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Biomedical subjects

E Katz

Publications and source records attributed to E Katz.

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

Effect of human hydrosalpinx fluid on murine embryo development and implantation.

OBJECTIVE: To determine the effect of hydrosalpinx fluid-containing medium on murine embryo development and implantation. DESIGN: The development of one-, two-, and four-cell mouse embryos in medium containing 5%, 10%, and 20% of human hydrosalpinx fluid was observed. Implantation rates of mouse embryos transferred into the uterine horn with hydrosalpinx fluid-containing media were determined. SETTING: Private hospital-based fertility center and IVF program. MAIN OUTCOME MEASURE(S): Percentage of embryos continuing cell division and implantation rates after ET. RESULT(S): Hydrosalpinx fluid in culture medium affected embryo development in a dose-dependent fashion. The injection of hydrosalpinx fluid-containing medium into the uterine horn did not affect embryo implantation. CONCLUSION(S): Hydrosalpinx fluid negatively affects murine embryo development, but its presence in the uterine horn at ET did not affect implantation.

Animals↗
PubMed1997

Successful in vitro maturation of human oocytes not exposed to human chorionic gonadotropin during ovulation induction, resulting in pregnancy.

OBJECTIVE: To report a case of successful in vitro maturation of human oocytes not exposed to hCG during ovulation induction, resulting in pregnancy after transfer of a frozen-thawed embryo resulting from intracytoplasmic sperm injection (ICSI) of the in vitro-matured human oocytes. DESIGN: Clinical study. SETTING: Hospital-based private IVF center. PATIENT(S): A couple with infertility due to severe oligospermia. INTERVENTION(S): Five immature oocytes were retrieved from a patient who failed to use hCG during ovarian stimulation and were cultured for 48 hours in B2 medium containing FSH and hCG. Five oocytes extruded the first polar body and underwent ICSI with frozen-thawed husband spermatozoa. MAIN OUTCOME MEASURE(S): In vitro maturation, fertilization after ICSI, embryo development, and pregnancy. RESULT(S): All five oocytes extruded the first polar body and were injected using ICSI. Three oocytes were fertilized, but two showed three pronuclei. The remainder, a two-pronuclei embryo subsequently cleaved and was cryopreserved. An ongoing pregnancy was obtained after-the transfer of this frozen-thawed embryo. CONCLUSION(S): Immature human oocytes at the germinal-vesicle stage that have not been exposed to hCG during ovarian stimulation can be matured in vitro and a normal pregnancy can result from ICSI of the in vitro-matured oocytes.

Adult↗
PubMed1997

High fertilization rate obtained after intracytoplasmic sperm injection with 100% nonmotile spermatozoa selected by using a simple modified hypo-osmotic swelling test.

OBJECTIVE: To report a high fertilization rate after intracytoplasmic sperm injection (ICSI) in patients with 100% nonmotile spermatozoa selected by a simple modified hypo-osmotic swelling test. DESIGN: Clinical study. SETTING: Hospital-based IVF center. PATIENT(S): Three couples with infertility due to asthenospermia. INTERVENTION(S): The hypo-osmotic swelling test with 150-mOsm NaCl solution was used to select viable spermatozoa before ICSI. Three patients provided semen samples and one of these three also had a testicular biopsy. MAIN OUTCOME MEASURE(S): Selection of viable spermatozoa using the hypo-osmotic swelling test with 150-mOsm NaCl solution for ICSI. RESULT(S): No motile spermatozoa were found in three ejaculated semen samples and one testicular biopsy. Fifty-seven metaphase-II oocytes were injected with hypo-osmotic swelling test-positive ejaculated or testicular spermatozoa. Fifty-five (96.5%) of these oocytes were intact after injection. Forty-two (76.4%) of 55 oocytes showed two pronuclei, and 40 of the 42 fertilized oocytes cleaved. One patient had all embryos cryopreserved because of the risk of hyperstimulation; two other patients had embryos transferred. One ongoing pregnancy resulted. CONCLUSION: This hypo-osmotic swelling test with 150-mOsm NaCl solution is a simple and efficient method for selection of viable spermatozoa. A high fertilization rate can be obtained using ICSI with viable spermatozoa selected by using this hypo-osmotic swelling test.

Cryopreservation↗
PubMed1997

Structure-binding relation of philanthotoxins from nicotinic acetylcholine receptor binding assay.

