Search PubMed⌕ Search

Biomedical subjects

W Schulze

Publications and source records attributed to W Schulze.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ignition of calcium sparks in arterial and cardiac muscle through caveolae.

Ca(2+) sparks are localized intracellular Ca(2+) events released through ryanodine receptors (RyRs) that control excitation-contraction coupling in heart and smooth muscle. Ca(2+) spark triggering depends on precise delivery of Ca(2+) ions through dihydropyridine (DHP)-sensitive Ca(2+) channels to RyRs of the sarcoplasmic reticulum (SR), a process requiring a very precise alignment of surface and SR membranes containing Ca(2+) influx channels and RyRs. Because caveolae contain DHP-sensitive Ca(2+) channels and may colocalize with SR, we tested the hypothesis that caveolae are the structural element necessary for the generation of Ca(2+) sparks. Using methyl-ss-cyclodextrin (dextrin) to deplete caveolae, we found that dextrin dose-dependently decreased the frequency, amplitude, and spatial size of Ca(2+) sparks in arterial smooth muscle cells and neonatal cardiomyocytes. However, temporal characteristics of Ca(2+) sparks were not significantly affected. We ruled out the possibility that the decreases in Ca(2+) spark frequency and size are caused by changes in DHP-sensitive L-type channels, SR Ca(2+) load, or changes in membrane potential. Our results suggest a novel signaling model that explains the formation of Ca(2+) sparks in a caveolae microdomain. The transient elevation in [Ca(2+)](i) at the inner mouth of a single caveolemmal Ca(2+) channel induces simultaneous activation and thus opens several RyRs to generate a local Ca(2+) release event, a Ca(2+) spark. Alterations in the molecular assembly and ultrastructure of caveolae may lead to pathophysiological changes in Ca(2+) signaling. Thus, caveolae may be intimately involved in cardiovascular cell dysfunction and disease.

Aging↗
PubMed2000

[Diaphyseal femur pseudarthroses--only a technical problem?].

Between 1981 and 1994 at the Bergmannsheil Ruhr University Hospital in Bochum, Germany, we treated 145 patients with femoral diaphyseal nonunions following initial operative treatment. Of these patients, 138 received this initial operative treatment at an outside institution. The primary reconstructions for the fractures utilized plates in 112 cases, reamed nails in 24 cases and external fixators in 9 cases. The average age of the patients was 35 years and the mean time from the initial operative treatment was 2 years. Twenty-seven patients (19%) presented with a hypertrophic nonunion and 118 (81%) with an atrophic nonunion. There was a significant correlation between primary "classic" plating and development of an atrophic nonunion (chi 2-test: P < 0.01). We observed 34 wound infections (23%) with no significant correlation to the type of primary osteosynthesis. We determined that 73 of the pseudarthroses were due to improper osteosynthesis techniques. Of these cases, 41% involved the use of plates, 83% involved the use of reamed nails, and 78% involved the use of external fixators. Fracture location near the diaphyseal-metaphyseal junctions was common in this problematic group. Ninety-two percent of all plates led to atrophic nonunions. There were 21 open fractures and of these 90% (n = 19) developed an atrophic pseudarthrosis and 29% (n = 6) developed a wound infection. Fifty-seven (39%) of all patients had additional injuries, but we found that did not increase the risk of disturbed bone healing. Our revision operations focused on the elimination of wound infections, refreshment of bone healing, and improvement in fragment stability. Only 28% of all "classic" plates and 11% of all external fixators were changed to an intramedullary implant at the time of the first revision surgery. Hypertrophic nonunions required a mean of 1.3 revision operations to achieve bone healing whereas a mean of 2 revision operations were necessary to fuse atrophic bone ends (P < 0.05). In cases of diaphyseal pseudarthrosis healing time was not affected by the type of osteosynthesis used for primary reconstructions. Since lack of fracture healing can often already be observed directly from postoperative X-rays, we recommend that revision procedures be performed early. The prolonged length of time to care for femoral nonunions underlines the importance of appropriate primary fracture treatment. That takes into consideration both the biomechanical and the biological aspects of bone healing.

