Search PubMed⌕ Search

Biomedical subjects

P Berger

Publications and source records attributed to P Berger.

At least 55 records · Page 3Linked to original sources
PubMed2000

High levels of zinc ions induce loss of mitochondrial potential and degradation of antiapoptotic Bcl-2 protein in in vitro cultivated human prostate epithelial cells.

Prostate epithelial cells contain the highest levels of zinc among all organs and tissues in the human body. Zinc is accumulated primarily in the mitochondria, where it is responsible for inhibition of mitochondrial aconitase activity, thereby increasing citrate production. The present study was designed to clarify the role of zinc for human prostate epithelial cell growth and apoptosis. Apoptosis of in vitro cultivated human prostate epithelial cells exposed to ZnCl(2) was analyzed by determination of phospholipid membrane asymmetry, nuclear fragmentation, DNA strand breaks, changes of mitochondrial potential and cellular pro/antiapoptotic proteins. Zinc induced apoptosis without involvement of p53 by decreasing mitochondrial transmembrane potential (DeltaPsi(m)) and Bcl-2 protein levels in proliferating epithelial cells. Thus, the high local concentrations of zinc ions in the prostatic lumen seem to be necessary to regulate proliferative activities and to enforce epithelial differentiation processes.

Actins↗
PubMed2000

An unusual member of the human growth hormone/placental lactogen (GH/PL) family, the testicular alternative splicing variant hPL-A2: recombinant expression revealed a membrane-associated growth factor molecule.

The human growth hormone/placental lactogen (GH/PL) gene cluster consists of five highly-related genes (GH-N, GH-V, PL-L, PL-A, PL-B). This evolutionarily young gene cluster codes for an array of mRNAs and proteins, such as the major 22 k forms (hGH-N/V, identical PL-A and B), 20 k and 17.5 k hGH-N and the recently described 25 k hGH-Delta4, a presumably chimeric molecule. In addition, two longer alternatively spliced, (intron D retaining) mRNAs isoforms, termed PL-A2 and GH-V2, have been described in placenta and testis. To elucidate the role of hPL-A2 in male reproduction and pregnancy, testicular PL-A2 cDNA was cloned in a complementary overlapping 2-way RT-PCR approach to analyze translation, localization and structure/function of this unusual member of the GH/PL growth factor family. Analysis of insect mRNA revealed that intron D-retaining PL-A2 cDNA was expressed without splicing in the baculovirus expression system. Thus, PL-A2 mRNA does not represent a nuclear intermediate splicing product simply co-isolated with the mature RNA, but is a stable mRNA isoform generated by placental/testis-specific splicing factors. Recombinant protein was present in whole cell extracts, and no secreted protein was detected in the supernatant. Immunologically, the N-terminus of the 230 amino acid protein is similar to 22 k hPL-A/B, as determined by hPL-specific monoclonal antibodies. In contrast, the C-terminus shares a hydrophobic region presumably responsible for membrane insertion. By the use of confocal microscopy recombinant hPL-A2 was localized in the cell membrane. Thus, hPL-A2 might exert its function by modulating GH/PL actions or act as an independent growth-regulatory molecule itself and its functions in male reproduction and embryonic development remain to be investigated.

Aged↗
PubMed2000

Inhibition of matrix metalloproteinases by lung TIMP-1 gene transfer or doxycycline aggravates pulmonary hypertension in rats.

Chronic hypoxic pulmonary hypertension (PH) results from persistent vasoconstriction, excess muscularization, and extracellular matrix remodeling of pulmonary arteries. The matrix metalloproteinases (MMPs) are a family of proteinases implicated in extracellular matrix turnover and hence in smooth muscle and endothelial cell migration and proliferation. Because MMP expression and activity are increased in PH, we designed the present study to investigate whether inhibition of lung MMPs in rats subjected to chronic hypoxia (CH) contributes to or protects against vascular remodeling and PH. To achieve lung MMP inhibition, rats exposed to 10% O(2) for 15 days were treated with either doxycycline (20 mg/kg per day by gavage starting 2 days before and continuing throughout the CH period) or a single dose of recombinant adenovirus (Ad) for the human tissue inhibitors of metalloproteinases-1 (hTIMP-1) gene (Ad.hTIMP-1, 10(8) plaque-forming units given intratracheally 2 days before CH initiation). Control groups either received no treatment or were treated with an adenovirus containing no gene in the expression cassette (Ad.Null). Efficacy of hTIMP-1 gene transfer was assessed both by ELISA on bronchoalveolar lavages and by hTIMP-1 immunofluorescence on lung sections. MMP inhibition in lungs was evaluated by in situ zymography and gelatinolytic activity assessment using [(3)H]gelatin. Rats treated with either doxycycline or Ad.hTIMP-1 had higher pulmonary artery pressure and right heart ventricular hypertrophy more severe than their respective controls. Worsening of PH was associated with increased muscularization and periadventitial collagen accumulation in distal arteries. In conclusion, our study provides compelling evidence that MMPs play a pivotal role in protecting against pulmonary artery remodeling.

