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H J Sommerfeld

Publications and source records attributed to H J Sommerfeld.

14 recordsLinked to original sources
PubMed2003

[Prostate cancer diagnosis using ultrasound elastography. Introduction of a novel technique and first clinical results].

During the last decade screening has improved prostate cancer detection. The main reason for this development is a better understanding of the margins of prostate-specific antigen (PSA) serum levels and the classification of PSA subtypes. In contrast, the introduction of transrectal ultrasound has not led to a measurable change in the prostate cancer detection rate. Our aim was to develop a novel ultrasound system for the acquisition of elastographic images of the prostate and evaluate the system regarding its clinical applicability. We used a technically modified conventional ultrasound system and analyzed the high-frequency ultrasonic data with a computer program. The first patient-based results suggest that elastography allows an accurate measurement of tumor size and localization in contrast to conventional transrectal ultrasound. Elastography visualizes different tissue elasticities to distinguish benign and cancerous tissue. Thus, we were able to even correctly classify prostate cancer lesions which are iso- or hyperechoic in B-mode sonography.

Aged↗
PubMed2003

Ultrasonic tissue characterization for prostate diagnostics: spectral parameters vs. texture parameters.

An ultrasonic multi-feature tissue characterizing system for the detection of prostate cancer is presented. The system is based on the processing of radio frequency (RF) ultrasonic echo data. Data from 100 patients was acquired in a clinical study. Parameters are extracted from the RF echo data and classified using two adaptive network-based fuzzy inference systems (FIS) working in parallel as a nonlinear classifier. Next to spectral parameters, conventional texture parameters are calculated using demodulated and log-compressed echo data. In the first approach, the classifier is trained on both, spectral and texture parameters. In the second approach, the classifier is only trained on texture parameters. Classification results of both approaches are compared and it is demonstrated, that only the use of spectral parameters yields satisfying classification results. Results of a minimum distance classifier (MDC) are presented for comparison with the fuzzy inference system. For the final fuzzy inference systems used in this approach, the area under the ROC curve is between 84% and 86% for the combined approach and between 70% and 74% for the approach based on texture parameters only.

Aged↗
PubMed2000

Combined intravesical and oral oxybutynin chloride in adult patients with spinal cord injury.

OBJECTIVES: Detrusor hyperreflexia with elevated storage pressures presents a major risk factor for renal damage in patients with neurogenic lower urinary tract dysfunction. If standard anticholinergic treatment is unsuccessful, surgical treatment must be considered. We evaluated the effects of intravesical oxybutynin treatment on detrusor hyperreflexia in patients in whom standard oral treatment had failed. METHODS: Twenty-five patients (mean age 36. 7 years) with storage pressures greater than 40 cm H(2)O despite standard anticholinergic treatment received intravesical (15 mg three times daily) and oral oxybutynin chloride treatment. The follow-up evaluations included urodynamic testing, renal ultrasound, urine examination (urinalysis and urine culture), and evaluation of side effects. RESULTS: The mean follow-up was 6 months. Intravesical treatment led to an increase in bladder storage volume from 349 to 420 mL. The mean maximum storage pressure was significantly reduced from 54 to 26.5 cm H(2)O. Detrusor storage pressures returned to values less than 40 cm H(2)O in 21 of 25 patients. Dysreflexia was treated successfully in 3 of 5 patients. No patient developed renal damage. No severe side effects or drug-related discontinuation of treatment were observed. CONCLUSIONS: Intravesical oxybutynin therapy seems to be a safe and effective treatment option for detrusor hyperreflexia in adults and avoids surgical treatment in most patients. Long-term observations concerning side effects, acceptance, and efficacy are needed.

Administration, Intravesical↗
PubMed2000

[Ultrasound elastography of the prostate. A new technique for tumor detection].