Adolescent↗
PubMed2000

External trauma to the larynx: classification, diagnosis, therapy.

In contrast to internal trauma to the larynx caused by endolaryngeal procedures, trauma to the larynx caused by external forces is relatively rare. Nevertheless, the great variety of these external traumata warrants a thorough diagnosis and understanding of each case as well as a standardized and accepted method for classifying these injuries. These preconditions will facilitate successful therapy. At our three institutions cases of external trauma to the larynx, including the mechanisms of trauma, were reviewed and analyzed. Cases were classified according to the mechanisms and the sequelae of trauma. The three major categories were (a) external trauma due to the impact of blunt objects, (b) trauma after tearing of the neck and the larynx longitudinally, and (c) external trauma caused by sharp objects and gunshots. In the great majority of cases external trauma to the larynx was caused by blunt pressure and was most often due to strangulation in the course of (attempted) suicide or homicide. In a smaller number of cases sharp instruments caused external traumata. In patients surviving the immediate trauma a meticulous laryngological assessment is necessary. In addition to indirect laryngoscopy, we consider microlaryngoscopy as being indicated for investigating the soft tissues of the endolarynx. The status of the laryngeal skeleton can be determined more precisely via high-resolution computed tomography and ultrasound. Early diagnosis and appropriate therapy have a significant impact on the patient's condition later, especially as regards scar formation, ease of breathing, and voice quality.

Humans↗
PubMed2000

Telomerase activity and expression of telomerase subunits in the testicular tissue of infertile patients.

OBJECTIVE: Determination of telomerase activity and the expression of human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) in the testicular tissue of patients with infertility arising from various causes. DESIGN: Prospective observational study. SETTING: A university hospital. PATIENT(S): Thirty-three patients with azoospermia arising from various causes. There were 12 testicular biopsy specimens from patients with Sertoli cell-only syndrome, 9 from patients with maturation arrest, and 12 from patients with obstructive azoospermia and normal histologic findings. INTERVENTION(S): Thirty-three testicular biopsies. MAIN OUTCOME MEASURE(S): Correlation of histologic findings at testicular biopsy with telomerase activity, hTERT, and hTR. RESULT(S): All 12 biopsy specimens from patients with obstructive azoospermia were positive for telomerase activity, hTR, and hTERT. Biopsy specimens from the 9 patients with maturation arrest were positive for telomerase activity in 8 cases, hTR in 9 cases, and hTERT in 5 cases. None of the patients with Sertoli cell-only syndrome showed either telomerase activity or hTERT, but all of them showed hTR. CONCLUSION(S): Telomerase activity and evidence of hTERT in testicular tissue are highly sensitive and highly specific markers of gametogenesis, which could gain in importance as part of the fertility workup before microinjection procedures.

DNA-Binding Proteins↗
PubMed2000

Myocardial hypertrophy in transgenic mice overexpressing the bovine growth hormone (bGH) gene.

OBJECTIVES: The main purpose of the present study was to characterize cardiac muscle hypertrophy using both qualitative and quantitative microscopy in mice overexpressing the bovine growth hormone. RESULTS: Measurements of 30 fibres from each group revealed that fibre diameter in transgenic hearts was significantly larger than in control hearts. There was a significant decrease in interfibrillar space in transgenic hearts as compared with control hearts. The enlarged transgenic hearts displayed unchanged organelles such as normal myofibrils and mitochondria in a normal pattern, suggesting balanced growth. Myelin structures were occasionally observed between normal myofibrils. Moreover, myocardial beta-adrenergic receptors and muscarinic receptors in the hearts of transgenic mice overproducing GH were studied to see whether they are involved in the hypertrophic process. It was shown that the density of muscarinic receptors had decreased and the super-high affinity of muscarinic receptors was lost, without any significant changes in either the density or the affinity of beta-adrenergic receptors, as compared with controls. CONCLUSIONS: These results demonstrate that a GH excess was able to induce significant myocardial hypertrophy and that there was a downregulation of muscarinic receptors.

