bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled syntheses of natural and disulfide‐mispaired regioisomers of α‐conotoxin SI*
Authors: Hargittai B. , Barany G.
Published: May 2003

Abstract: Methods are reported for the unambiguous syntheses of all three possible disulfide regioisomers with the sequence of α‐conotoxin SI, a tridecapeptide amide from marine cone snail venom that binds selectively to the muscle subtype of nicotinic acetylcholine receptors. The naturally occurring peptide has two ‘interlocking’ disulfide bridges connecting Cys2–Cys7 and Cys3–Cys13 (2/7&3/13), while in the two mispaired isomers the disulfide bridges connect Cys2–Cys13 and Cys3–Cys7 (2/13 & 3/7, ‘nested’) and Cys2–Cys3 and Cys7–Cys13 (2/3 & 7/13, ‘discrete’), respectively. Alignment of disulfide bridges was controlled at the level of orthogonal protection schemes for the linear precursors, assembled by Fmoc solid‐phase peptide synthesis on acidolyzable tris(alkoxy)benzylamide (PAL) supports. Side‐chain protection of cysteine was provided by suitable pairwise combination of the S‐9H‐xanthen‐9‐yl (Xan) and S‐acetamidomethyl (Acm) protecting groups. The first disulfide bridge was formed from the corresponding bis(thiol) precursor obtained by selective deprotection of S‐Xan, and the second disulfide bridge was formed by orthogonal co‐oxidation ofS‐Acm groups on the remaining two Cys residues. It was possible to achieve the desired alignments with either order of loop formation (smaller loop before larger, or vice versa). The highest overall yields were obtained when both disulfides were formed in solution, while experiments where either the first or both bridges were formed while the peptide was on the solid support revealed lower overall yields and poorer selectivities towards the desired isomers.
Synthesis and cytostatic properties of structure‐simplified analogs of dolastatin 15*
Authors: Hu M.‐K. , Huang W.‐S.
Published: May 2003

Abstract: The linear peptide dolastatin 15 (1), a potent antineoplastic constituent from the shell‐less mollusk Dolabella auricularia, has been selected as the lead compound for developing novel antitumor drugs. Recently LU103793 (2), a synthetic and structure‐simplified analog of dolastatin 15, has been demonstrated to be highly cytotoxic [IC50 = 0.1 nm; M. De Arruda, C.A. Cocchiaro, C.M. Nelson, C. M. Grinnel, B. Janssen, A. Haupt & T. Barlozzari (1995) Cancer Res. 55, 3085–3092]. Both compounds have been undergoing human cancer clinical trials in Europe and North America. Based on the novel structure of LU103793, a series of analogs modified at the N‐terminal dolavalyl moiety and ‐Pro‐Pro‐benzylamide unit was developed. These synthesized analogs were tested using a sulforhodamine B (SRB) assay for the drug‐screening program at NCI on a variety of human cancer cell lines. As expected, most analogs exhibited potent and selective growth inhibition against leukemia. Analog 18 was specifically active against HL‐60 and K‐562 cell lines (GI50s: 0.05 µm and 0.07 µm, respectively) while analogs 14 and 17 were selectively potent against prostate and breast cancer cell lines (GI50s at micromolar levels). However, all analogs were less potent than 2 as growth inhibitors of some breast and colon cancer cell lines (e.g. MDA‐MB‐435 and HT‐29). We believe that modification of novel marine natural products as synthetic analogs might show particular promise for developing novel anticancer candidates with moderate specificity.
Systematic study of the substituted active C‐terminus of hirudin
Authors: Liu G. , Mu S.‐F. , Yun L.‐H. , Ding Z.‐K. , Sun M.‐J.
Published: May 2003

Abstract: Hirudin, a potent clinical thrombin inhibitor from Hirudo medicinalis, consists of 65 amino acids in a single chain. In this paper, we systematically synthesize a series of C‐terminal (desulfo hirudin45–65) peptides substituted by 20 natural l‐amino acids via the Multipin method. The resulting peptide library is subsequently screened using an α‐thrombin‐mediated fibrinogen clotting assay and α‐thrombin‐induced amidolytic hydrolysis assay.
Consequences of introducing a disulfide bond into an antibacterial and hemolytic peptide
Authors: Krishnakumari V. , Sharadadevi A. , Sitaram N. , Nagaraj R.
Published: May 2003

Abstract: The effect of introducing a disulfide bridge between the N‐ and C‐terminal ends on the structure and biological activities of the 13‐residue linear peptide PKLLKTFLSKWIG(SPFK), which has both antibacterial and hemolytic activity, have been investigated. The terminal amino acids P and G in SPFK were replaced by cysteines to form a disulfide bridge. The linear peptides C(Acm)KLLKTFLSKWIC(Acm) and C(Acm) KLLKTFLSKWIC(Acm)‐amide, where Acm is acetamidomethyl group, showed antibacterial activity but did not possess hemolytic activity unlike SPFK. Introduction of an S–S bridge resulted in enhanced hemolytic activity compared with SPFK. The hemolytic activity was particularly pronounced in the cyclic peptide CKLLKTFLSKWIC‐amide. Circular dichroism studies indicate that the cyclic peptides tend to adopt distorted helical structures. The cyclic peptides also have a greater affinity for lipid vesicles, which could be the reason for the effective perturbation of the erythrocyte membrane.
Synthesis and activity of NH2‐ and COOH‐terminal elastase recognition sequences on cotton
Authors: Edwards J.V. , Batiste S.L. , . Gibbins E.M. , Goheen S.C.
Published: May 2003

