in situ hybridization of representative probes. The genomic extent of individual grouped sets encompassed between 1100 and 2100 kb, covering a total of approximately 22 Mb of the distal chromosome 1p region. One particular grouped set was shown to contain seven polymorphic marker loci that were previously suggested to be distributed across the entire 1pter-p35 region. The increase in the number of hybridization marker probes in 1p36 and their physical mapping is expected to facilitate positional cloning experiments in this region; in particular, the construction of clone contigs may be greatly facilitated.

Blotting, Southern↗
PubMed1995

Identification of two functionally distinct lysine-binding sites in kringle 37 and in kringles 32-36 of human apolipoprotein(a).

The well documented association between high plasma levels of lipoprotein(a) (Lp(a)) and cardiovascular disease might be mediated by the lysine binding of apolipoprotein(a) (apo(a)), the plasminogen-like, multikringle glycoprotein in Lp(a). We employed a mutational analysis to localize the lysine-binding domains within human apo(a). Recombinant apo(a) (r-apo(a)) with 17 plasminogen kringle IV-like domains, one plasminogen kringle V-like domain, and a protease domain or mutants thereof were expressed in the human hepatocarcinoma cell line HepG2. The lysine binding of plasma Lp(a) and r-apo(a) in the culture supernatants of transfected HepG2 cells was analyzed by lysine-Sepharose affinity chromatography. Wild type recombinant Lp(a) (r-Lp(a)) revealed lysine binding in the range observed for human plasma Lp(a). A single accessible lysine binding site in Lp(a) is indicated by a complete loss of lysine binding observed for r-Lp(a) species that contain either a truncated r-apo(a) lacking kringle IV-37, kringle V, and the protease or a point-mutated r-apo(a) with a Trp-4174-->Arg substitution in the putative lysine-binding pocket of kringle IV-37. Evidence is also presented for additional lysine-binding sites within kringles 32-36 of apo(a) that are masked in Lp(a) as indicated by an increased lysine binding for the point mutant (Cys-4057-->Ser), which is unable to assemble into particles. An important role of these lysine-binding site(s) for Lp(a) assembly is suggested by a decreased assembly efficiency for deletion mutants lacking either kringle 32 or kringles 32-35.

Amino Acid Sequence↗
PubMed1995

Sequence polymorphism in kringle IV 37 in linkage disequilibrium with the apolipoprotein (a) size polymorphism.

Apolipoprotein(a) [apo(a)] contains a variable number of identical (K-IV A/B) or nearly identical (K-IV 1, K-IV 30-37) kringle repeats that are homologous to K-IV from plasminogen. The sizes of 414 apo(a) alleles were determined by pulsed-field gel electrophoresis (PFGE) of KpnI-digested DNA. Furthermore, sequence variation in the apo(a) K-IV 30-37 domain was analysed. Reverse transcription/polymerase chain reaction (RT-PCR) cloning of human liver poly A+ RNA followed by sequencing revealed a single nucleotide exchange in the ultimate K-IV (K-IV 37) of apo(a) (codon 4168); this results in an ATG (Met) to ACG (Thr) substitution. A PCR-based restriction assay of genomic DNA demonstrated that this substitution represents a common polymorphism. In 231 unrelated Tyroleans, the frequencies for the K-IV 37 Thr and K-IV 37 Met alleles were 0.66 and 0.34, respectively. The phase between the K-IV 37 Met/Thr and the KpnI size polymorphism was determined for 224 alleles. A significant linkage disequilibrium was detected between the sequence and size polymorphisms of apo(a). K-IV 37 Met was significantly associated with KpnI allele no. 18 (DAB = 0.0267 +/- 0.0101; chi 2 = 10.09, df = 1). The Met/Thr polymorphism was further used to test whether deletions or duplications of K-IV 37 occur frequently in the apo(a) gene. Some 40 apo(a) alleles, 22 of which were from subjects that appeared to be double heterozygotes for K-IV repeat number and the Met/Thr variation were separated by PFGE and analysed for the 4168 Met/Thr polymorphism. The Met and Thr sequences were always present on different size alleles and no evidence for a duplication or deletion of K-IV 37 was obtained. This suggests that the copy number of K-IV 37 is invariable, in contrast to the highly variable K-IV A/B domain of the gene. The 4168 Met/Thr polymorphism had no effect on Lp(a) concentration, neither did it influence the lysine-binding property of the Lp(a) particle.

