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Abstract
BACKGROUND Penile cancer represents a rarity in daily clinical practice. OBJECTIVES The aim is to identify global differences concerning the incidence, social and risk factors. METHODS The past and current epidemiologic literature is analyzed concerning incidence rates and risk factors. The latter are discussed concerning their potential with regard to disease prevention. RESULTS Globally, incidence rates of penile cancer range from low to nonexistent. Distinct differences are found when comparing industrialized countries with emerging and developing countries. Phimosis seems to be a crucial risk factor in the formation of penile cancer. Additionally, chronic inflammatory diseases of the penis were found to be associated with a higher risk. CONCLUSIONS Preventive measures should be considered in relation to the rarity of the disease, especially in the valuation of circumcision during early childhood. Regular clinical examination of the penis is a sensible measure of early detection.
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Comparison of adjustable male slings and artificial urinary sphincter in the treatment of male urinary incontinence: a retrospective analysis of patient selection and postoperative continence status. World J Urol 2018; 37:1415-1420. [PMID: 30341450 DOI: 10.1007/s00345-018-2523-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/08/2018] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To analyze and compare preoperative patient characteristics and postoperative results in men with stress urinary incontinence (SUI) selected for an adjustable male sling system or an artificial urinary sphincter (AUS) in a large, contemporary, multi-institutional patient cohort. METHODS 658 male patients who underwent implantation between 2010 and 2012 in 13 participating institutions were included in this study (n = 176 adjustable male sling; n = 482 AUS). Preoperative patient characteristics and postoperative outcomes were analyzed. For statistical analysis, the independent T test and Mann-Whitney U test were used. RESULTS Patients undergoing adjustable male sling implantation were less likely to have a neurological disease (4.5% vs. 8.9%, p = 0.021), a history of urethral stricture (21.6% vs. 33.8%, p = 0.024) or a radiation therapy (22.7% vs. 29.9%, p = 0.020) compared to patients that underwent AUS implantation. Mean pad usage per day (6.87 vs. 5.82; p < 0.00) and the ratio of patients with a prior incontinence surgery were higher in patients selected for an AUS implantation (36.7% vs. 22.7%; p < 0.001). At maximum follow-up, patients that underwent an AUS implantation had a significantly lower mean pad usage during daytime (p < 0.001) and nighttime (p = 0.018). Furthermore, the patients' perception of their continence status was better with a subjective complete dry rate of 57.3% vs. 22.0% (p < 0.001). CONCLUSIONS Patients selected for an AUS implantation showed a more complex prior history and pathogenesis of urinary incontinence as well as a more severe grade of SUI. Postoperative results reflect a better continence status after AUS implantation, favoring the AUS despite the more complicated patient cohort.
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Application of ultrasound imaging biomarkers (HistoScanning™) improves staging reliability of prostate biopsies. BMC Res Notes 2017; 10:579. [PMID: 29121982 PMCID: PMC5679156 DOI: 10.1186/s13104-017-2896-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
Objective Imaging biomarkers like HistoScanning™ augment the informative value of ultrasound. Analogue image-guidance might improve the diagnostic accuracy of prostate biopsies and reduce misclassifications in preoperative staging and grading. Results Comparison of 77 image-guided versus 88 systematic prostate biopsies revealed that incorrect staging and Gleason misclassification occurs less frequently in image-guided than in systematic prostate biopsies. Systematic prostate biopsies (4–36 cores, median 12 cores) tended to detect predominantly unilateral tumors (39% sensitivity, 90.9% specificity, 17.5% negative and 50% positive predictive values). Bilateral tumors were diagnosed more frequently by image-guided prostate biopsies (87.9% sensitivity, 72.7% specificity, 50% negative and 96.8% positive predictive values). Regarding the detection of lesions with high Gleason scores ≥ 3 + 4, systematic prostate and image-guided biopsies yielded sensitivity and specificity rates of 66.7% vs 93.5%, 86% vs 64.5%, as well as negative and positive predictive values of 71.2% vs 87%, and 83.3% vs 79.6%, respectively. Potential reason for systematic prostate biopsies missing the correct laterality and the correct Gleason score was a mismatch between the biopsy template and the respective pathological cancer localization. This supports the need for improved detection techniques such as ultrasound imaging biomarkers and image-adapted biopsies.
