The controlled fabrication of nanopores by focused electron-beam-induced etching

The fabrication of nanometric holes within thin silicon-based membranes is of great importance for various nanotechnology applications. The preparation of such holes with accurate control over their size and shape is, thus, gaining a lot of interest. In this work we demonstrate the use of a focused electron-beam-induced etching (FEBIE) process as a promising tool for the fabrication of such nanopores in silicon nitride membranes and study the process parameters. The reduction of silicon nitride by the electron beam followed by chemical etching of the residual elemental silicon results in a linear dependence of pore diameter on electron beam exposure time, enabling accurate control of nanopore size in the range of 17-200 nm in diameter. An optimal pressure of 5.3 x 10(-6) Torr for the production of smaller pores with faster process rates, as a result of mass transport effects, was found. The pore formation process is also shown to be dependent on the details of the pulsed process cycle, which control the rate of the pore extension, and its minimal and maximal size. Our results suggest that the FEBIE process may play a key role in the fabrication of nanopores for future devices both in sensing and nano-electronics applications.

Menopause-related oral alveolar bone resorption: a review of relatively unexplored consequences of estrogen deficiency

OBJECTIVE

The alveolar processes of the maxilla and mandible provide the bony framework for tooth support. Osteoporotic changes of these bones may directly affect tooth stability and retention. This report reviews studies that have evaluated the relationship between systemic osteoporosis and oral alveolar bone mass as well as the effect of estrogen use on oral alveolar bone and tooth retention.

DESIGN

Ten years (1989-1998) literature review.

RESULTS

Studies reviewed demonstrate a positive correlation between systemic bone mass and systemic osteoporosis to oral bone resorption. Estrogen replacement therapy affects oral bone in a manner similar to the way it affects other sites.

CONCLUSIONS

It is evident that postmenopausal estrogen users may retain more teeth after menopause. Sustained oral health and better tooth retention are potentially additional benefits for hormone replacement therapy users after menopause.

Intracytoplasmic injection of spermatids retrieved from testicular tissue: influence of testicular pathology, type of selected spermatids and oocyte activation

Spermatid microinjection into oocytes has proven to be a successful assisted reproduction procedure in the animal model and in the human species, since in the latter a few full-term pregnancies were actually obtained. Patients entering our spermatid injection study included those with a total absence of spermatozoa in the testicular tissue notwithstanding previous positive biopsies (n = 29): an obstructive problem (n = 3), secretory azoospermia (n = 26), and those with total arrest at the spermatogenesis level in previous explorative biopsies (n = 15). In the latter group, absence of spermatids was recorded in four cases. Mature, elongated, elongating and round spermatids (ROS) were injected in respectively 3, 2, 3, and 32 attempts. A total of 260 metaphase II oocytes were injected with ROS, 36 oocytes with spermatids at other stages of maturity. The rates of oocytes showing two pronuclei (2PN) and two polar bodies reached 22% and 64% respectively after injection of round or elongated-mature spermatids. The fertilization rate after ROS injection was influenced by the percentage of spermatozoa observed in a previous biopsy. Patients with a positive preliminary biopsy had significantly more 2PN (33%) when compared to those with a severe spermatogenic dysfunction and in whom no spermatozoa were found (only 11%) (P < 0.05). Incubation of oocytes in calcium ionophore after ROS injection had a positive effect on the rate of 2PN formation (36 versus 16%). Ninety per cent of all the normally fertilized oocytes cleaved. The percentage of grade A and B embryos depended on the type of injected cells: 12% after ROS and 30% with the other types of haploid cells. A total of 39 transfers resulted in five pregnancies: three full term with healthy babies delivered (one after ROS injection, and two after injection of an elongating and a mature spermatid), one 4 months ongoing (after elongating spermatid injection) and one miscarriage at 4 weeks (after elongated cell injection). Compared to our conventional intracytoplasmic sperm injection-testicular sperm extraction (ICSI-TESE) programme, the implantation rate after ROS injection was very low (5.5 versus 10.5%).

Intracytoplasmic sperm injection, fertilization, and embryo transfer after retrieval of spermatozoa by testicular biopsy from an azoospermic male with testicular tubular atrophy

OBJECTIVE

To achieve fertilization and cleavage by spermatozoa retrieved by testicular biopsy from a male with testicular tubular atrophy.

