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Biomedical subjects

M Hampl

Publications and source records attributed to M Hampl.

At least 19 recordsLinked to original sources
PubMed2001

Therapeutic effects of viral vector-mediated antiangiogenic gene transfer in malignant ascites.

Malignant ascites is a common complication of advanced intraabdominal neoplasms for which standard treatments are suboptimal. Evidence suggests that tumor-mediated angiogenesis and enhanced vascular permeability in the peritoneal wall due to high levels of vascular endothelial growth factor play a fundamental role in the pathogenesis of malignant ascites. To explore the advantage of viral vector-mediated "targeted antiangiogenic therapy" in ascites formation, we constructed and administered adenoviral vectors encoding several different antiangiogenic proteins (angiostatin, endostatin, platelet factor 4, and a fusion protein between angiostatin and endostatin) alone or in combination intraperitoneally in mice with peritoneal carcinomatosis from breast cancer (TA3 cells) and ovarian cancer (SKOV-3 i.p. and ES-2 cell lines) to explore the potential of additive or synergistic activity. Our data demonstrated statistically significant downregulation of ascites formation, tumor growth, vascularity, and prolongation of animal survival after intraperitoneal treatment with antiangiogenic adenoviral vectors in three different ascites tumor models. Combined treatment proved to be more effective than treatment with one vector alone. Reduced ascites formation was accompanied by decreased microvascular density in the peritoneal wall and increased apoptosis of tumor cells after administration of antiangiogenic vectors in vivo. Of interest was the observation that AdPF4 caused a significant decrease in the level of VEGF secreted by tumor cells both in vitro and in TA3 ascites tumor-bearing animals in vivo. These data suggest that adenoviral vector-mediated delivery of genes encoding antiangiogenic proteins may represent a potentially new treatment modality for malignant ascites.

Adenoviridae↗
PubMed1999

[Mammographic screening starting in the fifth or sixth decade of life].

Mammography is an established diagnostic procedure for breast cancer. Data concerning screening mammography are available from nine prospectively controlled trials, the largest series being presented from Sweden. Mammographic screening leads to a significant reduction of breast cancer of 30% in women ages 50-59 years. In younger women (40-49 years) the benefit accounts to only 20% and has not proven to be statistically significant. Nevertheless, the major advantage of mammographic screening is detection of the non-palpable tumor < or = 10 mm in size. The treatment of these small breast carcinomas leads to long-term survival rates of > or = 90%. Mammographic screening programs have been introduced in the USA, Canada, Iceland and Sweden for women in their 5th decade of life. Starting yearly lifelong mammography-screening at the age of 40, the theoretical cancer induction by radiation exposure does not exceed 0.1%. Under highly qualified conditions, it should be possible to minimize false-positive and false-negative screening results. In Germany, screening-mammography is only introduced in patients at high risk for breast cancer. Based on medical data, mammography must be a part of screening for women with an average risk--starting at the age of 40, although there are still open questions needing further clinical research.

Aged↗
PubMed1999

Loss of heterozygosity accumulation in primary breast carcinomas and additionally in corresponding distant metastases is associated with poor outcome.

The occurrence of distant metastases is the most feared manifestation of breast cancer, often occurring years after the primary surgery and associated with poor survival. The dominant metastatic clone is characterized by an accumulation of genetic alterations, but it is not actually known at what stage of the metastatic cascade these alterations have occurred. We investigated allelic losses during breast cancer progression in a series of 17 primary breast carcinomas and 22 corresponding brain, liver, lung, and bone metastases (mean metastasis-free interval, 31 months) by analyzing 19 microsatellite markers on seven breast cancer- or metastasis-related chromosomal regions and correlated the incidence of combined loss of heterozygosity (LOH) with metastasis-free and postmetastatic survival. We found that, in comparison with the corresponding primary tumor, additional LOH events are frequently found in metastases and that the incidence of combined LOH in the primary tumor, plus the occurrence of additional LOH events in the distant metastases, correlated significantly with decreased postmetastatic survival. Combined LOH of the three breast cancer-related chromosomal regions alone or in combination with allelic loss at the p53 gene region seems to have a specific influence on the aggressive behavior of metastases. We hypothesize that the occurrence of additional LOH events is either involved in termination of dormancy of micrometastatic tumor cells at distant organ sites or acquired during further progression of metastases.

