Search PubMed⌕ Search

Biomedical subjects

C McCaffrey

Publications and source records attributed to C McCaffrey.

13 recordsLinked to original sources
PubMed1996

Development of a microchamber which spontaneously selects high-quality sperm for use in in vitro fertilization or micromanipulation.

BACKGROUND: A microchamber has been developed which allows motile sperm to swim from a central loading site to peripheral sidewells. The sidewells are designed such that oocytes may be placed within them for in vitro fertilization (IVF) or sperm may be harvested from them for use in standard IVF or micromanipulation. Because only motile sperm can reach the sidewells, the microchamber can select relatively high-quality sperm from a crude preparation. Moreover the steep walls of the sidewells create the potential to trap sperm. OBJECTIVE: The present study was under taken to compare sperm in the sidewells to those found in randomly sampled regions of microchamber after various periods of incubation. RESULTS: We find that the sidewells concentrate motile sperm and that a higher percentage of sperm removed from sidewells is acrosome reacted. Motile sperm from oligospermic patients can be harvested from microchamber sidewells for use in micromanipulation after loading the microchamber with unprocessed specimens. Results suggest that this microchamber could be used to enhance sperm:egg interaction in IVF or to harvest sperm for micromanipulation.

Acrosome↗
PubMed1996

Hydrosalpinx fluid has embryotoxic effects on murine embryogenesis: a case for prophylactic salpingectomy.

OBJECTIVE: To ascertain if hydrosalpinges are associated with reduced pregnancy rates and increased pregnancy loss after IVF-ET. Increased volume and leakage of hydrosalpinx fluid may exert negative effects on follicular development and embryo quality and/or render the uterine environment hostile to embryogenesis. We undertook this study to examine the effect of hydrosalpinx fluid on murine embryogenesis in vitro. DESIGN: Descriptive study. SETTING: Tertiary care facility. PATIENT(S): Premenopausal females undergoing salpingectomy or salpingostomy for hydrosalpinges. INTERVENTION(S): Collection of discarded hydrosalpinx fluid and development of a dose response curve for the effect of hydrosalpinx fluid on murine embryogenesis. MAIN OUTCOME MEASURE(S): Development of single cell mouse embryos in vitro. RESULT(S): All samples of tubal fluid obtained from hydrosalpinges demonstrated a significant embryo toxic effect at either the 100% or 10% concentration. Hydrosalpinx fluid demonstrated pH values (8.45 to 8.65) significantly higher than the physiologic range. Correction of pH to that of media did not affect cavitation rate. CONCLUSION(S): There is a well-defined and significant toxic effect of hydrosalpinx fluid. Procedures such as salpingectomy or proximal tubal occlusion to circumvent the passage of hydrosalpinx fluid into the uterine cavity may have beneficial effects on the developmental environment for embryos in vivo.

Animals↗
PubMed1994

beta-Lactamase hydrolysis of cephalosporin 3'-quinolone esters, carbamates, and tertiary amines.

The beta-lactam hydrolysis of five cephalosporin 3'-quinolones (dual-action cephalosporins) by three gram-negative beta-lactamases was examined. The dual-action cephalosporins tested were the ester Ro 23-9424; the carbamates Ro 25-2016, Ro 25-4095, and Ro 25-4835; and the tertiary amine Ro 25-0534. Also tested were cephalosporins with similar side chains (cefotaxime, desacetylcefotaxime, cephalothin, cephacetrile, and Ro 09-1227 [SR 0124]) and standard beta-lactams (penicillin G, cephaloridine). The beta-lactamases used were the plasmid-mediated TEM-1 and TEM-3 enzymes and the chromosomal AmpC. The cephacetrile-related compounds Ro 25-4095 and Ro 25-4835 were hydrolyzed by all three beta-lactamases with catalytic efficiencies (relative to penicillin G) ranging from approximately 5 (TEM-1, AmpC) to approximately 25 (TEM-3). The cephalothin-related Ro 25-2016 was also hydrolyzed by all three beta-lactamases, particularly the AmpC enzyme (relative catalytic efficiency, 110). The cefotaxime-related compounds Ro 25-0534 and Ro 23-9424 were hydrolyzed to any significant extent only by the TEM-3 enzyme (relative catalytic efficiencies, 1.2 and 4.7, respectively.

Amines↗
PubMed1993

Porins and lipopolysaccharide of Escherichia coli ATCC 25922 and isogenic rough mutants.

The lipopolysaccharide and porin profile of Escherichia coli ATCC 25922, a smooth strain commonly used in antibiotic susceptibility testing, and five isogenic rough mutants was examined. The lipopolysaccharide of the parent strain had the characteristic ladder pattern on polyacrylamide gels, while that of the mutants appeared similar to chemotypes Ra and Rc of Salmonella typhimurium with some changes in chemical composition. Of the porins, OmpC appeared markedly reduced in the parent strain while OmpF appeared markedly reduced in the mutants. In addition, a new outer-membrane protein of size intermediate to that of OmpC and OmpF was detected in all mutants. Neither parent nor mutants were susceptible to the LPS core-specific P1 phage or the porin-specific PA2 and K20 phages.

