Biomedical subjects

H Strasser

Publications and source records attributed to H Strasser.

At least 37 records · Page 2Linked to original sources

PubMed1998

Intraurethral ultrasound: diagnostic evaluation of the striated urethral sphincter in incontinent females.

The aim of our study was to evaluate the striated urethral sphincter (rhabdosphincter) in incontinent females by means of intraurethral ultrasound (IUUS). Thirty-four incontinent and 11 continent female patients were examined by means of 12.5-MHz endoluminal ultrasound (US). The distance between the inner contour of the sphincter muscle and the US catheter was measured in the contracted and the non-contracted condition. The US findings were correlated with those obtained by urodynamic studies. Partial or complete loss of sphincter function was detected in patients with stress urinary incontinence (SUI). Reduced sphincter function was not observed in patients with urge incontinence and continent volunteers. The findings on US were found to correlate well with the grade of SUI. The IUUS technique offers the benefit of direct visualization of the sphincter mechanism. Therefore, endoluminal US may become an important adjunct in the diagnostic evaluation of SUI and will possibly provide new insights for a better therapeutic strategy.

Adult↗

PubMed1998

The female urethral sphincter: a morphological and topographical study.

PURPOSE: We reassess the anatomy and topography of the female urethral sphincter system and its innervation in regard to urethra sparing anterior exenteration and other surgical procedures. MATERIALS AND METHODS: Anatomical and histological studies were performed on 9 fetal specimens and 4 adult cadavers. Using graphics software the anatomical structures of the true pelvis were reconstructed based on computerized tomography cross sections and digitized histological sections. On the adult cadavers anterior exenteration was performed to study the implications of the isolated urethra and its sphincter mechanism. RESULTS: Strata of connective tissue were found to divide the smooth muscles of the proximal two-thirds of the female urethra into 3 layers. Computer guided 3-dimensional reconstruction of digitized histological sections showed that thin fibers of the pelvic plexus course to this part of the urethra. The majority of these fibers may be preserved by carefully dissecting the bladder neck and the proximal portion of the urethra, leaving the lateral vaginal walls intact. The striated rhabdosphincter, which is innervated by fibers of the pudendal nerve, was in the caudal third of the urethra. CONCLUSIONS: A well-defined sphincteric structure or sphincter could not be anatomically recognized in the bladder neck region. The majority of rhabdosphincter fibers were found in the middle and caudal thirds of the urethra. Thus, in patients undergoing removal of the bladder neck and part of the proximal portion of the urethra continence can be maintained by the remaining urethral sphincter system, provided that innervation remains essentially intact.

Cadaver↗

PubMed1998

Transurethral ultrasound: evaluation of anatomy and function of the rhabdosphincter of the male urethra.

PURPOSE: A combined anatomic-sonographic study was undertaken to investigate whether the anatomical arrangement and the contractions of the rhabdosphincter of the male urethra could be visualized by transurethral ultrasound. Furthermore, this new technique was compared with standard urodynamic tests. MATERIALS AND METHODS: In 7 cadavers transurethral ultrasound was performed to define sono-morphological criteria of the rhabdosphincter, and the sonographic pictures were then compared to histological sections. In 48 patients the rhabdosphincter of the male urethra was investigated by transurethral ultrasound and urodynamic techniques. Of these patients 40 were completely continent after radical prostatectomy and 8 presented with urinary stress incontinence after transurethral resection of the prostate or radical prostatectomy. The decrease of the distance between the rhabdosphincter and the transducer during contraction served as quantitative parameter for the contractility of the muscle. RESULTS: The anatomical arrangement and contractions of the rhabdosphincter loop could be clearly visualized on transurethral ultrasound (during contraction the rhabdosphincter retracts the urethra, pulling it towards the rectum). Ultrasound showed scars in 3 patients with postoperative urinary stress incontinence, thinning of the muscle in 3 complete atrophy of the rhabdosphincter in 2 and minimal contractions of the rhabdosphincter in 1. Urethral closure pressures were decreased and decrease in rhabdosphincter-transducer distance was statistically significantly decreased in the incontinent patients. CONCLUSIONS: Our sono-morphological data and anatomical histological results strongly suggest that the rhabdosphincter constitutes the main component of the continence mechanism in post-prostatectomy patients. Unlike urethral pressure profiles, which can only reveal zones of higher intraluminal pressure between the bladder and the penile urethra, transurethral ultrasound is highly specific for measurement of the function of the rhabdosphincter.

Humans↗

PubMed1997

Are contact laser, interstitial laser, and transurethral ultrasound-guided laser-induced prostatectomy superior to transurethral prostatectomy?