Bone Neoplasms↗
PubMed1998

Evidence that TSG101 aberrant transcripts are PCR artifacts.

Critical analysis of the data published so far concerning the TSG101 gene revealed some inconsistencies leading us to its re-evaluation in 80 breast, brain, colon, and neuroectodermal tumors and 37 normal tissue specimens. In this study, the occurrence of TSG101 cDNA aberrant transcripts was verified, but in addition we made observations that are in apparent conflict with the aberrant splicing theory supposed as the underlying mechanism for transcript formation: the location of most deletion breakpoints within exons and nonconformity of these putative splice sites with the highly conserved GT-AG rule, detection of insertions as well as nonreproducible and highly variable results in repeated RT-nested PCRs. Furthermore, we found that reamplification of full-length TSG101 cDNA products leads to the generation of deleted transcripts. In summary, for the first time we provide evidence that the acquired TSG101 transcripts are caused by PCR artifacts.

Artifacts↗
PubMed1998

Multiple intracerebral haemangioblastomas in identical twins with von Hippel-Lindau disease--a clinical and molecular study.

Von Hippel-Lindau (VHL) disease is an inherited autosomal dominant neoplastic disorder causing central nervous system haemangioblastomas. The VHL gene (3p25-3p26) is known to be a tumour suppressor gene, with its inactivation being responsible for a predisposition to tumour development. As far as we know, the present report of VHL disease manifestation in identical twins is unique. Genetic inquiry into the family background did not reveal this disease among their progenitors. For presymptomatic diagnosis of 17 presently unaffected family members, constitutional DNA of the twins was screened for VHL germline mutations, using loss of heterozygosity studies and exon-specific DNA sequencing. To determine the influence of somatic mutations of the VHL gene in tumourigenesis, DNA of five surgically removed intracerebral haemangioblastomas of the identical twins was analyzed in comparison with their constitutional DNA by DNA sequencing of the complete VHL coding region. However, no allelic losses were found for the VHL gene or for various other tumour suppressor genes (p53, BRCA1, BRCA2, DCC, and MCC). Furthermore, no mutations were found in the constitutional DNA of either twin sister or in the DNA of all five tumour lesions. Based on our observations, we conclude that in certain VHL families, presymptomatic molecular diagnosis of the disease is not feasible and requires close clinical surveillance of all individuals at risk.

Adult↗
PubMed1998

[Surgical procedure in primary and metastatic breast carcinoma].

We know that breast cancer is already a systemic disease in the majority of patients at the time it is first diagnosed, requiring an interdisciplinary treatment concept. This fact has changed the surgical treatment approach of primary breast cancer which currently follows the principle: "As much as necessary, as little as possible". Improved early detection of breast carcinomas allows the treatment of a majority of early stage breast cancer patients with breast-conservation surgery, followed by irradiation except for a few contraindications. Although survival is not significantly different for patients who undergo breast conservation surgery plus irradiation than for those having modified radical mastectomy, the pattern and prognostic value of locoregional failure are different. Locoregional failure after breast conservation requires mastectomy, thoracic wall recurrence will be treated by (en-bloc) resection and irradiation. Following rigorous selection criteria and indications, surgical resection of distant metastases to the liver, lung or brain can improve the quality of life and prolong survival, it should therefore be taken into consideration in individual cases. Since the two breast cancer susceptibility genes, BRCA1 and BRCA2, have been detected, high-risk patients should be offered the possibility of genetic counseling and genetic testing. Based on our present knowledge, the surgical approaches for BRCA1 or BRCA2 mutation carriers with breast cancer remain unchanged. There are some indications that molecular tumor parameters can be used to identify a subgroup of primary breast cancer patients who are characterized by a poorer prognosis. The results achieved in our own patients add further evidence in favor of this theory.

Biomarkers, Tumor↗
PubMed1998

[Sequence analysis of BRCA1 gene in young breast cancer patients and/or positive family history].

