Biomedical subjects

G M Pinggera

Publications and source records attributed to G M Pinggera.

8 recordsLinked to original sources

PubMed2005

[Ultrasound contrast agents and prostate cancer].

Prostatic carcinoma is the most frequent malignant disease in men and associated with very high mortality. The diagnostic work-up of prostatic carcinoma is based on tests to determine the level of prostate-specific antigen (PSA), digital rectal examination, and transrectal sonography. Due to diagnostic limitations, ultrasound-guided prostate biopsy is the method of choice for diagnosis of prostatic carcinoma. New imaging technologies allow detection of prostatic carcinoma, thus facilitating removal of specific biopsy specimens from these regions. Introduction of ultrasound contrast agents ("echo signal enhancers") significantly increased the diagnostic potential of this method, making it possible to visualize tumor vascularization.

Biopsy↗

PubMed2004

Three-dimensional transrectal ultrasound of the male urethral rhabdosphincter.

The rhabdosphincter of the male urethra is an omega-shaped loop of striated muscle fibers that surrounds the membranous urethra at its lateral and anterior aspects. We investigated whether this muscle can be visualized by means of three-dimensional ultrasound to define morphological and dynamic ultrasound criteria. We examined the rhabdosphincter of the male urethra in 77 patients by means of this new imaging technique; 37 patients presented with urinary stress incontinence after transurethral resection of the prostate or radical prostatectomy while 40 were fully continent after radical prostatectomy and served as a control group. Contractility of the muscle was quantified by a specially defined parameter (rhabdosphincter-urethra distance). The anatomical arrangement and the contractions of the rhabdosphincter-loop could be clearly visualized in three-dimensional transrectal and transurethral ultrasound; during contraction the rhabdosphincter retracts the urethra, pulling it towards the rectum. We detected defects and postoperative scarrings in the majority of the patients with postoperative urinary stress incontinence. Furthermore, the patients presented with thinnings in parts of the muscle and atrophies of the rhabdosphincter. The rhabdosphincter-urethra distance was significantly lower in the incontinent group than in the continent group (59 vs. 1.42 mm). Our study shows that the rhabdosphincter of the male urethra can be visualized by means of three-dimensional transrectal ultrasound. The sonographic pathomorphological findings of postoperative urinary stress incontinence are well correlated well with the clinical symptoms.

Humans↗

PubMed2004

[Transrectal three dimensional sonography. Techniques and indications].

In 3-D transrectal ultrasound it is possible, for the first time, to investigate the region of interest in three planes simultaneously. Exact examination of the organs of the small pelvis as well as of pathologic changes in the region of the pelvic floor can be performed with this new imaging technique. The bulbourethral glands can be investigated routinely, which enables the diagnosis of cysts of these glands. The prostatic zones, their relations as well as the growth of the transitional zone during the development of benign prostatic hyperplasia can be visualized. Furthermore, 3-D transrectal ultrasound allows investigation of morphology and function of the rhabdosphincter. The contractility of the muscle can be quantified. 3-D ultrasound guided puncture and drainage of prostatic abscesses represents a minimally invasive therapeutic modality. This technique can be used to place needles as well as implants in the lower urinary tract. Generally, 3-D transrectal ultrasound offers new diagnostic and therapeutic possibilities.

Animals↗

PubMed2004

Tissue perfusion essential for spermatogenesis and outcome of testicular sperm extraction (TESE) for assisted reproduction.

PURPOSE: In order to determine if there are areas of major and minor perfusion in a single testicle and if the quality of sperm is correlated with quantity of perfusion we collected testicle tissue for TESE in accordance to the local testicle tissue perfusion. METHODS: A patient undergoing TESE underwent testicular perfusion mapping using contrast enhanced ultrasound. The exposed tissue was scanned with a Laser Doppler scanner and perfusion rates were determined measuring tissue perfusion units (TPUs). Tissue was biopsied and sperm were selected and prepared for assisted reproduction. RESULTS: The total amount of isolated sperm correlated highly with the intensity of tissue perfusion showing high number of sperm in areas with high TPUs. CONCLUSIONS: This is the first demonstration that sperm quality and quantity is depending on tissue perfusion within the testicle. To further improve infertility treatment we propose that random biopsies could be replaced by perfusion-dependent collection of testicular tissue.

Biopsy↗

PubMed2003

[The value of ultrasound (US) in the diagnosis of prostate cancer].