DESIGN

Clinical trial.

SETTING

Private reproductive institute.

PATIENT

Azoospermic male with demonstrated testicular tubular atrophy and almost complete spermatogenic arrest.

INTERVENTION

Open biopsy retrieval of testicular tissue and sperm followed by intracytoplasmic sperm injection.

MAIN OUTCOME MEASURES

Fertilization and cleavage.

RESULTS

One four- to six-cell embryo was formed after intracytoplasmic sperm injection of five eggs with extruded polar bodies by retrieved sperm.

CONCLUSION

Intracytoplasmic sperm injection after testicular sperm aspiration may be attempted in cases with severely decreased spermatogenesis and result in fertilization, cleavage, and embryo transfer.

Incidence of autoimmune antibodies in failed embryo transfer cycles

PROBLEM

The presence of antiphospholipid antibodies lupus anticoagulant (LAC), anticardiolipin antibody (ACA) as well as antinuclear antibody (ANA) has been associated with early spontaneous pregnancy loss and adverse pregnancy outcome. The purpose of this study was to investigate the possible role of autoimmune antibodies (LAC, ACA, and ANA) as a cause of implantation failure following embryo transfer (ET) after in vitro fertilization (IVF).

METHOD

Three groups were studied: Group I, 56 patients who failed to conceive following ET; group II, 14 patients who have conceived following IVF-ET and delivered or are carrying an uncomplicated ongoing pregnancy; and group III, 69 patients who were new candidates for IVF-ET.

RESULTS

Eighteen out of 56 (32.1%) of patients who failed to conceive following previous IVF-ET cycle (group I) tested positive for one or more of the autoimmune antibodies. None of the 14 patients of group II tested positive for autoimmune antibodies (P < .02). Seven out of the 69 patients (10%) of group III were found positive to one or more of the autoimmune factor. This rate is significantly lower than the rate of positive autoimmune antibodies detected in group I (P < .003). Fifteen patients of the 18 who tested positive for autoimmune antibodies and who had previously failed to conceive following ET underwent a subsequent IVF-ET cycle while being treated with prednisone and aspirin. Seven out of the 15 (46.6%) conceived and were able to sustain a clinical ongoing pregnancy.

CONCLUSIONS

Patients receiving ET are carrying viable embryos within the intrauterine environment. Therefore, in this unique group of patients, failure to demonstrate a positive pregnancy test represents an implantation failure or a very early postimplantation loss. The results of this study suggest that periimplantation events may be affected by autoimmune antibodies. Very early miscarriage or implantation failure may be related to the same pathophysiological mechanism that causes recurrent miscarriages and is diagnosed incorrectly as infertility.

Gynecologic manifestations of Sjögren's syndrome

OBJECTIVE

Sjögren's syndrome is a chronic, inflammatory autoimmune disease in which the salivary and lacrimal glands are progressively destroyed by lymphocytes and plasma cells. Because women are affected 10 times more often than men, we studied gynecologic manifestations of Sjögren's syndrome.

STUDY DESIGN

One thousand questionnaires were sent to women with Sjögren's syndrome in New York, New Jersey, Connecticut, and Pennsylvania. Five hundred thirty-nine women responded.

RESULTS

Women with Sjögren's syndrome reported significant vaginal dryness. There was no relationship of Sjögren's syndrome to either the incidence of infertility or miscarriage, although the 4% incidence of congenital anomalies in offspring was relatively high. Of the congenital anomalies, nine of 19 (47%) were cardiac. A long menstrual cycle (> 35 days) was associated with infertility and neuropathy.

CONCLUSIONS

The vaginal dryness in women with Sjögren's syndrome is not surprising, because the nasal and esophageal mucosae are also dry in this disorder. The relationship of infertility to a long menstrual cycle may simply indicate the presence of ovulatory dysfunction or inadequate luteal phase unrelated to Sjögren's syndrome. The relationship of neuropathy to a long menstrual cycle may be related to repeated, prolonged estrogen or progesterone exposure during the long cycles or to involvement of hypothalamic-pituitary-ovarian function.