AIM: Prostate tumours are often of harder consistency than the surrounding tissue. During digital rectal examination, this fact can be used not only to detect hypertrophy but also localized hardenings. The examination by digital palpation is inaccurate and, even in combination with PSA-value and a transrectal ultrasonic examination, the result is often not reliable. Ultrasound elastography enables us to measure and visualize the elastic properties of a tissue region and is a useful supplement to the examination by digital palpation. Ultrasound elastography is able to measure and visualize the elastic properties of a tissue region, therefore it is a useful supplement to commonly used diagnostic procedures. METHOD: We have developed a new system for elastographic prostate diagnosis which can be used during the transrectal ultrasonic examination. During the examination a sequence of ultrasonic images is acquired while the organ is slightly compressed by the ultrasound probe. Using numerical analysis of image pairs for the acquired sequence we calculate the tissue strain which represents the spatial elasticity distribution of a specific cross-section of the organ. This enables us to distinguish hard areas in the tissue. Image artifacts resulting from lateral motion components, i.e., orthogonal to the direction of the applied force, are compensated for by a special approach. RESULTS: We present results obtained from a typical elastography phantom and also the first in vivo images from patients who were undergoing radical prostatectomy. Our images prove that ultrasound elastography has the potential to detect malignant tissue areas, which are inconspicuous in the B-mode image. Our findings are confirmed by the corresponding histological specimens.

Elasticity↗
PubMed1998

[Telomerase in tumors: facts and perspectives].

Recent reports have indicated the ribonucleoprotein enzyme telomerase to play an important role in tumorigenesis. Activation of this enzyme is known to prevent progressive shortening of the end of the chromosomes, or telomeres, and hence to be critical in maintaining chromosomal integrity. The telomerase expressing cells require immortality. Supported by recent findings which suggest that telomerase activity is expressed in virtually all cancers but not in normal tissues, except those of the germline, hope grew up toward a potentially important new therapeutic target in the fight against cancer. An emerging hypothesis is that the inactivation of telomerase results in the death of immortal cells. If telomerase activation represents a tumor-specific feature, (gene) therapeutic applications would become most promising in regard to an effective anticancer therapy, possibly with limited side-effects. However, most recent studies report on telomerase activity to be also expressed in normal, non-neoplastic tissues as well as in non-neoplastic hyperproliferative lesions. The questions whether telomerase activity is tumor-specific or associated with (physiologic or pathologic) hyperproliferation is intriguing and remains to be clarified.

Cell Division↗
PubMed1998

Ovarian cystoid causing Kock pouch incontinence.

The Kock pouch is a well-known standard technique for continent urinary diversion. If incontinence occurs, it is mostly related to insufficiency of the efferent nipple valve. We present the rare case of a young woman with a Kock pouch suffering from urine loss caused by a large cystoid in the left ovary leading to compression of the pouch and destabilization of the nipple.

Adult↗
PubMed1996

Telomerase activity: a prevalent marker of malignant human prostate tissue.

We urgently need biochemical markers to detect the malignant nature and pathological states of the human prostate. We report that telomerase activity is associated with prostate cancer but absent in the benign disease and normal gland. Telomerase is, therefore, a potential diagnostic marker for prostate cancer. Twenty-five human prostates resected at the time of radical prostatectomy were dissected to obtain matched adjacent areas of normal, central zone benign prostatic hyperplasia (BPH), and pathologically confirmed cancer tissue. These matched tissue samples were assayed for telomerase activity using a sensitive PCR technique. None of the normal tissues exhibited telomerase activity. In contrast, 21 of the 25 (84%) cancers were strongly positive. At the time of prostatectomy, four lymph nodes were positive for metastases and all were strongly positive for telomerase activity. In adjacent BPH tissues taken from the cancerous prostates, only 3 of the 25 tissues (12%) were weakly positive. Telomerase activity was not detected in ten BPH samples recovered from patients who underwent open surgery solely for BPH. All five available cell lines of human prostate cancer (DU145, LNCaP, PC3, PPC1, and TSU) were strongly positive. Short telomere lengths have been observed in several human cancers. We also measured the telomere lengths in 27 matched samples of normal, BPH, and cancer tissue taken from nine radical prostatectomies. The telomeres from cancer tissue were significantly and consistently shorter than either the adjacent normal or adjacent BPH tissues. Our results indicate that telomerase activity, as well as telomere lengths, may be markers for distinguishing prostate cancer from normal and benign prostate tissues.

Aged↗
PubMed1996

Telomerase is activated in the prostate and seminal vesicles of the castrated rat.