Philanthotoxins are noncompetitive inhibitors of the nicotinic acetylcholine receptor and the various glutamate receptors. Analogues carrying photoaffinity labels, fluorine atoms for solid-state NMR studies of ligand/receptor interaction, and large head groups such as porphyrins and planar bulky aromatic rings (BIG analogues) for clarifying mode of entry and orientation of analogues in receptors have been synthesized, assayed against the nicotinic acetylcholine receptor, and brief comments are given for the assay results.

Amino Acids↗
PubMed1997

Effects of alcohol intoxication on the perceived consequences of risk taking.

In 2 laboratory studies, the authors tested the hypothesis that intoxicated risk taking results from alcohol's effects on negative outcome expectancies. Young adults (N = 107) consumed alcohol or no alcohol and made ratings of the likelihood that negative and positive consequences would result from a variety of risky activities. Consistent with study hypotheses, participants rated negative consequences as less likely when they were intoxicated than when sober. Results were replicated in a second study (N = 88), which further showed that alcohol, rather than expectancy set, contributed to these reduced perceptions of risk. Findings provide the first experimental evidence that alcohol intoxication may contribute to risk-taking behavior be altering expectations about negative consequences.

Adult↗
PubMed1997

Effects of Ca2+ channel blocker neurotoxins on transmitter release and presynaptic currents at the mouse neuromuscular junction.

1. The effects of the voltage-dependent calcium channel (VDCC) blockers omega-agatoxin IVA (omega-AgaIVA), omega-conotoxin GVIA (omega-CgTx), omega-conotoxin MVIIC (omega-MVIIC) and omega-conotoxin MVIID (omega-MVIID) were evaluated on transmitter release in the mouse diaphragm preparation. The effects of omega-AgaIVA and omega-MVIIC were also evaluated on the perineurial calcium and calcium-dependent potassium currents, ICa and IK(Ca), respectively, in the mouse levator auris preparation. 2. The P- and Q-type VDCC blocker omega-AgaIVA (100 nM) and P- Q- and N-type channel blockers omega-MVIIC (1 microM) and omega-MVIID (3 microM) strongly reduced transmitter release (> 80-90% blockade) whereas the selective N-type channel blocker omega-CgTx (5 microM) was ineffective. 3. The process of release was much more sensitive to omega-MVIIC (IC50 = 39 nM) than to omega-MVIID (IC50 = 1.4 microM). After almost completely blocking transmitter release (quantal content approximately 0.3% of its control value) with 3 microM omega-MVIIC, elevating the external [Ca2+] from 2 to 10 mM induced an increase of approximately 20 fold on the quantal content of the endplate potential (e.p.p.) (from 0.2 +/- 0.04 to 4.8 +/- 1.4). 4. Nerve-evoked transmitter release in a low Ca(2+)-high Mg2+ medium (low release probability, quantal content = 2 +/- 0.1) had the same sensitivity to omega-AgaIVA (IC50 = 16.8 nM) as that in normal saline solutions. In addition, K(+)-evoked transmitter release was also highly sensitive to the action of this toxin (IC50 = 11.5 nM; 100 nM > 95% blockade). The action of omega-AgaIVA on transmitter release could be reversed by toxin washout if the experiments were carried out at 31-33 degrees C. Conversely, the effect of omega-AgaIVA persisted even after two hours of toxin washout at room temperature. 5. Both the calcium and calcium-dependent potassium presynaptic currents, ICa and IK(Ca), respectively, were highly sensitive to low concentrations (10-30 nM) of omega-AgaIVA. The ICa and the IK(Ca) were also strongly reduced by 1 microM omega-MVIIC. The most marked difference between the action of these two toxins was the long incubation times required to achieve maximal effects with omega-MVIIC. 6. In summary these results provide more evidence that synaptic transmission at the mammalian neuromuscular junction is mediated by Ca2+ entry through P- and/or Q-type calcium channels.

Animals↗
PubMed1997

Establishment of an optimal hypo-osmotic swelling test by examining single spermatozoa in four different hypo-osmotic solutions.

In order to find an optimal hypo-osmotic swelling test (HOST) and to identify viable sperm cells from patients with asthenozoospermia for intracytoplasmic sperm injection (ICSI), we tested single motile and non-motile spermatozoa in four hypo-osmotic solutions by micromanipulation. The four solutions were: A, H2O; B, 50 mOsm NaCl; C, 150 mOsm NaCl and D, 150 mOsm sodium citrate and fructose. Eosin Y staining was then carried out for evaluation of viability of the spermatozoa after HOST. Using motile spermatozoa, no statistical difference was found in HOST-positive spermatozoa between these four solutions. There were more viable sperm cells after HOST in solutions C and D, as noted by Eosin Y staining. After non-motile spermatozoa were incubated for 1 min in the four solutions, HOST with solution C gave the best results for identification of viable sperm cells compared to the other three solutions. When motile spermatozoa were incubated in solution C or solution D for 30 min, the result of HOST with solution C (10.8% dead spermatozoa) was superior to that of solution D (49.1% dead spermatozoa). In conclusion, the HOST protocol using 150 mOsm NaCl (solution C) for 1 min yielded the best results for selection of viable spermatozoa. This procedure should be used for selection of viable spermatozoa for ICSI in patients with 100% non-motile spermatozoa.