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Computer-aided transrectal ultrasound: does prostate HistoScanning™ improve detection performance of prostate cancer in repeat biopsies? BMC Urol 2015. [PMID: 26223353 PMCID: PMC4518605 DOI: 10.1186/s12894-015-0072-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background An imaging tool providing reliable prostate cancer (PCa) detection and localization is necessary to improve common diagnostic pathway with ultrasound targeted biopsies. To determine the performance of transrectal ultrasound (TRUS) augmented by prostate HistoScanningTM analysis (PHS) we investigated the detection of prostate cancer (PCa) foci in repeat prostate biopsies (Bx). Methods 97 men with a mean age of 66.2 (44 – 82) years underwent PHS augmented TRUS analysis prior to a repeat Bx. Three PHS positive foci were defined in accordance with 6 bilateral prostatic sectors. Targeted Bx (tBx) limited to PHS positive foci and a systematic 14-core backup Bx (sBx) were taken. Results were correlated to biopsy outcome. Sensitivity, specificity, predictive accuracy, negative predictive value (NPV) and positive predictive value (PPV) were calculated. Results PCa was found in 31 of 97 (32 %) patients. Detection rate in tBx was significantly higher (p < .001). Detection rate in tBx and sBx did not differ on patient level(p ≥ 0.7). PHS sensitivity, specificity, predictive accuracy, PPV and NPV were 45 %, 83 %, 80 %, 19 % and 95 %, respectively. Conclusions PHS augmented TRUS identifies abnormal prostatic tissue. Although sensitivity and PPV for PCa are low, PHS information facilitates Bx targeting to vulnerable foci and results in a higher cancer detection rate. PHS targeted Bx should be considered in patients at persistent risk of PCa.
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[Urogynecology II: urinary incontinence in men and women: surgical treatment of urinary incontinence and prolapse]. Urologe A 2014; 53:1671-80; quiz 1681-2. [PMID: 25316184 DOI: 10.1007/s00120-014-3607-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Numerous surgical procedures are available for the treatment of stress urinary incontinence in women and men. On a par with classical therapy options (e.g. colposuspension and artificial sphincter prosthesis) suburethral tape procedures have become established as the minimally invasive standard of care. Regarding comorbidities and recurrent urinary incontinence, therapeutic procedures should be modified on an individual basis. It is crucial to involve patients in therapeutic decision-making and counseling should be given with respect to all conservative and operative alternatives.
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Abstract
The treatment of patients with overactive bladder (OAB) refractory to conventional treatment is gaining clinical significance. This article intends to review alternative therapy options for patients with OAB refractory to conventional treatment. A search of the PubMed database as well as the abstracts presented at the European Association of Urology and the American Urological Association annual meetings was conducted. Keywords used during this search included overactive bladder (OAB) refractory to conventional treatment, electromotive drug administration (EMDA), sacral neuromodulation, augmentation cystoplasty and cystectomy. Eighteen articles with an adequate number of patients were identified. All articles published before 2001 were not included in this analysis. Because of first-line treatment failure, 30% of the patients required alternative treatment. This included EMDA, botulinum toxin injections into the detrusor, sacral neuromodulation, augmentation cystoplasty or cystectomy. Based on this review it appears that a significant improvement in micturition parameters, continence and in quality of life was achieved. Overall EMDA, intradetrusor injections of botulinum toxin and sacral neuromodulation seem to be highly effective and safe. Augmentation cystoplasty or cystectomy remains the last choice of treatment in refractory cases.Overall EMDA, intradetrusor injections of botulinum toxin and sacral neuromodulation seem to be highly effective and safe. Augmentation cystoplasty or cystectomy remains to be the last choice of treatment in refractory cases.
