RESUMO
PURPOSE: We aimed to investigate controversial pediatric urolithiasis issues systematically, integrating expert consensus and comprehensive guidelines reviews. METHODS: Two semi-structured online focus group meetings were conducted to discuss the study's need and content, review current literature, and prepare the initial survey. Data were collected through surveys and focus group discussions. Existing guidelines were reviewed, and a second survey was conducted using the Delphi method to validate findings and facilitate consensus. The primary outcome measures investigated controversial issues, integrating expert consensus and guideline reviews. RESULTS: Experts from 15 countries participated, including 20 with 16+ years of experience, 2 with 11-15 years, and 4 with 6-10 years. The initial survey identified nine main themes, emphasizing the need for standardized diagnostic and treatment protocols and tailored treatments. Inter-rater reliability was high, with controversies in treatment approaches (score 4.6, 92% agreement), follow-up protocols (score 4.8, 100% agreement), and diagnostic criteria (score 4.6, 92% agreement). The second survey underscored the critical need for consensus on identification, diagnostic criteria (score 4.6, 92% agreement), and standardized follow-up protocols (score 4.8, 100% agreement). CONCLUSION: The importance of personalized treatment in pediatric urolithiasis is clear. Prioritizing low-radiation diagnostic tools, effectively managing residual stone fragments, and standardized follow-up protocols are crucial for improving patient outcomes. Integrating new technologies while ensuring safety and reliability is also essential. Harmonizing guidelines across regions can provide consistent and effective management. Future efforts should focus on collaborative research, specialized training, and the integration of new technologies in treatment protocols.
Assuntos
Guias de Prática Clínica como Assunto , Urolitíase , Humanos , Criança , Urolitíase/terapia , Urolitíase/diagnóstico , Consenso , Técnica DelphiRESUMO
PURPOSE: To compare vapor tunnel (VT) and virtual basket (VB) tools to reduce retropulsion in the treatment of proximal ureteral stones. METHODS: Patients with a single proximal ureteral stone were randomly assigned to holmium laser lithotripsy with the use of VT (Group A) or VB (Group B) tool. The 150W holmium:YAG cyber Ho generator was used. We compared operative time, dusting time, need for flexible ureteroscopy due to stone push-up and occurrence of ureteral lesions. The stone-free rate (SFR) and the occurrence of postoperative ureteral strictures were assessed. RESULTS: 186 patients were treated, of which 92 with the VT (49.5%, Group A) and 94 with the VB (50.5%, Group B). Mean stone size was 0.92 vs. 0.91 cm in Groups A vs. B (p = 0.32). Mean total operative time and dusting time were comparable between groups. 7 (7.6%) vs. 6 (6.4%) patients in Groups A vs. B required a flexible ureteroscope because of stone push-up (p = 0.12). Ureteral mucosa lesions were observed in 15 (16.3%) vs. 18 (19.1%) cases in the VT vs. VB group (p = 0.09). 1-Month SFR was comparable (97.8% vs. 95.7%, p = 0.41). We observed one case (1.1%) of postoperative ureteral stricture in the VT group vs. two cases (2.1%) in the VB group (p = 0.19). CONCLUSIONS: VT and VB are equally safe and effective tools in reducing retropulsion of ureteral stones. Operative time, dusting time and SFR were comparable. They also equally avoided stone push-up and prevented ureteral lesions, which may later occur in ureteral strictures.