Abstract: The application of peptide recognition sequences of elastase to fibers of wound dressings is a possible route to inhibiting high levels of destructive elastase in the chronic wound. For this reason we have synthesized the elastase recognition sequence Val‐Pro‐Val on both cotton cellulose, and carboxymethylated cellulose cotton (CMC) and prepared chromatography columns of these to examine elastase retention. The tripeptide was synthesized on cotton‐based cellulose fibers both in sequence and as a tripeptide methyl ester. Glycine was employed as a linker of the recognition sequence to the cotton cellulose. Pre‐treatment of cotton cellulose with cellulase improved the substitution level of glycine. The peptidocellulose conjugates were employed as a chromatographic stationary phase to assess elastase retention. The sequence Val‐Pro‐Val‐OMe was amino‐terminally anchored to carboxymethylated cotton and demonstrated retention of up to 58% of elastase when first applied to the column. Higher repetitive retention was demonstrated subsequently. Cotton gauze similarly modified with Val‐Pro‐Val‐Gly cellulose was compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastase that were treated with Val‐Pro‐Val‐Gly cellulose cotton gauze, demonstrated reduced elastase activity. This study demonstrates the use of elastase recognition sequences as sequestering agents of elastase when attached to cotton fibers and constitutes a model for the design of peptidocellulose analogs in dressing fibers for chronic wounds.
Enzyme mimics complexing Cu(II) ion: structure–function relationships
Authors: Corazza A. , Scarpa M. , Corazza A. , Vianello F. , Zennaro L. , Gourova N. , Di Paolo M.L. , Signor L. , Marin O. , Rigo A.
Published: May 2003

Abstract:Five peptides containing (His‐X2)‐His or (His‐X3)‐His motifs have been designed and synthesized to coordinate Cu(II). Structural information was obtained by various spectroscopic techniques and was used as constraint to search for local conformational energy minima by molecular mechanics. Thermodynamic stability constants of the Cu(II) chelates was obtained by19F‐NMR. The synthesized Cu(II)–peptide chelates were tested as catalysts of some important red‐ox processes occuring in biological systems, in particular oxidation of ascorbate and dismutation of superoxide ion. The catalytic efficiency of the five chelates was much lower than that of ascorbate oxidase. On the contrary, two of them showed kinetic constants for superoxide dismutation about one order of magnitude lower than that of the enzyme Cu,Zn superoxide dismutase. In both cases, the catalytic properties were dependent on the peptide sequence. The relationships between structure and activity are discussed to find the structural parameters crucial for catalytic activity that can be modulated by appropriate design and synthesis of the peptides.
N‐Hydroxy peptides as substrates for α‐chymotrypsin
Authors: Bianco A. , Kaiser D. , Jung G.
Published: May 2003

Abstract: An N‐hydroxylated peptide bond was found to be cleaved faster by an endopeptidase than the corresponding peptide bond. This preferred enzymatic cleavage was detected during proteolytic studies of the N‐hydroxy peptide SIINFψ[CO‐N(OH)]GKL in the presence of the serine protease α‐chymotrypsin in comparison with the natural SIINFEKL epitope and related analogs. For the first time, the replacement of the peptide bond by another motif afforded an oligomer which is degraded faster than the natural peptide. The N‐hydroxy peptide is also more sensitive to the enzymatic degradation than the Gly‐containing analog SIINFGKL. A tentative explanation for the unexpected higher cleavage rate of the CO‐N(OH) bond is given on the basis of the N‐OH intramolecular H‐bonding capacity as indicated by NMR experiments. This property of the hydroxamate group may be of particular advantage for the introduction of a specific cleavage site within peptidomimetics or in prodrugs.
Effect of peptide conformation on membrane permeability
Authors: Boguslavsky V. , Hruby V.J. , O'Brien D.F. , Misicka A. , Lipkowski A.W.
Published: May 2003

Abstract: The effect of peptide conformational constraint on the peptide permeation across the model membranes was examined by determining the permeability of pairs of cyclic and acyclic peptides related to c[d‐Pen2, d‐Pen5] enkephalin (DPDPE). The peptides were cyclized by formation of an intramolecular disulfide bridge between the second and fifth residues composed of either d‐penicillamine or cysteine. In each case the acyclic peptide was three to seven times more permeable than corresponding cyclic peptide. The possibility that the differences in permeability of cyclic and acyclic peptides is based on the greater conformational freedom of the acyclic peptides in the presence of membrane was examined in more detail by isothermal titration calorimetric studies of Trp6‐DPDPE and its acyclic analog. The membrane binding of the acyclic peptide is a more exothermic process than binding of its cyclic Trp6‐DPDPE. The transfer of acyclic peptide from water to membrane is an enthalpy driven process, whereas the transfer of the cyclic peptide is driven by entropy.
Direct binding properties of conantokins to native N‐methyl‐d‐aspartate receptors
Authors: Klein R.C. , Prorok M. , Castellino F.J.
Published: May 2003