Adult↗
PubMed1993

Cys4057 of apolipoprotein(a) is essential for lipoprotein(a) assembly.

Lipoprotein(a) contains one copy each of apolipoprotein B-100 and apolipoprotein(a). It has been hypothesized that a disulfide bond might exist between Cys4057 of apolipoprotein(a) and Cys3734 in apolipoprotein B-100. To investigate the role of Cys4057 for lipoprotein(a) assembly, wild-type and in vitro mutagenized apolipoprotein(a) cDNA plasmids were expressed in the human hepatocarcinoma line HepG2. The mutant plasmids encoded apolipoprotein(a) species with Cys4057 exchanged to either serine or glycine. Untransfected HepG2 cells, although able to secrete apolipoprotein B-100-containing lipoproteins, do not synthesize detectable amounts of apolipoprotein(a). After transfection of wild-type plasmid, almost all apolipoprotein(a) in the culture supernatant was present in lipoprotein(a)-like particles as demonstrated by immunoblotting, density-gradient centrifugation, and ELISA. The same analysis performed with supernatants of cells transfected with plasmids mutated in codon 4057 revealed free apolipoprotein(a) glycoprotein without detectable amounts of lipoprotein-associated apolipoprotein(a). Our results strongly suggest the existence of a disulfide bridge between Cys4057 of apolipoprotein(a) and apolipoprotein B-100 within recombinant lipoprotein(a) particles. Furthermore, they indicate that disulfide bridge formation is essential for assembly of the lipoprotein(a)-like complex produced by HepG2 cells and suggest a similar role of Cys4057 during lipoprotein(a) assembly in vivo.

Amino Acid Sequence↗
PubMed1993

Left ventricular diastolic impairment in type 1 diabetic patients with microalbuminuria.

The high incidence of cardiac mortality in type 1 diabetic patients is further increased when diabetic nephropathy is present. Since microalbuminuria (albumin excretion rate > 30 mg/day) represents an incipient stage of diabetic nephropathy, we decided to investigate whether incipient renal changes correlate with early diastolic cardiac dysfunction, known to preceed systolic dysfunction. To test this hypothesis, 13 normotensive type 1 diabetics with incipient nephropathy (mean age 37.8 +/- 3.5, diabetes duration 18.8 +/- 2.6 years), 13 type 1 diabetics without nephropathy (matched for age, diabetes duration and metabolic control) or other microangiopathic changes and 13 normal controls were studied. Diseases known to affect left ventricular performance were ruled out before investigation. Right and left ventricular parameters were assessed by M-mode and Doppler echocardiography. While parameters for left ventricular systolic function stayed within the normal range and did not differ between the two diabetic groups (ejection fraction 69.3 +/- 2.4 vs. 69.6 +/- 1.4%; fractional shortening 40.3 +/- 2.2 vs. 38.5 +/- 1.1%), diastolic function was significantly impaired in diabetic patients with microalbuminuria. This is expressed by an inversed early and late peak flow velocity ratio in patients with microalbuminuria (0.988 +/- 0.04 vs. 1.362 +/- 0.1; p < 0.05) and a significant percentual increase in late (atrial) filling (39.1 +/- 1.7 vs. 29.9 +/- 1.4% when compared to whole filling; p < 0.05) despite a similar rate-corrected isovolumetric relaxation period in both diabetic groups (98.4 +/- 5.8 vs. 95.5 +/- 6.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Lysolecithin actions on vascular smooth muscle cells.