Bacterial Outer Membrane Proteins↗
PubMed1992

In vitro preimplantation mouse embryo development with incubation temperatures of 37 and 39 degrees C.

Embryos from two strains of mice were used to assess the effect of incubation temperature on pronuclear and two-cell development to the morula/blastocyst (M/B) stage. Embryos from B6D2F2 and B6SJLF1 strains were cultured in medium M16 at either 37 or 39 degrees C until 120 hr post human chorionic gonadotropin (hCG) or 0, 24, or 48 hr at 37 degrees C and the remaining time at 39 degrees C. Overall M/B development for pronuclear embryos was 0.6, 0, 32.3, and 52.4% for 0-96, 24-72, 48-48, and 96-0 hr at 37 and 39 degrees C, respectively. Only 0-96 and 24-72 hr at 37 and 39 degrees C were not different (P greater than 0.10). Overall M/B development for two-cell embryos was 48.1, 78.1, and 98.0% for 0-72, 24-48, and 72-0 hr at 37 and 39 degrees C, respectively. Percentage development at each time was different (P less than .01) for each category. Additionally, the number of nuclei for morulae and blastocysts tended to be higher for embryos initiating culture at the two-cell stage compared to pronuclear embryos. The first cell cycle was most dramatically affected by a 2 degrees C increase in incubator temperature. More advanced embryos can tolerate slight increases in incubator temperature more readily than pronuclear embryos.

Animals↗
PubMed1992

Quinolone accumulation in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

The accumulation of quinolones by Escherichia coli JF568, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 29213 was measured by a modified fluorometric assay (J. S. Chapman and N. H. Georgopapadakou, Antimicrob. Agents Chemother. 33:27-29, 1989). The quinolones examined were fleroxacin, pefloxacin, norfloxacin, difloxacin, A56620, ciprofloxacin, ofloxacin, and Ro 09-1168. In all three organisms, uptake was complete in less than 5 min and was proportional to extracellular quinolone concentrations between 2 and 50 micrograms/ml, which is consistent with simple diffusion. Washing cells with quinolone-free buffer decreased accumulation by up to 70% in E. coli and P. aeruginosa but not in S. aureus. Similarly, incubation with the uncouplers 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone increased accumulation up to fourfold in E. coli and P. aeruginosa, though not in S. aureus, suggesting endogenous, energy-dependent efflux. High quinolone hydrophobicity was generally associated with decreased accumulation in E. coli and P. aeruginosa (except in the case of pefloxacin) but was associated with increased accumulation in S. aureus (except in the case of difloxacin). Ciprofloxacin had the highest accumulation in E. coli and P. aeruginosa, while pefloxacin had the highest accumulation in S. aureus.

4-Quinolones↗
PubMed1991

Successful co-culture of 1-4-cell cattle ova to the morula or blastocyst stage.

Bovine ova (n = 326) collected at the 1-4-cell stage were cultured in TCM-199 + 10% foetal calf serum with or without oviducal cells. The bovine oviducal cells were collected and seeded either on the day of ovum recovery (BOC-0) or 3 days earlier (BOC-3). In Exp. 1, the effect of age of oviducal cells in co-culture on ovum development was examined. In the BOC-0 and BOC-3 treatments, respectively, 36/46 (78%) and 30/37 (81%) of ova developed to morulae or blastocysts, while no ova developed past the 8-16-cell stage in the absence of oviducal cells. In Exp. 2, the effect of age of oviducal cells and of physical contact between the oviducal cells and ova on ovum development was examined. In the BOC-0 and BOC-3 treatments, respectively, 29/42 (69%) and 23/43 (53%) of the ova developed to morulae or blastocysts, while 1/42 (2%) developed to the morula stage in the absence of oviducal cells. Physical separation of the ova using a microporous membrane inserted between the oviducal cells and the ova did not affect ovum development, with 26/42 (62%) and 22/42 (52%) of ova developing to morulae or blastocysts in the BOC-0 and BOC-3 treatments, respectively. A high proportion of the morulae and blastocysts in Exp. 1 (57/66, 86%) and Exp. 2 (67/100, 67%) were of quality grades 1 or 2, with mean nuclei counts of 85 for morulae and 111 for blastocysts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Effects of thyroid status on renal calcium and magnesium handling.

Renal calcium and magnesium handling was studied in rats with chronic thyroid hormone deficiency or excess, hyperthyroidism. Mean kidney weight of the thyroid deficient rats was 42% of age matched, euthyroid and hyperthyroid animals and glomerular filtration rate was 71% of normal. Fractional sodium excretion was consistently elevated in thyroid deficient rats (0.26%) as compared to euthyroid (0.07%) and hyperthyroid animals (0.07%). Urinary calcium excretion (0.39%) was also elevated and parallel to sodium excretion in thyroid deficiency. Despite this renal leak of sodium and calcium, thyroid deficient animals conserved magnesium much more efficiently than either euthyroid or hyperthyroid rats (5.7% vs 17.4% respectively). Plasma magnesium concentration was elevated by acute MgCl2 infusions to determine the reabsorptive capacity of magnesium. Thyroid deficient rats reabsorbed 15-30% more of the filtered magnesium at any given plasma concentration. Although these effects on electrolyte reabsorption are modest compared to the hemodynamic alterations, the data suggest that thyroid hormone has a direct effect on the tubule which if chronically absent results in subtle sodium and calcium wasting and renal retention of magnesium. Administration of thyroid hormone to euthyroid or thyroid deficient rats twenty-four hours prior to experimentation had no effect on calcium and magnesium handling.