Animals↗
PubMed2000

[Pattern of injuries and prophylaxis in paragliding].

This study will present trends and recommendations to increase active and passive safety in paragliding on the basis of current state-of-the-art equipment and typical patterns of injury. This German-Swiss teamwork presents data of 55 male and 9 female patients treated after paragliding accidents between 1994 to 1998 respectively 1996 to 1998. 43.7% of the pilots presented with multiple injuries, 62.5% suffered spinal fractures and 18.8% pelvic fractures. 28.4% of the injured pilots were admitted with injuries of the lower extremities mainly affecting the tarsus or the ankle joint. Only three patients with single injuries could be treated in an ambulatory setting. 54.0% of the injuries left the patients with lasting functional residues and complaints. Main causes of accidents were either pilot error in handling the paraglider or general lack of awareness about potential risk factors. 46.0% of injuries occurred during landing, 42.9% of injuries during the flight and another 11.1% of injuries during starting procedures. With noticeable enhanced performance sails of the beginners and intermediate level are increasingly popular. Protective helmets and sturdy footwear reaching above the ankle joint are indispensable pieces of equipment. The use of protective gloves is highly recommended. Back protection devices of the new generation provide the best passive prophylaxis for the pilot against pelvic and spinal cord injuries. This area hold the most promise for increasing safety and reducing risk of injury in future, apart from using beginners and intermediate wings. After acquisition of the pilot license performance and security training provide the best preparing to master unforeseeable situations.

Accident Prevention↗
PubMed2000

Autoantibodies against the angiotensin receptor (AT1) in patients with hypertension.

Sera from patients with malignant essential hypertension (n = 14), malignant secondary hypertension mainly attributable to renovascular diseases (n = 12) and renovascular diseases without malignant hypertension (n = 11) and from normotensive healthy blood donors (n = 35) were studied for the presence of autoantibodies against G-protein-coupled cardiovascular receptors. Autoantibodies against the angiotensin II receptor (AT1) were detected in 14, 33, 18 and 14% of patients with malignant essential hypertension, malignant secondary hypertension, renovascular diseases and control patients, respectively. Sensitivity of the enzyme immunoassay was assessed as 5 microg/ml IgG. Patients did not show antibodies against bradykinin (B2) or angiotensin II subtype 2 (AT2) receptors. Autoantibodies affinity-purified from positive patients localized AT receptors in Chinese hamster ovary transfected cells, and displayed a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These results demonstrate the existence of autoantibodies against a functional extracellular domain of human AT1 receptors in patients with malignant hypertension, and suggest that these autoantibodies might be involved in the pathogenesis of malignant hypertension.

Animals↗
PubMed2000

SUT2, a putative sucrose sensor in sieve elements.

In leaves, sucrose uptake kinetics involve high- and low-affinity components. A family of low- and high-affinity sucrose transporters (SUT) was identified. SUT1 serves as a high-affinity transporter essential for phloem loading and long-distance transport in solanaceous species. SUT4 is a low-affinity transporter with an expression pattern overlapping that of SUT1. Both SUT1 and SUT4 localize to enucleate sieve elements of tomato. New sucrose transporter-like proteins, named SUT2, from tomato and Arabidopsis contain extended cytoplasmic domains, thus structurally resembling the yeast sugar sensors SNF3 and RGT2. Features common to these sensors are low codon bias, environment of the start codon, low expression, and lack of detectable transport activity. In contrast to LeSUT1, which is induced during the sink-to-source transition of leaves, SUT2 is more highly expressed in sink than in source leaves and is inducible by sucrose. LeSUT2 protein colocalizes with the low- and high-affinity sucrose transporters in sieve elements of tomato petioles, indicating that multiple SUT mRNAs or proteins travel from companion cells to enucleate sieve elements. The SUT2 gene maps on chromosome V of potato and is linked to a major quantitative trait locus for tuber starch content and yield. Thus, the putative sugar sensor identified colocalizes with two other sucrose transporters, differs from them in kinetic properties, and potentially regulates the relative activity of low- and high-affinity sucrose transport into sieve elements.

