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Biomedical subjects

M T Kane

Publications and source records attributed to M T Kane.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effects of lithium chloride on rabbit blastocyst expansion, and accumulation of phosphoinositides and inositol phosphates.

The effects of lithium, an inhibitor of the recycling of inositol in the phosphatidylinositol cycle, on rabbit blastocyst growth and metabolism of phosphoinositides were investigated. Day 2 rabbit morulae were first cultured for 2 days in basic culture medium and then transferred to medium containing myo-[2-3H]inositol for culture for a further 3 days. At the end of culture, the resulting blastocysts were incubated with LiCl (0, 1, 5, 10, 20 mmol l-1) for 1 h. The blastocysts were then lysed and both the aqueous and lipid portions were analysed for incorporated radioactivity. Thin layer chromatographic separation of the lipid portion indicated that lithium had no significant effect on formation of radiolabelled phosphoinositides. However, high performance anion exchange chromatography indicated that lithium significantly stimulated accumulation of radiolabelled inositol monophosphate and inositol 1,4,5-trisphosphate. This result indicates that the phosphatidylinositol cycle is turning over in rabbit blastocysts. Continuous culture of rabbit embryos for 5 days in media containing LiCl (5, 10, 15 and 20 mmol l-1) significantly decreased blastocyst growth as measured by blastocyst expansion and incorporation of [3H]thymidine. However, supplementing the medium with excess inositol (up to 9375 mumol l-1), in an attempt to increase the intracellular uptake of inositol and thus compensate for the inhibitory effect of lithium on inositol recycling, did not reverse the inhibitory effect of lithium on blastocyst growth.

Animals↗
PubMed1993

Incorporation of [3H]inositol into phosphoinositides and inositol phosphates by rabbit blastocysts.

Preimplantation rabbit embryos collected at the early morula stage were cultured to blastocysts in the presence of [3H]inositol. The blastocysts were lysed, and both the aqueous and lipid portions were analysed for incorporated radioactivity. Thin-layer chromatographic separation of the lipid portion indicated that [3H]inositol was incorporated into phosphatidylinositol, phosphatidylinositol 4-phosphate, and phosphatidylinositol 4,5-bisphosphate. HPLC anion-exchange chromatography indicated that [3H]inositol was incorporated into inositol phosphates, including the two second messengers, inositol 1,4,5-triphosphate and inositol 1,3,4,5-tetrakisphosphate, and also inositol monophosphate and inositol 1,4-bisphosphate. These results provide evidence that rabbit blastocysts may have an active phosphatidylinositol second messenger system, which may be responsive to intrauterine factors or intraembryonic paracrine factors.

Animals↗
PubMed1993

Protein content of rabbit embryos: one cell to peri-implantation blastocyst.

The protein content of rabbit embryos during the first 7 days of development in vivo was determined. The protein content of intact embryos, embryonic cells (intact embryos without mucin coats for developmental stages up to 96 h post-coitum and free of blastocyst coverings for later stages) and blastocyst coverings were determined by the Pierce Micro BCA assay. The mean protein content of intact one-cell or two-cell embryos was 0.16 micrograms and increased at the four- to six-cell stage with no further increase until the late morula/early blastocyst stages (days 3 to 4). There was a 53-fold increase in protein from the early to late blastocyst stages. The protein content of embryonic cells was stable at a mean value of 0.16 micrograms until the late morula stage (day 3) and then increased to a mean of 6.85 micrograms on day 6 and 50.38 micrograms on day 7. The increase in protein content of intact embryos up to about 72 h appeared to be due solely to an increase in the protein content of the mucin coat. The protein content of the blastocyst coverings increased from a mean of 2 micrograms on day 5 to a mean of 35 micrograms on day 7. For blastocyst stages, the total protein content of intact blastocysts and of embryonic cells was correlated with the surface area of the embryos (r2 = 0.895 and 0.873, respectively) and, thus, an increase in blastocyst size is a true index of blastocyst development.

Animals↗
PubMed1992

The role of nutrients, peptide growth factors and co-culture cells in development of preimplantation embryos in vitro.

Our knowledge of the control of preimplantation embryo development and growth is deficient in many aspects as is evidenced by the great difficulty there is in growing embryos of many species in vitro while maintaining viability. This review discusses recent findings on the roles of nutrients, peptide growth factors and co-culture cells in embryo growth and development in vitro.

Journal Article↗
PubMed1992

Inositol stimulates DNA and protein synthesis, and expansion by rabbit blastocysts in vitro.