Cell Membrane↗
PubMed1997

Outcome of in-vitro culture of fresh and frozen-thawed human testicular spermatozoa.

The effect of in-vitro culture on the motility and morphology of fresh and frozen-thawed human testicular spermatozoa obtained from obstructive azoospermic patients and on the motility of testicular spermatozoa obtained from non-obstructive azoospermic patients was evaluated. The outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed human testicular spermatozoa was studied. The results showed that significant improvement of sperm morphology and motility was observed in culture of fresh (n = 17) and frozen-thawed (n = 15) testicular sperm samples obtained from patients with obstructive azoospermia. The motility of cultured testicular spermatozoa reached a peak at 72 h without the need for special media. In six of 20 samples obtained from patients with non-obstructive azoospermia, improvement of sperm motility was observed. When only non-motile testicular spermatozoa were cultured, they all remained non-motile (n = 9). In patients with obstructive azoospermia, fertilization rates of 80 and 81% were obtained using ICSI with fresh and frozen-thawed testicular spermatozoa respectively. Clinical pregnancies were observed in four out of nine patients with fresh testicular spermatozoa and two out of five patients after using frozen-thawed spermatozoa. When fresh testicular spermatozoa obtained from patients with non-obstructive azoospermia were used for ICSI, the fertilization rate was 68% and two out of seven patients achieved clinical pregnancies. In conclusion, the morphology and motility of fresh and frozen-thawed testicular spermatozoa in patients with obstructive azoospermia can be significantly improved after in-vitro culture. The outcome of in-vitro culture of testicular spermatozoa in patients with non-obstructive azoospermia is unpredictable. In-vitro culture of non-motile testicular spermatozoa is not successful so far. The outcome of ICSI with fresh and with frozen-thawed testicular spermatozoa was similar.

Adult↗
PubMed1997

The cytoplasmic and transmembrane domains of the vaccinia virus B5R protein target a chimeric human immunodeficiency virus type 1 glycoprotein to the outer envelope of nascent vaccinia virions.

The outer envelope of the extracellular form of vaccinia virus (EEV) is derived from the Golgi membrane and contains at least six viral proteins. Transfection studies indicated that the EEV protein encoded by the B5R gene associates with Golgi membranes when synthesized in the absence of other viral products. A domain swapping strategy was then used to investigate the possibility that the B5R protein contains an EEV targeting signal. We constructed chimeric genes encoding the human immunodeficiency virus (HIV) type 1 glycoprotein with the cytoplasmic and transmembrane domains replaced by the corresponding 42-amino-acid C-terminal segment of the B5R protein. Recombinant vaccinia viruses that stably express a chimeric B5R-HIV protein or a control HIV envelope protein with the original cytoplasmic and transmembrane domains were isolated. Cells infected with recombinant vaccinia viruses that expressed either the unmodified or the chimeric HIV envelope protein formed syncytia with cells expressing the CD4 receptor for HIV. However, biochemical and microscopic studies demonstrated that the HIV envelope proteins with the B5R cytoplasmic and transmembrane domains were preferentially targeted to the EEV. These data are consistent with the presence of EEV localization signals in the cytoplasmic and transmembrane domains of the B5R protein.

Amino Acid Sequence↗
PubMed1997

The A34R glycoprotein gene is required for induction of specialized actin-containing microvilli and efficient cell-to-cell transmission of vaccinia virus.

The mechanisms allowing vaccinia virus to spread from cell to cell are incompletely understood. The A34R gene of vaccinia virus encodes a glycoprotein that is localized in the outer membranes of extracellular virions. The small-plaque phenotype of an A34R deletion mutant was similar to that of mutants with deletions in other envelope genes that fail to produce extracellular vaccinia virions. Transmission electron microscopy, however, revealed that the A34R mutant produced numerous extracellular particles that were labeled with antibodies to other outer-envelope proteins and with protein A-colloidal gold. Fluorescence and scanning electron microscopy indicated that expression of the A34R protein was necessary for detection of vaccinia virus-induced actin tails, which provide motility to the intracellular enveloped form of vaccinia virus, and of virus-tipped specialized microvilli that project from the cell. The ability of vaccinia virus-infected cells to form syncytia after a brief exposure to a pH below 6, known as fusion from within, failed to occur in the absence of expression of the A34R protein; nevertheless, purified A34R- virions were capable of mediating low-pH-induced fusion from without. The present study provides genetic and microscopic evidence for the involvement of a specific viral protein in the formation or stability of actin-containing microvilli and for a role of these structures in cell-to-cell spread rather than in formation of extracellular virions.