BACKGROUND: In order to assess the value of various new therapeutic modalities in the management of benign prostatic hyperplasia (BPH), we performed a prospective study comparing transurethral resection of the prostate (TURP) to contact Laser, interstitial Laser, and transurethral ultrasound-guided laser-induced prostatectomy (TULIP). METHODS: The following parameters were evaluated preoperatively as well as 3, 6, and 12 months after surgery: prostatic volume, urinary flow rate, postvoid residual volume, and the AUA symptom score. The diagnosis of bladder outlet obstruction was established preoperatively by means of pressure/flow studies which were repeated 1 year after the operation. RESULTS AND CONCLUSIONS: In conclusion, TURP is still the gold standard in the treatment of BPH. The results of TULIP, contact laser, and interstitial laser are about the same. The time intervals within which the patients become free of symptoms, however, vary widely. Contact laser is limited to prostates below 50 cc, while interstitial laser is ideal for patients in poor general health who present with large prostates. Furthermore, our results demonstrate that the only reliable data for determining the degree of posttherapeutic disobstruction can be provided by urodynamic investigations including pressure/flow diagrams.

Humans↗

PubMed1997

Frequency and clinical significance of transition zone cancer in prostate cancer screening.

Approximately 20% of prostate cancers originate in the transition zone (TZ). Although transrectal ultrasound (TRUS) and systematic biopsies have improved peripheral zone (PZ) cancer diagnosis, additional biopsies directed into the TZ may further improve cancer detection. To evaluate the frequency and clinical significance of TZ cancers, we added two TZ biopsies to the routinely performed sextant biopsies. Three hundred forty patients (aged 45-75) from our prostate-specific antigen (PSA) screening study (21,078 volunteers) with negative rectal examination findings underwent systematic and TZ biopsies with three-dimensional ultrasound equipment. All patients had elevated PSA levels according to age-specific reference ranges. Ninety-eight of 340 men (28.5%) had biopsies positive for cancer. Of these 98 cancers, 28 (28%) originated in the TZ only and 5 (5%) were located in the TZ as well as the PZ. Eight men showed TZ abnormalities on ultrasound images, of whom four had biopsies positive for TZ cancer. The TZ cancers detected were pathologically significant in 96% (27 of 28). Seventy-one percent (20 of 28) of pathologically staged cancers were found to be organ confined and all combined TZ and PZ cancers were advanced tumors. We conclude that TZ biopsies enhance the cancer detection rate in prostate cancer screening and should therefore be added to the routinely done sextant biopsies in men with PSA elevation and normal digital rectal examination findings.

Aged↗

PubMed1997

PSA-based screening for prostate cancer in asymptomatic younger males: pilot study in blood donors.

BACKGROUND: The efficacy and success of a screening program for prostate cancer in young and healthy asymptomatic volunteers are described. METHODS: In the present study, prostate specific antigen (PSA) samples obtained from 2,272 males (aged 40-65 years) who donated blood at the local Red Cross Blood Bank were evaluated. Two groups of donors were distinguished, which were investigated in different ways. Group 1 comprised individuals aged 40-49 years (n = 568), while group 2 consisted of males aged 50-65 years (n = 1,704). Volunteers in group 2 who had PSA levels greater than 4 ng/ml (n = 302) were referred for ultrasound guided biopsy irrespective of findings on digital rectal examination (DRE). In group 2, individuals with PSA levels exceeding 4 ng/ml and positive DRE findings biopsy specimen was ordered (n = 2). In patients with unremarkable findings on DRE, serum PSA was determined 1 year later and in case of more than 20% increase in the PSA level biopsy was obtained under ultrasound guidance. RESULTS: The biopsy specimen yielded prostatic carcinoma in 58 patients in group 1. As a screening test, serum PSA determination was superior to digital rectal examination. On digital palpation only 2 presented with abnormal prostates. These 58 patients underwent radical prostatectomy and histological examination revealed organ-confined disease in all but 8. In group 2, in 4 of 12 males the biopsy specimen yielded prostatic carcinoma. CONCLUSIONS: This study shows that PSA measurement in blood donors is a useful method for recruiting screening volunteers, and therefore represents an additional possibility for early detection of prostate cancer in asymptomatic younger males. Furthermore, it represents an effective tool for following relatively young patients known to have a significant risk of prostate cancer.

Adult↗

PubMed1996

Anatomy and innervation of the rhabdosphincter of the male urethra.