Abstract: Conantokin‐G (con‐G) is a small, γ‐carboxyglutamic acid (Gla)‐containing peptide that functions neurophysiologically by inhibiting the N‐methyl‐d‐aspartate receptor (NMDAR). In the current study, the receptor binding properties of an alanine‐rich, Gla‐deficient con‐G variant, Ala‐con‐G, were assessed following tracer radioiodination with 125I. Direct binding experiments with [125I]Ala‐con‐G yielded a single site defined by a Kd value of 516 ± 120 nm. Displacement of [125I]Ala‐con‐G binding by Ala‐con‐G resulted in 100% displacement with an IC50 value of 564 ± 33 nm, while heterologous displacement by con‐G[S16Y], con‐G, con‐T, and con‐R[1–17] yielded IC50 values in the range of 15–45 μm. No displacement was observed with d‐γ‐con‐G or con‐G[L5A], analogs that are inactive at NMDARs. Specific [125I]Ala‐con‐G binding was displaced by NMDA and 2‐amino‐5‐phosphopentanoic acid in a dose‐dependent manner, suggesting an interaction at the glutamate binding site. The direct binding of [125I]Ala‐con‐G to adult rat brain sections revealed an anatomical distribution of binding sites in all regions known to contain the NR2B subunit of the NMDAR. These results constitute the only known demonstration of the direct binding of a radiolabeled conantokin to the NMDARs present in rat brain membrane preparations and rat brain sections, and suggest that radiolabeled Ala‐con‐G, and similar conantokin derivatives, may find utility as probes of NMDARs in a variety of systems.
Association between testicular dysgenesis syndrome (TDS) and testicular neoplasia: Evidence from 20 adult patients with signs of maldevelopment of the testis
Authors: SKAKKEBæK NIELS E. , HOLM METTE , HOEI‐HANSEN CHRISTINA , JØRGENSEN NIELS , RAJPERT‐DE MEYTS EWA
Published: May 2003

Based on a well established association between testicular cancer and undescended testis and more recent publications on epidemiological links between these disorders and male infertility, we proposed the existence of a testicular dysgenesis syndrome (TDS). In most cases TDS presents with impaired spermatogenesis, only in rare cases the full range of its signs, including genital malformations and testicular cancer can be seen in one patient. In order to further corroborate our hypothesis about the presence of testicular dysgenesis in patients with testicular abnormalities, we decided to re‐analyse recent testicular biopsies derived from patients with infertility, hypospadias and undescended testis. We searched for histological signs of testicular dysgenesis: microliths, Sertoli‐cell‐only tubules, immature seminiferous tubules with undifferentiated Sertoli cells, and tubules containing carcinoma in situ (CIS) cells. We identified 20 patients who fulfilled the histological criteria for testicular dysgenesis, 9 of whom were diagnosed with uni‐ or bilateral testicular germ cell neoplasia, and the remaining ones with subfertility. The presence of CIS was detected in 5 patients (3 of them with overt contralateral germ cell tumours). In all but one of the CIS cases, at least one additional sign of testicular dysgenesis was detected. Clinical records of all patients were subsequently analysed. The majority of cases had oligozoospermia or azoospermia. Their reproductive hormone profiles correlated with the results of semen sampling and testicular histology. In conclusion, our study of 20 patients with various reproductive abnormalities provided evidence that TDS is a real clinical entity. We speculate that most of these abnormalities are caused by adverse environmental effects rather than specific gene mutations.
Multinucleated spermatogonia in cryptorchid boys: A possible association with an increased risk of testicular malignancy later in life?
Authors: CORTES DINA , THORUP JØRGEN , VISFELDT JAKOB
Published: May 2003

At birth, undescended testes contain germ cells, but after 1 year of life, a reduced number of germ cells is generally found. Microlithiasis and carcinoma‐in‐situ‐testis occur in cryptorchid boys. Multinucleated germ cells, including at least 3 nuclei in the cell, exist in impaired spermatogenesis and in the senescent testis. Aim of the study. We investigated whether multinucleated spermatogonia were present in undescended testes of cryptorchid boys, and if such a pattern is associated with special clinical features. Results. Multinucleated spermatogonia occurred in 13/168 (8%) of 163 consecutive cryptorchid boys, who underwent surgery for cryptorchidism with simultaneous testicular biopsy showing seminiferous tubules. The patients with multinucleated spermatogonia more often exhibited a normal germ cell number (Fisher's exact test, p<0.0005), and were younger at surgery (Mann Whitney, p<0.005) than the rest of the patients. Before surgery, 3 patients underwent treatment with Erythropoietin because of renal failure. An intra‐abdominal testis underwent clipping and division of the spermatic vessels, and a biopsy at final surgery 7 months later, exhibited multinucleated spermatogonia. In 1 case the undescended testicular position, a fixed retraction, was acquired after surgery for an inguinal hernia. Multinucleated spermatogonia were found in cases of carcinoma‐in situ‐testis in 2 cryptorchid boys. No case of multinucleated germ cells appeared in our normal material. Conclusion. Multinucleated spermatogonia are a further abnormality present in cryptorchidism. The cryptorchid boys with multinucleated spermatogonia in general exhibited rather many germ cells. This feature may be associated with an increased risk of testicular malignancy later in life, and we propose a careful follow up regime in these cases including ultrasound examination and a testicular biopsy in cases of symptoms or clinical findings.
Epidemiology of gonadal germ cell cancer in males and females
Authors: MØLLER HENRIK , EVANS HELEN
Published: May 2003

The epidemiology of testicular germ cell cancer is relatively well understood, but less is known about the epidemiology of ovarian germ cell cancer. Cases of testicular (7910) and ovarian (453) germ cell cancer diagnosed 1960–1999 were extracted from the Thames Cancer Registry. The incidence rate in males doubled in the period from 2.0 to 4.4 per 100,000. In females the rate was much lower but the rate of increase over the period was similar to the increase in males. In both sexes the incidence increased sharply around the age of onset of puberty and decreased in older age groups. The biological mechanism of initiation of germ cell carcinogenesis is similar in males and females and probably occurs with roughly the same frequency in the two sexes. In males, the initiated cell population is promoted by the normal action of adult sex hormones to form carcinoma in situ, consisting of many millions of cells. The incidence of testicular cancer is rate limited by the development of carcinoma in situ. The key difference between males and females, which may explain the different levels of incidence, is the much lower number of susceptible cells in females at the time of puberty.
Extragonadal germ cell tumors: relation to testicular neoplasia and management options
Authors: BOKEMEYER CARSTEN , HARTMANN JÖRG T. , FOSSA SOPHIE D. , DROZ JEAN‐P. , SCHMOL HANS‐J. , HORWICH ALAN , GERL ARTHUR , BEYER JÖRG , PONT JÖRG , KANZ LOTHAR , NICHOLS CRAIG R. , EINHORN LAWRENCE
Published: May 2003