Actins↗
PubMed1997

Living related liver transplantation in Oklahoma.

Living related liver transplantation (LRLT) presents several advantages as compared to cadaveric liver transplantation, and it has become an increasingly popular option for children with end-stage liver diseases. Since 1995, five LRLT procedures have been performed at the authors' facility. Recipients were three boys and two girls, whose mean age was 2.6 years. Recipients' primary diagnoses were primary hyperoxaluria (PH) (n = 3), Alagille's syndrome (n = 1), and Byler's disease (n = 1). Left lateral segments harvested from their parents were used as the liver grafts on all patients. The donors included three mothers and two fathers, with a mean age of 29 years. Tacrolimus with steroids was used as immunosuppressive therapy. In all cases (mean follow-up time of 11 months), graft function was excellent and four children are doing very well. One boy died of post-transplant lymphoproliferative disorder (PTLD) 7 months after LRLT. All donors are doing very well with no postoperative complications. The authors believe that LRLT is a safe procedure for both the donor and the recipient, and provides, in children, an excellent alternative to cadaveric liver transplantation.

Adult↗
PubMed1996

Calcium channels involved in synaptic transmission at the mature and regenerating mouse neuromuscular junction.

1. The involvement of the different types of voltage-dependent calcium channels (VDCCs) in synaptic transmission at the mature and newly formed mammalian neuromuscular junction was studied by evaluating the effects of L-, P/Q- and N-type VDCC antagonists on transmitter release in normal and reinnervating levator auris preparations of adult mice. 2. Nerve-evoked transmitter release was blocked by omega-agatoxin IVA (omega-AgaIVA), a P/Q-type VDCC blocker, both in normal and reinnervating endplates (100 nM omega-AgaIVA caused > 90% inhibition). The N-type VDCC antagonist omega-conotoxin GVIA (omega-CgTX; 1 and 5 microM), as occurs in normal preparations, did not significantly affect this type of release during reinnervation. Nitrendipine (1-10 microM), an L-type VDCC blocker, strongly antagonized release in reinnervating muscles (approximately 40-69% blockade) and lacked any effect in normal preparations. 3. In reinnervating muscles, spontaneous release was not dependent on Ca2+ entry through either P- or L-type VDCCs. Neither 100 nM omega-AgaIVA nor 10 microM nitrendipine affected the miniature endplate potential (MEPP) frequency or amplitude. 4. At the newly formed endplates, K(+)-evoked release was dependent on Ca2+ entry through VDCCs of the P-type family (100 nM omega-AgaIVA reduced approximately 70% of the K(+)-evoked MEPP frequency). L-type VDCCs were found not to participate in this type of release (10 microM nitrendipine lacked any effect). 5. In reinnervating muscles, the L-type VDCC blocker, nitrendipine (10 microM), provoked a significant increase (approximately 25%) in the latency of the evoked endplate potential (EPP). This drug also caused an increase (approximately 0.3 ms) in the latency of the presynaptic currents. The P/Q- and Ny-type VDCC blockers did not affect the latency of the EPP. 6. These results show that at newly formed mouse neuromuscular junctions, as occurs in mature preparations, VDCCs of the P-type family play a prominent role in evoked transmitter release whereas N-type channels are not involved in this process. In addition, signal conduction and transmitter release become highly sensitive to nitrendipine during reinnervation. This suggests that L-type VDCCs may play a role in synaptic transmission at the immature mammalian neuromuscular junction.

Animals↗
PubMed1996

Application of redox enzymes for probing the antigen-antibody association at monolayer interfaces: development of amperometric immunosensor electrodes.