Animals↗
PubMed2000

Diseases of aging.

By definition, diseases of aging become clinically manifested in elderly patients. However, their pathogenetic basis has to be sought earlier in life. The general thread of this presentation relies on the concept of an evolutionary-Darwinian view of the development of age-related diseases. In essence, this concept states that we may have to "pay" for genetic traits that play a beneficial role earlier in life by the later development of diseases since there is no post-reproductive selective pressure that may have eliminated the potential late onset detrimental effects of such genes. Examples for this kind of trade-off are taken from diseases involving the immune system (infections), the endocrine system (andropause), the nervous system (Alzheimer's disease), the locomoter system (osteoporosis), the cardio-vascular system (atherosclerosis) and cancer.

Adult↗
PubMed2000

Rotational atherectomy or balloon angioplasty in the treatment of intra-stent restenosis: BARASTER multicenter registry.

The BARASTER registry was formed to evaluate the initial success and long-term results of rotational atherectomy in the management of in-stent restenosis. Rotational atherectomy was used in 197 cases of in-stent restenosis: 46 with stand-alone rotational atherectomy or at most 1 atmosphere of balloon inflation (Rota strategy), and 151 with rotational atherectomy and adjunctive balloon angioplasty <1 atmosphere (Combination strategy). These were compared with 107 episodes of in-stent restenosis treated with balloon angioplasty alone. In this observational study, the use of Combination therapy was associated with a slightly higher initial success rate (95% vs. 87% with the Rota strategy and 89% with Balloons, P = 0.08). There was a reduction in one year clinical outcomes (death, myocardial infarction or target lesion revascularization) in the combination group (38% vs. 60% with Rota and 52% with balloons, P = 0.02). These data support a benefit of the strategy of debulking with rotational atherectomy followed by adjunctive balloon angioplasty, in the management of in-stent restenosis.

Aged↗
PubMed2000

Antibodies and immunoassays.

As a glycoprotein hormone, human chorionic gonadotropin (hCG) is not a single molecular entity. This term comprises not only the bioactive heterodimer hCG but also an array of molecular protein backbone and glycosylation variants, such as its free beta (hCGbeta) and alpha (hCGalpha) subunits and clipped, cleaved, terminally differently sialylated, and overglycosylated forms. This heterogeneity places great demands on selective detection systems for hCG-derived molecules. Measurement of hCG and/or its derivatives is highly dependent on the selection of target molecules and the natural variability of hCG in the specimens analyzed. Monoclonal antibody (mAb)-based immunoassays are still the state-of-the-art technique for both clinical and research applications but a major problem is the different extents of recognition of hCG variants by mAbs used in different immunoassays. On the whole, construction of sandwich-type assays obviously must take into consideration mAb characteristics, such as main and fine specificities, cross-reactivities, epitope locations and compatibilities, overlap and overhang in specificities (pairs of mAbs), and, finally, overspecificity. Consequences of overhang and overlap in antigen recognition of coating and detection mAb specificities are nondesirable assay cross-reactions and competitive interference by antigenic variants. The general agreement on the most favorable assay design is contrasted by the variety of isotopic and nonisotopic detection systems in current use. The immunoenzymometric assay (IEMA) technique is hampered by a relatively small measuring range and limited sensitivity. By measuring substrate absorption values off the absorption maximum, the measuring range of any IEMA can be extended significantly, as shown for 3,3',5, 5'-tetramethylbenzidine (TMB), without jeopardizing assay characteristics. Sensitivity of the IEMA can be enhanced by modifying the horseradish peroxidase (HRPO) labeling technique by using highly purified mAb preparations and higher-input HRPO/mAb ratios. We have also compared the assay characteristics of time-resolved fluoroimmunoassay (IFMA), IEMA, immunoradiometric assay (IRMA), and competitive radioimmunoassay (RIA) based on identical mAbs. Reasons for the observed superiority of the IFMA lie in its concept of signal detection and the high specific labeling of the detection mAb which on a molar basis can be up to 7-fold and 15-fold higher compared with (125)I and HRPO, respectively.