Amino Acid Sequence↗
PubMed2000

Impairment of cardiac function and bioenergetics in adult transgenic mice overexpressing the bovine growth hormone gene.

Cardiovascular abnormalities represent the major cause of death in patients with acromegaly. We evaluated cardiac structure, function, and energy status in adult transgenic mice overexpressing bovine GH (bGH) gene. Female transgenic mice expressing bGH gene (n = 11) 8 months old and aged matched controls (n = 11) were used. They were studied with two-dimensional guided M-mode and Doppler echocardiography. The animals (n = 6) for each group were examined with 31P magnetic resonance spectroscopy to determine the cardiac energy status. Transgenic mice had a significantly higher body weight (BW), 53.2+/-2.4 vs. 34.6+/-3.7 g (P < 0.0001) and hypertrophy of left ventricle (LV) compared with normal controls: LV mass/BW 5.6+/-1.6 vs. 2.7+/-0.2 mg/g, P < 0.01. Several indexes of systolic function were depressed in transgenic animals compared with controls mice such as shortening fraction 25+/-3.0% vs. 39.9+/-3.1%; ejection fraction, 57+/-9 vs. 77+/-5; mean velocity of circumferential shortening, 4.5+/-0.8 vs. 7.0+/-1.1 circ/sec, p < 0.01. Creatine phosphate-to-ATP ratio was significantly lower in bGH overexpressing mice (1.3+/-0.08 vs. 2.1+/-0.23 in controls, P < 0.05). Ultrastructural examination of the hearts from transgenic mice revealed substantial changes of mitochondria. This study provides new insight into possible mechanisms behind the deteriorating effects of long exposure to high level of GH on heart function.

Acromegaly↗
PubMed2000

Significance of mutations in the androgen receptor gene in males with idiopathic infertility.

Abnormal human spermatogenesis is caused by a variety of genetic and acquired conditions. Because spermatogenesis is dependent on androgens, some males may have a minimal form of androgen insensitivity that does not inhibit virilization but impairs fertility. This has lead us to investigate the possibility of abnormalities in the androgen receptor (AR) gene in a large cohort of males suffering from infertility of unknown cause. We studied 180 males with variable impairment of spermatogenesis. In all patients, serum levels of testosterone and gonadotropins were analyzed to define an androgen sensitivity index (ASI). Single-strand conformation analysis and direct DNA sequencing of PCR-amplified blood leukocyte DNA were used to identify mutations within the whole coding region of the AR-gene. Endocrine and molecular investigations were compared with 53 normal males with proven fertility. In three infertile males, mutations in the AR were identified. Two unrelated males had the same variation within the first exon encoding for the transactivation domain of the receptor (Pro390Ser), whereas, in the third, a mutation in the hormone-binding region was characterized (Gln798Glu). All identified mutation carriers had a significantly elevated ASI. A proportion of males with idiopathic infertility carry relevant variations within the AR-gene. These males may be distinguished on the basis of hormone levels, calculating the ASI, although this index lacks specificity.

Adult↗
PubMed2000

Induction of cardiomyopathy in severe combined immunodeficiency mice by transfer of lymphocytes from patients with idiopathic dilated cardiomyopathy.