The striated sphincter of the male urethra and its innervation are still a subject of controversy. Essentially, two concepts of its anatomy can be found in the literature. Some authors describe the rhabdosphincter as part of the urogenital diaphragm caudal to the prostate, others as a striated muscle which extends from the base of the bladder to the "urogenital diaphragm." In a combined anatomic-histologic study the striated sphincter and the pudendal nerve were examined by means of anatomical dissections and serial anatomical as well as histological sections of 12 male pelves. Furthermore, radical prostatectomy was performed in a cadaver specimen; subsequently, the so-called "urogenital diaphragm" was excised and then examined histologically. The varying number of striated muscle fibers caudal to the prostate is of particular interest. In fetuses, there are abundant striated muscle fibers dorsal to the membranous urethra, where they are arranged as a circular collar around the urethra. In the adult male, hardly any striated muscle fibers can be found dorsal to the urethra; in a majority of cases this region is devoid of striated muscle fibers. Inserting dorsally in the perineal body, the fibers form an omega-shaped loop around the anterior and lateral aspects of the membranous urethra. The existence of a "urogenital diaphragm" and a strong, circular, striated "external sphincter urethrae" completely encircling the urethra caudal to the apex of the prostate could not be confirmed by our anatomical and histological investigations. Our study shows that the striated muscle fibers run in a cranial direction from the bulb of the penis to the base of the bladder along the anterior and lateral aspects of the prostate and the membranous urethra. Further dissection studies revealed that the rhabdosphincter is supplied by branches of the pudendal nerve after leaving the pudendal canal.

Aged↗

PubMed1996

Transurethral prostatectomy: mortality and morbidity.

In 1989 two large-scale multicenter studies on the mortality and morbidity of transurethral resection of the prostate were published [Mebust et al.: J Urol 141:243-247, 1989; Roos et al.: N Engl J Med 320:1120-1124, 1989]. These studies caused us to perform a retrospective study on a total of 1,211 consecutive patients who underwent transurethral resection of the prostate at our department between January 1988 and July 1991. The mortality rate in the 1,211 patients subjected to transurethral resection of the prostate was 0.00%; none of the patients died of intraoperative or postoperative complications. Intraoperative complications were observed in 8.9% of the patients, while the rate of early postoperative complications was 15.8%. Of the 1,211 patients operated on, 775 were followed for at least 1 year postoperatively. Late complications were noted in 11.2% of the patients. Repeat resection had to be performed in 0.9% of patients within 1 year, and in 2.5% within 3 years after surgery. A comparison of the studies by Mebust et al. and Roos et al. yielded similar rates of intraoperative and postoperative complications, whereas our mortality rate and repeat transurethral resection rate were significantly lower.

Adult↗

PubMed1996

Blood pressure changes after extracorporeal shock wave nephrolithotripsy: prediction by intrarenal resistive index.

In order to identify a high-risk group for the development of arterial hypertension after extracorporeal shock wave nephrolithotripsy (ESWL), we correlated the increase in renovascular resistance induced by ESWL in 79 normotensive patients with changes in arterial blood pressure occurring 20 (+/- 3) months after therapy. Renal vascular resistance was measured as resistive index (RI) by duplex Doppler sonography in both kidneys. Mean RI before treatment was 0.620 +/- 0.035 (SD). After treatment, we observed a significant and age-dependent increase in the RI in the treated kidney to 0.673 +/- 0.06. Of the patients with a post-ESWL RI > 0.690, 39% developed hypertension. Posttherapy RI values surpassing 0.690 showed a 0.8 sensitivity and a 0.7 specificity in predicting arterial hypertension. Intrarenal Doppler ultrasound (US) is useful to find the high-risk group for arterial hypertension after ESWL.

Adolescent↗

PubMed1996

Usefulness of the ratio free/total prostate-specific antigen in addition to total PSA levels in prostate cancer screening.

