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Biomedical subjects

M Montag

Publications and source records attributed to M Montag.

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

Cytogenetic and andrological status and ICSI-results in couples with severe male factor infertility.

AIM: To pursue whether cytogenetic aberrations correlate with specific spermatological or hormonal abnormalities. METHODS: 305 infertile couples were investigated. All male partners were referred to a complete andrological work-up with physical examination, determination of hormones, HIV testing and semen analysis. Cytogenetic analysis was carried out in both partners by means of standard techniques using cultured lymphocytes from peripheral blood. RESULTS: Among the 305 couples, 10 men (3.2%) and 10 women (3.2%) showed constitutional chromosomal aberrations, including reciprocal translocations (n = 7), Robertsonian translocations (n = 3), inversions (n = 3), other structural aberrations (n = 4) and sex chromosome aberration (n = 3). In addition to the impaired sperm count in most of the patients, a tendency to an increased proportion of spermatozoa with acrosome defect was observed. CONCLUSION: Chromosomal aberrations may contribute to the low fertilization and pregnancy rates in the infertile couples.

Chromosome Aberrations↗
PubMed1999

Characterization of testicular mouse glucosamine 6-phosphate deaminase (GNPDA).

Mammalian glucosamine 6-phosphate deaminase (GNPDA) was first detected in hamster spermatozoa. To further elucidate its role, we have cloned mouse GNPDA and produced a polyclonal rabbit anti-GNPDA antibody. This antibody recognized a 33 kDa protein in soluble extracts from mouse brain, liver, kidney, muscle, ovary, testis and sperm. Immunofluorescent analysis of the localization of GNPDA in male reproductive tissue revealed its presence in spermatids and in spermatozoa. In spermatids, GNPDA localized close to the developing acrosome vesicle and in spermatozoa close to the acrosomal region. Following the induction of the acrosome reaction, GNPDA fluorescence in spermatozoa was either reduced or GNPDA was absent. These data suggest that GNPDA might play a role in the acrosome reaction.

Acrosome↗
PubMed1999

Laser-assisted cryopreservation of single human spermatozoa in cell-free zona pellucida.

Improved procedure for efficient cryopreservation of single human spermatozoa in cell-free human zona pellucida is reported. We used a diode laser system for efficient and precise creation of a single hole into the zona pellucida of a degenerated or immature human oocyte. This allowed the extraction of the cytoplasm using a micropipette with a diameter of 10-15 microns. Through the same opening, human spermatozoa were inserted into the empty zona. We used motile and laser immobilized spermatozoa. Immobilized sperm were obtained by a single laser irradiation delivered in the vicinity of the sperm tail prior to insertion. This new immobilization procedure was shown to have no deleterious effect on membrane integrity and sperm viability. Following sperm transfer into the zona, the laser-drilled hole was closed with an oil droplet which was expelled from the micropipette during withdrawal to avoid loss of spermatozoa. This facilitated detection of the otherwise translucent zona during the cryopreservation procedure. After thawing, all cryopreserved zonae (20/20) could be successfully retrieved. Spermatozoa were recovered from the zona pellucida through the hole used for insertion. The rate of sperm recovery for initially motile spermatozoa was 80% vs. 92% for laser immobilized spermatozoa. Sperm viability was 81% and 84%, respectively, detected by a Hoechst stain. This technique makes cryopreservation of single human spermatozoa easy and feasible and appears beneficial for couples with severe male infertility and for those facing repeated surgical sperm extraction.

Cryopreservation↗
PubMed1999

Recovery of ejaculated spermatozoa for intracytoplasmic sperm injection after anti-inflammatory treatment of an azoospermic patient with genital tract infection: a case report.

In this paper our experiences with anti-inflammatory treatment of an infertile patient with azoospermia and concomitant silent genital infection are reported. The patient was referred to our fertility centre with prediagnosed non-obstructive azoospermia and no spermatozoa were found in the ejaculate on two occasions. The patient showed leukocytospermia and was suspected to be affected by genital infection. Therefore, anti-inflammatory treatment was initiated and 8 weeks later examination of the ejaculate revealed a decreased number of leukocytes and the presence of few but motile spermatozoa. Subsequently, two ICSI cycles were performed with anti-inflammatory therapy in parallel and a sufficient number of spermatozoa could be retrieved for injection. However, in a third cycle without previous treatment, examination of the ejaculate again revealed azoospermia and leukocytospermia. It is concluded that, in cases of azoospermia and chronic genital infection, some patients will benefit from anti-inflammatory treatment prior to and during ICSI treatment. This may allow retrieval of spermatozoa from the ejaculate and thus may avoid the need for a therapeutic testicular biopsy. Using this approach, sufficient spermatozoa in three out of four ICSI cycles could be retrieved and a pregnancy was finally achieved.