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[Erectile dysfunction after radical prostatectomy : patient information, contact persons, postoperative proerectile therapy]. Urologe A 2010; 49:525-9. [PMID: 20033666 DOI: 10.1007/s00120-009-2190-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Postoperative erectile dysfunction (ED) is one of the potential after-effects of radical prostatectomy. The aim of this study was to learn which caregivers inform the patients prior to the intervention about the risk of ED, which individuals the patients discuss this issue with, and whether the patients preoperatively consider use of a PDE5 inhibitor for proerectile therapy after the operation. METHODS Using the IIEF-5 questionnaire, the preoperative erectile function of 110 patients was evaluated after the hospital admission interview. The patients were asked who had informed them about the risk of postoperative ED. They were also asked in whom they had confided to discuss this issue and whether they were prepared to undergo postoperative proerectile therapy with a PDE5 inhibitor. The patients were subsequently assigned to one of two groups: group I, consisting of those with a preoperative IIEF score > or = 21, or group II, those with a preoperative IIEF score <21. RESULTS The answers given by groups I and II did not differ significantly. The median patient age was the same, 68, in both groups. In addition to being informed about postoperative ED by the hospital doctor on admission (100%), the patients were informed about this by the following individuals (results for group II in parentheses): board-certified urologist, 81.8% (74%); general practitioner (GP), 27.3%; partner, 12.1% (11.7%); self-help groups, 0% (2.6%); and friends, 3% (6.5%). Patients also discussed the risk of postoperative ED with the following individuals (results for group II in parentheses): local urologist, 66.7% (63.4%); partner, 45.5% (42.9%); hospital doctor, 39.4% (42.9%); GP, 21.2% (23.4%); friends, 9.1% (14.3); or no one, 3% (5.2%). Regarding whether patients were willing to undergo postoperative therapy using a PDE5 inhibitor, 36.4% in group I and 32.5% in group II said yes, 12.1% in group I and 11.7% in group II said no, and 51.5% in group I and 55.8% in group II were undecided. CONCLUSION Irrespective of the patient's erectile status, the hospital doctor and the local urologist informed the patients about the risk of postoperative ED. Satisfactory information delivered by at least two people occurred in over 70% of all cases. The most frequent confidant of the patient for discussing this issue was his local urologist. Fewer than 50% of the patients discussed this topic with their partners. Possible reasons for underestimating the importance of sexual function could be the frequent taboo status of sexuality as a discussion topic in relationships, as well as preoperative distress. These circumstances should be taken into account by offering sufficient information, including that on the availability of postoperative proerectile therapy, for both the patient and his partner as early as possible, i.e., at the stage of choosing a treatment option.
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[Functional results after temporary continuous drainage of the hypocontractile bladder. The potential rehabilitation of the detrusor]. Urologe A 2008; 47:988-93. [PMID: 18415071 DOI: 10.1007/s00120-008-1693-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Impaired bladder emptying is a common problem in older people and a challenging task in treatment. Conservative and medical treatment options have shown beneficial effects on micturition; however, in a substantial number of patients the effectiveness of these therapies is disappointing. In the end the decompensated bladder needs indwelling catheterisation. To study the effects on the detrusor function, we analysed the urodynamic data of 31 patients during long-term bladder drainage retrospectively. PATIENTS AND METHODS All 17 female and 14 male patients showed impaired detrusor contractility, enlarged bladder capacity, decreased sensitivity and a high post-void residual urine volume (PVR). After exclusion of an acute pathology, the patients were treated continuously with a suprapubic catheter for an average of 13.1 weeks. By urodynamic measurements before and after the drainage period, we analysed the filling parameters, pressure-flow patterns, PVR and detrusor contractility. RESULTS At the end of the drainage period, significant changes in the detrusor function were obvious. Compared with the pre-treatment situation, the bladder volume at first desire to void decreased from 306.92 ml to 281.7 ml and the maximum bladder capacity from 691.8 ml to 496.8 ml, respectively. The compliance of the detrusor muscle diminished in the same period of time from 65.6 ml/cmH2O to 51.8 ml/cmH2O. The PVR dropped by 227.2 ml in average. The maximum flow rate was 9.4 ml/s, and the maximum detrusor pressure increased slightly up to 23.6 cmH2O. CONCLUSION The continuous drainage of the bladder results in significant changes in the motoric as well as sensoric detrusor function. The reduced bladder capacity and the decreased PVR might be indications of a regenerating process of the detrusor. The long-term drainage of the bladder shows beneficial and therefore therapeutic effects. It still remains to be investigated on a functional as well as structural basis to what extent age, gender and pathogenesis influences the rehabilitation of the detrusor.