Growing evidence suggests that autoimmune mechanisms play an important role in the pathogenesis of idiopathic dilated cardiomyopathy (DCM). The aim of the study was to evaluate the effects of transfer of lymphocytes from patients with DCM into severe combined immunodeficiency (SCID) mice on the heart structure and function. Thirty CB-17 SCID (6-8 weeks old) mice were used and divided into 3 groups (n = 10). Mice were injected intraperitoneally with up to 25 x 10(6) peripheral blood lymphocytes (PBL) from either patients with DCM which contain human autoantibodies against cardiac beta1-adrenergic receptors and M2-muscarinic receptors (DCM group) or PBL from healthy controls (control-H group). Ten mice did not receive any injections and were used as baseline controls (control-N group). Echocardiography and morphological studies were performed seventy five days after the transfer. Results showed that in DCM group, left ventricle dimensions (LVD) in diastole were increased (4.2 +/- 0.1mm) as compared to both control-H group (3.8 +/- 0.1mm) and control-N group (3.6 +/- 0.1 mm) (p < 0.01). Further, there was a trend for increased LVD in systole. Fractional shortening was not different between groups. Histological evaluation revealed accumulation of human lymphocytes in the capillaries and scarce infiltration of the lymphocytes in the hearts from DCM group. Diffuse fibrosis was significant increased in DCM mice as compared to mice receiving PBL from normal subjects (2.2 +/- 0.3% vs. 0.8 +/- 0.1%, p < 0.01). In conclusion, transfer of the PBL from the patients with DCM was able to induce early stage of heart dilatation in SCID mice. These data provide for the first time the direct evidence supporting that the autoimmune mechanism is important in the pathogenesis of human DCM.

Animals↗
PubMed1999

[Iodine therapy for iodine deficiency goiter and autoimmune thyroiditis. A prospective study].

PROBLEM: There is epidemiological and clinical evidence that iodine may induce or promote the manifestation of autoimmune thyroiditis. For this reason it is important to know if substitution of alimentary iodine deficiency or iodine treatment of endemic goitre can cause formation of thyroid antibodies. On the other hand the practical importance of this phenomenon should be evaluated. PATIENTS AND METHODS: During a prospective study we examined 209 patients with endemic non-toxic goitre and 53 healthy people. For treatment were used 200 micrograms iodine/d (n = 119), 500 micrograms iodine/d (n = 27), 1.5 mg iodine/week (n = 41), 150 micrograms iodine/d plus 75 to 100 micrograms T4/d (n = 26), 100 micrograms iodine plus 100 micrograms T4/d (n = 24). The observation took 1 year with a 3-month interval for check ups including clinical examination, ultrasound, TSH, T3, fT4, TPO- and thyreoglobuline antibodies and urinary iodine. RESULTS: After 12 months 7.5% of iodine treated persons had produced antibodies, most of them at low levels. In healthy people we found increased antibody-levels in 3.8%, in patients with goitre in 9.0%, in patients with nodular goitres in 11.1%. 500 micrograms iodine caused the most antibody reaction in 14.8%. People treated with 200 micrograms iodine/d showed positive antibody levels in 5%. T4 seems to reduce antibody-reactions. Pathological antibody-levels were not found in patients with combined iodine/T4- and single-T4 therapy. Among the 22 primary pathological antibody levels only 4 increased further (18.2%). Three of them belonged to the group of 5 persons treated with 500 micrograms iodine/d. Primary high antibody values were normalized in 5 patients (22.7%). Hypothyroid disturbances were not found. Ultrasound did not show any alterations, and the reduction of thyroid volumes in antibody-positive patients was not affected. Median urinary iodine excretion during the observation-interval was 5.2 to 7.2 micrograms/dl. CONCLUSIONS: Possible antibody reactions have no clinical importance at all. Individual cases must be observed. Low iodine doses should be preferred. Combined iodine/T4 treatment seems to have an advantage regarding immunological thyroidal reactions.

Adult↗
PubMed1999

[Stable ankle joint fractures. Indication for surgical or conservative management?].

