PubMed Health⌕ Search

Biomedical subjects

L Bassas

Publications and source records attributed to L Bassas.

At least 19 recordsLinked to original sources
PubMed2005

Molecular evaluation of CFTR sequence variants in male infertility of testicular origin.

Although the involvement of the CFTR gene has been well established in congenital agenesia of vas deferens, its role in non-obstructive (NOb) infertility is still a matter of debate. In order to definitively define the involvement of the CFTR gene in spermatogenic impairment and a potential synergistic contribution to known genetic and clinical factors, genetic variants in the entire coding sequence and the immediately flanking regions of the CFTR gene, along with a thorough clinical evaluation, were analysed in 83 NOb infertile patients and 87 clinically well-defined fertile individuals as controls. The results of our study showed no statistical difference between CFTR carrier frequency in the infertile and fertile population. Specifically, the IVS8-6(5T) allele carrier frequency was similar in NOb infertile patients when compared with fertile men, but it is noteworthy that, when fertile men were classified into having optimal and suboptimal fertility, no 5T allele was found among the 35 men with optimal fertility parameters. In conclusion, extensive CFTR analysis in infertile individuals and fertile population as adequate control definitively excludes the involvement of the CFTR gene variants in sperm production and stresses the importance of carefully identifying those individuals with obstructive defects, in whom CFTR screening will be beneficial.

Base Sequence↗
PubMed2003

Cyclamate intake and cyclohexylamine excretion are not related to male fertility in humans.

Cyclamate and its metabolite cyclohexylamine affect male fertility in high dose animal studies, but this affect has not been investigated in epidemiological studies. This paper reports the first epidemiological study designed to investigate the possibility of a relationship between cyclamate and cyclohexylamine and male fertility in humans, in which 405 cases of clinically defined infertility in men and 379 controls were surveyed. Semen evaluation, urine analysis for cyclamate and cyclohexylamine and dietary questionnaires were compared between cases and controls. No evidence was found of a significant association between cyclamate intake and male infertility; neither high cyclamate nor high cyclohexylamine excretion were associated with elevated risk. The lack of association remained after adjusting by age, area of residence, education, total energy intake and other variables. No significant correlations were observed between cyclamate intake, metabolism or excretion, and sperm count and motility. The results demonstrate no effect of cyclamate or cyclohexylamine on male fertility at the present levels of cyclamate consumption.

Adult↗
PubMed2001

Adenosine triphosphate-binding cassette superfamily transporter gene expression in severe male infertility.

Cystic fibrosis transmembrane regulator (CFTR), multidrug-resistant (MDR)1, and multidrug resistance-associated (MRP) proteins belong to the ATP-binding cassette (ABC) transporter superfamily. A compensatory regulation of MDR1 and CFTR gene expression has been observed in CFTR knockout rodent intestine and in an epithelial cell line of human colon, whereas a high homology and similar anion binding site are shared by MRP and CFTR proteins. To provide better insight into the relationship among the expression behavior in vivo of the three genes in human testis, analysis of MDR1 and MRP gene expression in testicular biopsies was performed and related to the presence of CFTR gene mutations in congenital absence of the vas deferens (CAVD: n = 20) and non-CAVD (n = 30) infertile patients with azoospermia or severe oligozoospermia. A CFTR mutation analysis performed in both groups of patients supported the involvement of CFTR gene mutations in CAVD phenotype (85%) and in defective spermatogenesis (19%). Quantitative reverse transcription-polymerase chain reaction analysis of testicular tissue showed a CFTR-independent MDR1 and MRP gene expression in human testis, suggesting that the mechanisms underlying CFTR gene regulation in testis are different from those in intestine. These findings should contribute to the understanding of patterns of in vivo expression of CFTR, MDR1, and MRP genes in CFTR-related infertility.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

[Response to intracavernous administration of 3 different drugs in the same group of patients with erectile dysfunction].