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Abstract
Stress urinary incontinence is rare in men. Despite the improvements in diagnostic approaches to prostate diseases and surgical interventions on the prostate, stress incontinence has tended to increase in recent decades. The most frightening operative complication for both the patient and the surgeon is incontinence, which is one of the important factors in the treatment of the affected patients. The limited degree of continence considerably lowers the quality of life for the affected men and their partners. There is little information available about the pathophysiology of iatrogenic stress incontinence, which more likely affects older men rather than young men. The available information is based on a few experimental studies. Besides the direct damage to the muscular or neurological component of the external sphincter, insufficient length of the functional urethra and impaired bladder function seem to play an important role in the genesis of postoperative incontinence. In order to improve the postoperative continence status after radical prostatectomy a number of different operative modifications have been introduced. Preservation of the bladder neck, puboprostatic ligaments, and the neurovascular bundle as well as leaving the tips of the seminal vesicles seem to have a positive impact on the degree of postoperative continence.
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[Dysfunctions of artificial urinary sphincters (AMS 800) and their management via a transscrotal access. Optimum procedure illustrated by reference to clinical examples]. Urologe A 2007; 46:1704-9. [PMID: 17932644 DOI: 10.1007/s00120-007-1558-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The introduction of a transscrotal access for implantation of an artificial urinary sphincter (AUS) offers an alternative to the perineal approach for dealing with post-prostatectomy incontinence. Should a revision be necessary, the entire implant can be explored via this access and only one incision is needed. The aim of our study was to present the advantage of the transscrotal approach in different malfunctions of AUSs (AMS 800). MATERIALS AND METHODS Surgical exploration was exemplary indicated in three male patients because of recurrent incontinence after artificial sphincter implantation. The reasons for malfunction were urethral atrophy, a mechanical defect of the device, and urethral erosion of the cuff, which led to explantation via the perineal approach of the entire artificial sphincter system. The patient whose sphincter system had a mechanical defect had the entire system substituted by the transscrotal route. In the case of perineal explantation a complete new AMS 800 system was implanted transscrotally at the unaffected bulbar ureter following complete healing. In the case of urethral atrophy a tandem-cuff was implanted by a transscrotal approach. Because of mechanical complications the whole system was exchanged, a completely new AUS (AMS 800) system being implanted by the transscrotal approach after perineal explantation. RESULTS There were no complications of any of the revision operations. The postoperative course was uneventful and after activation of the system all patients regained their former continence status. Three months after implantation all patients remained continent and their AMS 800 sphincter systems were fully functional. CONCLUSION When a revision operation is needed, the transscrotal access offers a quick and easy alternative to the perineal method. Our patients had no postoperative complications, and their continence rates were satisfactory. Further studies are needed to reveal whether this approach will prove superior to the perineal approach in the long term.
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[30 Years of sentinel lymph node diagnostic in penile carcinoma: development of a diagnostic procedure and current results]. Urologe A 2007; 46:1514-8. [PMID: 17926016 DOI: 10.1007/s00120-007-1570-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cabanas, working 30 years ago, was the first to use the term "sentinel lymph node" in urology. His definition of the sentinel lymph node was based on typical anatomical patterns and therefore could not do justice to any individual variability in lymphatic drainage. This meant that application of the technique yielded high false-negative rates, and because of this it was largely abandoned. Dynamic visualization of lymphatic drainage by blue dye in melanoma patients resulted in a renaissance of the sentinel node concept in penile cancer in the mid-1990s. With constant improvements and standardization of the technique it proved possible to reduce the incidence of false-negative results from the initial 22% to 4.8%. This technique requires that specialists in urology, pathology, and nuclear medicine collaborate closely, and high standards are also essential in quality control.
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[Mesonephroid carcinoma of the urinary bladder (clear cell carcinoma). Two case reports and review of the literature in a rare variation of the primary adenocarcinoma]. Aktuelle Urol 2007; 38:247-51. [PMID: 17516385 DOI: 10.1055/s-2006-932177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Mesonephroid adenocarcinoma of the bladder may be a malignant form of nephrogenic adenoma or nephroid metaplasia. The lesion is extremely rare in the urinary bladder, and to our knowledge 19 cases have been reported in the literature. We report two cases of mesonephroid adenocarcinoma of the bladder which were treated by radical cystectomy.