The effect of different concentrations (0, 0.6, 3, 15, 75 and 375 microM) of myo-inositol on the development of rabbit morulae to expanded blastocysts was investigated in terms of blastocyst expansion and synthesis of DNA and protein, as measured by incorporation of [3H]thymidine and [14C]amino acids into acid-precipitable material. A concentration of 15 microM inositol caused a 2.8-fold increase in blastocyst expansion (P less than 0.01), a 9.9-fold increase in thymidine incorporation into DNA (P less than 0.01) and a 3.6-fold increase in amino acid incorporation into protein (P less than 0.01). There were no significant differences in the range from 15 to 375 microM inositol.

Animals↗
PubMed1992

The assessment of professional competence.

Valid assessment of professional competence has proven to be an elusive goal. Objective tests, direct observation of performance, overall ratings of competence, and simulations have been tried and found wanting in one way or another. Objective test items are criticized as being unrealistic and therefore invalid. Direct observation tends to be very unreliable and therefore invalid. Simulations and overall ratings of competence share both of these flaws to some extent. Basically, you can't win. This article outlines some of the many ways to lose and some ways to cut these losses. In doing so, it proposes a general framework for evaluating the validity of measures of competence, and it uses this framework to examine the strengths and weaknesses of three approaches to the assessment of professional competence: direct observation, simulation, and objective testing.

Clinical Competence↗
PubMed1992

Purification of an embryotrophic factor from commercial bovine serum albumin and its identification as citrate.

A factor of low M(r) with growth-promoting effects on rabbit embryos was extracted and purified from commercial bovine serum albumin (BSA). This embryotrophic factor was extracted from BSA dissolved in formic acid by membrane filtration (membrane cutoff of M(r) 10,000) and then freeze-drying of the filtrate. The extract was purified successively by chromatography on G-10 Sephadex, QAE-Sephadex A-25 anion exchange and high-performance liquid chromatography (HPLC) reverse-phase columns. Mass spectrometry of the active reverse-phase material indicated that the major component in this material had an M(r) of 192. The embryotrophic factor in the low M(r) extract of BSA was shown to be citrate, because: (i) the mass spectra of the active reverse-phase material and citrate were identical, (ii) the activity was eluted at the identical position to citrate on an analytical HPLC anion-exchange column, (iii) the original BSA sample was shown by enzyme assay to be heavily contaminated by citrate and (iv) citrate stimulated cell proliferation and expansion of blastocysts.

Animals↗
PubMed1992

Uptake and incorporation of inositol by preimplantation mouse embryos.

The uptake of myo-inositol by preimplantation mouse embryos was investigated using [3H]myo-inositol. Uptake increased about 12-fold between one- and two-cell stages and increased again at the blastocyst stage (> 6-fold compared with the two-cell stage). Uptake at the blastocyst stage was time and temperature dependent; it was stimulated by sodium, inhibited by glucose and appeared to take place mainly via a saturable mechanism. Uptake in the presence of 6.25 mmol inositol l-1 was 1424 fmol inositol per blastocyst per h. About 10% of the [3H]inositol taken up by blastocysts during 8 h in culture was incorporated into lipid. Thin layer chromatography of the lipid showed that most of this inositol was incorporated into lipid material co-migrating with phosphatidylinositol with a small proportion co-migrating with phosphatidylinositol 4-phosphate.

Analysis of Variance↗
PubMed1991

Control of growth in preimplantation embryos.

I would like to thank the President and the Selection Committee of the Academy for the honour of an invitation to present the 1990 Conway Review Lecture. The subject of the topic is the Control of Growth in Preimplantation Embryos.

Animals↗
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↗
PubMed1990

Role delineation for dietetic practitioners: empirical results.

In order to meet its need for a current, integrated picture of the dynamic profession of dietetics, The American Dietetic Association, with assistance from American College Testing, undertook a study focusing on the roles of entry-level dietetic technicians and registered dietitians and beyond-entry-level registered dietitians. A nationwide mail survey was conducted on random samples of 3,559 dietitians who had been registered for up to 3 years, 6,647 dietitians who had been registered for more than 3 years, and all 1,226 graduates (in the previous 3 years) from the 70 ADA-approved programs preparing dietetic technicians that agreed to participate (out of the 77 ADA-approved programs). Response rates of 77.5%, 78.7%, and 68.5% were achieved for the two samples of registered dietitians and the sample of dietetic technicians, respectively. The results show that the most commonly chosen work setting for the three respondent groups was "inpatient-care, acute-care facility." There were substantial differences among the three groups in the types of activities performed and in the level of responsibility for various kinds of activities. The beyond-entry-level registered dietitians were involved in the broadest range of activities and had the most responsibility for policy setting and other administrative activities, such as preparing budgets. The results of the study provide a detailed description of dietetic practice over a broad range of practitioner-experience levels, practice settings, and client groups.

