PubMed Health⌕ Search

Biomedical subjects

F H Pierik

Publications and source records attributed to F H Pierik.

12 recordsLinked to original sources
PubMed2006

Does folic acid and zinc sulphate intervention affect endocrine parameters and sperm characteristics in men?

We evaluated pre- and post-intervention endocrine and semen parameters in a double-blind, placebo-controlled intervention study to investigate the underlying mechanism of increased sperm concentration after folic acid and zinc sulphate intervention. A total of 47 fertile and 40 subfertile males participated in a 26-week intervention study consisting of a daily treatment with folic acid (5 mg/day) and zinc sulphate (66 mg/day), or placebo. Pre- and post-intervention semen parameters, serum folate, zinc, follicle-stimulating hormone (FSH), testosterone and inhibin B concentrations were measured. The results indicated that intervention treatment significantly increased sperm concentration in subfertile males. Other semen and endocrine parameters were not affected by intervention treatment. At baseline, positive correlations were found between serum zinc and sperm concentration, motility and inhibin B. Serum zinc and FSH were inversely correlated. As (already) well known from previous research, inhibin B positively correlated with sperm concentration, motility and morphology, and was inversely correlated with FSH. The latter was positively correlated with testosterone. In addition, testosterone and inhibin B were inversely correlated. After intervention, the correlations with zinc disappeared. We conclude that the increase in sperm concentration after folic acid and zinc sulphate intervention is not the result of alterations in FSH, testosterone or inhibin B concentrations. Although zinc and folate have several effects on spermatogenesis, the underlying mechanisms involved are not clear.

Adult↗
PubMed2004

Bilateral testicular microlithiasis predicts the presence of the precursor of testicular germ cell tumors in subfertile men.

PURPOSE: A high prevalence of testicular microlithiasis has been described in adolescent and adult clinical cases of invasive testicular germ cell tumor (TGCT), that is seminomas and nonseminomas. However, to our knowledge it remains to be established whether testicular microlithiasis also indicates the presence of the pre-invasive lesion of this cancer, known as carcinoma in situ (CIS). We determined the predictive value of unilateral and bilateral testicular microlithiasis for CIS in subfertile men, a known risk population for TGCTs (approximately 1%). MATERIALS AND METHODS: In a retrospective cross-sectional study the association between testicular microlithiasis and CIS was studied in a group of 263 men referred for subfertility. Testicular microlithiasis and CIS were diagnosed in all men by scrotal ultrasound and in testicular histology specimens as part of the routine evaluation of all patients. RESULTS: Of the 263 subfertile men 53 (20%) had testicular microlithiasis. No CIS or TGCT was identified in the 23 men with unilateral testicular microlithiasis. In contrast, 6 of the 30 men (20%) with bilateral testicular microlithiasis were diagnosed with CIS. Therefore, the prevalence of CIS in subfertile men with bilateral testicular microlithiasis is significantly higher than in patients without testicular microlithiasis (1 of 210, 0.5%) and with unilateral testicular microlithiasis (0 of 23, 0%) (p <0.0001). CONCLUSIONS: Bilateral testicular microlithiasis is indicative for CIS in subfertile men. Since these men are at particular risk for invasive TGCT, an assessment of testicular microlithiasis is a valuable tool for the early diagnosis of this disease.

Adult↗
PubMed2003

Subtotal obstruction of the male reproductive tract.

Bilateral obstruction of the male reproductive tract is suspected in men with azoospermia, normal testicular volume and normal FSH. A testicular biopsy is required to differentiate between an obstruction and a testicular insufficiency. Unilateral or subtotal bilateral obstructions and epididymal dysfunction may cause severe oligozoospermia in men with a normal spermatogenesis. However, information on spermatogenesis in oligozoospermic men is lacking, since testicular biopsy is not routinely performed. Men with a sperm concentration of <1 x 10(6) spermatozoa/ml were investigated for possible partial obstruction by performing a testicular biopsy under local anaesthesia. Spermatogenesis was determined by the Johnsen scoring method. A testicular biopsy was performed in 78 men with severe oligozoospermia. The medical history showed male accessory gland infection in 12.8%, previous hernia repair in 14.1% and a history of cryptorchidism in 12.8%. A normal or slightly disturbed spermatogenesis (Johnsen score >8) was present in 39/78 (50%) of the men. Hernia repair occurred more often in men with normal spermatogenesis. A varicocele was predominantly seen in men with a disturbed spermatogenesis. FSH was significantly lower ( P<0.0001) in men with normal spermatogenesis. Subtotal obstruction of the male reproductive tract is a frequent cause of severe oligozoospermia in men with a normal testicular volume and a normal FSH. In other cases, an epididymal dysfunction might explain the oligozoospermia in men with a normal testicular biopsy score.