Assuntos
Lasers de Estado Sólido , Litotripsia a Laser , Cálculos Ureterais , Humanos , Hólmio , Lasers de Estado Sólido/uso terapêutico , Constrição Patológica/etiologia , Ureteroscopia/efeitos adversos , Resultado do Tratamento , Cálculos Ureterais/cirurgia , Litotripsia a Laser/efeitos adversos , Complicações Pós-Operatórias/etiologiaRESUMO
To evaluate the performance of a mathematical model to drive preoperative planning between RIRS and MiniPerc (MP) for the treatment of renal stones between 10 and 20 mm. Patients with a renal stone between 10 and 20 mm were enrolled. A mathematical model named Stone Management According to Size-Hardness (SMASH) score was calculated: hounsfield units (HU) χ stone maximum size (cm)/100. Patients were divided into 4 groups: RIRS with score < 15 (Group A), RIRS with score ≥ 15 (Group B), MP with score < 15 (Group C), MP with score ≥ 15 (Group D). Cyber Ho device was always used. Stone free rate (SFR) was assessed after 3 months. Complication rate and need for auxiliary procedures were evaluated. Between January 2019 and December 2021, 350 patients were enrolled (87, 88, 82 and 93 in Groups A, B, C and D). Mean stone size was 13.1 vs 13.3 mm in Group A vs B (p = 0.18) and 16.2 vs 18.1 mm in Group C vs D (p = 0.12). SFR was 82%, 61%, 75% and 85% for Groups A, B, C and D. SFR was comparable between Groups C and D (p = 0.32) and Groups A and C (p = 0.22). SFR was significantly higher in Group A over B (p = 0.03) and in Group D over B (p = 0.02). Complication rate was 2.2%, 3.4%, 12.1%, 12.9% for Groups A, B, C, D. RIRS and MP are both safe and effective. The mathematical model with the proposed cut-off allowed a proper allocation of patients between endoscopic and percutaneous approaches.Registration number of the study ISRCTN55546280.
Assuntos
Cálculos Renais , Lasers de Estado Sólido , Nefrostomia Percutânea , Humanos , Hólmio , Lasers de Estado Sólido/efeitos adversos , Dureza , Nefrostomia Percutânea/métodos , Cálculos Renais/cirurgia , Resultado do TratamentoRESUMO
PURPOSE: To assess the learning curve of Thulium laser enucleation of the prostate (ThuLEP) of a single surgeon. METHODS: Hundred patients suffering from benign prostatic hyperplasia were treated by the same surgeon. In all cases, a well-trained urologist was present in the operating room. Patients urinary function was assessed preoperatively using the International Prostate Symptoms Score (IPSS), maximum flow rate and Post-Void Residual volume. Preoperative prostate volume was recorded. Enucleation and morcellation efficiency and complication rate were evaluated. Patients were divided into 5 cohorts of 20 consecutive cases to assess changes in outcomes through time. RESULTS: Mean age of patients was 73.1 years (SD 17.5) and mean prostate volume was 89.7 ml (SD 55.1). Overall, mean enucleation and morcellation efficiency were 1.7 (SD 2.9) and 5.1 (SD 2.7) g/min. A statistically significant increase in enucleation efficiency was observed when comparing cohort 1 vs 2 (0.9 vs 1.3 g/min, p = 0.03) and cohort 2 vs 3 (1.3 vs 1.7 g/min, p = 0.02). A statistically significant increase in morcellation efficiency was observed when comparing cohort 1 vs 2 (2.8 vs 3.7 g/min, p = 0.02) and cohort 2 vs 3 (3.7 vs 4.9 g/min, p = 0.03). In both cases, no significant differences were observed when comparing the following cohorts. Complication rate showed no significant differences throughout the caseload. CONCLUSIONS: In our single-surgeon experience, we observed a learning curve of nearly 60 cases for the ThuLEP procedure in presence of a well-trained surgeon. Complication rate was low from the beginning of surgical experience.