Antibodies, Monoclonal↗
PubMed2000

Serum antibodies to heat shock proteins are of no diagnostic value for human kidney allograft rejection.

Because of the prevailing evidence that heat shock proteins (hsp) are involved in transplantation immunology, we investigate in this study the serum levels of anti-hsp60, and anti-hsp70 antibodies in human kidney allograft recipients. We analyzed 67 sera from 20 patients immediately before and 2 weeks after receiving a kidney allograft, and from 27 healthy age-matched controls with an ELISA. Eleven kidneys had normal allograft function, six had a mild rejection episode, all of which could be reversed successfully; three kidneys had to be removed later on because of resistant rejection. Hsp antibody frequency and titres were the same for transplant recipients and for healthy controls. In patients receiving a kidney allograft, no difference in the level of hsp-antibodies before and after transplantation was observed. Additionally, anti-hsp60 and anti-hsp70 antibody titres were found to be independent of the clinical course. These data suggest that the determination of anti-hsp60 and 70 antibody titers are of no diagnostic value for renal allograft rejection.

Adult↗
PubMed2000

Serum antibodies against the heat shock protein 60 are elevated in patients with osteosarcoma.

Osteosarcoma is the most frequent malignant bone tumor, mainly occurring in the second and third decade of life. Diagnosis is limited to clinical symptoms, radiology and histology, but so far no diagnostic laboratory tests are available. Heat shock proteins (hsp), highly conserved proteins performing vital intracellular chaperoning functions and preventing cells from death, have been shown to be involved in tumor immunity. We analyzed 75 sera from 23 patients with high-grade osteosarcoma, 8 patients with chondrosarcoma, 10 patients with Ewing's sarcoma, 5 patients with soft tissue sarcoma, 11 patients with benign bone tumors at the time of diagnosis and from 18 healthy controls with an indirect one-site enzyme linked immunosorbent assay (ELISA) for the presence of anti-hsp60 and 70 antibodies. In these assays 10/23 osteosarcoma patients (43%) had anti-hsp60 antibodies with a mean +/- S.D. titer of 0.382 +/- 0.243 U/ml. Only one of the 18 healthy controls (1/18, 5.6%; titer 0.22 U/ml), two of the Ewing's sarcoma patients (2/10, 20%; titer 0.2 +/- 0.09 U/ml), two of the patients with a benign bone tumor (2/11, 18%; titer 0.22 +/- 0.16 U/ml) and one of the chondrosarcoma patients (1/8, 12.5%; titer 0.14 U/ml) were positive, whereas all others, including all soft tissue sarcomas were negative throughout. Anti-hsp60 antibodies in patients with osteosarcoma are therefore significantly increased (p < 0.05). 19/23 (83%) of osteosarcoma biopsy specimens expressed hsp60 immunohistochemically and all specimens from patients with a positive anti-hsp60 serum titer expressed hsp60. The level of the anti-hsp60 antibodies did not correlate with clinical parameters such as response to preoperative chemotherapy, duration of symptoms, age, gender, tumor size, serum alkaline-phosphatase levels and metastases. Although no difference in anti-hsp70 antibodies could be observed between sera from patients and healthy controls, a positive correlation was found for the presence of anti-hsp70 serum antibodies and lung metastases at the time of diagnosis in osteosarcoma patients. These data suggest an increase of anti-hsp60 antibodies at the time of first diagnosis of osteosarcoma. These findings should therefore give rise to further investigations on a group of new markers for the diagnosis of osteosarcoma.

Adolescent↗
PubMed2000

The value of peri-operative consultation on a general surgical ward by the internist.