In German literature, ankle joint fractures are mostly classified in three groups according to Weber. In cases of the type A, the fracture line runs below, in cases of type B at height of the syndesmotic ligaments. C-type fractures are typically seen above this region. However, this practical and simple classification allows no inferences at accompanying injuries which in turn influence the functional outcome. We observed isolated fractures of the lateral malleolus in more than 60% of all type B-fractures, as soon as in the majority the type A-fractures. Since isolated medial ankle fractures occur very rarely, careful exclusion of further injuries is advisable here. In order to differentiate stable ones from unstable type B ankle injuries, we carry out a manual stress test, if there is less than 2 mm fracture dislocation and a congruent ankle mortise. In this manner we could find that stable lateral ankle fractures are characterized with a combination of an intact dorsal syndesmotic and medial ligament. Stable type B and undisplaced type A fractures were treated conservatively with an ankle brace (Aircast?). Unstable ankle injuries were treated by ORIF. Conservative treatment for undisplaced medial malleolar fractures is recommended, if x-rays showed less than 2 mm dislocation which allows a tibio-talare impingement. Biomechanical investigations could prove a significant increase in ankle joint stability, when an axial load of 300 N was applied to various horizontal loads. The talus does not follow automatically a displaced fibular fracture. The dorsal syndesmotic and the medial deltoid ligaments control ankle joint stability.

Ankle Injuries↗
PubMed1999

Transporters for ammonium, amino acids and peptides are expressed in pitchers of the carnivorous plant Nepenthes.

Insect capture and digestion contribute substantially to the nitrogen budget of carnivorous plants. In Nepenthes, insect-derived nitrogenous compounds are imported from the pitcher fluid and transported throughout the plant via the vascular tissue to support growth. Import and distribution of nutrients may require transmembrane nitrogen transporters. Representatives of three classes of genes encoding transporters for the nitrogenous compounds ammonium, amino acids and peptides were identified in Nepenthes pitchers. The expression at the cellular level of an ammonium transporter gene, three amino acid transporter genes, and one peptide transporter gene were investigated in the insect trapping organs of Nepenthes. Expression of the ammonium transporter gene NaAMT1 was detected in the head cells of digestive glands in the lower part of the pitcher where NaAMT1 may function in ammonium uptake from the pitcher fluid. One amino acid transporter gene, NaAAP1, was expressed in bundle sheath cells surrounding the vascular tissue. To understand the locations where transmembrane transport could be required within the pitcher, symplasmic and apoplasmic continuity was probed using fluorescent dyes. Symplasmic connections were not found between cortical cells and vascular bundles. Therefore, the amino acid transporter encoded by NaAAP1 may be involved in transport of amino acids into the vascular tissue. In contrast, expression of the peptide transporter gene NaNTR1 was detected in phloem cells of the vascular tissue within pitchers. NaNTR1 may function in the export of nitrogen from the pitcher by loading peptides into the phloem.

Amino Acid Sequence↗
PubMed1999

Mast cells in testicular biopsies of infertile men with 'mixed atrophy' of seminiferous tubules.

Mast cells in the bilateral testicular biopsies of 30 patients with a 'mixed atrophy' of seminiferous tubules were analysed. Seven biopsies from vasectomized patients served as controls. With regard to their characteristic location within testicular tissue, two groups of mast cells could be distinguished, in both control and infertile patients: 'interstitial' mast cells (located between Leydig and other interstitial cells as well as in the vicinity of blood vessels) and 'peritubular' mast cells (located in the close proximity of the tubular lamina propria or incorporated in the lamina propria itself). Morphometric data indicated a significant increase in the number and volume of mast cells in infertile patients when compared with controls. In the biopsies of infertile patients that were analysed both 'interstitial' and 'peritubular' mast cells showed a significant increase in their number and volume, although it appeared that 'peritubular' mast cells increased at a higher rate than 'interstitial' mast cells. A significant negative correlation was found between the following variables: volume and number of mast cells, testis volume and the status of spermatogenesis evaluated by Johnsen's scoring. It was concluded that the increased presence of mast cells is closely associated with an impairment of spermatogenesis.