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Abstract
BACKGROUND Controversies persist over the therapeutic approach to T1 penile carcinoma, particularly in patients with negative inguinal lymph nodes. Available data on lymph nodes metastases (LNM) in T1 carcinoma are contradictory. The aim of this study was to evaluate the metastatic risk of T1 carcinoma and to compare it with that of T2 carcinoma. MATERIAL AND METHODS A total of 37 patients (pts) with T1 or T2 tumors were reviewed. Assessment of the inguinal lymph node condition was based on node dissection in 29 pts and surveillance in eight pts (mean 62 months, range 22-162). RESULTS Grading was classified as good (G1), moderate (G2) and poor (G3) in seven, 26 and four pts, respectively. Tumor stage was T1 in 21 and T2 in 16 pts. LNM were observed in eight of 21 T1 (38%) and six of 16 T2 tumors (38%). No G1 and all G3 tumors developed LNM independently of tumor stage. Ten of the 26 G2 carcinomas (38%) harboured LNM and seven of these pts (70%) had a T1 tumor. CONCLUSIONS According to our data, the metastatic potential of T1 penile carcinoma has been underestimated in the recent literature. Tumor grading has a substantially stronger impact on the metastatic risk in T1 and T2 penile carcinoma than tumor stage, indicating a surgical lymph node staging starting at the pT1G2 stage.
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Das sarkomatoide Nierenzellkarzinom als eine seltene, aggressive Variante des primären Nierenzellkarzinoms. Aktuelle Urol 2006. [DOI: 10.1055/s-2006-947401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Das mesonephroide Adenokarzinom der Harnblase: 2 Kasuistiken eines seltenen Tumors in der Urologie. Aktuelle Urol 2006. [DOI: 10.1055/s-2006-947572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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„Second–Line“ Polychemotherapie beim metastasierten Urothelkarzinom des Nierenbeckens: Ein bemerkenswerter Langzeitverlauf. Aktuelle Urol 2006. [DOI: 10.1055/s-2006-947408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Perkutane transluminale Embolisation zur Therapie von Makrohämaturien bei fortgeschrittenen urologischen Neoplasien. ROFO-FORTSCHR RONTG 2006. [DOI: 10.1055/s-2006-941151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
This article reviews the current status of information on external male genital injuries, focusing on the causes as well as diagnostic and therapeutic management of this uncommon entity. Because of the high risk of infection and the major importance of preserving fertility, male genital injuries represent a serious urological disorder that demands immediate urological treatment. The diagnostic procedure classically consists of taking a history and inspecting the wound, which provides enough diagnostic information for the correct choice of conservative or surgical treatment. In most cases open injuries of the genitalia require surgical exploration to determine the extent of possible scrotal, testicular, epididymal, cavernous, or urethral damage, to débride nonviable superficial or deep tissue, to drain existing hematomas, or to control active bleeding. Furthermore, the correct therapeutic approach is crucial for preserving fertility and penile erection. In cases where bilateral ablation is necessary, measures to preserve sperm, e.g., testicular or microsurgical sperm extraction, or squeezing the ductus during orchidectomy must be considered.
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[Pudendal nerve stimulation therapy of the overactive bladder -- an alternative to sacral neuromodulation?]. Aktuelle Urol 2005; 36:234-8. [PMID: 16001339 DOI: 10.1055/s-2004-830204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE Sacral neuromodulation is known to be an alternative therapeutic option for patients with anticholinergic resistant overactive bladder (OAB). For the same indication, a microstimulation system called BION is available since last year. The BION-stimulator, which only measures 2.8 x 0.3 cm, is designed for pudendal nerve stimulation. Its implantation technique as well as the first clinical results are presented and discussed. MATERIALS AND METHODS During an outpatient percutaneous screening test (PST), a pudendal nerve stimulation is performed with a needle electrode in local anesthesia. A 50 % increase in the urodynamic parameters (bladder capacity, first desire to void, compliance, etc.) is an indication for a chronic implantation of the BION stimulator, which also can be placed in local anesthesia. RESULTS Two patients have been treated with a BION-stimulator in our clinic so far. Patient I suffered from an OAB with frequent urinary incontinence and patient II had a sensory OAB with high voiding frequency. After the BION(R)-implantation, patient I showed a reduction in incontinence episodes by 31.5 % a day and patient II had lowered voiding frequencies from 12.6 to 7 a day. The postoperative urodynamic investigations confirmed these clinical results. CONCLUSIONS The BION-system and chronic pudendal nerve stimulation seem to be alternatives to sacral neuromodulation, however, patient selection is difficult as subchronic stimulation for a longer period of time is not possible so far.