Adult↗
PubMed1999

Type and frequency of chromosome aberrations in 781 couples undergoing intracytoplasmic sperm injection.

Cytogenetic investigations were performed in 781 couples prior to intracytoplasmic sperm injection (ICSI) because of severe male infertility or fertilization failures in previous in-vitro fertilization attempts. Out of these 1562 patients, 1012 had a normal karyotype without any aberrations (64.8%), 204 patients had an abnormal karyotypes (13.1%). These chromosome aberrations included constitutional aberrations (4.4%), fragile sites of autosomes (3.0%), low level mosaicism of sex chromosomes (4.0%) and secondary structural chromosome aberrations (4.2%). Combinations of different types of abnormalities were stated. Another 346 patients (22.1%) showed single cell aberrations; the significance of these is unclear at the moment. Constitutional chromosome aberrations were detected in 69 patients. The following chromosome aberrations were observed: 35 sex chromosomal aberrations (comprising hyperploidies of X or Y chromosomes, mosaicisms and derivative X and Y chromosomes), 34 autosomal aberrations including 14 reciprocal translocations, five Robertsonian translocations, six inversions, one marker chromosome, one trisomy 18 mosaicism and seven other structural aberrations. Three autosomal regions showed fragile sites: 6q13 in 2.9% of the patients, 17p12 and 10q24 in 0.05% each. In conclusion, our data show that a high number of infertile couples in an ICSI programme are affected by chromosome aberrations which occur in both sexes. It is suggested that a chromosomal analysis should be performed on both partners before ICSI treatment is initiated.

Chromosome Aberrations↗
PubMed1999

Laser-assisted hatching in assisted reproduction.

AIM: The use of a 1.48 um diode laser for assisted hatching was investigated in animal experimentation. Laser assisted hatching was offered to patients with advanced maternal age to evaluate a possible benefit. METHODS: Using the Fertilase(r) system we investigated the impact of openings with different size in the zona of mouse embryos on the hatching process, as well as that of two openings. Laser-drilling was performed at the blastocyst stage to look for differences in timing and efficacy of hatching. The possible benefit of assisted hatching was studied in 24 couples with advanced maternal age (38.8+2.1 years) and compared to a control group (37.8+2.5 years) treated in the same time period but without assisted hatching. RESULTS: A certain diameter of a laser drilled opening in the zona pellucida is necessary for efficient hatching. When two openings are present in the zona, the embryo will use both openings for hatching and subsequently become trapped. Laser-drilling at th e expanded blastocyst stage causes an immediate collapse of treated blastocysts and the onset of hatching is retarded. Assisted hatching in 24 patients with advanced maternal age resulted in a significant increase (p<0.01) in the implantation rate when compared to 24 untreated patients. CONCLUSION: The use of a 1.48 microm diode laser to drill an opening into the zona pellucida provides a good alternate to conventionally applied techniques. The procedure is efficient and safe as long as it is applied properly. In a human in vitro fertilization program, selected patients will have a benefit form assisted hatching.

Adult↗
PubMed1998

Presence and localization of oscillin in human spermatozoa in relation to the integrity of the sperm membrane.

We investigated the presence and localization of oscillin in human spermatozoa in relation to the integrity of the sperm membrane, which was assessed by the hypo-osmotic swelling (HOS) test. We found no gross differences in the presence of oscillin in semen samples from men who presented with 70%, 40%, 25% or 2% of membrane-intact spermatozoa. By immunofluorescence, membrane-intact (HOS-positive) spermatozoa showed staining of a single band at the equatorial region, whereas over 80% of HOS-negative spermatozoa consistently showed a diffuse distribution of oscillin over the sperm head. However, some individuals presented with up to 50% of HOS-positive spermatozoa showing an aberrant localization of oscillin. We found a significant correlation rate (r=0.70, P < 0.05) between the percentage of HOS-positive spermatozoa with an equatorial oscillin localization and the fertilization rates achieved after intracytoplasmic sperm injection. These data suggest that the localization of oscillin in human spermatozoa might have an impact on egg activation and fertilization rates.