Insulation of the electrical contact between a redox protein and an electrode surface upon association of an antibody to an antigen monolayer assembled on the electrode is used to develop immunosensor devices. In one configuration, a mixed monolayer consisting of the N epsilon-(2,4-dinitrophenyl)lysine antigen and ferrocene units acting as electron transfer mediators is applied to sense the dinitrophenyl antibody (DNP-Ab) in the presence of glucose oxidase (GOx) and glucose. In the absence of DNP-Ab, the mixed monolayer electrode stimulates the mediated electrocatalyzed oxidation of glucose that results in an amplified amperometric response. Association of the DNP-Ab to the modified electrode blocks the electrocatalytic transformation. The extent of the electrode insulation by the DNP-Ab is controlled by the Ab concentration in the sample. In the second configuration, a N epsilon-(2,4-dinitrophenyl)lysine antigen monolayer assembled on a Au electrode is applied to sense the DNP-Ab in the presence of a redox-modified GOx, exhibiting electrical communication with the electrode surface. Two kinds of redox-modified "electrically wired" GOx are applied: GOx modified by N-(ferrocenylmethyl)caproic acid, Fc-GOx, and a novel electrobiocatalyst generated by reconstitution of apo-GOx with a ferrocene-modified FAD semisynthetic cofactor. Electrocatalytic oxidation of glucose by the electrically wired biocatalysts proceeds in the presence of the antigen monolayer electrode, giving rise to an amplified amperometric signal. The electrocatalytic transformation is blocked upon association of the DNP-Ab to the monolayer electrode. The extent of electrode insulation toward the bioelectrocatalytic oxidation of glucose is controlled by the DNP-Ab concentrations in the samples. The application of biocatalysts for amperometric sensing of antigen-antibody interactions at the electrode surface makes the electrode insensitive to microscopic pinhole defects in the monolayer assembly. The antigen monolayer electrode is applied to sense the DNP-Ab in the concentration range 1-50 micrograms mL-1.

Antigen-Antibody Reactions↗
PubMed1996

Effect of incremental time experience on the results of in vitro fertilization with intracytoplasmic sperm injection (ICSI).

PURPOSE: Our objective was to determine the effect of experience on the results with intracytoplasmic sperm injection. METHODS: The quarterly outcome with both ICSI and traditional in vitro fertilization (IVF) in 1994 was analyzed in 475 patients under age 40 undergoing 595 oocyte retrievals. The data represent 307 patients undergoing 379 retrievals for IVF and 165 patients undergoing 216 retrievals for ICSI. RESULTS: Fertilization rates with ICSI improved significantly each quarter (52.96, 62.17, 70.17, and 74.87% in Q-I, Q-II, Q-III, and Q-IV, respectively), while the rate with IVF improved significantly between Q-I (69.9%) and Q-II (80.10%) and slightly but significantly between Q-II and Q-IV (82.88%). The implantation rate per embryo after ICSI improved significantly after Q-I (6.17%) compared to Q-II (10.70%) and Q-IV (12.14%). The pregnancy rate per transfer with ICSI increased steadily after Q-I (13.79, 21.88, 23.53, and 25.00% in Q-I through Q-IV), reaching statistical significance between Q-I and Q-III and between Q-I and Q-IV. CONCLUSIONS: Although acceptable results can be obtained with ICSI after a relatively short period of time, optimum results require substantial experience.

Embryo Transfer↗
PubMed1996

Deleterious effect of the presence of hydrosalpinx on implantation and pregnancy rates with in vitro fertilization.

OBJECTIVE: To determine the effect of the presence of a unilateral or bilateral hydrosalpinx on the outcome with IVF-ET. DESIGN: Retrospective analysis of clinical and laboratory data. SETTING: Hospital-based private IVF center. PATIENTS: Eight hundred forty-six patients with tubal disease younger than age 40 years undergoing 1,766 stimulation cycles. In 118 cycles, a hydrosalpinx was noted sonographically (group I) whereas, in 1,648 cycles, no such image was documented. MAIN OUTCOME MEASURES: Pregnancy and implantation rates. RESULTS: Group I displayed a significantly lower pregnancy rate per transfer than group II (16.84% versus 36.83%) and a lower implantation rate (3.92% versus 11.53%). CONCLUSION: The presence of hydrosalpinx adversely affects the outcome of IVF.

Adult↗
PubMed1996

A unique case of massive ascites before ovulation associated with gonadotropin therapy.

OBJECTIVE: To describe a unique case of massive ascites associated with gonadotropin therapy. DESIGN: Case report. SETTING: Patient in a hospital-based private IVF center. INTERVENTION(S): Ovulation induction with gonadotropins for subsequent IVF. RESULT(S): Ovulation induction with gonadotropins resulted in the accumulation, before ovulation, of 1,200 and 2,000 mL of peritoneal fluid in two consecutive cycles. The stimulation yielded four and six oocytes, respectively. CONCLUSION(S): Gonadotropin therapy can result in ascites before ovulation without an exaggerated ovarian response and without interfering with follicular development.

Adult↗