The value of ultrasound (US) in the diagnosis of prostate cancer has increased in importance in the past decade, which is mainly related due to the increasing incidence of prostate cancer, the most common malignancy in men. The value of conventional gray-scale US for prostate cancer detection has been extensively investigated. The introduction of US contrast agents has dramatically changed the role of US for prostate cancer detection. Advances in US techniques were introduced to further increase the role of US contrast agents. Although most of these advances in US techniques, which use the interaction of the contrast agent with the transmitted US waves are very sensitive for the detection of microbubbles, are mostly unexplored, in particular for prostate applications. First reports of contrast-enhanced US investigations of blood flow of the prostate have shown that contrast-enhanced US adds important information to the conventional US technique. We present a critical evaluation of the current status of transrectal US imaging for prostate cancer detection. Furthermore, we give background information on US contrast agents and imaging modalities. Early results of contrast-enhanced US suggest the feasibility of the use of US contrast agents to enhance US imaging of the prostate. The application of US contrast agents for the detection and clinical staging of prostate cancer is promising. However, future clinical trials will be needed to determine the promise of contrast-enhanced US of the prostate evolves into clinical application.

Biopsy↗

PubMed1996

Chromosomal localization of the genes (CLNS1A and CLNS1B) coding for the swelling-dependent chloride channel ICln.

ICln is a cloned chloride channel paramount for regulatory volume decrease. Two different loci that carry the coding region for ICln were identified in the human genome. By PCR strategies an intronless copy of the gene was located on chromosome 6 at position 6p12.1-6q13 (CLNS1B). By fluorescence in situ hybridization a copy carrying introns with a putative length of 19 kb was located at chromosome 11 on position 11q13.5-q14.1 (CLNS1A). The characterization and chromosomal localization of the ICln gene offer the opportunity to study the regulatory sites of this gene in greater detail and could be helpful in establishing linkages between ICln and potential human diseases.

Chloride Channels↗

PubMed1996

Blockade of swelling-induced chloride channels by phenol derivatives.

1. In NIH3T3 fibroblasts, the chloride channel involved in regulatory volume decrease (RVD) was identified as ICln, a protein isolated from a cDNA library derived from Madin Darby canine Kidney (MDCK) cells. ICln expressed in Xenopus laevis oocytes gives rise to an outwardly rectifying chloride current, sensitive to the extracellular addition of nucleotides and the known chloride channel blockers, DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid) and NPPB (5-nitro-2-(3-phenylpropylamino)-benzoic acid). We set out to study whether substances structurally similar to NPPB are able to interfere with RVD. 2. RVD in NIH3T3 fibroblasts and MDCK cells is temperature-dependent. 3. RVD, the swelling-dependent chloride current and the depolarization seen after reducing extracellular osmolarity can be blocked by gossypol and NDGA (nordihydroguaiaretic acid), both structurally related to NPPB. 4. The cyclic AMP-dependent chloride current elicited in CaCo cells is less sensitive to the two substances tested while the calcium-activated chloride current in fibroblasts is insensitive. 5. The binding site for the two phenol derivatives onto ICln seems to be distinct but closely related to the nucleotide binding site identified as G x G x G, a glycine repeat located at the predicted outer mouth of the ICln channel protein.

3T3 Cells↗

PubMed1995

Antiviral drugs from the nucleoside analog family block volume-activated chloride channels.

BACKGROUND: The antiviral drugs AZT and acyclovir are generally used in the treatment of infections with human immunodeficiency virus (HIV) and herpes simplex virus (HSV). These substances are known to impede virus replication by premature nucleic acid chain termination. It is not yet clear, however, if this is the sole mechanism responsible for the antiviral and/or the numerous side effects observed in patients treated with these agents. We investigated the swelling-induced chloride current in fibroblasts, which we demonstrated is closely related or identical to a cloned epithelial chloride channel, ICln: This chloride channel can be blocked by nucleotides. MATERIALS AND METHODS: Electrophysiological, fluorescence optical, and volume measurements were made to determine the effect of nucleoside analogs on the swelling-dependent chloride current (ICl) in NIH 3T3 fibroblasts and in human T cell lymphoma (H9) cells and the cAMP-dependent chloride current in CaCo cells. RESULTS: AZT and acyclovir block the swelling-dependent chloride current and the chloride flux in fibroblasts, and the regulatory volume decrease (RVD) and ICl in H9 cells. This immediate effect can be substantially reduced by the simultaneous incubation of the cells with thymidine-5'-diphosphate (TDP) or uridine, both of which are by themselves unable to affect ICl. CONCLUSIONS: We show here a novel molecular mechanism by which antiviral drugs of the nucleoside analog family could lead to impairments of the kidney, bone marrow, gastrointestinal, and neuronal functions, and how these side effects could possibly be restricted by the presence of TDP or uridine.

3T3 Cells↗