BACKGROUND: Medical peri-operative consultation plays an important role in the practice of the internist. It represents 13-33% of the total consultation done by the internist. The value of preoperative consultation by the internist is still unclear and the place of the consultations is under discussion. METHODS: Consecutive medical consultations--by internist-intensivists from the surgical ICU--of 408 patients in the department of Surgery of the University Hospital Groningen were retrospectively analyzed, with specific attention to the consultation request, the consultation report and the outcome of the consultation. RESULTS: The main problems were cardiac (34%) or pulmonary (20%). In 78% well defined questions about the patients were asked and in 29% of the preoperative requests, the requesting surgeon asked specific advice about diagnosis and management. In 49% the requesting physician asked for an 'evaluation' of the patients. Of all consultations 271 (67%) were preoperative consultations. In 12% the findings of the preoperative consultation had a significant impact on the course of the patient, whereas in 7% of the preoperative requests the operation was postponed. The consulting internist recommended in 2% to cancel the operation for this admission, which was shared by the surgeon and anesthesiologist. In 10% of all cases new diseases or processes were diagnosed, or were found not to be treated adequately before consultation, so the diagnosis or management was changed. CONCLUSIONS: Our data show that (semi-) elective consultations by internists at the department of Surgery, on indication of the surgeon, changes the course of a significant percentage of patients. (See Editorials p. 1 and p. 4).

Adolescent↗
PubMed2000

Effects of aging on male fertility?

The increase in male life expectancy has raised issues concerning the impact of aging on the endocrine system and male fertility. This review focuses on the relationship of spermatogenesis to changes with age in androgen production and testicular morphology, the influence of age on semen parameters and chromosomal quality, and the impact of paternal age and pregnancy outcome. While age-related endocrine changes are well documented, those concerning semen parameters and consequent fertility are based on cross-sectional studies alone. Nevertheless, characteristic age-related morphological testicular alternations have been described, such as decreased numbers of Leydig cells paralleling decreased testosterone production, arteriosclerotic lesions, thickening and hernia-like protrusions of the basal membrane of the seminiferi tubules, and fibrotic thickening of the tunica albuginea. Surprisingly, these alterations do not lead to significant differences in sperm-morphology, time of spermatozoa development or sperm function between young and elderly males. Reports on decreased sperm motility, semen volume and changes in sperm count are contradictory. Although numerical chromosomal abnormalities of spermatozoa are not higher in aging males, an increase in structural aberrations can be observed. Consequently, children of elderly fathers show a 20% higher risk for autosomal dominant diseases, presumably due to increasing numbers of germ cell meioses and mitoses. Thus, the American Fertility Society recommends an age limit for semen donors of 50 years or less.

Aging↗
PubMed2000

Aging of the male reproductive system.

Reproductive and sexual physiology, changes in body composition and mental performance in the aging male cannot simply be reduced to presumptive hypogonadism defined by low androgen serum levels or by decreasing levels of growth hormone (GH) and melatonin. Morphological changes in organs at different regulatory levels of hormonal networks governing, for example reproduction, such as diminished hypothalamic pulse generator mass, focal degeneration and loss of Leydig cells in testicular tissue, lead to diminished reserve capacities in production and to loss of coordinated pulsatile release of hypothalamic neuropeptides (e.g. gonadotropin releasing hormone, GnRH) and consequently diminished release of pituitary protein and glycoprotein hormones and testicular steroid hormones. Owing to presumptive alterations in feedback sensitivity, decreased testosterone levels do not necessarily upregulate pituitary LH secretion. Alternatively, increased serum levels of LH and FSH can be observed in old men either because of primary hypogonadism or to decreased hypothalamic opioid tone. In general, endocrine functions are sufficient to maintain fertility in elderly men because, except for sperm motility, quantitative and qualitative functional semen parameters are apparently not affected by age. Nevertheless, reduced endocrine and organic functions might become critical at different levels, with high inter-individual variability, of the hypothalamo/pituitary/gonadal-axis. One of the most intriguing organic manifestations of male aging is benign prostatic hyperplasia (BPH), the pathologic prevalence of which closely matches age. Age-associated changes in the endocrine system and in local networks of epithelial, stromal and luminal factors may play important roles in BPH development.

Aging↗
PubMed2000

Apheresis registry in France: indications, techniques, and complications. French Registry Study Group.

