Search PubMed⌕ Search

Biomedical subjects

S Silber

Publications and source records attributed to S Silber.

At least 73 records · Page 4Linked to original sources
PubMed1997

Sheath pulling immediately after PTCA: comparison of two different deployment techniques for the hemostatic puncture closure device: a prospective, randomized study.

Sheath pulling immediately after percutaneous transluminal coronary angioplasty (PTCA) increases patients' comfort, decreases burden for the medical staff, and may reduce hospital costs by shortening the length of stay. Immediate sheath pulling in anticoagulated patients with a low risk of bleeding complications is feasible using hemostatic devices. For the hemostatic puncture closing device (HPCD), published data regarding sheath pulling in patients immediately after PTCA is limited. Furthermore, no study addressed the question whether the recommended deployment time (DT) of 30 min can be reduced to a few minutes. We, therefore, performed a prospective study, randomizing 140 patients to a DT of 5 and 30 min, respectively. There were no statistical differences in gender, age, height, weight, or cardiovascular risk factors between the two groups. Blood pressures measured invasively immediately before sheath removal were comparable. Activated coagulation time just prior to sheath removal was 227 +/- 52 sec in the DT-5 group and 223 +/- 37 sec in the DT-30 group. After deployment, 74% of the DT-5 patients and 71% of the DT-30 patients showed immediate and complete hemostasis. The remaining patients showed only little oozing with complete hemostasis at the time of the final device removal. Hematoma size after 24 hr was 6.2 +/- 4.4 cm2 for DT-5 and 6.8 +/- 8.2 cm2 for DT-30 patients. There was no statistical difference between both groups. No severe bleeding or major complications were observed in either group. Thus, the use of a collagen system with an intra-arterial anchor (HPCD) is effective and safe when sheaths are pulled immediately after PTCA. The reduction of deployment time from 30 to 5 min is not related to an increased risk of bleeding or other vascular complications; patients can be transferred much faster to the ward, therefore reducing the burden on the personnel in the catheterization laboratory and increasing patients' comfort by allowing them to return to their rooms without a sheath.

Adult↗
PubMed1997

Rapid hemostasis of arterial puncture sites with collagen in patients undergoing diagnostic and interventional cardiac catheterization.

Despite the continuous reduction of sheath sizes in diagnostic and interventional cardiac catheterizations and the discontinuation of coumadin use after coronary stent implantation, a challenging role remains for hemostatic devices in the sealing femoral puncture sites. Since the introduction of the vascular hemostatic device (VHD) in 1991 and the hemostatic puncture closing device (HPCD) in 1992, numerous studies investigating these devices have been published. The deployment success rates reported in 2,292 patients for VHD is 97%, ranging from 88 to 100%. For HPCD, the mean deployment success rate resulting from 622 published patients leads to an identical result of 97%, ranging between 91 and 100%. For time to hemostasis, data have been analyzed according to the four different clinical situations, depending on level of anticoagulation (none or full) and the time of sheath removal (immediate or delayed). In randomized studies, when compared with the manual control groups, both devices revealed a statistically significant reduction in time to hemostasis: 12 to 16 minutes less for diagnostic catheterization and 14 to 30 minutes less for PTCA. As for minor local complications, no clinically relevant differences seem to exist. None of these devices has been proven to reduce major local complications. Prospective trials addressing early mobilization after percutaneous transluminal coronary angioplasty and the cost effectiveness of arterial closure devices in defined subgroups are warranted.

Angioplasty, Balloon, Coronary↗
PubMed1997

Are there any predictive factors for successful testicular sperm recovery in azoospermic patients?

Recovery of testicular spermatozoa from azoospermic patients with testicular failure followed by intracytoplasmic sperm injection (ICSI) is a recent advance in the treatment of male infertility. This study aimed at investigating which parameter(s) may predict successful testicular sperm recovery. We reviewed 395 testicular sperm recovery procedures and analysed the most frequently available parameters for clinical decision-making in azoospermic patients: (i) presence of at least one single spermatozoon in at least one preliminary semen analysis; (ii) maximum testicular volume; (iii) serum follicle stimulating hormone (FSH); and (iv) presence of spermatozoa in the histology of a randomly-taken testicular biopsy. Sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio and accuracy were calculated for the above index parameters in different clinically relevant subgroups using receiver operating characteristic (ROC) curves whenever possible. Spermatozoa were always successfully recovered in patients with normal testicular histological findings (n = 173) or hypospermatogenesis (n = 16) but not in some patients with tubular sclerosis (seven out of 18), Sertoli cell-only pattern (55 out of 112) or maturation arrest (39 out of 76). Histopathology was the best test for predicting successful sperm recovery in the whole population (sensitivity: 86%, specificity: 93%, accuracy: 0.87). In patients with secretory azoospermia, histopathology was again the most accurate parameter (accuracy: 0.74), especially in patients showing Sertoli cell-only pattern (accuracy: 0.83) but not in patients showing maturation arrest (accuracy: 0.55). In patients with serum FSH concentrations > 12 IU/l and maximum testicular volume < 15 ml, histopathology was not found to be accurate. Semen analysis, maximum testicular volume and serum FSH were not highly predictive in all subgroups studied. Our analysis shows that no strong predictors for successful testicular sperm recovery are available except for testicular histopathology.

