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Biomedical subjects

P Rogalla

Publications and source records attributed to P Rogalla.

At least 91 records · Page 5Linked to original sources
PubMed1998

Virtual endoscopy of the nose and paranasal sinuses.

The purpose of this study was to evaluate the applicability of virtual endoscopy (VE) in the region of the nose and paranasal sinuses on the basis of volume-rendered spiral CT data. Forty-five patients underwent a low-dose spiral CT of the sinuses. The data were transferred to a workstation running software for volume rendering (EasyVision, Philips Medical Systems, Eindhoven, The Netherlands). Six orthogonal views of the maxillary sinuses and the nasopharynx and a fly-through movie of the nose were calculated. Two radiologists evaluated the coronal reconstructions and virtual endoscopy with respect to detectability of pathology using a checklist comprising 10 points. In 30 patients who underwent subsequent endoscopic surgery, surgeons were asked to rank the degree of assistance of the preoperative virtual endoscopy. In general, virtual endoscopy was possible in all 45 patients. The mean time required for path definition and movie calculation for virtual endoscopy were 8 (+/- 2) min and 3 (+/- 1) min, respectively. Overall, more anatomical details were depicted on coronal reconstructions; however, a high degree of similarity between virtual endoscopy and the intraoperative impression was reported by the surgeons. We conclude that virtual endoscopy of the nose and paranasal sinuses may develop into a standard means to guide surgeons during endoscopic interventions.

Adolescent↗
PubMed1998

Low-dose spiral computed tomography for measuring abdominal fat volume and distribution in a clinical setting.

OBJECTIVES: Computed tomography (CT) has been used to measure body composition, however, a technique with reduced radiation exposure has not yet been introduced. This study tested a low-dose spiral CT technique on a phantom to determine its validity and reproducibility. The method was then applied for volume and distribution measurements in patients. DESIGN: Construction and measurement of a phantom followed by measurement of patients referred to CT for clinical indications. SETTING: Radiology Department, University Hospital. SUBJECTS: Twenty-four post-gastrectomy patients. INTERVENTION: A 22 cm phantom with a known amount of water and fat was scanned using high- and low-dose technique, standard and double table speed during a volumetric scan. The low-dose technique was implemented in the patient group. Total volume, total fat and four defined compartmental fat volumes in the truncal area were measured. RESULTS: The mean fat volume measured using the low-dose CT technique in the phantom was 0.2% above the actual fat content. The coefficient of variation for this method was 5%. By using low-dose, double speed instead of standard-dose technique, radiation exposure to the skin was decreased by more than 90% (equivalent to 4 mGy) of what is used in diagnostic imaging. The patient scans showed that no significant differences in BMI and total measured volume existed between female and male patients, but percent fat and percent subcutaneous fat were significantly larger in women (P = 0.006 and 0.002, respectively), as were percent intraabdominal and mediastinal fat in men (P = 0.002 and 0.003 respectively). CONCLUSIONS: Low-dose spiral CT accurately measures fat volume in vitro, and can be used in vivo for compartmental fat measurements.

Abdomen↗
PubMed1998

Mapping and molecular characterization of five HMG1-related DNA sequences.

Recently, the high mobility group (HMG) proteins have attracted a lot of interest since it was shown that some members of that group can causally be involved in tumorigenesis. One HMG protein gene member is HMG1 for which the number of related DNA sequences has been estimated to be approximately 20-30. Nevertheless, besides the gene for HMG1 only one retropseudogene has been molecularly characterized. It was the aim of this study to map and characterize further sequences related to HMG1. PCR-screening of a PAC library resulted in 25 very strongly positive clones apparently containing HMG1-like cDNA sequences. Of eight clones which were further investigated five were distinguishable from each other based on their chromosome assignment and DNA sequence. Due to their homology to the HMG1 gene the DNA sequences were designated as HMG1L1, HMG1L3, HMG1L4, HMG1L5, and HMG1L6. By FISH experiments they were assigned to 2q32, 2q35, 3p24, 15q22, and 20q13, respectively. Except for one sequence, they did not show mutations leading to a frame shift or a new termination codon. Thus, we cannot exclude that these four HMG1-related DNA sequences represent active genes or can at least be activated e.g. by chromosome rearrangements in tumor cells. So far, the existence of six genes encoding HMG proteins has been described but because of a high frequency of closely related DNA sequences in the human genome it can be assumed that some of them are either pseudogenes or very similar genes.

Blotting, Southern↗
PubMed1998

A method for adjusting a malpositioned bifurcated aortic endograft.