OBJECTIVE: To compare the subjective and objective penile rigidity in the same group of patients with erectile dysfunction after intracavernous injection of different vasoactive drugs. METHODS: 91 impotent males were randomly assigned to three groups of intracavernous injection: A: 20 micrograms PGE1 B: 30 mg papaverine hydrochloride + 1 mg phentolamine (bimix), and C: 10 micrograms PGE1 + 15 mg papaverine hydrochloride + 0.5 mg phentolamine (trimix). Each patient was scheduled to receive the three modalities of intracavernous injection randomly with an interval of 7-10 days between injections. Penile rigidity equal to or more than 60% was considered positive. Subjective and objective penile rigidity were evaluated with callipers by the same observer. RESULTS: 82 patients completed the study and 9 dropped out after prolonged erection with one of the ICI modalities. Rigidity after treatment with C (66 +/- 15%) was significantly superior to that of B (59 +/- 15%, p = 0.0001) and A (60 +/- 13%, p = 0.0115). No differences were observed between A and B (p = 0.4644). Analysis of only the positive response showed significant differences between A and C, but not between C and B (p = 0.3323). Differences were not found between the response to PGE1 (A) and bimix (B) (p = 0.1275). The order of application of the drug had no effect on response (p = 0.026). CONCLUSIONS: A higher percentage of positive response in patients with erectile dysfunction was achieved with the trimix modality. Choice of more potent ICI regimens can improve the diagnostic and/or therapeutic efficacy in males that do not respond to PGE1 alone.

Adrenergic alpha-Antagonists↗
PubMed2000

Heterogeneity for mutations in the CFTR gene and clinical correlations in patients with congenital absence of the vas deferens.

Congenital absence of the vas deferens (CAVD) is a heterogeneous disorder, largely due to mutations in the cystic fibrosis (CFTR) gene. Patients with unilateral absence of the vas deferens (CUAVD) and patients with CAVD in association with renal agenesis appear to have a different aetiology to those with isolated CAVD. We have studied 134 Spanish CAVD patients [110 congenital bilateral absence of the vas deferens (CBAVD) and 24 CUAVD], 16 of whom (six CBAVD, 10 CUAVD) had additional renal anomalies. Forty-two different CFTR mutations were identified, seven of them being novel. Some 45% of the CFTR mutations were specific to CAVD, and were not found in patients with cystic fibrosis or in the general Spanish population. CFTR mutations were detected in 85% of CBAVD patients and in 38% of those with CUAVD. Among those patients with renal anomalies, 31% carried one CFTR mutation. Anomalies in seminal vesicles and ejaculatory ducts were common in patients with CAVD. The prevalence of cryptorchidism and inguinal hernia appeared to be increased in CAVD patients, as well as nasal pathology and frequent respiratory infections. This study confirms the molecular heterogeneity of CFTR mutations in CAVD, and emphasizes the importance of an extensive CFTR analysis in these patients. In contrast with previous studies, this report suggests that CFTR might have a role in urogenital anomalies.

Abnormalities, Multiple↗
PubMed1998

Testicular CFTR splice variants in patients with congenital absence of the vas deferens.

The involvement of the five thymidine (5T) variant in intron 8 of the cystic fibrosis membrane regulator (CFTR) gene in congenital bilateral absence of the vas deferens (CBAVD) phenotype has been extensively demonstrated. This variant leads to alternative splicing of the CFTR gene which results in a wild-type transcript and one without exon 9. Little is known about expression of the CFTR gene in the testis. We analysed the level of the aberrantly spliced transcripts in testicular biopsies and correlated it with disease expression. Quantitative RT-PCR analysis in testicular biopsies from control and CBAVD patients showed a correlation between the length of the IVS8-6(T) n tract and the level of alternatively spliced transcripts. Results from histological analysis also suggest an involvement of the alternative transcript in the spermatogenic status of patients, leading to a decreased number of mature sperm forms in the tubule.

Alternative Splicing↗
PubMed1995

Mutations in the cystic fibrosis gene in patients with congenital absence of the vas deferens.