Calcium-Binding Proteins↗
PubMed1998

Laser-assisted microdissection of the zona pellucida facilitates polar body biopsy.

OBJECTIVE: To investigate whether polar body biopsy can be performed after laser microdissection of the zona pellucida (ZP). DESIGN: Mouse zygotes were allocated randomly to three groups. The zygotes were subjected to laser microdissection of the ZP and polar body biopsy (group 1), laser microdissection alone (group 2), or no treatment (group 3). SETTING: University-based IVF program. PATIENT(S): Animal study. INTERVENTION(S): A hole was drilled in the ZP of mouse zygotes using a 1.48-micron noncontact diode laser. A microneedle was inserted and the polar body was aspirated. MAIN OUTCOME MEASURE(S): The efficacy of polar body biopsy after laser microdissection of the ZP was evaluated. RESULT(S): The laser diode beam allowed for precise drilling of a 14- to 18-micron hole in the ZP. Polar bodies could be aspirated without damaging the zygote and did not disintegrate during the biopsy. Zygotes developed to blastocysts and underwent the same hatching as control zygotes. Lower hatching rates were observed in untreated zygotes. CONCLUSION(S): Laser microdissection of the ZP with a noncontact laser system facilitates subsequent polar body biopsy. The use of blunt-ended micropipettes greatly reduces the risk of damage to the zygote or the polar body. This procedure makes polar body biopsy more accurate and effective for preimplantation genetic diagnosis.

Animals↗
PubMed1998

Methylation levels at selected CpG sites in the factor VIII and FGFR3 genes, in mature female and male germ cells: implications for male-driven evolution.

Transitional mutations at CpG dinucleotides account for approximately a third of all point mutations. These mutations probably arise through spontaneous deamination of 5-methylcytosine. Studies of CpG mutation rates in disease-linked genes, such as factor VIII and FGFR3, have indicated that they more frequently originate in male than in female germ cells. It has been speculated that these sex-biased mutation rates might be a consequence of sex-specific methylation differences between the female and the male germ lines. Using the bisulfite-based genomic-sequencing method, we investigated the methylation status of the human factor VIII and FGFR3 genes in mature male and female germ cells. With the exception of a single CpG, both genes were found to be equally and highly methylated in oocytes and spermatocytes. Whereas these observations strongly support the notion that DNA methylation is the major determining factor for recurrent CpG germ-line mutations in patients with hemophilia and achondroplasia, the higher mutation rate in the male germ line is apparently not a simple reflection of sex-specific methylation differences.

Achondroplasia↗
PubMed1998

Increased frequency of congenital chromosomal aberrations in female partners of couples undergoing intracytoplasmic sperm injection.

We evaluated the frequency of congenital chromosomal aberrations in a sample of 305 couples included in an intracytoplasmic sperm injection (ICSI) programme. Twenty individuals (3.3%) with congenital chromosomal abnormalities could be identified. The following types of abnormalities were observed: reciprocal translocations (n = 7), Robertsonian translocations (n = 3), inversions (n = 3), other structural aberrations (n = 4) and sex chromosome aberrations (n = 3). The rate of chromosomally abnormal males (10/305, 3.3%) lay within the expected range for patients with reduced semen quality. Surprisingly, 50% (10/20) of all abnormal karyotypes were contributed by the female partner of ICSI patients. These data confirm the higher incidence of chromosomal aberrations in infertile populations as compared with the baseline population risk. Additionally, the data imply that in some cases of male factor infertility a hidden female chromosomal factor may be present, which cannot be identified by standard clinical evaluation. In conclusion, we recommend chromosomal analysis in both partners of couples undergoing ICSI treatment.

Adult↗
PubMed1997

Success of intracytoplasmic sperm injection in couples with male and/or female chromosome aberrations.

This paper reports on results of intracytoplasmic sperm injection (ICSI) in patients in whom constitutional or secondary chromosome aberrations were detected in the male and/or female partner. Out of 434 couples treated by ICSI (590 cycles), 16 couples (3.7%) were affected by constitutional chromosome aberrations and 96 (22.1%) by secondary chromosome aberrations. Constitutional chromosome aberrations were found in eight male and eight female patients. Couples with the aberration in the male showed significantly lower fertilization, implantation and pregnancy rates (P < 0.05). The occurrence of female constitutional chromosome aberrations led to lower fertilization rates but implantation and pregnancy rates were similar to a control group; however, a higher abortion rate was noted. In the group with secondary chromosome aberrations, 22 males and 59 females carried an abnormality and in 15 couples, both partners. Compared to the remaining (unaffected) 322 couples, fertilization and embryo transfer rates were reduced but implantation rates and pregnancy rates were not different. In all couples where an abortion occurred, mainly parental autosomal aberrations were involved (six out of eight). Our retrospective analysis shows that an unexpectedly high number of infertile couples in an ICSI programme are affected by chromosome aberrations, which in turn may explain the reduced fertilization rates observed in this subgroup of patients.