Adult↗
PubMed1996

Seminoma discovered in two males undergoing successful testicular sperm extraction for intracytoplasmic sperm injection.

OBJECTIVE: To describe two cases with testicular seminoma incidentally discovered at the time of successful testicular sperm extraction for intracytoplasmic sperm injection (ICSI)> DESIGN: Report of two cases. SETTING: Tertiary care academic center. PATIENTS: Two males with nonobstructive azoospermia with history of cryptorchidism. INTERVENTION: Testicular biopsy combined with ICSI; orchiectomy with radiotherapy. RESULTS: From two couples and in three different cycles, 17 of 55 (31%) metaphase II oocytes fertilized after microinjection. Eleven of these fertilized oocytes cleaved normally and all 11 were replaced. One twin pregnancy was established and was delivered successfully later. In both cases, a seminoma was discovered at the time of testicular biopsy. CONCLUSIONS: At the time of testicular biopsy for ICSI, a specimen for histopathology must be sent to exclude the presence of seminoma in males with nonobstructive azoospermia with a history of cryptorchidism. The effectiveness of testicular sperm extraction in combination with ICSI also has been demonstrated even against the background of testicular tumor.

Biopsy↗
PubMed1996

Cystic fibrosis and infertility caused by congenital bilateral absence of the vas deferens and related clinical entities.

The condition of congenital bilateral absence of the vas deferens (CBAVD) is, in the majority of patients, related to defects in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CBAVD patients either are compound heterozygotes (carrying different mutations in their two CFTR genes) or carry a mutation in one of their CFTR genes and an intron 8 5T splice variant, associated with low levels of functional CFTR protein, in their second gene. The relationship between cystic fibrosis (CF) and CBAVD requires a proper clinical examination of the patient, a CFTR mutation analysis for himself and his family and genetic counselling. A mutation analysis should also be performed for the wives of CBAVD males because such couples now have the possibility of having their own genetic children but are at increased risk of having children with CF and/or CBAVD. The aetiology of some conditions of CBAVD is not related to CF, especially when CBAVD is associated with urinary tract malformations (up to 20% of cases). In couples with CBAVD not related to CF there is no increased risk of CF children, but it is not known whether they have an increased risk of having sons with CBAVD. In some of the patients with congenital unilateral absence of the vas deferens (CUAVD) the condition is also related to CF, especially in cases where there is an occlusion of the palpable vas. The CFTR gene is probably not involved in the aetiology of Young's syndrome. Follow-up studies of children born to couples where the males have CBAVD, CUAVD or Young's syndrome are mandatory and will help to better define the risk to their offspring of CF and/or of inheriting their paternal infertility condition.

Cystic Fibrosis↗
PubMed1996

Correlation between testicular histology and outcome after intracytoplasmic sperm injection using testicular spermatozoa.

A comprehensive study is presented of a series of 124 infertile men undergoing testicular sperm retrieval for intracytoplasmic sperm injection (ICSI). In this study we correlated the histological changes observed in the testicular tissue with the results of the wet preparation and the outcome after ICSI using testicular spermatozoa. In all patients with normal spermatogenesis and hypospermatogenesis spermatozoa were recovered from the wet preparation. The sperm recovery rate as 84% in patients with incomplete germ-cell-aplasia and maturation arrest, while in patients with complete germ-cell aplasia or maturation arrest this figure was 76%. In these patients more specimens were sampled and fewer spermatozoa were recovered. Since no spermatozoa were recovered in only 10 patients, ICSI with testicular sperm was performed in the remaining 114 couples (91.9%). The normal fertilization rate was 57. 8%. The fertilization rate was significantly lower in couples among whom the husband showed germ-cell aplasia and maturation arrest. Overall, 55.2% of normally fertilized oocytes developed into embryos showing <=50% of anucleate fragments. There were no major differences between the different histological categories in terms of embryonic development in vitro. The overall pregnancy rates per testicular sperm extraction (TESE) procedure, per ICSI procedure and per transfer were respectively 36.3, 39.5 and 43.7%. The overall implantation rate per embryo (sacs/embryos replaced) was 20.3%. A lower implantation rate was observed in couples among whom the husband had maturation arrest (not statistically significant). The above data show that testicular biopsies may have an important therapeutic role in the management of infertility in azoospermic patients.