An unselected population of 635 consecutive extragonadal GCT patients (EGCT) treated between 1975 through 1996 at 11 cancer centers was retrospectively evaluated for clinical prognosis and biological features of this disease. Five hundred twenty‐four patients (83%) had a nonseminomatous GCT, and 104 patients (16%) a seminomatous histology; 341 (54%) patients had a primary mediastinal EGCT, and 283 patients (45%) a retroperitoneal EGCT. Following platinum based induction chemotherapy±secondary surgery, 141 patients (49%) with mediastinal nonseminomas (median follow up period: 19 months) and 144 patients (63%) with retroperitoneal nonseminoma (median follow up period: 29 months) are alive [p=0.0006]. In contrast, the overall survival rate for patients with seminomatous EGCT is 88% with no difference between patients with mediastinal or retroperitoneal tumor location (median follow up period: 49 months). Multivariate analysis revealed nonseminomatous histology, the presence of non‐pulmonary visceral metastases, primary mediastinal GCT location, and elevated β‐HCG as independent prognostic factors for shorter survival. Sixteen patients (4.1%) developed a metachronous testicular cancer despite the use of platinum based chemotherapy. The cumulative risk of developing a MTC 10‐years after a diagnosis of EGCT was 10.3% (95% CI=4.9 to 15.6%), but higher among patients with nonseminomatous EGCT (14.3%; 95% CI=6.7 to 21.9%) or retroperitoneal EGCT location (14.2%; 95% CI=5.6 to 22.8%) than among patients with seminomatous EGCT (1.4%; 95% CI=0.0 to 4.2) or mediastinal EGCT location (6.2%; 95% CI=0.1 to 12.2). After a median follow‐up of 51 months (range=1 to 154 months), all 16 MTC patients were alive without disease. Patients with pure seminomatous EGCT histology have a long term chance of cure of almost 90% irrespective of the primary tumor site. Patients with mediastinal nonseminomas have a five‐years survival rate of 45%. This outcome is clearly inferior compared to patients with nonseminomatous retroperitoneal primaries who have a five‐year survival rate of 62%.
Diagnosis and management of testicular intraepithelial neoplasia (carcinoma in situ) – surgical aspects
Authors: DIECKMANN KLAUS‐PETER , CLASSEN JOHANNES , LOY VOLKER
Published: May 2003

Germ cell tumours (CT) are no true carcinomas; therefore the term testicular intraepithelial neoplasia (IN) is probably more appropriate than “CIS”. The diagnostic accuracy of a single‐site biopsy is an open question. We experienced 9 false‐negative biopsies among 1859 cases. Thus, the proportion of a failed diagnosis is 0.5%. The main reason for diagnostic failure is the non‐random distribution of TIN within the testicle. Currently we are investigating whether a two‐site biopsy is more accurate than a single biopsy. In the ongoing trial, the over‐all prevalence of TIN is around 5.3%, so far. In one quarter of the positive cases the lesion was found in only one of the two specimens. Thus, a double biopsy appears to be more favourable than the traditional single biopsy. Surgical complications amount to 2.5% in that double biopsy study. Only one surgical re‐intervention was required among 983 patients. Serial imaging studies with scrotal sonography and magnetic resonance imaging (MRI) disclosed a transient intratesticular haematoma/oedema postoperatively. So, testicular biopsy, even when performed at two sites is in fact a low‐complication procedure. Low dose radiotherapy to the testis is the treatment of choice for TIN. However, more than one quarter of patients require testosterone supplementation secondary to androgen‐deficiency. Two dose‐reduction studies (Denmark and Germany) had to be terminated prematurely because unexpected relapse of TIN was encountered at 14 Gy and 16 Gy. Possibly, hyperfragmentation schedules can overcome the antagonism of androgenic compromise and oncological safety. In a nation‐wide survey, it was shown that contralateral biopsies were routinely performed in 66% of the urological departments in Germany. Another 19% offered the biopsy to particular “risk‐cases”; only 15% never did a biopsy. Among those refusing biopsies, there was a higher proportion of small hospitals and a significantly lower annual case‐number of GCT, when compared to those doing the biopsy. Thus, the contralateral biopsy is a well‐established procedure among German urologists; those with a high caseload of GCT particularly appreciate it.
Update on the diagnostic safety for detection of testicular intraepithelial neoplasia (TIN)
Authors: KLIESCH SABINE , THOMAIDIS THOMAS , SCHÜTTE BÄRBEL , PÜHSE GERALD , KATER BERND , ROTH STEFAN , BERGMANN MARTIN
Published: May 2003