Adult↗
PubMed1999

Agonist-like activity of antibodies to angiotensin II receptor subtype 1 (AT1) from rats immunized with AT1 receptor peptide.

In the present study, rats were immunized with angiotensin II receptor subtype 1 (AT1) receptor peptides for 3 months to see if the immunization produced specific anti-AT1 receptor antibodies and if continuous stimulation for 3 months affected blood pressure or induced morphological changes in the organs containing AT1 receptors. Our results showed that there were constant high levels of circulating antibodies throughout the study period in all rats of the immunized group, but not in the control rats, and that there were almost no significant cross-reactions of antisera with AT2 receptor peptide and alpha1 adrenoceptor peptide, except in four rats, which showed low cross-reactions with alpha1 adrenoceptor and AT2 receptor peptides. When an affinity-purified anti-AT1 receptor antibody was used, it specifically displayed the AT1-stimulatory positive chronotropic effect and also localized AT1 receptors. However, in the immunized group, saturation binding of AT1 in homogenates from kidneys showed no difference either in maximal binding sites (Bmax) or in antagonist affinity (Kd). No difference in mRNA of AT1a was found in either kidney or heart, and no morphological changes in the organs were observed, as compared with the control group. Furthermore, immunization did not cause hypertension. In conclusion, the synthetic peptide corresponding to the second extra-cellular loop of the human AT1 receptor was able to produce highly specific and functionally active anti-AT1 receptor antibodies, but unable to induce pathological structural changes or hypertension.

Amino Acid Sequence↗
PubMed1999

Testicular sperm extraction: comprehensive analysis with simultaneously performed histology in 1418 biopsies from 766 subfertile men.

The introduction of intracytoplasmic sperm injection (ICSI) has revolutionized treatment of male-factor infertility. Even with a single spermatozoon a pregnancy can be achieved. In cases of azoospermia due to obstruction or highly impaired spermatogenesis, spermatozoa can be retrieved directly from testicular tissue recovered by testicular biopsy followed by sperm extraction. The predictive value of histology from semi-thin sections of testicular biopsies was assessed in relation to testicular sperm extraction (TESE) results, using 1418 biopsy samples from 766 subfertile men which were evaluated simultaneously using a modified Johnsen score and an ordinal classification system for spermatozoa in TESE samples. In 655 men bilateral samples were available. Based on histological findings and TESE results, the quality of spermatogenesis in the right testes was significantly better than that in the left testes. There was a difference between the two sides in 35.7% of all patients for histology and 32.7% for TESE results. When best results from either testis were used for analysis, 76.9% of all men revealed spermatozoa in TESE preparations, although during histological evaluation of semi-thin sections only 64% of all men had shown mature spermatids. In a core group of 250 azoospermic men without anamnestic hints to obstruction and most likely to benefit from ICSI, TESE was successful in 62.8% men. Subdivision of this group dependent on follicle stimulating hormone (FSH) serum concentrations revealed that even in cases of increased FSH concentration, between 39.1 and 64.7% of men showed mature spermatids in their TESE samples. A subset of 70 azoospermic men from the main sample with symptoms and history suggestive of an obstruction and considered as positive controls showed a positive TESE result in all patients. The histology had failed to predict this in 2.9% of all cases. Nevertheless, in five men an early stage of testicular tumour (carcinoma in situ = CIS) was detected. Two of these males suffered from bilateral CIS. This reflects a prevalence of 0.7% testicular malignancy in the group of patients without a history of excurrent duct obstruction. The data demonstrate that a trial TESE with histology based on the semi-thin sectioning technique is a powerful diagnostic and therapeutic procedure, which justifies the invasive nature of sperm retrieval for ICSI. In addition, the results stress the importance of bilateral biopsies to gain optimal diagnostic and therapeutic results.

Adult↗