OBJECTIVES: Two different studies were performed. The aim of the first study was to define whether the measurement of the ratio between free and total prostate-specific antigen (f/t PSA) in serum may enhance the ability of PSA-based screening for early detection of prostate cancer in men with elevated serum PSA levels. A second study was undertaken to investigate the value of f/t PSA ratio in serum to improve the specificity of prostate cancer screening in men with serum PSA levels between 2.5 and 10.0 ng/mL. METHODS: In a retrospective study of 266 men with elevated PSA levels and proven biopsy results, f/t PSA levels were measured using deep frozen serum samples. In a second study we enrolled 158 men with elevated PSA levels according to age reference ranges apparent from our current PSA screening study with additional measurement of the f/t PSA ratio. All study volunteers with a free f/t PSA ratio cutoff point of < or = 22% underwent digital rectal examination, transrectal ultrasonography, and biopsy of the prostate. Free and total PSA levels were measured with the Delfia PSA dual label f/t PSA kit (Wallac Oy Turku, Finland). RESULTS: 106 of 158 men with elevated total PSA values between 2.5 and 10.0 ng/mL (group 1) have been further evaluated and 37 prostate cancers were detected. Mean percentage of free PSA was 10% in men with cancer and 22% in men with benign prostatic hyperplasia. Using a f/t PSA ratio of < or = 22% as a biopsy criterion 30% of the negative biopsies could be eliminated while still detecting 98% carcinomas. CONCLUSIONS: Measurement of f/t PSA reduces the number of unnecessary biopsies in PSA screening without missing many cancers.

Aged↗

PubMed1996

Prostate zones in three-dimensional transrectal ultrasound.

OBJECTIVES: This study was undertaken to evaluate the efficacy of three-dimensional transrectal ultrasound to identify and measure the prostate zones. METHODS: In an anatomic-sonographic study, eight specimens were investigated by means of three-dimensional transrectal ultrasound. Subsequently, the volumes of the prostate and the transition zone were measured by means of a special planimetric program; the images and results obtained were compared with anatomic sections and water displacement volume measurement. Then two groups of patients were investigated by means of three-dimensional transrectal ultrasound; the first group included 90 patients ranging in age from 55 to 85 years who presented with benign prostatic hyperplasia (BPH), which was verified by means of histologic examination. Three-dimensional transrectal ultrasound was performed prior to ultrasound-guided biopsies of the prostate. The second group comprised 10 patients aged between 17 and 30 years whose prostates were free of disease. RESULTS: Three-dimensional transrectal sonography is the first imaging technique that can simultaneously demonstrate relevant structures in three planes; apart from the sagittal and the horizontal (or axial) plane, the region of interest can be examined in the coronal plane as well. The structural differences of the prostatic zones in BPH and the juvenile gland can be clearly identified with the help of three-dimensional transrectal ultrasound. The coronal plane provides important additional information; the central zone and the enlarged transition zone can be identified best in this third plane. CONCLUSIONS: The prostate zones, their interrelations, and, in particular, the hyperplasia of the transition zone in BPH are clearly demonstrable. Furthermore, the size of the enlarged transition zone can be exactly measured.

Adolescent↗

PubMed1995

Comparison of different prostate-specific antigen cutpoints for early detection of prostate cancer: results of a large screening study.

OBJECTIVES: This study was designed to compare the usefulness of the normal prostate-specific antigen (PSA) level and the age-referenced PSA level in a large screening study for early detection of prostate cancer. METHODS: A total of 21,078 subjects (aged 45 to 75 years) were participants in a 1-year prostate cancer screening project with PSA as the initial test. Of the volunteers, 1618 (8%) showed an elevated PSA level according to age-specific reference ranges, and using the normal PSA cutoff point (4.0 ng/mL), 1872 (9%) had elevated PSA levels between 4.0 and 6.5 ng/mL. RESULTS: Biopsies in both groups were performed if the PSA level was elevated. We evaluated the effect on biopsy rate and cancer detection. A PSA cutoff point of 2.5 ng/mL in men 45 to 49 years old and a PSA cutoff point of 3.5 ng/mL in men 50 to 59 years old with normal digital rectal examination findings resulted in an 8% increase in the number of biopsies (66 of 778) and an 8% increase in organ-confined cancer detection. An increasing cutoff of 4.5 ng/mL in men 60 to 69 years old and 6.5 ng/mL in men 70 to 75 years old resulted in 21% fewer biopsies (205 of 983) and would have missed 4% of organ-confined tumors (8 of 220). CONCLUSIONS: We conclude that the use of PSA age-specific reference ranges increases the detection of clinically important and organ-confined cancers in young men and decreases the number of biopsies in older men.

Aged↗

PubMed1995

Three-dimensional sonographic guidance for interstitial laser therapy in benign prostatic hyperplasia.

In recent years, interstitial laser therapy was introduced to provide a new treatment of benign prostatic hyperplasia (BPH). However, the precise positioning of the laser fibers has remained a major unsettled issue. Three-dimensional (3-D) transrectal ultrasound scanning permits precise differentiation of the prostatic zones, in particular the transition zone, which is enlarged in BPH. Initially, a volume scan of the prostate is obtained. On the monitor, three sections of the prostate in the coronal, sagittal, and horizontal planes are displayed simultaneously. This new 3-D technology enables precise and reproducible positioning of the laser fibers at any selected site in the adenoma under sonographic guidance, thus providing the basis for complete laser prostatectomy. Placement of the laser fibers proved to be precise, quick, and uncomplicated.