Adult↗
PubMed1996

Outcome of intracytoplasmic sperm injection with testicular spermatozoa in obstructive and non-obstructive azoospermia.

From 1 August 1993 until 30 September 1994, 69 couples suffering from azoospermia underwent testicular sperm extraction and intracytoplasmic sperm injection. In 50 couples with obstructive azoospermia a total of 631 metaphase-II oocytes were injected after testicular sperm extraction yielding a 2-PN fertilization rate of 57%. In female patients <40 years of age an ongoing pregnancy rate per transfer of 42% (14/33) was obtained. So far, eight healthy babies have been born, including two singletons and three twin gestations. In 19 couples with non-obstructive azoospermia a total of 264 metaphase-II oocytes were injected after testicular sperm extraction, yielding a 2-PN fertilization rate of 58%. An ongoing pregnancy rate per transfer of 31% (5/16) was established. So far, six healthy babies have been born including one singleton, one twin and one triplet gestation.

Adult↗
PubMed1996

-Differential antithrombotic therapy in patients with low and high PTCA risk-.

Acute coronary occlusion as well as restenosis still represent the major limitations of coronary interventions. Either event seems to be related to thrombus formation. The purpose of this overview is to summarize the current status of the usefulness of conventional and newer antithrombotic drugs regarding the prevention of acute occlusion and restenosis (excluding stents). ANTICOAGULATION: For ethical reasons, no placebo-controlled studies were conducted to prove the usefulness of heparin in preventing acute occlusions. The dosage mostly used is 10,000 U, although a relationship between dosage and complication rate has not been documented. A prolonged heparin infusion in patients with low risk and uncomplicated PTCA has no advantages. Restenosis is not influenced by prolonged infusion of heparin or administration of coumadin as well. Low molecular weight heparin is currently under investigation. Hirudin and hirulog have shown promising results with less acute occlusions; however, their therapeutic range must be considered. ANTIAGGREGATION: In controlled studies, ASA significantly reduced acute occlusions during PTCA when given in addition to heparin. Ticlopidin is as effective as ASA, but due to its side effects should only be administered when contraindications to ASA exist. ASA significantly reduced restenosis in only 1 of 4 studies with limited number of patients. Thromboxane inhibitors such as ridogrel or clopidogrel showed promising initial results. Trapidil significantly reduced restenosis in 2 studies; quantitative stenosis analysis, however, was not performed. Inhibition of platelets by glycoprotein (GP) IIb/IIIa receptor antagonists represents an innovative therapeutic concept: numerous controlled trials have documented a significant reduction in cardiac ischemic events and therefore indirectly in restenosis rates. The recombinant monoclonal antibody c7E3 Fab seems to be more effective than the synthetic integrelin. Unfortunately, efficacy appears to be in direct relationship to the risk of bleeding complications. The clinical role of oral GP IIb/IIIa inhibitors has yet to be established. For patients with high risk PTCA, the use of hirudin instead of heparin as well as the addition of GP IIb/IIIa inhibitors should be considered.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Characteristics of angina pectoris therapy with nitrates].