We analyzed the complete coding region with adjacent intron sequences of the BRCA1 gene in eight patients with hereditary and/or early-onset breast/ovarian cancer. We detected one germline mutation in exon 5 in a 35-year-old woman with early-onset breast and ovarian cancer and 10 polymorphisms, of which one has not been published so far. To determine whether certain BRCA1 polymorphisms are associated with an increased risk for breast cancer, we will compare genotype distributions of early-onset breast cancer populations with matched controls.

Adult↗
PubMed1997

The putative tumor suppressor gene FHIT at 3p14.2 is rarely affected by loss of heterozygosity in primary human brain tumors.

To elucidate the role of the recently identified FHIT gene, located at 3p14.2 in human brain tumor carcinogenesis, a total of 259 tumors were analyzed for loss of heterozygosity (LOH) at microsatellite loci D3S1313, D3S1234, D3S1300, and D3S1481. In primary brain tumors, LOH was detected at a frequency of 8.4% (n = 214). Low-grade gliomas exhibited insignificantly lower LOH rates in comparison to high-grade gliomas (5.3%, n = 19, versus 11.1%, n = 90). Notably, no allelic loss was observed in 12 recurrent glioblastomas analyzed in comparison to their corresponding primary tumor lesions and in two astrocytomas with progression to higher grades of malignancy. Our data indicate that allelic loss of the FHIT gene is neither a critical event in carcinogenesis of primary brain tumors nor tumor grade-associated in astrocytic tumors. In contrast, observed LOH rate for brain metastases was as high as 54.5% (n = 45), in accordance with data thus far accumulated from analyses of corresponding primary tumors.

Acid Anhydride Hydrolases↗
PubMed1997

An intronic germline transition in the HNPCC gene hMSH2 is associated with sporadic colorectal cancer.

The aim of this study was to determine whether an intronic germline substitution in the hereditary non-polyposis colorectal cancer (HNPCC) gene hMSH2 represents a genetic risk factor for sporadic CRC. Possible effects of this substitution were investigated by assessment of microsatellite instability and hMSH2 cDNA sequencing. Constitutional DNA from patients with sporadic CRC and healthy controls from the same region in Germany was analysed for the intronic germline T-->C transition six bases upstream of exon 13 of hMSH2. 29 of 106 patients (27%) were found to harbour the germline T-->C transition as opposed to only 13 of 125 controls (10%; P < 0.001; OR 3.2, CI 1.58-6.63). CRCs from patients with the substitution displayed neither clinical HNPCC-like features nor an increased rate of microsatellite instability. No abnormal cDNA sequence was found at the exon 12-13 border. These data suggest a 3.2-fold increased risk of sporadic CRC for individuals with the intronic hMSH2 transition. However, this substitution might not be pathogenic itself, but may be linked to a locus nearby that is.

Adult↗
PubMed1997

[Molecular genetics of hereditary breast carcinoma].

Breast cancer is the most common malignancy among women. Genetic predisposition is considered to account for 5-10% of all cases while the majority of these cancers are sporadic and caused by complex interactions of exogenous and endogenous factors. The inherited predisposition can be due to germline mutations in one of several cancer susceptibility genes. For high risk families the two most important genes are BRCA1 on chromosome 17q, which confers a high risk of both, breast and ovarian cancer and BRCA2 on chromosome 13 associated with high penetrance of breast cancer but lower risk of ovarian cancer. A high risk of breast cancer is conferred by mutations in the p53 tumor suppressor gene as part of the rare Li-Fraumeni-syndrome, and possibly also by the estrogen receptor gene. Other cancer genes associated with a less increased risk of breast cancer are the autosomal recessive ataxia telangiectasia (AT) gene and the HRAS1 gene. Germline mutations in BRCA1 and BRCA2 account for the majority of families with multiple cases of breast and/or ovarian cancer and also at least 10% of cases below the age of 40 years. Genetic testing for BRCA1 mutations is not generally recommended except for women with a strong family history. The aim for the management of familial breast cancer should be the establishment of interdisciplinary teams to cover genetic counseling, molecular analysis, onco-surgical therapy, psychosocial support and clinical follow-up.