Testicular intraepithelial neoplasia (TIN) of the testis is the noninvasive precursor of testicular germ cell tumours (GCT) and can be detected by a single random biopsy in 5% of patients with GCT in the contralateral testes. Although it is generally presumed that TIN is dispersed throughout the testis, we realize in about 60% of TIN bearing tissue close to testis tumours that its distribution is not homogenously diffuse, but may be focal. Thus we tested whether we can improve diagnostic safety in detecting TIN by increasing the number of biopsies. We could finally evaluate 295 men with proven testicular tumours. Three biopsies of contralateral testes were taken (each 5 mm length) from one surgical incision site and fixed in Bouin's solution or glutaraldehyde. TIN cells were histologically identified by their typical morphological characteristics and additionally by placental alkaline phophatase (PlAP) immunohistochemistry. Patients revealed testicular tumour without contralateral TIN in 271 cases and with contralateral TIN in 24 cases (8.1%). In 6 of these 24 men with contralateral TIN the cells could be detected in only one (n=5) or two (n=1) of the three specimen investigated. That means in these six patients TIN could have been missed if only one single random biopsy was taken. By increasing the number of biopsies (=increasing the number of investigated seminiferous tubules) the detection rate of contralateral TIN may be increased up to 8.1%. Thus we recommend multiple testicular biopsies to increase the diagnostic safety in detection of TIN. Biopsies may be taken from one randomly chosen surgical incision site.
Surveillance in stage I testicular cancer
Authors: DAUGAARD GEDSKE , PETERSEN PETER MEIDAHL , RØRTH MIKAEL
Published: May 2003

Treatment results on 695 stage I testicular cancer patients followed with surveillance are described. Seminoma (SGCT) was present in 394 patients and nonseminoma (NSGCT) in 301 patients. Relapses were detected in 155 patients (22%), in 69 patients with SGCT (17%) and 86 with NSGCT (29%). In patients with vascular invasion, relapse was detected in 54% of patients with NSGCT and 38% of patients with SGCT. Time to relapse was median 13 months (range 1 to 84 months) for SGCT and 5 months (range 1 to 171 months) for NSGCT. Forty‐nine percent of relapses in SGCT patients were seen within the first year, 87% of the relapses were diagnosed within the first two years, and 98% of the relapses were detected within 5 years. The figures for NSGCT were 80%, 89% and 95%, respectively. Forty‐five patients had carcinoma in situ in the contralateral testis, 62% had this together with a seminoma in the other testis. Ten patients died during the follow‐up period. None of these deaths were caused by the germ cell tumour or the treatment. The overall survival for patients with stage I disease is 98.6%, and the cause specific survival 100%.
Testis conserving chemotherapy in germ cell cancer: its potential to increase understanding of the biology and treatment of carcinoma‐in‐situ
Authors: OLIVER R. T. D. , ONG J. , BERNEY D. , NARGUND V. , BADENOCH D. , SHAMASH J.
Published: May 2003

Prompted by recognition of the potential of chemotherapy to increase the success of testis conserving surgery in patients with germ cell cancer, background and outcome data are reviewed and their contribution to the ongoing debate about how germ cell cancer develops discussed. The review is based on three previous studies of: a) time trends in tumour size in 578 personal series of all stages of testis cancer treated since 1978; b) impact of chemotherapy on actuarial risk of tumours in contralateral testis examined on 1221 patients treated in trials through the Anglian Germ Cell Cancer Consortium; and c) testes conservation attempted using chemotherapy in 78 patients. Since 1978 tumour size has decreased from 4.8 to 3.0 cms while cure has gone from 77 to 97%. There was no overall long term reduction in second cancers beyond 10 years in stage 1 patients after orchidectomy alone compared to stage 1 or metastatic disease patients receiving chemotherapy though the incidence was non significantly lower up to 10 years particularly in those patients receiving etoposide based combination. Testis conservation was initially successful in 28 of 78 (36%). An additional 25 (32%) had no viable cancer in orchidectomy specimen. In the 28 primary tumours cured by chemotherapy there was a 26% late relapse rate between 5 and 10 years (all cured by orchidectomy) compared to less than 5% in those cured with established metastases. In conclusion, testis conservation with chemotherapy is safe and feasible, though relapse is too frequent for routine service use. Confirmation of the high frequency of late relapse by others has raised the question whether these recurrences are due to post pubertal events reinducing CIS in intrauterine oestrogen primed germ cells and highlights the potential of testes conservation studies to better understand germ cell cancer development.
Endocrine function in patients treated for carcinoma in situ in the testis with irradiation
Authors: PETERSEN PETER MEIDAHL , DAUGAARD GEDSKE , RØRTH MIKAEL , SKAKKEBæK NIELS E.
Published: May 2003

CIS is found in the contralateral testis in 5% of the patients with testicular germ cell cancer. The management of CIS in the contralateral testis is important because the majority – if not all – cases of CIS will progress to invasive disease without treatment. It is well documented that testicular irradiation with a total dose of 14–20 Gy (2 Gy×7–10) is an effective and safe treatment for CIS in the contralateral testis in patients with unilateral testicular germ cell cancer. However few relapses of testicular cancer have been observed in testis treated with these regimens and the data on 14 Gy are sparse. One study has indicated that more radiotherapy with lower doses per fraction could be useful, but more data are needed to confirm this. Endocrine testicular function has been shown to be impaired already before treatment in patients with CIS and is further impaired after testicular irradiation with 14–20 Gy (2 Gy×7–10) and only minor dose dependency is seen in the impairment of Leydig cell function. The optimal treatment of CIS in the contralateral testicle in patients orchidectomised for testicular cancer seems to be local radiotherapy of the testis with CIS in order to preserve at least a part of the Leydig cell function. However, the optimal dose level has to be defined.
A new prognostic model for testicular germ cell tumours
Authors: VON EYBEN FINN EDLER , MADSEN EBBE LINDEGAARD , FRITSCHE HERBERT , SUCIU GABRIEL , LIU FRANK , AMATO ROBERT
Published: May 2003