The French Registry for Plasma Exchange (PE) was set up in 1985. For 13 years it has allowed for the analysis of the techniques used, along with the indications and complications. After a decrease in the number of participating centers due to the heaviness of the data collection mode, the telematic network created in 1991 led to a new increase in participants from 26 in 1990 to 69 in 1998. Follow-up shows a slight fall in activity since some protocols ended, while the neurological pathologies remain the most frequent indicators. The important modifications observed over the years are the increase of the centrifugation technique, the development of plasma treatment, and the plasma substitution by an association of albumin-pentastarch. The French Registry for plasma exchange is the largest data base dealing with therapeutic hemapheresis. The registry set-up through the internet is the first step toward an international data base.

Blood Component Removal↗
PubMed2000

Selective expression of trophoblastic hormones by lung carcinoma: neurendocrine tumors exclusively produce human chorionic gonadotropin alpha-subunit (hCGalpha).

Recent findings suggest that glycoprotein- and protein hormones act as local auto/paracrine growth/differentiation factors in normal and malignant tissue. An imbalanced or even selective production of human chorionic gonadotropin-alpha (hCGalpha) by neuroendocrine tumors in various organs has been reported. In this context, the ectopic production of trophoblastic hormones by lung carcinoma has not been investigated systemically. Because the determination of serum levels of hCGalpha are flawed by a number of factors, we designed an immunohistochemical study to precisely assess the comprehensive paraneoplastic auto-/paracrine hormone production by lung carcinoma of various histological types. To this end, 90 patients with primary lung neoplasms (40 neuroendocrine tumors, 29 adenocarcinomas, 20 squamous cell carcinomas, and 1 adenosquamous carcinoma) were analyzed by our well characterized monoclonal antibodies (mabs) against the glycoprotein hormones hCG, and its derivatives hCGalpha, hCGbeta, hCGbeta core-fragment (hCGbetacf), luteinizing hormone (LH, LHbeta), follicle-stimulating hormone (FSH, FSHbeta), and the protein hormones placental lactogen (PL) and growth hormone (GH). Overall, trophoblastic hormone immunoreactivity was found in 31% (28/90) of all lung carcinomas, regardless of histological differentiation. Detailed analysis showed 23% (21/90) hCGalpha-, 7% (6/90) hCGbeta, and 2% (2/90) hCGbetacf-positive cases. The tumors produced neither the intact heterodimer hCG, nor the other placental protein hormones PL-A/B and GH-V, or the hCG-related pituitary gonadotropins FSH/FSHbeta and LH/LHbeta. With regard to histological differentiation, it appeared that neuroendocrine tumors exclusively produced free hCGalpha in a distinct expression pattern depending on histological tumor grade. Thirty-eight percent (15/40) of all neuroendocrine neoplasms were hCGalpha-positive, and marker positivity increased with more mature, highly differentiated tumors (20% of small cell neuroendocrine carcinomas versus 90% of atypical and typical carcinoids). This is in striking contrast not only to trophoblastic malignancies and testicular germ cell tumors, but also to nontrophoblastic tumors, such as gynecological and urothelial malignancies, 60% of which produce hCGbeta and where marker positivity correlates with poor histological tumor differentiation. In conclusion, free hCGalpha, but not hCGbeta, is a useful marker for neuroendocrine differentiation in primary lung tumors. The fact that it is preferentially produced by the differentiated tumor types (carcinoids) points to a putative biological function in these tissues. The few hCGbeta-positive NSCLC must not be confounded with primary mediastinal choriocarcinoma.

Adult↗
PubMed2000

Antibodies to heat shock protein 90 in osteosarcoma patients correlate with response to neoadjuvant chemotherapy.

Autoantibodies to the heat shock protein 90 (Hsp 90) have been reported as prognostic marker in breast cancer patients. Sera from 20 high-grade osteosarcoma patients were tested at the time of diagnosis by enzyme-linked immunosorbent assay. Presence of anti-Hsp90 antibodies correlated with a better response to neoadjuvant chemotherapy (P < 0.01), whereas the absence correlated with development of metastases. These data suggest that anti-Hsp90 antibodies might be of predictive value in human osteosarcoma.

Adolescent↗
PubMed2000

Low- versus high-osmolality contrast media.