Biopsy↗
PubMed2003

The effect of cryptorchidism on inhibin B in a subfertile population.

OBJECTIVE: Prepubertal cryptorchidism may cause fertility problems in adulthood, due to impaired spermatogenesis. Serum inhibin B has emerged as an accurate marker of spermatogenesis. The aim of this study was to evaluate the impact of a history of cryptorchidism on serum inhibin B levels and other markers of spermatogenesis in subfertile men. PATIENTS AND MEASUREMENTS: In a retrospective study, the effect of cryptorchidism on inhibin B, FSH, LH, free testosterone, testicular volume and semen parameters was assessed in a case-control study within a population of 2613 subfertile men. Of these, 161 and 102 subjects had a history of, respectively, unilateral and bilateral cryptorchidism that was treated by orchiopexy in childhood. Hormone data were complete for 64 cryptorchid patients (32 unilateral and 32 bilateral). A group of 128 patients was randomly selected out of the remaining group of 2350 men with idiopathic subfertility. An additional control group consisted of 32 fertile men from the general population. RESULTS: In cryptorchid subfertile men, inhibin B concentrations were significantly lower than in noncryptorchid subfertile men and fertile men (103 ng/l, 143 ng/l and 148 ng/l, respectively; P < 0.01). The FSH concentration was significantly higher in cryptorchid men vs. noncryptorchid men and controls (6.1 IU/l vs. 3.3 and 2.9 IU/l, respectively; P < 0.01). Testicular volumes and sperm concentration of cryptorchid men were significantly lower than in noncryptorchid subfertile men (12 vs. 15 ml, P < 0.01 and 3.8 x 10(6) sperm/ml vs. 17.4 x 10(6) sperm/ml; P < 0.05). A significantly higher inhibin B level and sperm concentration was observed in men undergoing orchiopexy at an early age (1-4 years) compared with men treated between 5 and 9 years or later (P < 0.05). CONCLUSION: Spermatogenesis is more impaired in cryptorchid subfertile men compared to men with idiopathic subfertility, as reflected by a lower inhibin B concentration.

Adult↗
PubMed2001

Increased serum inhibin B levels after varicocele treatment.

OBJECTIVE: Inhibin B is secreted by Sertoli cells in response to FSH and is the major feedback regulator of FSH secretion in man. The serum inhibin B level has emerged as a good marker of spermatogenesis and Sertoli cell function. Varicocele has been associated with infertility and disturbed spermatogenesis. We have studied the effect of varicocele treatment on serum inhibin B levels, with the aim of investigating the effect on spermatogenesis and the involvement of the Sertoli cell in varicocele pathophysiology. DESIGN AND PATIENTS: In a pre-post test design, the effect of varicocele surgery on inhibin B levels was studied in 30 infertile men. MEASUREMENTS: Endocrinology (inhibin B, FSH, LH, SHBG and testosterone) and semen analysis (sperm concentration, motility and morphology). RESULTS: In men receiving varicocele treatment, a significant increase in serum inhibin B levels was observed from 133.9 +/- 13.4 pretreatment to 167.8 +/- 16.1 ng/l after treatment (mean +/- SEM, P < 0.0001). No significant changes were observed in serum levels of FSH, LH and testosterone. The serum SHBG level decreased from 32.9 +/- 3.5 to 28.6 +/- 3.4 nmol/l (mean +/- SEM, P = 0.04) and the free androgen index was significantly increased from 66 +/- 5.9 pretreatment to 85 +/- 6.8 after treatment (P = 0.02, mean +/- SEM). Semen analysis showed a significant improvement in sperm concentration, from 6.5 +/- 1.9 pretreatment to 19.3 +/- 4.9 x 106/ml after treatment (P = 0.003, mean +/- SEM), and in sperm motility from the baseline level of 17 +/- 3 to 32 +/- 4% after treatment (P = 0.001, mean +/- SEM). CONCLUSIONS: Varicocele treatment can increase serum inhibin B levels, indicating improvement of spermatogenesis and Sertoli cell function. This finding suggests that the pathophysiology of varicocele involves impairment of Sertoli cell function or a different distribution of germ cell stages.