Assuntos
Terapia a Laser , Lasers de Estado Sólido , Hiperplasia Prostática , Masculino , Humanos , Idoso , Próstata/cirurgia , Túlio , Curva de Aprendizado , Resultado do Tratamento , Terapia a Laser/métodos , Hiperplasia Prostática/cirurgia , Lasers de Estado Sólido/uso terapêuticoRESUMO
OBJECTIVE: To compare intra and early postoperative outcomes between pulsed-wave and continuous-wave Thulium Fiber Laser Enucleation of the Prostate (PW-ThuFLEP vs CW-ThuFLEP) for the treatment of benign prostatic hyperplasia. METHODS: 238 patients with lower urinary tract symptoms due to benign prostatic hyperplasia underwent PW-ThuFLEP (118 patients) vs CW-ThuFLEP (120 patients). Preoperative prostate volume, adenoma volume, prostate-specific antigen (PSA), and hemoglobin values were recorded. International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), post-void residual volume, and International Index of Erectile Function-5 score (IIEF-5) were assessed. Operative time, enucleation time, enucleation efficiency, catheterization time, irrigation volume, hospital stay, hemoglobin drop, and postoperative complications were recorded. Micturition improvements and sexual outcomes were evaluated 3months after surgery. RESULTS: CW-ThuFLEP showed shorter operative time (61.5 vs 67.4 minutes, P = .04). Enucleation time (50.2 vs 53.3 minutes, P = .12), enucleation efficiency (0.8 vs 0.7 g/min, P = .38), catheterization time (2.2 vs 2.1days, P = .29), irrigation volume (32.9 vs 32.8L, P = .71), hospital stay (2.8 vs 2.6days, P = .29) and hemoglobin drop (0.38 vs 0.39 g/dL, P = .53) were comparable. No significant difference in complication rate was observed. At 3-month follow-up, the procedures did not show any significant difference in IPSS, Qmax, post-void residual volume, IIEF-5, and PSA value. CONCLUSION: PW-ThuFLEP and CW-ThuFLEP both relieve lower urinary tract symptoms equally, with high efficacy and safety. Operative time was significantly shorter with CW-ThuFLEP, but with a small difference with low clinical impact. Enucleation time, enucleation efficiency, catheterization time, irrigation volume, hospital stay, hemoglobin and PSA drop, complication rate, and sexual outcomes showed no differences.
Assuntos
Terapia a Laser , Lasers de Estado Sólido , Sintomas do Trato Urinário Inferior , Hiperplasia Prostática , Ressecção Transuretral da Próstata , Masculino , Humanos , Próstata/cirurgia , Hiperplasia Prostática/cirurgia , Túlio/uso terapêutico , Ressecção Transuretral da Próstata/métodos , Antígeno Prostático Específico , Resultado do Tratamento , Lasers , Sintomas do Trato Urinário Inferior/cirurgia , Qualidade de Vida , Lasers de Estado Sólido/uso terapêuticoAssuntos
Neoplasias das Glândulas Suprarrenais/cirurgia , Adrenalectomia/métodos , Adenoma Adrenocortical/cirurgia , Carcinoma/cirurgia , Laparoscopia/métodos , Síndromes Endócrinas Paraneoplásicas/cirurgia , Feocromocitoma/cirurgia , Neoplasias das Glândulas Suprarrenais/diagnóstico , Neoplasias das Glândulas Suprarrenais/secundário , Adrenalectomia/instrumentação , Adenoma Adrenocortical/diagnóstico , Carcinoma/diagnóstico , Humanos , Laparoscopia/instrumentação , Síndromes Endócrinas Paraneoplásicas/diagnóstico , Posicionamento do Paciente , Feocromocitoma/diagnóstico , Cuidados Pré-Operatórios , Espaço Retroperitoneal/cirurgia , Instrumentos CirúrgicosRESUMO
INTRODUCTION: In our study, the efficiency and reliability of lidocaine (1 cc/1%) application during transrectal ultrasound-guided (TRUS) prostate biopsy to levatores prostate was studied. Levatores prostate was visualized on a cadaver dissection previously. PATIENTS AND METHODS: Eighty outpatients with lower urinary tract complaints or were suspected clinically to have prostate cancer were submitted to TRUS-guided prostate biopsy. The ages of outpatients were ranging from 45 to 81. Patients were randomized in 2 groups: Group-I, with 40 patients submitted to local anesthesia by periprostatic injection of 1 cc 1% lidocaine before biopsy; and group-II, with 40 controls the biopsy was performed without local anesthesia. The anatomical region for anesthesia was determined via dissection. The name of this anatomical region is levatores prostatae and it has got high nerve density. The process was explained to the patients and their approvals were obtained. Levatores prostatae was detected with TRUS before biopsy. Pain; related to digital rectal examination (DRE), probe insertion or biopsy, was scored via visual analog scale (VAS). The patients were evaluated about side effects of lidocaine and early and late complications of biopsy as well. RESULTS: Both groups were similar in terms of mean age, PSA levels, prostate volume and VAS scores (p > 0.05). As for VAS score, on the group submitted to anesthesia was determined 2.34 ± 1.08, while for VAS score on the group submitted conventional biopsy was determined 5.8 ± 1.6. Between two groups, there was a statistical difference in terms of VSA score (p < 0.05); but there was no statistical difference about early and late complications of biopsy. CONCLUSIONS: The periprostatic blockage use is clearly associated with more tolerance and patient comfort during TRUS-guided biopsy. Owing to the local anesthesia introduced to the periprostatic nerve bundle localization in levatores prostate area, the patients could tolerate the pain better.