PURPOSE: To report the successful application of a method to adjust a malpositioned bifurcated stent-graft after endovascular aortic aneurysm repair. METHOD AND RESULTS: A 62-year-old male patient underwent endovascular repair of a 5.1-cm abdominal aortic aneurysm (AAA) with a Vanguard bifurcated stent-graft. After complete deployment of the stent-graft, the intraoperative completion angiogram disclosed unexpected occlusion of the left renal artery. Intra-aortic adjustment of the bifurcated graft was possible with a crossover guidewire, which was pulled caudally. The method worked perfectly to restore blood flow to the left renal artery. The patient is well 16 months postoperatively without any evidence of endoleak or graft migration; the left renal artery remains open. CONCLUSIONS: A technique is demonstrated for intra-aortic repositioning of a bifurcated stentgraft to correct insufficient deployment. If required, this technique should be attempted before conversion to an open procedure.

Angiography, Digital Subtraction↗
PubMed1998

Combined surgical and endovascular removal of thrombus entirely occluding a bifurcated aortic stent-graft.

PURPOSE: To explore a method combining interventional, endovascular, and conventional surgical techniques for treating a completely occluded bifurcated stent-graft after endovascular aortic aneurysm repair. METHODS AND RESULTS: A 60-year-old patient underwent endovascular repair of an abdominal aortic aneurysm (AAA) with a Talent bifurcated stent-graft. Five months later, after chronic thrombotic occlusion of the right iliac limb, he presented with acute occlusion of the entire stent-graft. Local intra-arterial infiltration thrombolysis successfully reconstituted flow through the main aortic segment and left iliac limb. With a combination of conventional surgical and intraoperative endovascular procedures, thrombectomy and recanalization of the right iliac limb was completed by stenting a severe stenosis of the proximal iliac limb. CONCLUSIONS: A combination of techniques may be essential for successful management of thrombotic complications after endovascular AAA repair.

Acute Disease↗
PubMed1997

Tetraphocomelia and bilateral cleft lip in a historical case of Roberts syndrome [Virchow, 1898].

We discuss an unlabelled specimen of tetraphocomelia and bilaterally cleft lip from the former Virchow Museum of our Medical School. Identity of the subject with a case of what was later termed "Roberts syndrome" published by Rudolf Virchow in 1898 is demonstrated. Rediscovery of this important historical case is gratifying, since almost 95% of the specimens of Virchow's collection were lost during World War II. We have restudied Virchow's case. Recent CT scan images of the fetus are presented. We review data from the literature and present new clinical details. The fate of the original clinical data after passing through three reviews is documented briefly. We also reconstruct Virchow's view on phocomelia and its consequences for later research.

Abnormalities, Multiple↗
PubMed1997

HMGIC expressed in a uterine leiomyoma with a deletion of the long arm of chromosome 7 along with a 12q14-15 rearrangement but not in tumors showing del(7) as the sole cytogenetic abnormality.

Cytogenetic studies on uterine leiomyomas have shown that more than 60% of these tumors possess a normal karyotype and that 30% have clonal chromosomal aberrations. The most frequent changes are aberrations involving 12q14-15 and show rearrangements of the long arm of chromosome 7. Recently, we were able to demonstrate that in a variety of mesenchymal tumors showing 12q14-15 aberrations the HMGIC gene is rearranged thus playing a role in tumorigenesis. Here we report the results of HMGIC expression studies by RT-PCR of five uterine leiomyomas with different karyotypes. The RT-PCR studies were performed on two primary tumors showing a 12q14-15 aberration, one of which with an additional del(7) and three tumors with del(7) as the sole aberration. The tumor with the 12q14-15 aberration as the sole alteration and the leiomyoma with 12q14-15 rearrangement plus deletion of the long arm of chromosome 7 were shown to express HMGIC. In contrast, in all three tumors with the del(7) as the sole aberration no expression of HMGIC was noted.

Chromosome Aberrations↗
PubMed1997

Expression of HMGI-C, a member of the high mobility group protein family, in a subset of breast cancers: relationship to histologic grade.

The high-mobility-group (HMG) protein gene HMGI-C is apparently involved in the genesis of a variety of benign human solid tumors with rearrangements of chromosomal region 12q14-15 affecting the HMGI-C gene. So far, no expression of HMGI-C has been found in adult tissues, and no data are available on the expression of HMGI-C in primary human malignant tumors of epithelial origin. Therefore, we analysed the HMGI-C expression patterns in 44 breast cancer samples and 13 samples of nonmalignant adjacent tissue by hemi-nested reverse transcriptase-polymerase chain reaction for HMGI-C expression. There was no detectable expression of HMGI-C in any nonmalignant adjacent breast tissues analyzed. In contrast, we found expression in 20 of 44 breast cancer samples investigated. In invasive ductal tumors, expression was noted predominantly in tumors with high histologic grade: 17 of 21 breast cancer samples with histologic grade 3 but only three of 16 samples with histologic grades 1 or 2 showed expression of HMGI-C. In addition, all seven lobular breast cancer samples tested did not express HMGI-C. From these results, we concluded that HMGI-C expression may be of pathogenetic or prognostic importance in breast cancer.