In univariate analyses of patients with metastatic testicular germ cell tumours (TGCT), both the International Germ Cell Consensus Classification (IGCCC) and serum lactate dehydrogenase (S‐LD) isoenzyme 1 catalytic concentration (S‐LD‐1) significantly predicted survival. In complementary analyses of 81 patients with metastatic TGCT, S‐LD and S‐LD‐1 classified the prognosis differently for 23 patients. In multivariate Cox hazard analyses of risk factors, only IGCCC and S‐LD‐1 predicted the prognosis (p=0.036, and p=0.0007, respectively). A new prognostic model based on prognostic information from main histology, IGCCC, and S‐LD‐1 changed the prognostic prediction by IGCCC for 19 patients (24%). Judged by to the area under the curve for receiver operation characteristics curves, the new model predicted five‐years survival for the patients better than IGCCC and a modified version of the third edition of the TNM classification (p=0.025, and p=0.01, respectively). However, new studies should validate the new model before it is recommended as a general classification system of patients with metastatic TGCT.
Y chromosome haplogroups: A correlation with testicular dysgenesis syndrome?
Authors: McELREAVEY KEN , QUINTANA‐MURCI LLUIS
Published: May 2003

Testicular dysgenesis syndrome encompasses low sperm quality, hypospadias, cryptorchidism and testicular cancer. Epidemiological studies and genetic data from familial cases suggest that testicular dysgenesis syndrome has a common etiology. The Y chromosome is known to encode genes that are involved in germ cell development or maintenance. We have therefore investigated if different classes of Y chromosomes in the general population (Y chromosome haplogroups) are associated with aspects of the testicular dysgenesis syndrome. We defined the Y chromosome haplogroups in individuals from different European counties who presented with either (i) oligo‐ or azoospermia associated with a Y chromosome microdeletion, (ii) unexplained reduced sperm counts (<20×106/ml) or (iii) testicular cancer. We failed to find Y chromosome haplotype associations with either microdeletion formation or testicular cancer. However, in a study of the Danish population, we found that a specific Y chromosome haplogroup (hg26) is significantly overrepresented in men with unexplained reduced sperm counts compared with a Danish control population. The factors encoded by genes on this class of Y chromosome may be particularly susceptible to environmental influences that cause testicular dysgenesis syndrome. Our current data highlight the need for further analyses of clinically well‐defined patient groups from a wide range of ethnic and geographic origins.
Polymorphic DAZ gene family in polymorphic structure of AZFc locus: Artwork or functional for human spermatogenesis?
Authors: VOGT PETER H. , FERNANDES SUSANA
Published: May 2003

Human spermatogenesis is regulated by a network of genes located on autosomes and on sex chromosomes, but especially on the Y chromosome. Most results concerning the germ cell function of the Y genes were obtained by genomic breakpoint mapping studies of the Y chromosome of infertile patients. Although this approach has the benefit of focussing on those Y regions that contain most likely the Y genes of functional importance, its major drawback is the fact that fertile control samples were often missing. In fertile men, molecular and cytogenetic analyses of the Y chromosome has revealed highly polymorphic chromatin domains especially in the distal euchromatic part (Yq11.23) and in the heterochromatic part (Yq12) of the long arm. In sterile patients cytogenetic analyses mapped microscopically visible Y deletions and rearrangements in the same polymorphic Y regions. The presence of a Y chromosomal spermatogenesis locus was postulated to be located in Yq11.23 and designated as AZoospermia Factor (ZF). More recently, molecular deletion mapping in Yq11 has revealed a series of microdeletions that could be mapped to one of three different AZF loci: AZFa in proximal Yq11 (Yq11.21), AZFb and AZFc in two non‐overlapping Y‐regions in distal Yq11 (Yq11.23). This view was supported by the observation that AZFa and AZFb microdeletions were associated with a specific pathology in the patients' testis tissue. Only AZFc deletions were associated with a variable testicular pathology and in rare cases AZFc deletions were even found inherited from father to son. However, AZFc deletions were found with a frequency of 10–20% only in infertile men and most of them were proved to be “de novo”, i.e. the AZFc deletion was restricted to the patient's Y chromosome. Based mainly on positional cloning experiments of testis cDNA clones and on the Y chromosomal sequence now published in GenBank, a first blueprint for the putative gene content of the AZFc locus can now be given and the gene location compared to the polymorphic DNA domains. This artwork of repetitive sequence blocks called AZFc amplicons raised the question whether the AZFc chromatin is still part of the heterochromatic domain of the Y long arm well known for its polymorphic extensions or is decondensed and part of the Yq11.23 euchromatin? We discuss also the polymorphic DAZ gene family and disclose putative origins of its molecular heterogeneity in fertile and infertile men recently identified by the analyses of Single Nucleotide Variants (SNVs) in this AZFc gene locus.
The testicular germ cell tumour genome
Authors: SKOTHEIM ROLF I. , LOTHE RAGNHILD A.
Published: May 2003

Human testicular germ cell tumour (TGCT) of adolescents and young adults develop from precursor lesions called carcinoma in situ (CIS), which is believed to originate from diploid primordial germ cells during foetal life. CIS is initiated by an aneuploidisation event accompanied by extensive chromosome instability. The further transformation of CIS into invasive TGCT (seminomas and nonseminomas) is associated with increased copy number of chromosome arm 12p, most often seen as isochromosome 12p. Despite the morphological distinctions between seminomatous and nonseminomatous TGCTs, they have many of the same regional genomic disruptions, although frequencies may vary. However, the two histological subtypes have quite distinct epigenomes, which is further evident from their different gene expression patterns. CIS develops from cells with erased parental imprinting, and the seminoma genome is under‐methylated compared to that of the nonseminoma genome. High throughput microarray technologies have already pinpointed several genes important to TGCT, and will further unravel secrets of how specific genes and pathways are regulated and deregulated throughout the different stages of TGCT tumourigenesis. In addition to acquiring new insights into the molecular mechanisms of TGCT development, understanding the TGCT genome will also provide clues to the genetics of human embryonic development and of chemotherapy response, as TGCT is a good model system to both.
Germ cell tumours in neonates and infants: a distinct subgroup?
Authors: VELTMAN IMKE M. , SCHEPENS MARGA T. , LOOIJENGA LEENDERT H. J. , STRONG LOUISE C. , VAN KESSEL AD GEURTS
Published: May 2003