BRCA1 Protein↗
PubMed1995

[Torsion of the pregnant uterus].

Pathological version of the pregnant uterus is a rare complication. A case of 180 degrees sinistrotorsion of the uterus in the 39th gestational week is reported. The case was asymptomatic with the exception of preterm labor in the 30th week of pregnancy and was discovered during a cesarean section carried out because of myoma obstructing the birth canal. Mother and child were discharged in perfect health.

Adult↗
PubMed1995

[Determination of cytokines and cytokine receptors in premature labor].

One of the leading causes of preterm labour is a subclinical intrauterine infection. The diagnosis of this inapparent infection is an unsolved problem, because clinical parameters show the infection mostly too late and cannot be used for early detection of women at high risk for preterm labour. A prospective clinical study measuring cytokines and cytokine receptor concentration in amniotic fluid from patients with preterm labour and preterm rupture of membranes (PROM) was undertaken to answer the question whether the amount of cytokines is positively correlated to the risk of preterm delivery. In 78 patients (43 controls, 23 patients with PROM, 7 with preterm labour and delivery < 37 weeks of gestation, 7 with preterm labour and delivery at term) amniotic fluid was collected and the following cytokines were measured by an ELISA: IL1 beta, IL2, IL6, TNF alpha, IFN gamma, TNF receptor 55 und 75, IFN gamma receptor, IL2 receptor. We found significant, in some cases highly significant differences in the cytokine content of amniotic fluid of patients with PROM compared with controls and patients with preterm labour and delivery before 37 weeks of gestation compared with controls. There were no differences between patients with preterm labour and delivery at term and controls. Amniotic fluid cultures were positive only in 20-25% of the cases and therefore not a predictive sign. The determination of cytokines in amniotic fluid of patients with preterm labour seems to be a good marker to predict the risk of preterm delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Quantitative determination of fetal fibronectin in cervical smears: a new marker for evaluating the risk of premature labor].

There is a well-known correlation between ascending infection and preterm labour. Nevertheless, up to now an exact method to identify patients which are at high risk for preterm labour does not exist. Fetal fibronectin is an extracellular matrix protein, which is produced by fetal membranes. High concentrations are present in amniotic fluid, but not in cervical secretions in uncomplicated pregnancies (only in 3-4%). If there is an inflammatory mediated damage to fetal membranes (amnion/chorion) or a mechanical disruption caused by preterm contractions, fetal fibronectin should be released into the cervix and vagina. A prospective clinical study measuring quantitatively the content of fFN in cervicovaginal secretions in patients with preterm labour (n = 43), preterm rupture of membranes (n = 15) and 20 controls was undertaken. In 16 patients frequent specimen could be obtained over a period of several weeks. 14 of the 34 patients with preterm labour, which could be observed until delivery, delivered before term (< 37. WOP). In 13 fFN was present in a concentration > 75 ng/ml (sensitivity: 92.4%). 13 patients were negative for fFN and only one of these patients delivered before term (92% chance of term delivery in absence of fFN in cervicovaginal fluids). In 8 patients with beta-adrenergic treatment fFN was present. All patients delivered before term. The 15 patients with PROM had very high concentrations of fFN with a medium concentration of 967.3 ng/ml. 18 of the 20 control patients were negative for fFN (< 75 ng/ml), 2 had a slightly elevated concentration of 84 and 85 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Chorioamnionitis↗
PubMed1993

Migratory trends in former Czechoslovakia.

The authors analyze migration trends in the former Czechoslovakia. "Most attention is focused on the search for specificities of two sorts. On the one hand this is the peculiarity of the geographical organization of the migratory relationships in a concrete territory as a secondary specification of a general pattern (the effect of the peculiarities in the location and hierarchical differentiation of the centres, the positional exposure of the regions, etc.) and on the other hand...about the peculiarities resulting from the distorted control of the society." Sections are included on macroregional differentiation, the position of Prague, and the prospective development of migration. (SUMMARY IN CZE)

Czechoslovakia↗