Adult↗
PubMed2000

The advantages of standardized evaluation of male infertility.

Healthcare can be improved by standardization and by evaluation of diagnostic methods and treatments. In the field of andrology, in which large patient numbers are required for the evaluation of diagnostic procedures and treatments, structured data collection and multicentre studies are especially warranted. Concomitant with routine clinical practice, a large amount of clinical data are collected that may be used to evaluate andrological care. Structuring and electronic storage of data holds promise in terms of clarity and accessibility of the data and its use for validation studies. The aim of the present work was to study the merits of routine collection of a common dataset in a computer-based patient record (CPR) for standardization, quality of data and clinical research. It was studied whether the data were of sufficient quality and accessibility for much needed studies on aetiology, interventions and diagnostics in andrology. Data collection in a structured CPR promoted complete and comprehensive data. We describe the advantages, pitfalls and solutions with this approach. Data on the uniform examination of 1549 infertile men became readily accessible. Population characteristics, basal associations and original studies were enabled and provided insight into the efficiency of clinical practice. In 66% of men, a cause for their infertility was identified, which provides a better rationale for treatment than semen parameters alone. For more than 30% of the patients, a rational andrological treatment was available, which could be deployed before assisted reproductive technologies were resorted to. However, most treatments have not been properly validated. The thorough diagnostic evaluation identifies subgroups that require an evidence base for treatment and further study on aetiology and diagnosis. Structured collection of uniform patient data through a CPR was feasible and facilitated the evaluation of diagnostic and therapeutic modalities. The reported advantages, pitfalls and solutions with this approach may help other centres to decide on how to implement a CPR. Conscientious collection of a standard data set in infertility centres facilitates pooling of data and evidence-based multicentre research.

Adult↗
PubMed1999

Is routine scrotal ultrasound advantageous in infertile men?

PURPOSE: We determine the value of routine scrotal ultrasonography in the evaluation of male infertility. MATERIALS AND METHODS: Scrotal color Doppler ultrasonography reports of 1,372 infertile men were reviewed to assess the prevalence of scrotal abnormalities and compared to clinical findings. RESULTS: The prevalence of scrotal abnormalities was 38%. Testicular tumor was found in 0.5%, varicocele in 29.7%, testicular cyst in 0.7%, testicular microlithiasis in 0.9%, epididymal cyst in 7.6% and hydrocele in 3.2% of the cases. Overall, 67% of sonography findings were not evident on palpation, and only 1 of 7 testicular tumors was suspected. Of the varicoceles 60% were not found on physical examination. The rate of testicular tumors (1/200) was higher than that reported for the general European population (1/20,000). CONCLUSIONS: Routine scrotal ultrasound provides valuable information in the diagnostic evaluation of infertile men and substantially more pathological conditions are detected compared to clinical palpation. The high prevalence of testicular malignancies underlines the clinical relevance of routine scrotal ultrasonography in infertile men.

Adult↗
PubMed1998

Improvement of sperm count and motility after ligation of varicoceles detected with colour Doppler ultrasonography.