Assuntos
Anestesia Local/métodos , Anestésicos Locais/administração & dosagem , Lidocaína/administração & dosagem , Próstata/patologia , Idoso , Idoso de 80 Anos ou mais , Anestesia Local/efeitos adversos , Anestésicos Locais/efeitos adversos , Biópsia , Humanos , Lidocaína/efeitos adversos , Sintomas do Trato Urinário Inferior/diagnóstico , Sintomas do Trato Urinário Inferior/etiologia , Masculino , Pessoa de Meia-Idade , Dor/etiologia , Medição da Dor , Neoplasias da Próstata/diagnóstico , Fatores de Tempo , Ultrassonografia de IntervençãoRESUMO
PURPOSE: We assessed the impact of tumor volume, tumor volume ratio (tumor volume-to-prostate volume), surgical experience and type of nerve sparing procedure on biochemical recurrence after laparoscopic radical prostatectomy. MATERIALS AND METHODS: Of 1,600 laparoscopic radical prostatectomies performed between March 1999 and May 2006 we evaluated 555 patients who had at least 24 months of followup and received neither neoadjuvant nor adjuvant therapy. Of 555 patients 81 had biochemical recurrence and were match paired in 3 groups with those without recurrence. Matching decisions were based on factors such as age, preoperative prostate specific antigen, pathological stage, Gleason score, surgical margin status with localization, tumor volume, type of nerve sparing procedure, surgeon and date of operation that are related to surgical experience. We evaluated the impact of tumor volume and tumor volume ratio, type of nerve sparing procedure and surgeon on biochemical recurrence, and excluded the factor being investigated in each matched pair. RESULTS: Tumor volumes were 3.58 vs 3.3 cc and tumor volume ratios were 0.081 vs 0.071 in the biochemical recurrence and no biochemical recurrence groups, respectively (p=0.026 and p=0.040). At the second match pair the numbers of nonnerve sparing, unilateral and bilateral nerve sparing procedures were 65, 12 and 4 vs 62, 13 and 6, respectively, without statistical significance. At the last match pair the volume of cases for the first generation and the other generations were 56 and 25 vs 59 and 22, respectively, also without statistical significance. CONCLUSIONS: Although surgical experience based on an adequate training program and type of nerve sparing procedure do not have a significant impact on biochemical recurrence, tumor volume and tumor volume ratio do.
Assuntos
Competência Clínica , Laparoscopia , Recidiva Local de Neoplasia/sangue , Antígeno Prostático Específico/metabolismo , Próstata/inervação , Prostatectomia/métodos , Neoplasias da Próstata , Biomarcadores Tumorais/metabolismo , Biópsia , Progressão da Doença , Seguimentos , Humanos , Masculino , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Estudos Prospectivos , Próstata/diagnóstico por imagem , Próstata/patologia , Prostatectomia/normas , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/cirurgia , Fatores de Tempo , Resultado do Tratamento , UltrassonografiaRESUMO
Electrosurgery is a commonly used technology in laparoscopy. Electrosurgical devices are being used in many medical subdisciplines in order to coagulate, cut, and ablate tissue and to produce hemostasis. The latest advance in electrosurgery is the introduction of novel simultaneous hemostatic sealing and cutting bipolar devices that minimize force by delivering energy as high current and low voltage output. One of these systems is the Gyrus Plasma Trissector (GPT), (Gyrus Group PLC, Gyrus International, Ltd.UK), a novel radiofrequency (RF) system based on bipolar technology, which consists of a proprietary PlasmaKinetic (PK) generator and specific instruments, designed as a system. The instrument consists of a 17 mm long gold-coated curved jaw with a ceramic insulated cutting element. The PK system uses high-powered pulsed bipolar energy to produce a plasmakinetic field around the working elements and is designed to operate at temperatures that allow effective tissue dissection but result in minimal collateral damage and adherence to tissue. The GPT was used with the Gyrus G400 WorkStation generator in laparoscopic radical prostatectomies (LRP). Our initial experience with this novel bipolar device demonstrates it to be safe and effective in dissection and hemostasis. The GPT permits us to act quickly when bloody fields are present, improves coagulation, reduces or eliminates sticking, seals large vessels such as dorsal vein complex (DVC) and allows secure grasping and dissecting of tissue. The urologist is familiar with electrosurgery, as we have become comfortable using GPT to dissect, cut, and coagulate tissue. We feel that the GPT can be used in a variety of laparoscopic procedures in urology.