Telomeres, the repetitive non-coding DNA sequences found at the ends of all eukaryotic chromosomes, shorten with each cell division. It has been proposed that telomere shortening may be the counting element of a mitotic clock that keeps track of cell divisions; with shortening to a critical length acting as a senescence signal underlying cellular aging. The enzyme telomerase functions to maintain telomere length, thus allowing unlimited cell division, and has been associated with cellular immortalization and cancer. Stem cells have large, perhaps unlimited, replicative capacities. Since these cells are potentially immortal, we reasoned that they might posses active telomerase. We therefore assayed for telomerase activity in the stem cell enriched pools of the androgen-depleted sex accessory tissues in the castrated male rat. Following castration, the ventral prostate and seminal vesicles of the rat involute, losing approximately 90% of their cells by 21 days. These residual glands persist, and are enriched for stem cells, being capable of fully regenerating these glands if testosterone is re-introduced into the animal. We assayed telomerase activity in extracts from normal, involuted, and regenerating ventral prostate and seminal vesicles. Normal glands were found to be telomerase negative, whereas telomerase activity appeared as these glands involuted following castration. Conversely, telomerase activity disappeared during testosterone-induced regeneration of these residual glands. These results provide strong evidence for the ability of androgen to negatively-regulate telomerase activity in stem cell populations of the rat ventral prostate and seminal vesicles. and represent the first in vivo model system for the modulation of telomerase activity.

Animals↗
PubMed1996

Urodynamic and rectomanometric findings in urinary incontinence.

To investigate the correlation of urinary and fecal incontinence, 52 patients with urinary incontinence underwent cystometry and rectomanometry. Twenty-five patients suffered from stress, 20 from urge and 7 from overflow urinary incontinence. The rectomanometry showed normal results in 29 patients, 5 presented with a compensated and 18 with a partially compensated sphincter incompetence. Whereas 18 of 20 urge incontinent patients had a normal rectal sphincter function, in contrast 16 of 25 stress incontinent patients suffered from rectal sphincter incompetence. In conclusion, there is a marked correlation between stress urinary incontinence and rectal sphincter incompetence. This supports the general thesis that a weakness of the entire pelvic floor is one of the characteristic features of urinary incontinence.

Adult↗
PubMed1993

The morphological substrate of autonomic regulation of the bronchial epithelium.

Observations of explanted bronchial mucosa show that ciliary function is maintained for 7 days subsequent to explanation. This finding demonstrates that non-neural mechanisms exist which regulate ciliary function. Ultrastructural and immunohistochemical studies both for light and electron microscopy were performed on human bronchial biopsy material and lung resection specimens in order to recognize the morphological substrate of this regulatory mechanism. A complex system of cytokeratin filaments and microtubules radiate through the whole cytoplasm of ciliated cells with direct contact to the nucleus, cilia, microvilli, desmosomes and to the apical terminal adhesive complex. Between the basal bodies and the apical terminal adhesive complex microfilaments can be found. In the apical cytoplasm a dense filamentary network is seen in association with the adhesive complex. These morphological findings indicate that the cytoskeleton of the bronchial epithelium plays a key role in the co-ordination of ciliary function.

Bronchi↗
PubMed1993

[Immunotherapy of prostate cancer].

In recent years immunotherapy of prostate cancer has developed into an innovative field of investigation. Nevertheless, in contrast to some other human tumors in which immunotherapy has been demonstrated to be effective, no breakthrough has been achieved with respect to a successful clinical application of this modality to prostate cancer. So far studies focus either on immunologically specific or nonspecific treatment concepts. Based on this, the modes of action of monoclonal antibodies, adoptive immunotherapy techniques, tumor cell vaccination, various biological response modifiers and substances with immunological as well as tumoritoxic/-static attributes are studied. Not all of the results obtained so far offer new insights into tumor biology. Ongoing studies in all fields continue to pursue immunological mechanisms for effective systemic therapy of prostate cancer. Major impulses may be seen only via immunologically specific concepts. Through these, new therapeutic modalities for patients with advanced prostate cancer may be developed which are more efficacious than androgen ablation.

Antibodies, Monoclonal↗
PubMed1992

Recognition of SV40-VP2 in the infected cell by antipeptide antibodies.

Antipeptide antibodies were elicited against two synthetic peptides corresponding to amino acids 47-55 and 98-103 of the structural protein VP 2 of SV 40. The induced antibodies proved to be VP 2-specific in an immunoblot. In immunofluorescence these antibodies showed a discrete nuclear and perinuclear staining pattern. In immune electron microscopy studies the induced antibodies did not bind to major virions suggesting that VP 2 is not present at the surface of SV 40 particles.

Animals↗