Adult↗
PubMed1997

Computed tomography-guided transtracheal needle aspiration of paratracheal lymphadenopathy in endoscopically normal patients.

RATIONALE AND OBJECTIVES: The authors investigated the diagnostic value of computed tomography-guided bronchoscopic transtracheal needle biopsy of paratracheal lymphadenopathy without any endoscopical signs of stenosis or protrusion. METHODS: Twenty consecutive patients with an age of 22 to 76 years underwent fiberoptic bronchoscopy with transtracheal needle biopsy under computed tomography guidance of paratracheal lymphadenopathies (diameter between 10 to 19 mm). Computed tomography fluoroscopy as a special low-dose computed tomography technique was used in the region of interest. The results of needle aspirates (cytologic examination) were verified by surgical interventions (n = 4), mediastinoscopy (n = 9), percutaneous needle biopsy (n = 1), or clinical/radiologic follow-up (n = 10). RESULTS: All patients were without endoscopic signs of lymphadenopathy or tumor. Sufficient material of lymphatic tissue for cytologic assessment was obtained in 23 out of 24 patients (96%). In 5 of 10 patients with malignant diseases and 13 of 14 patients with benign enlarged lymph nodes, the lymph nodes were demonstrated exactly by transtracheal needle biopsy. There were no bleeding complications. CONCLUSIONS: Computed tomography-guided bronchoscopic needle biopsy of paratracheal lymphadenopathy is a low-risk procedure. If malignant cells can be demonstrated with these technique, other more invasive procedures (surgery, mediastinoscopy) can be avoided. The numerous false-negative results (5 of 10) suggest, that the cytologic evidence of benign cells is without any diagnostic value in cases of paratracheal lymphadenopathy.

Adult↗
PubMed1997

HMGI-C, a member of the high mobility group family of proteins, is expressed in hematopoietic stem cells and in leukemic cells.

The human HMGI-C gene encoding a member of the high mobility group protein family normally is expressed only during embryonic/fetal development but in none of the adult tissues tested so far. Recently, the HMGI-C gene has attracted a lot of interest since its rearrangements seem to underlie the development of frequent benign mesenchymal tumors. We have therefore checked CD34 positive hematopoietic stem cells and their normal and malignant descendants for HMGI-C expression. CD34 positive stem cells from healthy donors and the leukemia samples tested were positive while all peripheral blood samples from healthy volunteers were negative. We have concluded that the expression of the HMGI-C gene in leukemia seems to be a secondary effect due to abnormal stem cell proliferation and might be a sensitive tumor marker for particular types of leukemia.

Acute Disease↗
PubMed1996

Telomeric repeat fragment lengths are not correlated to histological grading in 85 breast cancers.

The mean telomeric repeat fragment (TRF) lengths of 85 breast cancer samples were determined. The TRF length varied between 7260 bp and 14570 bp (average 11370 bp) reflecting a unimodal distribution. There was no significant correlation between TRF length and the histological grade of the tumor. Neither were there differences in telomeric length between different histological types of tumors, in particular lobular and ductal types, nor correlations between TRF length and age of patient, tumor volume, lymph node status, or steroid receptor status. These results contradict the hypothesis that the telomere repeat fragment sizes represent limiting or promoting factors for the growth of breast cancer.

Breast Neoplasms↗
PubMed1996

An extended nomenclature of the canine karyotype.

In contrast to many other animals, knowledge about the canine karyotype is quite sparse. This is due in part to the rather difficult canine karyotypic pattern. Except for the X and the Y chromosome, there are only acrocentric chromosomes, which appear to be quite small and difficult to identify unambiguously. In previous reports, schematic representations of the canine karyotype have been described. However, a nomenclature comparable to that of the human karyotype or the karyotypes of sheep, cattle, or goats does not yet exist for the dog. Based on high-resolution banding of metaphase chromosomes from canine fibroblasts, we propose an ideogram of the canine karyotype with 460 numbered bands and characteristic landmarks. In addition, the centromere positions of the canine chromosomes are determined by a combined GTG-banding/FISH approach, and the R- and G-banding patterns are compared.

Animals↗
PubMed1996

HMGI-C expression patterns in human tissues. Implications for the genesis of frequent mesenchymal tumors.