BACKGROUND: Congenital bilateral absence of the vas deferens (CBAVD) is a form of male infertility in which mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been identified. The molecular basis of CBAVD is not completely understood. Although patients with cystic fibrosis have mutations in both copies of the CFTR gene, most patients with CBAVD have mutations in only one copy of the gene. METHODS: To investigate CBAVD at the molecular level, we have characterized the mutations in the CFTR gene in 102 patients with this condition. None had clinical manifestations of cystic fibrosis. We also analyzed a DNA variant (the 5T allele) in a noncoding region of CFTR that causes reduced levels of the normal CFTR protein. Parents of patients with cystic fibrosis, patients with types of infertility other than CBAVD, and normal subjects were studied as controls. RESULTS: Nineteen of the 102 patients with CBAVD had mutations in both copies of the CFTR gene, and none of them had the 5T allele. Fifty-four patients had a mutation in one copy of CFTR, and 34 of them (63 percent) had the 5T allele in the other CFTR gene. In 29 patients no CFTR mutations were found, but 7 of them (24 percent) had the 5T allele. In contrast, the frequency of this allele in the general population was about 5 percent. CONCLUSIONS: Most patients with CBAVD have mutations in the CFTR gene. The combination of the 5T allele in one copy of the CFTR gene with a cystic fibrosis mutation in the other copy is the most common cause of CBAVD: The 5T allele mutation has a wide range of clinical presentations, occurring in patients with CBAVD or moderate forms of cystic fibrosis and in fertile men.

Alleles↗
PubMed1995

Extensive analysis of 40 infertile patients with congenital absence of the vas deferens: in 50% of cases only one CFTR allele could be detected.

Mutations in the cystic fibrosis (CF) conductance transmembrane regulator (CFTR) gene have been detected in patients with CF and in males with infertility attributable to congenital bilateral absence of the vas deferens (CBAVD). Thirty individuals with CBAVD and 10 with congenital unilateral absence of the vas deferens (CUAVD) were analyzed by single-strand conformation analysis and denaturing gradient gel electrophoresis for mutations in most of the CFTR gene. All 40 individuals were pancreatic sufficient, but twenty patients had recurrent or sporadic respiratory infections, asthma/asthmatic bronchitis, and/or rhino-sinusitis. Agenesia or displasia of one or both seminal vesicles was detected in 30 men and other urogenital malformations were present in six subjects. Among the 40 samples, we identified 13 different CFTR mutations, two of which were previously unknown. One new mutation in exon 4 was the deletion of glutamic acid at codon 115 (delta E115). A second new mutation was found in exon 17b, viz., an A --> C substitution at position 3311, changing lysine to threonine at codon 1060 (K1060T). CFTR mutations were detected in 22 out of 30 (73.3%) CBAVD patients and in one out of 10 (10%) CUAVD individuals, showing a significantly lower incidence of CFTR mutations in CBAVD/CUAVD patients (P << 0.0001), compared with that found in the CF patient population. Only three CBAVD patients were found with more than one CFTR mutation (delta F508/L206W, delta F508/R74W + D1270N, R117H/712-1G --> T), highlighting L206W, R74W/D1270N, and R117H as benign CF mutations. Sweat electrolyte values were increased in 76.6% of CBAVD patients, but three individuals without CFTR mutations had normal sweat electrolyte levels (10% of the total CBAVD patients), suggesting that factors other than CFTR mutations are involved in CBAVD. The failure to identify a second mutation in exons and their flanking regions of the CFTR gene suggests that these mutations could be located in introns or in the promoter region of CFTR. Such mutations could result in CFTR levels below the minimum 6%-10% necessary for normal protein function.

Adolescent↗
PubMed1995

Effect of testicular damage induced by cryptorchidism on insulin-like growth factor I receptors in rat Sertoli cells.

The distribution and density of functional insulin-like growth factor I (IGF-I) receptors in cryptorchid and scrotal rat testes and epididymides during gonadal development were studied. Cryptorchidism was induced by unilateral gubernaculectomy in 4-day-old animals, and organs were studied at 15, 30, 60 and 90 days of age. Tissue membranes were assayed for 125I-labelled IGF-I binding. Characterization and specificity of binding sites showed that both normal and contralateral undescended testes and epididymides exhibited typical type 1 IGF receptors. In normal testes, IGF-I receptor density was 20.6 nmol g-1 wet mass at day 15, and decreased to 12.8 nmol g-1 wet mass at adult age (day 90). Cryptorchid testes showed IGF-I receptor concentrations similar to normal testes at day 15 and day 30, but in postpubertal stages displayed a divergent pattern, with a continuous increase at day 60 and day 90, reaching a higher density than those found for immature ages (62 nmol g-1 wet mass). Both normal and cryptorchid epididymides had a similar concentration and a comparable decrease in IGF-I receptors throughout development. In studies with immunohistochemical techniques (alpha IR-3 antibody), IGF-I receptors were found in primary spermatocytes, Sertoli cells and Leydig cells. Cryptorchid tubules showed a lack of germinal epithelium and a marked increase of immunoreactive IGF-I receptors in Sertoli cells, compared with normal tubules from scrotal testes. Intense immunoreactivity for IGF-I receptors was present in the principal cells of epididymal tubules in both normal and cryptorchid organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Critical evaluation of the present experience on microsurgical sperm aspiration.