Assuntos
Dissecação/instrumentação , Hemostasia Cirúrgica/instrumentação , Eletrocoagulação/instrumentação , Eletrocirurgia , Humanos , Laparoscopia , Procedimentos Cirúrgicos Urológicos/instrumentaçãoRESUMO
Seminal-vesicle cysts associated with renal agenesis are rare congenital or acquired lesions. We report a case of seminal-vesicle cyst causing urinary retention in a young patient with right renal agenesis who was treated successfully with transurethral unroofing. Magnetic resonance imaging aided us in making the conclusive diagnosis without the need for any invasive investigations.
Assuntos
Cistos/complicações , Doenças dos Genitais Masculinos/complicações , Rim/anormalidades , Glândulas Seminais/patologia , Doenças da Bexiga Urinária/complicações , Retenção Urinária/etiologia , Doença Aguda , Adulto , Cistos/patologia , Cistos/cirurgia , Doenças dos Genitais Masculinos/patologia , Doenças dos Genitais Masculinos/cirurgia , Humanos , Hipertrofia , Rim/patologia , Imageamento por Ressonância Magnética , Masculino , Glândulas Seminais/cirurgia , Doenças da Bexiga Urinária/patologia , Doenças da Bexiga Urinária/cirurgia , Retenção Urinária/patologiaRESUMO
It has been reported that mental stress causes abnormality of spermiogram parameters. We investigated the effect of psychological stress on the L-arginine-nitric oxide (NO) pathway. Semen samples were collected from 29 healthy fourth semester medical students just before (stress) and 3 months after (non-stress) the final examinations. Psychological stress was measured by the State Anxiety Inventory questionnaire. After standard semen analysis, arginase activity and NO concentration were measured spectrophotometrically in the seminal plasma. Measurements were made in duplicate. During the stress period, sperm concentration (41.28 +/- 3.70 vs 77.62 +/- 7.13 x 10(6)/mL), rapid progressive motility of spermatozoa (8.79 +/- 1.66 vs 20.86 +/- 1.63%) and seminal plasma arginase activity (0.12 +/- 0.01 vs 0.22 +/- 0.01 U/mL) were significantly lower than in the non-stress situation, whereas seminal plasma NO (17.28 +/- 0.56 vs 10.02 +/- 0.49 micromol/L) was higher compared to the non-stress period (P < 0.001 for all). During stress there was a negative correlation between NO concentration and sperm concentration, the percentage of rapid progressive motility and arginase activity (r = -0.622, P < 0.01; r = -0.425, P < 0.05 and r = -0.445, P < 0.05, respectively). These results indicate that psychological stress causes an increase of NO level and a decrease of arginase activity in the L-arginine-NO pathway. Furthermore, poor sperm quality may be due to excessive production of NO under psychological stress. In the light of these results, we suggest that the arginine-NO pathway, together with arginase and NO synthase, are involved in semen quality under stress conditions.