Culdoscopic gamete tubal transfer: a new approach to gamete intrafallopian tubal transfer

Twelve infertile couples who failed to conceive by previous infertility treatments and who qualified for culdoscopy had oocyte retrieval and gamete transfer through an operative culdoscopy method. Six patients achieved clinical pregnancy. Five are ongoing pregnancies, and one patient miscarried. There were no complications of the procedures.

Combined diagnostic laparoscopy and follicular aspiration for human in vitro fertilization

Laparoscopic retrieval of oocytes from stimulated follicles for in vitro fertilization and embryo transfer (IVF-ET) was performed at the time of diagnostic laparoscopy in 36 infertile women. Their mean rates of cleavage, embryo transfer and pregnancy did not differ from those obtained in 86 patients (101 cycles) who underwent ultrasonically guided transvaginal oocyte retrieval following diagnostic laparoscopy performed earlier as a separate procedure. In view of the advantages in terms of reduced patient morbidity, time and cost benefits, and the opportunity for oocyte-sperm compatibility testing in vitro, the combined procedure appears to be the best method in patients scheduled to undergo diagnostic laparoscopy.

Fibronectin in reproduction

The fibronectin (FN) levels in human follicular fluids have been shown to correlate well with follicular size and oocyte maturity, suggesting a role of FN in oocyte maturation. When added to the culture medium, the synthetic peptide Gly-Arg-Gly-Asp-Ser (GRGDS), which specifically inhibits the cell-binding of FN, has been shown to inhibit both spontaneous resumption of meiosis and gonadotropin-releasing hormone-induced meiosis of the oocytes. In another set of experiments, GRGDS has been found to inhibit the in vitro cleavage of mouse embryos by a still unknown mechanism.

Tamoxifen treatment in women with failure of clomiphene citrate therapy

Fourteen pregnancies were achieved with tamoxifen therapy in 12 women who failed to conceive with clomiphene citrate. There were no side-effects and fewer treatment cycles were required than with clomiphene citrate treatment. Ovulation and cervical score with tamoxifen therapy were significantly higher (p less than 0.005).

Lupus-like syndrome in a mother and newborn following administration of hydralazine; a case report

A very-low-birth-weight infant died from pericardial effusion and cardiac tamponade confirmed by the post-mortem findings. The mother suffered from lupus-like syndrome consequent to hydralazine treatment for pregnancy-induced hypertension. The possible relationship between mother-infant pathology and hydralazine administration is discussed.

Effectiveness of silicone sheeting in preventing the formation of pelvic adhesions

The uterine horns of 35 female rabbits were subjected to injury by cautery. Ten days later the adhesions were scored and lysed, and in 30 animals the lesion on one side was covered with a segment of silicone. The contralateral uterine horn served as an internal control. After 5, 10, or 15 days, the silicone was removed (groups A, B, and C, respectively). Five animals (group D) in which no silicone barrier was introduced served as an external control. The rabbits were killed ten days later, and the pelvic adhesions were scored again. A significant reduction in adhesion formation following lysis was found in groups A, B, and C. The largest difference between the treated and the untreated side was obtained in group A. In each of these groups, the mean adhesions score on the treated side was significantly lower following lysis than in group D.

Complications associated with genital colonization in pregnancies with and without cerclage

Cultures from the cervical milieu were taken from 24 antibiotic-treated patients (group A) and from 25 patients with no antibiotic treatment (group B). Both groups had undergone cerclage and were compared to 30 randomly chosen pregnant patients without cerclage (group C). Positive cultures were obtained in 70.8% and 48% before cerclage and in 66.7% and 68% after cerclage in groups A and B, respectively. These were not significantly different from group C (56.7%). Escherichia coli was found in over 75% of positive cultures. The rate of premature deliveries and premature rupture of the membranes were significantly higher in the cerclage groups. Maternal morbidity was significantly higher in group A compared to B and C. Our data suggest that bacterial colonization of the cervix and the vagina is not influenced by cerclage and antibiotics. It is concluded that cervical cerclage is associated with increased morbidity, therefore it is indicated only for definite anatomic and/or functional defects.

Predictive value of roll-over test in women with mild preeclampsia

Fifty women with mild preeclampsia underwent a roll-over test upon admission and again during treatment. The results of the second test showed significant correlation with the severity of the disease and the clinical course until delivery.