Abortion, Spontaneous↗
PubMed1997

Combined cytogenetic and Y chromosome microdeletion screening in males undergoing intracytoplasmic sperm injection.

We evaluated the frequency of chromosomal aberrations and microdeletions of the Y chromosome in a sample of 204 patients included in an intracytoplasmic sperm injection (ICSI) programme. The prevalence of Y chromosome deletions in males with severely or only moderately reduced sparm counts is mainly unknown, so that patients were chosen with sperm counts ranging from mild oligozoospermia to azoospermia. While six out of 158 (3.8%) patients showed constitutional chromosomal aberrations, only two out of 204 (0.98%) patients were diagnosed with a microdeletion of Yq11. One had a terminal deletion in subinterval 6 of Yq11.23 which included the DAZ gene and a corresponding sperm count < 0.1 x 10(6) spermatozoa/ml. The second patient had an isolated deletion of marker Y6PH54c, a more proximal site in subinterval 5 on Yq11.23, but repeatedly showed sperm counts of 3-8 x 10(8) spermatozoa/ml. Thus, of the 158 patients who underwent a combined cytogenetic and Y-microdeletion screening, eight patients (5.1%) showed chromosomal abnormalities, either at the cytogenatic (n = 6) or the molecular level (n = 2). In conclusion, although rare in number, microdeletions of the Y chromosome can also be observed in patients with moderately reduced sperm counts. A more proximal site of the deletion breakpoint does not necessarily imply a more severe impairment of spermatogenesis than a distal deletion site. In our sample, the overall frequency of constitutional chromosomal aberrations exceeded the incidence of microdeletions of the Y chromosome even in patients with idiopathic azoo- or severe oligozoospermia.

Chromosome Deletion↗
PubMed1997

[Parenchymal thoracic endometriosis--diagnosis and therapy].

We report a case of parenchymal pulmonary endometriosis in combination with severe endometriosis genitalis externa. The difficulties on the way to final diagnosis are described, also the different possibilities of hormonal treatment that results in ovarian suppression. In our case the patient is without any symptoms since three years using a GnRH-Agonist as first line therapy and as second line therapy high-dose medroxyprogesterone acetate. Because of the very good clinical results after hormonal suppression surgical intervention might become necessary only in certain cases. This can be the case when after intolerance of hormonal treatment angiography of lung vascular system on the bases of number and localization of endometrial lesions shows good operative conditions.

Adult↗
PubMed1996

Beyond recanalizing proximal tube occlusion: the argument for further diagnosis and classification.

Proximal tube occlusion (PTO) accounts for 20% of tubal factor cases. The classification into nodular (salpingitis isthmica nodosa or endometriosis), non-nodular (true fibrotic occlusion) and so-called pseudo occlusion (detritus, polyps, hypoplastic tubes) is essential. Using falloposcopy, PTO that is already diagnosed by laparoscopy and hysterosalpingography (HSG) can be confirmed or bypassed (false PTO); patients with false PTO were placed on a temporary waiting period. Nodular and pseudo occlusion patients were pre-treated with gonadotrophin-releasing hormone analogue (GnRH-a) for at least 6 weeks to shrink the underlying pathology, after which tubal re-catheterization was performed. In a prospective study starting in July 1993, 53 patients prediagnosed as having PTO were examined by falloposcopy. Three of these patients had non-nodular occlusion and were directed to microsurgical repair (conservative treatment not possible). A total of 19 cases revealed patent tubes with healthy mucosa and no underlying pathology (false PTO). Of the remaining 31 patients, 18 were classified as nodular and 13 as pseudo occlusion. In all of these patients at least one tube was patent after GnRH-a treatment. After a 6 month period, 37% of the false PTO patients achieved a spontaneous pregnancy (6% per cycle). The spontaneous pregnancy rate in the true PTO group was significantly lower (10% per patient, 1.6% per month; P < 0.05). Using assisted reproduction techniques, in particular gamete intra-Fallopian transfer (GIFT), as a subsequent treatment for the true PTO group, a pregnancy rate of 50% per cycle was achieved. A retrospective analysis of our entire PTO population (n = 109) showed a spontaneous pregnancy rate after achieving tubal patency (using falloposcopy and GnRH-a) that was dramatically low (1.8%), with no difference between the nodular and pseudo groups. The chance for pregnancy can be enhanced significantly (P < 0.001) using assisted reproduction techniques (GIFT) following tubal re-catheterization and GnRH-a treatment.