Humans↗

PubMed1995

Age-related changes in resistive index following extracorporeal shock wave lithotripsy.

PURPOSE: Changes in intrarenal vascular resistance after extracorporeal shock wave lithotripsy (ESWL*) were studied with Doppler ultrasound techniques. MATERIALS AND METHODS: In 76 patients the resistive index was measured at an interlobar artery before and after ESWL in the treated and contralateral kidneys. The resistive index levels were compared to N-acetyl-beta-D-glucosaminidase levels in 40 patients. RESULTS: We found an age-related positive linear correlation between post-therapeutic resistive index increases and patient age. N-acetyl-beta-D-glucosaminidase levels were also elevated after ESWL but these elevations were not age-related. CONCLUSIONS: Elderly patients have a higher risk of post-ESWL renal tissue damage.

Acetylglucosaminidase↗

PubMed1994

High-yield production of oxalic acid for metal leaching processes by Aspergillus niger.

The complex-forming compound oxalic acid can effectively solubilise metals such as aluminium, iron, lithium and manganese. In order to produce high amounts of oxalic acid for biohydrometallurgical processes, it was the aim of this work to optimise oxalic acid production by Aspergillus niger, a fungus well known for its ability to produce oxalic acid. A. niger excreted 427 mmol oxalic acid l-1 if it was cultivated in a pH-controlled (pH 6.0) fed-batch run in a 2-l stirred tank reactor. Sucrose and lactose permeate were suitable carbon sources for oxalic acid production. In sucrose medium, A. niger produced high amounts of gluconic and oxalic acids, whereas in lactose permeate medium only oxalic acid was produced. Cultivation in green syrup and molasses media lead to high yields of biomass, but low oxalic acid production (< 20 mmol l-1).

Aspergillus niger↗

PubMed1994

Ergonomic assessment of handle design by means of electromyography and subjective rating.

Stress and strain during manual tool handling not only depend on factors such as weight to be handled, but are also determined by the design of the man-machine interface. In this study, three different handles of electric hedge-clippers were analysed; the results of a comparative investigation into the physiological cost demanded by the use of the different handles are discussed. Muscular strain was measured via surface electromyography in laboratory experiments with nine male subjects. The results showed significant differences in physiological cost depending on both work height and the handles' shape. Systematic differences in muscular strain between the utilized tools were found, despite the fact that all clippers were compensated with respect to weight and location of the centre of gravity. One of the handle designs enabled working under varying conditions (work height and direction) at a reduced level of muscular strain of the right arm. Results from the physiological evaluation were partly supported by the working persons' own subjective experience. The results of this investigation show that further ergonomic tool and handle design is necessary.

Journal Article↗

PubMed1994

A system for a strain-oriented analysis of the layout of assembly workplaces.

A measuring system for the more thorough analysis of muscular strain at assembly workplaces was developed. These workplaces were often based on the application of systems of predetermined motion time. The new measuring system makes use of the well-established method of electromyography, and synchronous recording of the hand-arm-shoulder motions by means of ultrasonic signals. Furthermore, a new calibration apparatus was installed, and used for the recording of maximum forces of several hand-arm-shoulder muscles during dynamic arm movements. The experimental arrangement aimed to support the design of a workplace layout, which could be used to indicate low strain motions and low strain work areas for the reach of the upper extremities. The results, yielded by the application of the measuring and evaluation system, can be the basis for a system of predetermined strain. Monitoring five muscles as an example, the application of the system for the analysis of different work rates and a worker-friendly assembly area is illustrated.

Arm↗

PubMed1994

[Value of the neurovascular guide plate for pelvic surgery].

In the past few years great effort has been made to reduce the morbidity after oncologic operations in the small pelvis of the male. In this respect it is essential for urologic surgeons to orient themselves with the anatomic structures that mark the course of the important vessels and nerves. For this reason an anatomic study of the connective tissue in the male pelvis was performed in which dissections and serial sections were analyzed. The results show that the connective tissue in the male pelvis does not represent a monomorphic block but consists of several portions of varying density. The looser portions are also known as the "connective tissue spaces" of the pelvis. The comparatively dense portions--the so-called "vessel-nerve guiding plate" and its three "connective tissue pillars"--envelop the vessels and nerves supplying the corresponding pelvic organs. Therefore, they provide ideal landmarks for urologic surgery.

Adult↗