Prevention of premature labor by 17 alpha-hydroxyprogesterone caproate

Eighty pregnant women at high risk of giving birth prematurely were divided randomly into two groups. Treatment with either 17 alpha-hydroxyprogesterone caproate, 250 mg by intramuscular injection once a week, or a placebo was given in a double-blind fashion. Imminent premature labor occurred in 29.0% of the treated group and in 59.4% of the control group (p less than 0.025). The rate of premature deliveries was also significantly lower in the treated group (16.1%) than in the control group (37.82%) (p less than 0.05). There were no cases of perinatal death or fetal malformations in either group. The mean birth weight of all infants of the treated group was significantly higher than in those of the control group (3111.9 +/- 905 gm versus 2680 +/- 813.4 gm, p less than 0.05). The results support treatment with progesterone caproate for the prevention of premature labor.

Treatment of premature labor contractions with combined ritodrine and indomethacine

The results of combined ritodrine and indomethacine treatment (RI) in premature labor contractions were compared with ritodrine alone (R). One hundred and twenty patients with threatened premature labor in weeks 26-34 were studied. Sixty RI women received 100 mg ritodrine in infusion followed by 60 mg daily orally until 35 weeks and indomethacine 200 mg on the first day of treatment only. The R group included 60 women with identical tocolysis indices, age of pregnancy and anamnestic parameters who received ritodrine only. The mean prolongation index (PI) was 18.2 in the RI group, against 11.5 in the R patients (P less than 0.05). The mean prolongation of pregnancy was 5.6 weeks in the first and 3.6 in the control group (P less than 0.05). Birthweight and Apgar scores were similar in the two groups. In order to examine the possible early closure of the ductus arteriosus due to the indomethacin therapy, echocardiograms were done on all newborn in the RI group: the pre-ejection period and right ventricular ejection time ratio was 0.19-0.26 after delivery and 0.17-0.22 1 month later, which excludes pulmonary diastolic hypertension due to premature closure of the duct. The combined RI treatment is more effective that R alone and does not give rise to any complications in the mother or the fetus.

Non-aggressive management of post-date pregnancies

A non-aggressive approach to the management of post-date pregnancies was tested in a clinical trial involving 156 patients who had reached 294 days of amenorrhea and had a pelvic score of 4 or less. Dates had been established with certainty in each case. In half of the patients (the study group) no time limit was imposed on the pregnancy, but the women were checked at frequent intervals for any increase in pelvic score and for changes in any of the following: fetal movement count recorded daily by the mother, an oxytocin challenge test, and amnioscopy. The pregnancy ended either through spontaneous contractions or through surgical induction carried out because of a change in any one of the parameters or an increase above 4 in the pelvic score. In the 78 control patients labor was induced surgically on day 294, even if the pelvic score was low. In the study group, labor started spontaneously in 52 patients; labor was induced in 17 women after they showed an elevated pelvic score, in 7 because of a pathologic parameter and in one because a mild pre-eclampsia developed. There were 7 cesarean sections in the study group compared with 16 in the control group (P less than 0.05). The average duration of labor was 6.7 h in the study group, compared with 9.4 h in the control (P less than 0.01). There was no significant difference between the two groups with regard to meconium staining during labor, pathologic fetal heart rate, or the 5 min Apgar score. In the study group there was one neonatal death as a result of severe congenital heart disease, and in the control group one infant died due to asphyxia. It is concluded that conservative management of prolonged pregnancies, with close supervision, gives better results than routine induction of labor at 42 wk. The importance of the pelvic score as an indication for induction is stressed. A protocol has been developed which can be used in cases of uncertain dates as well.

Prolonged survival of allogeneic mouse skin grafts following preservation

Skin of C57BL mice was preserved in skin-graft fluid at 4 C for six weeks. The mean survival time of such skin grafted to BALB/c mice was 17.1 +/- 0.29 (SD) days. Control grafts transplanted immediately after removal from animals had a mean survival time of 11.5 +/- 0.32 days, whereas in a second control group, transplanted with C57BL skin preserved up to two weeks in serum-free medium, rejection occurred after 10.9 +/- 0.16 days. Some hypotheses on the mechanism of such graft prolongation are discussed.