Microsurgical epididymal sperm aspiration (MESA) and IVF techniques are indicated in those cases of bilateral congenital absence of the vas deferens (BCAVD) and in cases of epididymal obstruction (EO) of other aetiologies were vasoepididymostomy is not possible or has failed. Microsurgical deferential sperm aspiration (MDSA) is indicated in those cases where spermatogenesis and epididymal permeability are conserved but spermatozoa, for different causes, cannot reach the ejaculate and other therapies have failed. We have performed this procedure in 70 patients by two different human reproduction teams. Both teams achieved very similar results regarding fertilization rate: 5.5 and 7.2% in cases of BCAVD, 6.5 and 8.8% in cases of EO and 33.3 and 26.7% in cases of non-epididymal pathology (NEP). However, the fertilization rate per patient presents differences between both teams: 27 and 44.4% in BCAVD, 31 and 11% in EO and 80 and 100% in NEP. In spite of a better fertilization rate per patient in team two, it was in the other where pregnancies were achieved (7% in BCAVD, 15% in EO and 20% in NEP). One pregnancy in EO group was achieved by intracytoplasmatic sperm injection. The pregnancy rates per transfer were 25% in BCAVD, 50% in EO and 25% in NEP.

Epididymis↗
PubMed1993

Complete selective absence of protamine P2 in humans.

Male sterility due to abnormal sperm morphology or motion has been widely reported, although relatively little has been published on the sperm nuclear protein abnormalities. We report the first cases worldwide of infertile patients having a complete selective absence of protamine P2 in the sperm nucleus. This provides a selective phenotype that will aid understanding of the mechanisms of synthesis, processing, or function of the P2 protamines. In addition, it is of marked immediate relevance to medicine as it allows the diagnosis of this type of human male sterility and the opportunity to understand the basis of this defect.

Electrophoresis, Polyacrylamide Gel↗
PubMed1993

Sperm selection by PD-10 sephadex columns: comparison with SpermPrep filtration and Percoll centrifugation.

The efficacy of a disposable, prepacked column (PD-10) containing Sephadex G-25, to select motile spermatozoa, was compared with another column for sperm filtration (SpermPrep) and centrifugation through Percoll gradients. Aliquots of washed sperm suspensions were processed by the three techniques. The number of motile cells and the proportion of total spermatozoa selected was similar for all methods. Recovery of spermatozoa showing optimal movement was 145.9 +/- 30% (mean +/- SEM) with PD-10 columns and 131.9 +/- 32% with Percoll, both significantly higher than SpermPrep (71.9 +/- 11%; P < 0.05). The straight line velocity of motile cells was lower in samples processed by SpermPrep (29.3 +/- 2 microns/S) compared to both PD-10 (34.7 +/- 1 micron/s) and Percoll (34.9 +/- 2 microns/s; P = 0.07). When whole semen was processed, total sperm recovery with PD-10 was 61.7 +/- 8% versus 47.7 +/- 7% with Percoll (P < 0.001). Percoll centrifugation improved the percentage of morphologically normal spermatozoa more than PD-10. Similar proportions of motile spermatozoa and cells with optimal motility were obtained by both methods. We conclude that PD-10 filtration columns can be used to prepare semen in the laboratory as a practical alternative to other methods.

Cell Separation↗
PubMed1992

Insulin receptors and insulin-like growth factor I receptors in embryos from gastrula until organogenesis.