Human germ cell tumours (GCTs) constitute a heterogeneous group of tumours that can be classified into four major subgroups. One of these subgroups encompasses (immature) teratomas and yolk sac tumours of patients under the age of 5 years. In this paper we review the various clinical, histological and cytogenetical aspects of these infantile GCTs. The primordial germ cell (PGC) has been suggested to be the cell of origin for GCTs. Infantile GCTs, however, have been suggested to originate from PGCs at a different stage of maturation than adult GCTs. The cytogenetic constitution of infantile GCTs also appears to differ from the adult GCTs and includes recurrent losses of 1p and 6q. Recently, two cases of infantile GCT were detected with constitutional 12q13 translocations. These exceptional cases may be instrumental in the search for candidate genes related to infantile and/or adult GCT development.
Role of gain of 12p in germ cell tumour development
Authors: LOOIJENGA LEENDERT H. J. , ZAFARANA GAETANO , GRYGALEWICZ BEATA , SUMMERSGILL BRENDA , DEBIEC‐RYCHTER MARIA , VELTMAN JORIS , SCHOENMAKERS ERIC F. P. M. , RODRIGUEZ SANDRINE , JAFER OSMAN , CLARK JEREMY , VAN KESSEL AD GEURTS , SHIPLEY JANET , VAN GURP RUUD J. H. L. M. , GILLIS AD J. M. , OOSTERHUIS J. WOLTER
Published: May 2003

Within the human testis, three entities of germ cell tumours are distinguished: the teratomas and yolk sac tumors of newborn and infants, the seminomas and nonseminomas of adolescents and young adults, referred to as testicular germ cell tumours (TGCT), and the spermatocytic seminomas. Characteristic chromosomal anomalies have been reported for each group, supporting their distinct pathogenesis. TGCT are the most common cancer in young adult men. The initiating pathogenetic event of these tumours occurs during embryonal development, affecting a primordial germ cell or gonocyte. Despite this intra‐uterine initiation, the tumour will only be clinically manifest after puberty, with carcinoma in situ (IS) as the precursor. All invasive TGCT, both seminomas and nonseminomas, as well as CIS cells are aneuploid. The only consistent (structural) chromosomal abnormalities in invasive TGCT are gains of the short arm of chromosome 12, mostly due to isochromosome (i(12p)) formation. This suggests that an increase in copy number of a gene(s) on 12p is associated with the development of a clinically manifest TGCT. Despite the numerous (positional) candidate gene approaches that have been undertaken thus far, identification of a causative gene(s) has been hampered by the fact that most 12p gains involve rather large genomic intervals, containing unmanageable numbers of candidate genes. Several years ago, we initiated a search for 12p candidate genes using TGCT with a restricted 12p‐amplification, cytogenetically identified as 12p11.2–p12.1. This approach is mainly based on identification of candidate genes mapped within the shortest region of overlap of amplification (SROA). In this review, data will be presented, which support the model that gain of 12p‐sequences is associated with suppression of apoptosis and Sertoli cell‐independence of CIS cells. So far, DAD‐R is one of the most likely candidate genes involved in this process, possibly via N‐glycosylation. Preliminary results on high through‐put DNA‐ and cDNA array analyses of 12p‐sequences will be presented.
Genetic control of susceptibility to spontaneous testicular germ cell tumors in mice
Authors: LAM MAN‐YEE JOSEPHINE , NADEAU JOSEPH H.
Published: May 2003

Testicular germ cell tumors (TGCTs) are the most common cancer affecting young men. TGCT is a polygenic trait and genes that control susceptibility for TGCT development have not yet been identified. The 129/Sv inbred strain of mice is an important experimental model to study the genetics and development of TGCTs. We review several novel approaches that were developed to study the susceptibility of TGCTs in the 129/Sv mouse model and its application in humans. These approaches showed that several spontaneous and engineered mutations interact with 129/Sv‐derived susceptibility genes to enhance or suppress susceptibility; two of these mutations (Ter and Trp53) revealed novel linkages for susceptibility genes in sensitized polygenic trait analysis. Linkage analysis with a chromosome substitution strains suggests that as many as 100 genes control susceptibility. Bilateral TGCTs result from the coincidental occurrence of unilateral tumors. These results highlight the important contributions that this mouse model can make to studies of TGCT susceptibility in humans.
GDNF‐induced seminomatous tumours in mouse – an experimental model for human seminomas?
Authors: SARIOLA HANNU , MENG XIAOJUAN
Published: May 2003