Oxidation of low density lipoprotein increases its atherogenic potential. During oxidation there is an extensive conversion of lecithin to lysolecithin. In rat aortic smooth muscle cells, 2-25 micrograms/ml lysolecithin elevated cytosolic calcium concentration up to 560%. Lysolecithin (10-20 micrograms/ml) increased [3H]thymidine incorporation from 15 cpm/mg cell protein (controls) up to 189 cpm/mg cell protein. Lysolecithin (10 micrograms/ml) potentiated the PDGF-induced (50 ng/ml) [3H]thymidine incorporation up to 6.3 times. The results indicate that lysolecithin could induce mechanisms, by which oxidized low density lipoproteins could promote cell growth and thus contribute to atherosclerosis.

Animals↗
PubMed1991

Mammalian nuclei contain foci which are highly enriched in components of the pre-mRNA splicing machinery.

The organization of the major snRNP particles in mammalian cell nuclei has been analysed by in situ labelling using snRNA-specific antisense probes made of 2'-OMe RNA. U3 snRNA is exclusively detected in the nucleolus while all the spliceosomal snRNAs are found in the nucleoplasm outside of nucleoli. Surprisingly, U2, U4, U5 and U6 snRNAs are predominantly observed in discrete nucleoplasmic foci. U1 snRNA is also present in foci but in addition is detected widely distributed throughout the nucleoplasm. An anti-peptide antibody specific for the non-snRNP splicing factor U2AF reveals it to have a similar distribution to U1 snRNA. Co-localization studies using confocal fluorescence microscopy prove that U2AF is present in the snRNA-containing foci. Antibody staining also shows the foci to contain snRNP-specific proteins and m3G-cap structures. The presence of major components of the nuclear splicing apparatus in foci suggests that these structures may play a role in pre-mRNA processing.

Antisense Elements (Genetics)↗
PubMed1991

The effects of morphology and histopathologic findings on the mobility of the sacroiliac joint.

The sacroiliac joints of seven pelvic specimens were examined to determine functional, morphologic, and histopathologic aspects. The movements were measured in four intact pelvises (from two men and two women). The joint surfaces of all pelvises (from three men and four women) then were examined topographically by means of a photogrammetric method. After this, they were examined histologically to characterize any effects on function. The morphologic investigation revealed sex-specific differences. All joint surfaces from the female pelvises showed circular contours, the centers of which coincided with the iliac tuberosities. These morphologic characteristics were not discernible in the joint surfaces from the male pelvises; these had interlocking irregularities without a topographic pattern. As expected, this configuration involved distinct differences in mobility. Rotation of the sacrum was markedly less in the sacroiliac joints of men than in those of women.

Cadaver↗
PubMed1991

A new behavioral assessment scale for geriatric out- and in-patients: the NOSGER (Nurses' Observation Scale for Geriatric Patients).

Although a great number of psychometric tests and rating scales for the assessment of psychogeriatric patients is available, there is still an urgent need, in research and practice, for a clinical rating instrument that meets the following main requirements: (1) applicable to institutionalized and community patients and covering a wide range of behavioral pathology; (2) acceptable and easy to use for professionals and lay persons alike; (3) covering a wide range of behavior relevant to daily functioning but independent of sex or social status of the individual assessed. The NOSGER contains 30 items of behavior, each rated on a 5-point scale according to frequency of occurrence. Item scores are summarized into 6 Dimension scores (memory, instrumental activities of daily life, self-care, mood, social behavior, and disturbing behavior) which are clinically relevant in dementia, depression, and other psychiatric disorders of old age. Validation studies with a preliminary version of the NOSGER indicated good acceptance of the scale, high inter-rater and test-retest reliability, and high correlations of all NOSGER Dimension scores with results of a variety of established assessment instruments. The NOSGER is currently being used in a number of European and North American centers and should turn out to be a useful instrument for longitudinal studies in psychogeriatrics.

Activities of Daily Living↗