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Characterization of microsatellite loci in Amphitmetus transversus (Kolbe, 1897) (Coleoptera, Curculionidae). ACTA ACUST UNITED AC 2004. [DOI: 10.1111/j.1471-8286.2004.00610.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Characterization of microsatellite loci for Reissita simonyi (Rebel, 1899) (Lepidoptera, Zygaenidae). ACTA ACUST UNITED AC 2003. [DOI: 10.1046/j.1471-8286.2003.00500.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Stimulation of insulin release by glucose is widely thought to be coupled to a decrease in the activity of ATP-sensitive K+ channels (KATP channels) that is caused by a decreased concentration of free ADP. To date, most other investigators have reported only on total cellular ADP concentrations, even though only a small fraction of all ADP is free and only the free ADP affects KATP channels. We tested the hypothesis that amino acids elicit insulin release via a decrease in the activity of KATP channels owing to a decrease in the level of free ADP. We estimated the concentration of free ADP in betaHC9 hyperplastic insulin-secreting cells based on the cell diameter and on luminometric measurements of ATP, phosphocreatine, and total creatine. The concentration of free ADP fell exponentially as the concentration of glucose increased. A physiological mixture of amino acids greatly stimulated insulin release at 0-30 mmol/l glucose but affected the concentration of free ADP only to a minor degree and significantly so only at < or = 2 mmol/l glucose. In the presence of 2-deoxyglucose and NaN3, amino acids were unable to stimulate insulin release. When KATP channels were held open with diazoxide (and the plasma membrane partially depolarized with high extracellular KCl), amino acids still stimulated insulin release. We conclude that amino acid-induced insulin release depends on two components: a yet-unknown amino acid sensor and KATP channels, which serve to attenuate hormone release when cellular energy stores are low. We propose that glucose-induced insulin release may be regulated similarly by two components: glucokinase and KATP channels.
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Abstract
The liberation of hydrocyanic acid by intact not damaged living insects is described as “active cyanogenesis”. This phenomenon - as in contrast to “passive cyanogenesis” observed in plants, where enzyme and substrate get in contact only after tissue damage - is reported from the Zygaenidae. Quantitative data demonstrate that the Zygaenidae can increase the amount of emitted HCN upon irritation. The significance of this phenomenon as a mean of defense is discussed.
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Cuticular cavities: storage chambers for cyanoglucoside-containing defensive secretions in larvae of a Zygaenid moth. Tissue Cell 1985; 17:267-78. [PMID: 4012760 DOI: 10.1016/0040-8166(85)90093-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As a defensive reaction against predators the larvae of Zygaena trifolii Esper. 1783, release highly viscous fluid droplets out of cuticular cavities. The fluid appears on the cuticular surface upon contraction of the irritated segments, with no specialized muscles being involved. Two morphologically different types of cavities have been found: the larger ones are located beneath pigment spots, the smaller ones occupy the remaining surface except in the ventral region. Both types have complicated cuticular opening structures. The defensive fluid contains the cyanoglucosides linamarin and lotaustralin, the amino acid beta-cyano-L-alanine, proteins and water. Although a considerable amount of fluid (3-6 microliter per sixth-instar larva) is stored in the cuticle, fine structural examinations of the epidermis do not show any specific cells or cell areas with morphological adaptations for secretion. Further, there do not exist any major cytological differences between the cells below the cavities and in the ventral region, where those cavities are absent.
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Qualitative and quantitative studies on the compounds of the larval defensive secretion of Zygaena trifolii (Esper, 1783) (Insecta, Lepidoptera, Zygaenidae). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1984; 79:103-6. [PMID: 6149852 DOI: 10.1016/0742-8413(84)90170-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Beside the known existence of cyanoglucosides (linamarin and lotaustralin) and proteins the neurotoxin beta-cyanoalanine has been demonstrated for the first time in the defensive secretions of animals. It is proposed that beta-cyanoalanine is produced by metabolizing cyanide from the cyanoglucosides. The methanolic precipitated protein fraction contains high amounts of aspartic acid, glycine, alanine, leucine and serine, thus being similar to the composition of larval silks in Lepidoptera. The defensive secretion contains 85% water, 8% proteins, 7% cyanoglucosides, 0.3% beta-cyanoalanine and beta-glucosidase while beta-cyanoalanine-synthetase could only be detected in the haemolymph.
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