Nitrates have been periodically controversial since their introduction in 1867 as a treatment for angina pectoris. The goal of this synopsis is to delineate the special and unchanged high ranking of nitrates in the treatment of angina pectoris with particular consideration to the dosage and dosage intervals. The anti-anginal/anti-ischemic effect of nitrates originates predominantly from the preload reduction induced by venous dilation; additionally, an accompanying coronary dilation can be of assistance. The special role of the preload reduction differentiates nitrates from beta blockers and calcium antagonists. But the initial positive anti-anginal/anti-ischemic effect can be lost under long-term treatment due to nitrate tolerance. This development of tolerance has been demonstrated for oral, intravenous and transdermal administration. Various mechanisms have been held accountable for this complex occurrence: exhaustion of the thiol pool, neurohumoral counter-regulation, and recently, an overproduction of free radicals. Nitrate tolerance has mean-while been recognized as a relevant clinical problem. The key to avoidance of nitrate tolerance lies in the interval therapy recommended by Stewart as early as 1905: it concludes that continual, 24-hour protection by nitrates alone is impossible. The ideal compromise between avoiding the development of tolerance and an optimal anti-ischemic protection, the duration of which should be as long as possible, demonstrates that approximately 12 hours of protection are clinically possible. As we showed in 1983, the administration of a single, high dose of slow-release ISDN effects this compromise. Asymmetric dosage intervals that guarantee the maintenance of anti-anginal/anti-ischemic nitrate effect may be alternatively used. A 12-hour patch-free interval is generally recommended for treatment with nitrate patches. Similarly, a 12-hour infusion-free period has been recommended for intravenous nitrate administration in patients with stable angina pectoris. In patients with unstable angina pectoris, the situation is more complex-probably due to the anti-platelet effect of nitrates. As has been the practice in the past, nitrates are to be the basic treatment of angina pectoris; as opposed to nifedipine, nitrates lead to a decrease in end-diastolic volume primarily through preload reduction. Nitrates have been documented to be highly effective in treating angina pectoris and myocardial ischemia; they demonstrate a high rate of "responders". Nitrates are the physiological substitute treatment of atherosclerotic vessels with EDRF-deficiency; they improve hemodynamics in the presence of congestive heart failure. Nitrates inhibit platelets in vivo and are standard medication for PTCA as well as other coronary interventions. They demonstrate only few untoward effects and are inexpensive.

Angina Pectoris↗
PubMed1996

[Quality assurance in cardiology: Germany].

Quality assurance is a touchy subject: difficult to implement, time-demanding and expensive. The goal of quality assurance is to assist both the patients and the physicians. In addition to legal requirements, quality assurance is necessary for medical as well as economical reasons. It makes sense that the license to practice medicine does not automatically entail the right to perform all medical procedures; the development of new methods and the insights won from important scientific studies necessitates constant training. Furthermore, the decreasing allocation of funds for medical care combined with increased demand effected by new treatment methods and longer life expectancy force the development of instruments for specific and reasonable budgeting of medical expenditures. The primary goal of quality management in respect to economical regards must be the avoidance of unnecessary hospital admissions. But the patient must retain the right to choose the physician he prefers. The organization of the supervising structures in Germany is inconsistent: in 1995, a new Zentralstelle der Deutschen Arzteschaft zur Qualitätssicherung in der Medizin (German Physicians Headquarters for Quality Assurance in Medicine) was founded; it is proportionally staffed by representatives of the Bundesärztekammer (BAK, Federal Board of Physicians) and the Kassenärztliche Bundesvereinigung (KBV, Federal Commission of Panel Physicians). Furthermore, there is the Arbeitsgemeinschaft zur Förderung der Qualitätssicherung in der Medizin (Working Group for the Advancement of Quality Assurance in Medicine), in which the Bundesministerium für Gesundheit (Federal Ministry of Health) and the Kassenärztliche Vereinigung (KV, Public Health Insurance Providers) are represented. The KV is already seeing to it that stricter regulations govern physicians with private practice than those governing hospital physicians. There are three data banks existing on a voluntary basis for invasive diagnostic and therapy: a general, annual survey with baseline data from all German cardiac catheter laboratories; a data bank for storing records of PTCA's performed primarily in non-university-affiliated cardiac catheter labs (ALKK); and a data bank for recording diagnostic cardiac catheterization and PTCA's performed by physicians with private practice (BNK). In 1994, 15% of the diagnostic catheterizations and 16% of the coronary interventions were performed by physicians with private practice. Our survey shows that only 58% of German institutions record the data with a computer, 60% use their own developments; thus, the majority of groups in Germany are not linked to a central data bank. The least requirement for quality assurance should be the recording of major and minor complications as well as a comparison of one's own data with those of a central data bank.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Waiting times and death on the waiting list for coronary artery bypass operation. Experiences in Munich with over 1,000 patients].