The demonstration of growth factor receptors in very young embryos is limited by the difficulty in obtaining sufficient tissue to yield adequate membrane preparations. We have developed an in situ binding technique that allowed quantitation of [125I]insulin and [125I]insulin-like growth factor-I (IGF-I) binding to individual chick embryos. Specific binding per embryo increased from the youngest stage studied (Hamburger and Hamilton (HH) stages 3-4, gastrulating embryo of approximately 18-20 h) until the third day of development. At all ages, the binding of [125I]IGF-I was several fold higher than the binding of [125I]insulin. Autophosphorylation of the beta-subunit of the receptors was stimulated by insulin and IGF-I in a stage- and dose-dependent manner. The two peptides did not have an additive effect. The present studies further support our previous data showing the early developmental appearance of insulin and IGF-I receptors, which very likely are essential for normal embryo development. In addition, this in situ method for demonstration of receptors can be applied to other types of receptors present in isolated organs and young embryos.

Animals↗
PubMed1991

[Prolonged erections after diagnostic injection of papaverine chlorhydrate].

We analyzed the incidence of prolonged erection (PE) in 495 impotent subjects following intracavernous papaverine chlorhydrate injection to evaluate sexual dysfunction. Patient course was individually assessed. The overall the incidence of PE was 5.05%. The etiology of sexual dysfunction was psychogenic in all cases. No evidence of dose- or age-related PE was observed. Fibrosis of the corpus cavernosum, although more prevalent in PEs greater than 6 hours, was also observed in PEs of a shorter duration. This suggests that a probable predisposing factor might previously be present in some patients. None of the different methods utilized to achieve penile detumescence appears to afford any significant advantage.

Adult↗
PubMed1990

Insulin receptors and insulin-like growth factor I receptors are functional during organogenesis of the lens.

Insulin and insulin-like growth factor I (IGF-I) stimulate overall growth and development of the chick embryo in early organogenesis. Turning to individual organs, to clarify the cellular effects of these peptides and the activity of the receptors involved, we had demonstrated with developing lens that insulin and IGF-I increase the accumulation of delta-crystallin mRNA, a marker for lens differentiation, in part by stimulation of transcription. In this study we expand our previous work on lens receptors to an earlier time in organogenesis, day 4, which marks the beginning of differentiation of the lens epithelial cells into elongated fibers. Insulin receptors are demonstrable by affinity cross-linking in epithelial cells at day 6, and specific binding of [125I]insulin and [125I]IGF-I is detectable in day 4 lenses. Insulin and IGF-I stimulation of substrate phosphorylation in the presence of solubilized receptors occurs only with high concentrations (10-100 nM) of either peptide in day 4 lenses, while a clear response with low concentrations (1 nM) is elicited by day 6 of development. Low concentrations of both insulin and IGF-I (0.1-1 nM) increase the incorporation of [3H]leucine and [3H]uridine in day 6 lens cells, suggesting that each peptide acts through its own receptor. These results confirm and extend the finding of insulin and IGF-I receptors in the developing chicken lens, and demonstrate their functional activity. This embryonic model should be valuable for further analysis of the action of insulin and IGF-I in growth and differentiation processes during early development.

Affinity Labels↗
PubMed1989

Insulin reverses the growth retardation effect of phorbol ester in chicken embryos during organogenesis.

The tumor promoting phorbol esters can affect early embryonic development by causing interference with the normal pathways of cellular growth and differentiation. The present study was designed to: a) define a time in organogenesis when a vertebrate embryo model, the chicken, was sensitive to the phorbol ester 12-0-tetradecanoyl-13-acetate (TPA), and b) attempt a rescue of the embryos disturbed by TPA with simultaneous addition of insulin. In embryos treated at days 2 and 3 of development, TPA caused dose-dependent mortality. Survivors were biochemically retarded as indicated by their decreased weight, protein, DNA, RNA, total creatine kinase, triglycerides, phospholipids and cholesterol contents. When intermediate doses of TPA (50 ng/embryo) were applied together with insulin (100 ng/embryo), the embryonic growth disturbance was largely antagonized. These data, generated with an in vivo whole embryo, These data, generated with an in vivo whole embryo, support the strong link between the mode of action of insulin and signal transduction mechanisms typical of phorbol esters.

Age Factors↗