Animals↗
PubMed1980

Effect of furosemide on thoracic duct lymph flow in the dog.

Furosemide 20 mg/kg was given intravenously to 12 anesthetized dogs with clamped renal pedicles. Thoracic duct lymph flow (TDLF) increased promptly by 38% (P less than 0.05), an increment that lasted 80 min. Because in 6 of 12 dogs there was a transient increase in splanchnic blood flow, in separate groups splanchnic blood flow was either markedly constricted or markedly increased by intravenous isoproterenol. Thoracic duct lymph flow increased by 95 and 90%, respectively, following furosemid despite no further change in splanchnic blood flow. Furosemide had no effect on blood pressure, lymph protein, or plasma sodium. In four chronic caval dogs, TDLF was increased by 400%, yet furosemide produced a further increment in lymph flow of 30% (P less than 0.05). Infusion of a 25% albumin solution to contract the interstitial fluid did not abolish the furosemide effect, but a 10% mannitol solution did. Furosemide increased TDLF even after the infusion of papaverine reduced blood pressure to 60 mmHg. We conclude that furosemide increases TDLF by acting directly on splanchnic capillaries to allow increased filtration of fluid in the absence of increased splanchnic blood flow or capillary hydrostatic pressure.

Abdomen↗
PubMed1979

Peritoneal clearance of creatinine and inulin during dialysis in dogs: effect of splanchnic vasodilators.

The peritoneal clearance of creatinine and inulin during isotonic peritoneal dialysis was studied in dogs before and after the administration of two vasodilators: isoproterenol and glucagon. One-liter exchanges with 15-min dwell times were used. Blood flow in the superior mesenteric artery was recorded with an electromagnetic flow probe and used as an index for total splanchnic flow. Intravenous isoproterenol (2.4 microgram/min) increased blood flow by 88%, but did not alter peritoneal clearance. When isoproterenol was given i.p. (0.5 microgram/ml dialysis fluid), blood flow increased by 81%, and inulin clearance rose by 26.8% (2.06 +/- 0.18 to 2.61 +/- 0.23 ml/min; P less than 0.05). Creatinine clearance increased by 17.5%, from 10.94 +/- 0.32 to 12.85 +/- 0.34 ml/min (P less than 0.05). When blood flow was returned to control levels with a clamp, clearances also returned to control levels. Glucagon given i.p. (1.0 microgram/ml) had no effect on any measured variable. Glucagon given i.v. at 10 microgram/min caused blood flow to rise by 81% and inulin clearance to rise by 25% from 1.88 +/- 0.16 to 2.35 +/- 0.19 ml/min (P less than 0.05). Cp, inulin clearance remained at control levels. Vasodilators seem to exercise two effects in augmenting clearance of small and middle-sized molecules: a direct permeability effect and a blood-flow related effect, possibly in increasing the surface area available for exchange and/or increasing permeability of the capillary endothelium.

Animals↗
PubMedDate not supplied

Introduction of unnatural amino acids into chalcone isomerase.

The active site cysteine residue of chalcone isomerase was rapidly and selectively modified under denaturing conditions with a variety of electrophilic reagents. These denatured and modified enzyme were renatured to produce enzyme derivatives containing a series of unnatural amino acids in the active site. Addition of methyl, ethyl, butyl, heptyl, and benzyl groups to the cysteine sulfur does not abolish catalytic activity, although the activity decreases as the steric bulk of the amino acid side-chain increases. Modification of the cysteine to introduce a charged homoglutamate or a neutral homoglutamine analogue results in retention of 22% of the catalytic activity. Addition of a methylthio group (SMe) to the cysteine residue of native chalcone isomerase preserves 85% of the catalytic activity measured with 2',4',4-trihydroxychalcone, 2',4',6',4-tetrahydroxychalcone, or 2'-hydroxy-4-methoxychalcone as substrates. The competitive inhibition constant for 4',4-dihydroxychalcone, the substrate inhibition constant for 2',4',4-trihydroxychalcone, and other steady-state kinetic parameters for the methanethiolated enzyme are very similar to those of the native enzyme. The strong binding of 4',4-dihydroxychalcone to the methanethiolated enzyme shows that there is no steric repulsion between this modified amino acid residue and the substrate analogue. This structure-activity study clearly demonstrates that the active site cysteine residue does not function as an acid-base or nucleophilic group in producing the catalysis or substrate inhibition observed with chalcone isomerase. The method presented in this paper allows for the rapid introduction of a series of unnatural amino acids into the active site as a means of probing the structure-function relationship.

Alkylation↗