Buserelin↗
PubMed1994

Thoracoscopically assisted esophagectomy with gastric pull-up for esophageal cancer.

Thoracoscopically assisted esophagectomy with gastric pull-up was done in a 56-year-old man with esophageal cancer. The thoracoscopic technique, including the use of intraoperative ultrasound, is discussed. The addition of thoracoscopy offers safer and more complete esophageal dissection than transhiatal blunt esophagectomy and is less invasive than conventional thoracotomy.

Adenocarcinoma↗
PubMed1994

Three years experience with a new balloon catheter for the management of haemoptysis.

For the management of severe haemoptysis we have developed a double-lumen, bronchus-blocking catheter that can be introduced through the working channel of a standard fibrebronchoscope. We wondered whether this catheter would be suitable to control pulmonary haemorrhage in clinical practice. Over a period of 36 months, 30 of these catheters were used in 27 patients with moderate and massive pulmonary bleeding from various lesions. Underlying diseases were: malignancies (11), vascular deformities (5), tuberculosis (4), silicosis (2), carcinoids (2), silicosis (2), endometriosis (1), bronchiectasis (1). In 26 cases, the transbronchoscopic balloon tamponade was successful. In one patient, tumour growth close to the carina prevented securing of the balloon and double-lumen tube intubation was required. There were only minor complications attributable to the balloon. With the catheter in place for up to seven days, patients underwent surgery, received radiation, chemotherapy, drug treatment or bronchial arterial embolization. In conclusion, we found this double-lumen, bronchus-blocking device safe and the technique practicable to control pulmonary haemorrhage.

Balloon Occlusion↗
PubMed1993

Shiga-like toxin II-related cytotoxins in Citrobacter freundii strains from humans and beef samples.

By hybridizing colonies grown from 928 individual stool samples of patients suffering from diarrhea with oligonucleotide probes 772 and 849 complementary to Shiga-like toxin I (SLT-I) and SLT-II gene sequences, respectively, we identified two strains that hybridized with probe 849, which biochemical identification revealed as Citrobacter freundii. An additional five slt-II probe-positive isolates were screened from 81 beef samples. Polymerase chain reaction analysis and restriction of amplified products provided evidence for slt-II-related genes in all seven strains. From C. freundii LM 76, the genes encoding the A and B subunits were cloned in pUC 18 vectors and sequenced. The gene encoding the A subunit differed from that of Escherichia coli slt-IIvhc in 4 bases, resulting in two amino acid residue differences. In 11, 13, and 11 nucleotides, differentiation of slt-IIA, slt-IIcA, and vtx2haA, respectively, was found. These differences affected the predicted amino acid sequence as follows: there were six amino acid differences with SLT-IIA, five with SLT-IIcA, and four with VTx2haA. The nucleotide sequence of the gene encoding the B subunit is identical to slt-IIvhcB and differed from slt-IIcB and vtx2haB by only a single nucleotide base, but this resulted in a predicted amino acid sequence identical to that reported for these toxins. We therefore termed the toxin genes C. freundii slt-IIcA and slt-IIcB. Culture filtrates inoculated with material from the colonies from primary cultures were cytotoxic to Vero cells. Neutralization assays with antisera to E. coli SLT-I, SLT-II, and SLT-IIvhc revealed that antibodies against SLT-IIvhc reduced the C. freundii cytotoxic activity specifically and to the same degree as with the E. coli SLT-IIvhc control strain. In five of the seven strains tested, subcultivation on both a liquid or solid medium resulted in loss of cytotoxic activity. With polymerase chain reaction, we demonstrated that loss of cytotoxic activity ran parallel with the loss of slt genes. These data demonstrate the intergeneric occurrence of SLT-II-related toxins, which may well be a new marker of enteropathogenicity in C. freundii. Our findings that the toxin genes belong to the slt-II family plus their evident instability in the majority of strains should help pave the way to a better understanding of their role in diarrhea or food poisoning.

Animals↗