The debate regarding the efficacy of varicocele ligation for improvement of semen parameters and pregnancy rates is ongoing. In addition, no consensus exists as to the benefit of treatment of subclinical varicoceles. The aim of this study was to investigate, retrospectively, the effect of high ligation of both subclinical and clinical varicoceles on sperm count and motility. The value of several factors from history-taking and physical examination for the prediction of successful varicocelectomy was analysed. A total of 139 patients, operated on for a unilateral varicocele on the left side, were studied. Varicoceles were subclinical in 73 patients, based on colour Doppler ultrasonography, and 66 varicoceles were clinical, based on palpation in addition to ultrasonography. Comparison of semen parameters before and after surgery revealed a significant improvement. The median sperm count increased from 10.0 to 14.7, and from 18.2 to 28.6 million/ejaculate, in patients with subclinical and clinical varicoceles, respectively (p < 0.001). The percentage improvement in median sperm count in subclinical varicoceles was not statistically different from the improvement in clinical varicoceles. Mean progressive motility improved significantly after ligation (p < 0.001). The improvement in motility in subclinical varicoceles, from 16 to 23%, was significantly larger than the 24 to 27% improvement in clinical varicoceles. The increase in sperm count was related positively to testicular volume before surgery (p < 0.05). The increase in sperm motility was significantly lower in patients with a history of cryptorchidism (n = 22, p < 0.05). The present data show that ligation of varicoceles detected using Doppler ultrasonography, whether palpable or not, results in an increase in sperm concentration and motility.

Adult↗
PubMed1998

Serum inhibin B as a marker of spermatogenesis.

Inhibin B is produced by Sertoli cells, provides negative feedback on FSH secretion, and may prove to be an important marker for the functioning of seminiferous tubules. The purpose of the present study was to examine the relationship between the spermatogenic function of the testis of subfertile men and the plasma concentrations of inhibin B and FSH. These parameters were estimated in a group of 218 subfertile men. Serum inhibin B levels were closely correlated with the serum FSH levels (r = -0.78, P < 0.001), confirming the role of inhibin B as feedback signal for FSH production. The spermatogenic function of the testis was evaluated by determining testicular volume and total sperm count. Inhibin B levels were significantly correlated with the total sperm count and testicular volume (r = 0.54 and r = 0.63, respectively; P < 0.001). Testicular biopsies were obtained in 22 of these men. Inhibin B was significantly correlated with the biopsy score (r = 0.76, P < 0.001). Receiver operating characteristic analysis revealed a diagnostic accuracy of 95% for differentiating competent from impaired spermatogenesis for inhibin B, whereas for FSH, a value of 80% was found. We conclude that inhibin B is the best available endocrine marker of spermatogenesis in subfertile men.

Adult↗
PubMed1997

Restructuring routinely collected patient data: ORCA applied to andrology.

Hospital information systems do not always cover all required detail per specialty. This may lead to scattering of data over disparate systems and the paper record. The ORCA (Open Record for CAre) CPR offers a generic structure for record sharing, and record keeping tailored to specific needs. We studied whether a semantic integration of existing and new data was possible, using the ORCA structure. Existing andrology data, originating from separate sources, were utilized for this purpose. During normalization, validation and explication steps, latent problems in the source data were exposed and removed, followed by a merge with new data items. By conversion of source data to ORCA, a unique representation of medical concepts in the database was attained, facilitating retrieval of univocal data for multiple purposes. We conclude that the expansion to the andrology domain, including transparent integration of existing data, provides support for the generality of ORCA.

Ambulatory Care Information Systems↗
PubMed1993

Occupational exposure of animal caretakers to cyclophosphamide.

Little is known about the exposure of animal caretakers to toxic agents during the administration of such chemicals to laboratory animals. In this study, we have investigated the environmental contamination with cyclophosphamide (CP) in an animal laboratory where mice were housed and injected with this compound. Also the contamination of gloves, sleeve protectors, and masks used for personal protection was studied. The uptake of CP by the animal caretakers was determined by the analysis of unmetabolized CP in urine. For the estimation of CP in the air, air samples were taken and filters of the air-circulation system were analyzed. On the filters, amounts of CP were detected corresponding with < 0.1-1.0 microgram/day. Environmental contamination was also measured by analysis of wipe samples taken from different spots (objects and surfaces). The presence of CP was not only observed in the room where the mice were housed and treated with CP but also in adjacent rooms (< 0.02-44 ng/cm2). The gloves used during the injection of CP were always contaminated (2-199 micrograms/pair). No penetration of the gloves was established. The sleeve protectors were incidentally contaminated (< 0.3-10 micrograms) and on the masks no CP was found (< 0.2 microgram). Eighty seven urine samples from four animal caretakers were analyzed for unmetabolized CP. In one sample, CP was detected (0.7 microgram). The results show that in this particular study animal caretakers are exposed to CP during their work.

Animal Husbandry↗