Assuntos
Arginase/análise , Arginina/metabolismo , Óxido Nítrico Sintase/metabolismo , Sêmen/enzimologia , Espermatozoides/fisiologia , Estresse Psicológico/enzimologia , Adulto , Humanos , Masculino , Reprodutibilidade dos Testes , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Estudantes de MedicinaRESUMO
It has been reported that mental stress causes abnormality of spermiogram parameters. We investigated the effect of psychological stress on the L-arginine-nitric oxide (NO) pathway. Semen samples were collected from 29 healthy fourth semester medical students just before (stress) and 3 months after (non-stress) the final examinations. Psychological stress was measured by the State Anxiety Inventory questionnaire. After standard semen analysis, arginase activity and NO concentration were measured spectrophotometrically in the seminal plasma. Measurements were made in duplicate. During the stress period, sperm concentration (41.28 ± 3.70 vs 77.62 ± 7.13 x 10(6)/mL), rapid progressive motility of spermatozoa (8.79 ± 1.66 vs 20.86 ± 1.63 percent) and seminal plasma arginase activity (0.12 ± 0.01 vs 0.22 ± 0.01 U/mL) were significantly lower than in the non-stress situation, whereas seminal plasma NO (17.28 ± 0.56 vs 10.02 ± 0.49 æmol/L) was higher compared to the non-stress period (P < 0.001 for all). During stress there was a negative correlation between NO concentration and sperm concentration, the percentage of rapid progressive motility and arginase activity (r = -0.622, P < 0.01; r = -0.425, P < 0.05 and r = -0.445, P < 0.05, respectively). These results indicate that psychological stress causes an increase of NO level and a decrease of arginase activity in the L-arginine-NO pathway. Furthermore, poor sperm quality may be due to excessive production of NO under psychological stress. In the light of these results, we suggest that the arginine-NO pathway, together with arginase and NO synthase, are involved in semen quality under stress conditions.
Assuntos
Adulto , Humanos , Masculino , Arginase/análise , Arginina/metabolismo , Óxido Nítrico Sintase/metabolismo , Sêmen/enzimologia , Espermatozoides/fisiologia , Estresse Psicológico/enzimologia , Reprodutibilidade dos Testes , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Estudantes de MedicinaRESUMO
The most common cause of iatrogenic injuries to the ureter (75%) is a gynecological or surgical pelvic procedure. The diagnosis of ureteral injuries is delayed in 66% (after days or weeks). Lack of hematuria is an unreliable sign to exclude injury, since 30% of all ureteral injuries do not even demonstrate microscopic hematuria or classic clinical symptoms and signs. In view of this, the diagnosis must be one of suspicion and further evaluations are mandatory in all cases of penetrating or blunt abdominal injuries. The most accurate diagnostic tools are CT scan with delayed excretory images and retrograde ureterography, which can also be used to guide stent placement. Low-grade injuries can be sufficiently treated with urinary diversion by PCN drainage or endoscopic ureteric stenting. The treatment of high-grade injuries depends on the localization and extent of the damage. The principles of repair include débridement, spatulation, lack of tension, stenting, postoperative drainage, and a watertight anastomosis with fine nonreactive absorbable suture. A delay in diagnosis is the most important factor contributing to the morbidity of ureteric injuries, and early treatment can reduce the complication rate to below 5%.
Assuntos
Ureter/lesões , Ferimentos não Penetrantes/terapia , Ferimentos Penetrantes/terapia , Algoritmos , Seguimentos , Humanos , Doença Iatrogênica , Laparoscopia , Stents , Tomografia Computadorizada por Raios X , Ureteroscopia , Derivação Urinária , Urografia , Procedimentos Cirúrgicos Urológicos , Ferimentos não Penetrantes/diagnóstico , Ferimentos Penetrantes/diagnósticoRESUMO
BACKGROUND: It has been reported that there is a relationship between stress and infertility. The mechanisms of stress-related semen quality alterations have not been fully elucidated. In the present study, we investigated the effect of examination stress on seminal glutathione and free sulphydryl content and sperm quality. METHODS: Semen samples were collected from 34 healthy volunteers who were students of medical school in the fourth semester just before (stress period) and 3 months after (non-stress period) their final examinations. Their psychological examination stress was measured by the State Trait Anxiety Inventory (STAI) questionnaire. After standard semen analysis, semen samples were centrifuged at 10 000g for 15 min. Glutathione and free sulphydryl concentration of seminal plasma were measured. RESULTS: During the period of examination stress, the glutathione and free sulphydryl content of seminal plasma and the motility index of spermatozoa were significantly lower, whereas the percentage of morphologically abnormal spermatozoa was higher, than during the non-stress period (P < 0.001, for all). An association between seminal plasma glutathione and motility index was observed at both periods (P < 0.05 and P < 0.01, respectively). CONCLUSIONS: This study demonstrated that glutathione and free sulphydryl levels in seminal plasma decreased in subjects undergoing examination stress. Furthermore, poor sperm quality may be due to loss of glutathione and free sulphydryl content of seminal plasma.