Glial‐cell‐line‐derived neurotrophic factor (GDNF) is a distant member of the transforming growth factor superfamily. It binds to and activates a receptor complex consisting of GFR‐α1 and Ret receptor tyrosine kinase. In testis, GDNF is expressed by Sertoli cells. We have shown by transgenic loss‐ and gain‐of‐function mouse models that GDNF regulates the cell fate decision of undifferentiated spermatogonia. In the GDNF +/− mice, the spermatogonia differentiate in excess leading to the depletion of germ cells. In the mice overexpressing GDNF in testes, undifferentiated spermatogonia accumulate in the tubules, no sperm is produced, and the mice are infertile. After a year, the GDNF overexpressing mice frequently (89%) develop testicular tumours, and most of them are bilateral (56%). All these tumours show the same histological pattern. They are composed of round spermatogonial/gonocytic cells with only a scant cytoplasm. The tumours are locally invasive but do not metastasise. They express germ line markers, are positive for alkaline phosphatase, and aneuploid with a triploid peak. Thus, by several histological, molecular, and histochemical characteristics, the GDNF‐induced tumours mimic classical seminomas in men, but the precursor lesions are apparently different in mouse and man.
Growth regulatory factors and signalling proteins in testicular germ cell tumours
Authors: DEVOUASSOUX‐SHISHEBORAN MOJGAN , MAUDUIT CLAIRE , TABONE ERIC , DROZ JEAN PIERRE , BENAHMED MOHAMED
Published: May 2003

The molecular basis of testicular germ cell tumourigenesis are not well elucidated. Growth factors regulate cell growth, differentiation and apoptosis. Major families of growth factors are present in the male gonad from early fetal development to adult life. They are involved in germ cell proliferation and differentiation. Growth signalling pathways suffer deregulation in many human malignancies. Given the importance of growth signals in normal testicular development and their acquired deregulation in most human cancers, growth factors and signalling molecules that have been implicated in the genesis of testicular germ cell tumours, are reviewed. We detected a somatic mutation of SMAD4 gene, responsible for loss of protein function in seminomas. This mutational inactivation may affect the activity of several members of TGFβ superfamily (TGFβ, activin, inhibin, BMP). VEGF expression has been shown to predict metastasis in seminomas. A significant association of HST‐1 expression, a member of fibroblast growth factors, with the nonseminomatous phenotype and with tumour stage has been described. In contrast, C‐KIT is expressed by seminomas only, from the preinvasive stage. Despite intense expression in almost all seminomas, activating mutation of C‐KIT gene is seldom reported. Recently, the first animal model of classical testicular seminoma has been identified in transgenic mouse overexpressing GDNF. RET (GDNF receptor) expression is demonstrated in human seminomas, and not in nonseminomatous tumours. However, the exact molecular alterations of GDNF/RET/GFRα1 complex in germ cell tumours are not known. Finally, beside growth factors, other signalling molecules such as peptide hormones may be involved in testicular carcinogenesis. We have demonstrated a specific pattern of somatostatin receptors expression in each type of testicular germ cell tumours, with a loss of sst3 and sst4 in seminomas and loss of sst4 and expression of sst1 in nonseminomas only. These data suggest an antiproliferative action of somatostatin in testicular cancers. In summary, many growth factors and signalling molecules seem to represent specific markers for different histological types of germ cell tumours (seminomas versus nonseminomas) and may play a role in the differentiation of germ cell tumours. Despite a complex signalling pathway involved in the physiological functions of male gonad, little is known about the implication of this signalling network in testicular malignancies. From a practical stand‐point, further studies on the role of growth factors in human germ cell tumours may offer a new therapeutical perspective with the development of specific pharmacological signalling modulators that could be used as therapeutic agents.
Human tissue kallikreins and testicular cancer
Authors: LUOS LIU‐YING , YOUSEF GEORGE , DIAMANDIS ELEFTHERIOS P.
Published: May 2003

Human tissue kallikreins are fifteen homologous genes encoding for secreted serine proteases and residing tandemly on chromosome 19q13.4. These enzymes are highly expressed in a variety of tissues and participate in diverse physiological processes. Human tissue kallikreins were found to be associated with several malignancies, especially endocrine‐related cancers, including prostate, ovarian, breast and testicular cancer. In testicular germ cell tumors, some tissue kallikrein genes, including KLK5, KLK10, KLK13 and KLK14, were found to be significantly down‐regulated. Tissue‐specific splice variant forms of some kallikreins have been identified in the testis. In this paper, the expression of KLK5, KLK10, KLK13 and KLK14 in testicular cancer and their possible roles during testicular cancer development, as well as their clinical applications are briefly reviewed.
Angiotensin I‐converting enzyme and potential substrates in human testis and testicular tumours
Authors: FRANKE FOLKER E. , PAULS KATHARINA , METZGER ROMAN , DANILOV SERGEI M.
Published: May 2003

The angiotensin I‐converting enzyme (ACE, kininase II, CD143) shows a broad specificity for various oligopeptides. Besides the well‐known conversion of angiotensin I to II, ACE degrades efficiently kinins and the tetrapeptide AcSDKP (goralatide) and thus equally participates in the renin‐angiotensin system, the kallikrein‐kinin system, and the regulation of stem cell proliferation. In the mammalian testis, ACE occurs in two isoforms. The testicular isoform (tACE) is exclusively expressed during spermatogenesis and is generally thought to represent the germ cell‐specific isozyme. However, we have previously demonstrated that, in addition to tACE, the somatic isoform (sACE) is also present in human germ cells. Similar to other oncofoetal markers, sACE exhibits a transient expression during foetal germ cell development and appears to be a constant feature of intratubular germ cell neoplasm, the so‐called carcinoma‐in‐situ (CIS) and, in particular, of classic seminoma. This demands the existence of specific paracrine functions during male germ cell differentiation and development of male germ cell tumours, which are mediated by either of the two ACE isoforms. Considering the complexity of current data about ACE, a logical connection is required between () the precise localisation of ACE isoforms, (I) the local access to potential substrates and (II) functional data obtained by knockout mice models. The present article summarises the current knowledge about ACE and its potential substrates with special emphasis on the differentiation‐restricted ACE expression during human spermatogenesis and prespermatogenesis, the latter being closely linked to the pathogenesis of human germ cell tumours.