Short-term and long-term results are the classical parameters for quality assurance in coronary artery bypass graft surgery (CABGS). In contrast, waiting times and the inherent risks of waiting lists are usually neglected. Although the problem of "death on the waiting list" is generally known, related publications are scarce. Therefore, in January 1994, we started a prospective study to document the waiting times and the occurrence of severe complications in our patients waiting for CABGS. Between January 1, 1994 and July 31, 1996, we catheterized 1125 patients with indication for CABGS. 968 patients had social health insurance (SOCL); 157 patients were privately insured (PRIV). The urgency of CABGS was classified as "emergent", "ery urgent" and "less urgent" according to the clinical experience of the responsible cardiologists. All emergency cases could be operated the same day. 69% of the very urgent SOCL patients had to travel beyond the Munich area to be operated, while 84% of the respective PRIV patients were operated in Munich. SOCL patients were therefore separated from their families 4.3 times more frequently then PRIV. Not so urgent SOCL cases were separated from their families 1.8 times more often than PRIV. The mean waiting time for SOCL was 39.5 +/- 39.1 days in 1994, 34.9 +/- 31.5 days in 1995 and 22.7 +/- 16 days in 1996. The corresponding values of PRIV are 19.1 +/- 16.2, 19.8 +/- 14.1 and 17.2 +/- 12.6 days. The risk of dying while waiting for CABGS was 1.3% per month (15/1125). The reduction of waiting times by the factor of two between 1994 and 1996 did not, however, influence the death on the waiting list, because all deaths occurred within 4 weeks after diagnostic catheterization. Our results show that triage practices for patients requiring CABGS are not reliable. To minimize the risk of the "death on the waiting list", CABGS must be offered within a week after diagnostic coronary angiography, even for "elective" cases.

Adult↗
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

Using ejaculated, fresh, and frozen-thawed epididymal and testicular spermatozoa gives rise to comparable results after intracytoplasmic sperm injection.

OBJECTIVE: To describe the preparation of fresh or frozen-thawed epididymal and testicular sperm for intracytoplasmic single sperm injection and to compare the fertilization, embryo quality, and pregnancy rates (PRs) obtained after using these spermatozoa to the results when freshly ejaculated sperm was used for microinjection. DESIGN: Retrospective analysis of 1,034 consecutive microinjection cycles. Ejaculated (965 cycles), fresh epididymal (43 cycles), frozen-thawed epididymal (9 cycles), and testicular sperm (17 cycles) was used for intracytoplasmic sperm injection. SETTING: Procedures were performed in a tertiary IVF center coupled with an institutional research environment. MAIN OUTCOME MEASURES: Semen density and motility were judged by the World Health Organization criteria and sperm morphology was evaluated by the Tygerberg's strict criteria. After microinjection, oocyte intactness, fertilization, embryo cleavage, transfer, and PRs were evaluated and compared. RESULTS: The median values of total sperm count, total motility and normal morphology were 17.85 x 10(6), 37%, 8% for freshly ejaculated sperm; 46.20 x 10(6), 12%, 9% for fresh epididymal sperm; 0.15 x 10(6), 0%, 0% for frozen-thawed epididymal sperm; and 0.54 x 10(6), 0% for testicular sperm (morphology was not determined). The percentage of intact oocytes after microinjection ranged from 84% to 90%. Normal fertilization rates were high when fresh or frozen-thawed epididymal and testicular spermatozoa were used for the injection (56%, 56%, 48%, respectively) but were significantly lower than for ejaculated sperm (70%). There was a higher proportion of transferable embryos obtained after ejaculated sperm injection than after testicular sperm injection. Forty percent, 58%, 33%, and 46% of cycles had positive serum hCG using ejaculated, fresh, or frozen-thawed epididymal and testicular sperm. Initial pregnancy loss occurred in 26.3% of the conception cycles. CONCLUSION: Intracytoplasmic sperm injection can provide high normal fertilization, cleavage, and PRs when fresh or frozen-thawed epididymal and testicular spermatozoa are used, but normal fertilization rates are significantly lower than after microinjection with ejaculated sperm.

Adult↗
PubMed1995

Intracytoplasmic sperm injection (ICSI): the Brussels experience.

The present report covers the results of a 26-month period in which 1275 consecutive treatment cycles by intracytoplasmic sperm injection (ICSI) were performed in 919 couples. These couples were afflicted with male factor infertility and had had at least one previous failed conventional in vitro fertilization (IVF) treatment cycle. In other couples, the husband had semen parameters incompatible with conventional IVF or suffered from excretory azoospermia which required microsurgical epididymal sperm aspiration or testicular sperm retrieval. Overall, the 2 pronuclear (PN) fertilization rate was 47.7% per retrieved oocyte-cumulus complex and 66.4% per successfully injected metaphase II oocyte. Embryo transfer was performed in 90.8% of started cycles and 362 clinical pregnancies were recorded, giving a clinical pregnancy rate of 28.4% per started cycle or 31.3% per transfer. In addition, updated results on the outcome of pregnancies after microassisted fertilization are presented. As of 30 August 1994, 416 children have been born. Although 16 major congenital malformations have been observed (3.9%), there appears to be no reason for serious concern as regards the occurrence of major congenital anomalies after ICSI.

Belgium↗