PURPOSE: To evaluate the effects of contrast media pharmokinetic differences on aortic enhancement at abdominal CT angiography and to determine whether these effects are of clinical relevance. MATERIAL AND METHODS: Two hundred and twelve patients referred for abdominal CT angiography were included in the study. All abdominal CT angiograms were performed with the same parameters (collimation 3 mm, pitch ratio 1.7, scan delay 30 s) after i.v. injection of 120 ml of contrast medium at 3 ml/s. After randomization, patients received either iobitridol 300 (low-osmolar, 300 mg I/ml), iobitridol 350 (low-osmolar, 350 mg I/ml) or ioxithalamate 350 (high-osmolar, 350 mg I/ml). The time attenuation curves obtained with the three contrast media were compared. RESULTS: The time attenuation curve obtained with ioxithalamate 350 was not parallel to those obtained with iobitridol 300 and iobitridol 350. Mean peak enhancements obtained with iobitridol 350 and ioxithalamate 350 were not significantly different but iobitridol 350 provided higher mean peak enhancement than iobitridol 300. Mean delays of the peak enhancements were the same with the three contrast media. After peak enhancement, the decrease of aortic opacification under a selected threshold of 200 HU was significantly slower with iobitridol 350 than with iobitridol 300 and ioxithalamate 350, whereas iobitridol 300 and ioxithalamate 350 showed no significant differences. CONCLUSION: For a given iodine concentration, low-osmolality contrast media provide longer aortic opacification and may be recommended for CT angiography when long acquisition times are needed.

Adult↗
PubMed2000

Direct eye visualization of Cy5 fluorescence for immunocytochemistry and in situ hybridization.

Cyanine 5.18 (or Cy5) is a fluorochrome emitting in the long-red/far-red range, usually regarded as unsuitable for direct observation by the human eye. We describe here the optimization of a direct visualization approach to Cy5 labeling, based on a standard fluorescence microscope with mercury light excitation and applicable to both immunocytochemistry and fluorescent in situ hybridization. Crucial factors were (a) an excitation path in the microscope not absorbing light in the orange-red range, up to 640 nm, (b) a 588-640-nm excitation filter range, distinctly below the excitation optimum for Cy5, (c) a 650-700-nm emission filter range, transmitting the low-wavelength portion of Cy5 emission, and (d) high-efficiency filter set components allowing a narrow gap between excitation and emission ranges without visible cross-talk of excitation light in the emission path.

Animals↗
PubMed2000

Disulfide bond mutations in follicle-stimulating hormone result in uncoupling of biological activity from intracellular behavior.

The crystal structure of human CG reveals that each subunit is a member of the superfamily of cystine-knot growth factors. Although the distribution of the cysteine residues in all the beta-subunits is conserved, the conformation of the human FSH dimer differs from that of the CG/LH dimers. This suggests that the function of the cystine bonded loops in the human FSHbeta-subunit may differ from that in the CGbeta-subunit. To address this issue, we deleted two disulfide bonds in the FSHbeta domain: cys 20-104 and cys 28-82, which correspond to the disulfide bonds 26-110 and 34-88, respectively, in the CGbeta-subunit. The cys 26-110 bond is associated with the "seat-belt" region and cys 34-88 is a bond in the cystine knot. Coexpression of the wild-type alpha-subunit with the FSHbeta cysteine mutants in CHO cells revealed no detectable heterodimer. The FSHbeta mutants were then incorporated into a single chain where the beta-subunit is genetically fused to the alpha-subunit. In such a model, the rate-limiting subunit assembly step is by-passed and mutations that otherwise block heterodimer formation can be evaluated in terms of biological activity. Compared with the nonmutated single chain, the single-chain 28-82 mutant is secreted more slowly and its recovery is substantially reduced, whereas secretion and recovery of the 20-104 mutant was not significantly affected. The receptor binding affinity of the cys 28-82 mutant did not differ from wild-type and binding of the cys 20-104 mutant was decreased only 2-fold. The signal transduction data parallel the binding affinities, although the maximal accumulation of cAMP is less for the cys 20-104 mutant than that seen for cys 28-82 and nonmutated single-chains variants. These data support the hypothesis that the determinants for intracellular behavior and bioactivity of the gonadotropins are not the same, and that the cystine knot is a critical determinant for the formation of a stable, assembly-competent subunit. In addition, the data imply that the "seat-belt" conformation does not play a prominent role in the bioactivity of FSH.

Animals↗