Cytogenetically visible aberrations of chromosomal region 12q14-15 in a variety of frequent benign human tumors reflect rearrangements of the HMGI-C gene. The mechanisms by which the HMGI-C gene contributes to tumorigenesis are mostly unknown, although frequently aberrant transcripts containing exons 1 to 3 of HMGI-C and ectopic sequences from other genes due to breaks within the third intron of HMGI-C are detectable. This is the first report analyzing human tissue samples mainly of mesenchymal origin by a highly sensitive polymerase-chain-reaction-based approach detecting HMGI-C expression. We found HMGI-C expression in embryonic tissue but no expression in any of several adult tissues tested except for two myometrial tissues. These data suggest that HMGI-C is mainly expressed in human tissues during embryonal and fetal development. Thus, its particular role for tumor development may be due to the expression of at least exons 1 to 3 rather than to the formation of fusion transcripts.

Adult↗
PubMed1995

Description of a novel fusion transcript between HMGI-C, a gene encoding for a member of the high mobility group proteins, and the mitochondrial aldehyde dehydrogenase gene.

Aberrations involving the chromosomal region 12q24 are a nonrandom cytogenetic abnormality in frequent benign tumors mainly of mesenchymal origin, e.g., uterine leiomyomas, pleomorphic adenomas of the salivary gland, lipomas, or hamartomas of the lung. Mostly, these 12q24 abnormalities occur as a result of inversions also affecting chromosomal region 12q14-15. In addition to the frequent tumors mentioned above, these abnormalities have also been found in rare mesenchymal tumors, e.g., hemangiopericytomas. Although recently the molecular basis of the aberrations of chromosomal region 12q14-15, i.e., a rearrangement of the HMGI-C gene has been identified, the molecular roots of the 12q24 changes still remain to be elucidated. Herein we report on 3' rapid amplification of cDNA ends PCR results on cDNA from a primary uterine leiomyoma. As an ectopic sequence fused to exon 3 of the HMGI-C gene, we have identified a cDNA sequence that revealed 100% homology to exon 13 of the human mitochondrial aldehyde dehydrogenase gene (ALDH 2). Because ALDH 2 maps to 12q24.1, this fusion transcript is a good candidate underlying the chromosomal rearrangements involving 12q24.

Aldehyde Dehydrogenase↗
PubMed1995

Telomere repeat fragment sizes do not limit the growth potential of uterine leiomyomas.

We have compared the length of telomere repeat fragments (TRF's) in 19 uterine leiomyomas from 6 patients with the corresponding myometrium. The advantage of this study of TRF length is that cells from uterine leiymyoma and cells from corresponding myometrium do not contain any considerable proportions of other cells as revealed by analysis of clonality. In all tumor samples a loss of TRF length ranging from 1120 to 4690 bp was noted. There was no correlation between tumor volume or size of tumor population as revealed by histological examination and loss of TRF length. From the obtained TRF length data (an average myometrial TFR length of 13 kb and an average loss of TRF length in myoma cells of 83 bp per cell division) we concluded that TRF length reduction does not limit the growth potential of uterine leiomyomas.

Base Sequence↗
PubMed1995

CT for the evaluation of carcinomas in the colon and rectum.

The role of conventional CT in assessing patients with colorectal tumors is well established. The low accuracy of CT for identifying early stages of primary colorectal cancers prevents the routine use of CT for preoperative staging. Nevertheless, CT is useful in examining patients suspected of having extensive disease, in deciding whether a patient will benefit from preoperative radiation, in designing radiation ports, and in detecting complications related to the neoplasm. For recurrent colorectal neoplasm, CT has the premier role. CT surpasses colonoscopy in detecting early masslike tumor recurrence at the anastomotic site because of its extrinsic component, and CT and MRI are the only methods that can fully evaluate cases of total abdominoperineal resection. After total abdominoperineal resection, however, CT cannot determine with certainty that a soft tissue density in the surgical bed represents recurrent tumor. In patients with colorectal neoplasms, preliminary results with multiplanar and three-dimensional reconstructions of helical CT images are promising, but their role needs further investigation.

Colonic Neoplasms↗
PubMed1994

Two human breast cancer cell lines showing decreasing telomeric repeat length during early in vitro passaging.

Specific DNA repeats serve as a molecular protection shield at the telomeric ends of mammalian chromosomes. The absence of telomerase activity leads to a gradual decrease of telomeric repeat length in normal somatic cells. In contrast, immortalized cells from malignant tumors are usually thought to re-express telomerase to overcome a self-limited growth. Following this hypothesis, re-expression of telomerase is due to a rare mutational event. Herein we describe our results of telomeric length determination in two newly established breast cancer cell lines. During in vitro establishment from pleural effusions, both cell lines showed a marked decrease of the upper border range of telomeric repeat length distribution. The lower border remained within a constant range characteristic for each cell line. In no case was decrease of repeat length accompanied by an increased incidence of telomeric associations or fusions. The results show that a constant telomeric repeat length does not constitute a characteristic feature of immortalized cells. Furthermore, the kinetics of repeat length decrease and the constant range of the lower border reveal that the onset of telomerase activity is not necessarily due to a rare, i.e., mutational, event.

Adult↗