Administrative Personnel↗
PubMed1989

Effects of the putative phospholipid precursors, inositol, choline, serine and ethanolamine, on formation and expansion of rabbit blastocysts in vitro.

Rabbit morulae were cultured to blastocysts in various concentrations of the potential phospholipid precursors, myo-inositol, choline, serine and ethanolamine. Serine (20-2500 microM) had a significant stimulatory effect on blastocyst formation and blastocyst expansion and inositol (3-375 microM) had a significant stimulatory effect on blastocyst expansion. There was no significant stimulatory effect of choline or ethanolamine.

Animals↗
PubMed1988

The effects of water-soluble vitamins on the expansion of rabbit blastocysts in vitro.

The vitamin requirements for culture of rabbit morulae to expanded blastocysts were examined. Early morulae were cultured for 5 days either in a control complete medium containing all the 11 water-soluble vitamins of F10 culture medium (biotin, pantothenate, choline, inositol, niacinamide, pyridoxine, riboflavin, thiamine, folic acid, B12, and lipoic acid) or in media with each vitamin omitted individually. Blastocyst diameters were measured at the end of culture. The omission of inositol, pyridoxine, riboflavin, and niacinamide resulted in large statistically significant decreases in blastocyst expansion. The omission of B12 resulted in a significant increase in blastocyst expansion indicating that the level present in F10 is toxic to rabbit blastocysts.

Animals↗
PubMed1988

Protein-free culture medium containing polyvinylalcohol, vitamins, and amino acids supports development of eight-cell hamster embryos to hatching blastocysts.

In vitro development of eight-cell hamster embryos to hatching blastocysts requires the presence of amino acids and a group of water-soluble vitamins in the culture medium. The present studies investigated the effect of type of macromolecule on blastocyst hatching and on the requirement for vitamins. Embryos were cultured for 3 days in the presence of the synthetic macromolecule polyvinylalcohol (PVA) and of different types of bovine serum albumin (BSA), both with and without vitamins. The results showed th at eight-cell embryos develop to hatching blastocysts in the presence of vitamins and amino acids with PVA as the only macromolecule in the medium. The presence of certain types of BSA reduced but did not eliminate the need for vitamins. Glutamine alone was as efficient as a complete amino acid supplement in supporting blastocyst hatching. These results demonstrate for the first time that eight-cell hamster embryos can be cultured to hatching blastocysts in a chemically defined medium.

Amino Acids↗
PubMed1988

Vitamin requirements for development of eight-cell hamster embryos to hatching blastocysts in vitro.

We have shown in previous studies that development of 8-cell hamster embryos to hatching and hatched blastocysts in vitro is stimulated by the addition to the culture medium of a group of 11 water-soluble vitamins and growth factors from Ham's F10 medium. In the present study, the requirement for each of these vitamins for blastocyst hatching was examined by using a chemically defined protein-free medium. Eight-cell hamster embryos were cultured for 3 days either in medium with all 11 vitamins or in media with a single vitamin omitted at a time or in medium without any vitamins. The only vitamins whose omission caused a significant decrease in blastocyst hatching at any stage were inositol, pantothenate, and choline, with the omission of inositol having the most severe effect. This finding was confirmed in a subsequent experiment in which the addition of these 3 vitamins stimulated the same degree of hatching as all 11 vitamins.

Animals↗
PubMed1987

Minimal nutrient requirements for culture of one-cell rabbit embryos.

The minimal nutrient requirements of one-cell rabbit embryos for cleavage during in vitro culture were investigated. One-cell rabbit embryos were cultivated in a simple salt solution supplemented with the macromolecule polyvinylalcohol (PVA) either alone or with bovine serum albumin (BSA), amino acids, or one of a number of potential energy sources. At the end of 48 h culture, the embryos were stained with aceto-orcein HCl and the number of nucleated cells per embryo counted. One-cell embryos in medium with PVA but without an exogenous, fixed nitrogen source or energy substrate cleaved to a mean of 10.4 cells per embryo. Addition of the putative energy substrates--phosphoenolpyruvate, malate, acetate, and lactate--resulted in nonsignificant increases in cleavage rate. Glucose, pyruvate, a group of 20 amino acids from Ham's F-10 medium, and BSA gave a statistically significant doubling of the cleavage rate. These results indicate that the one-cell rabbit embryo, unlike the mouse embryo, has significant endogenous energy sources and that an exogenous, fixed nitrogen source is not essential for cleavage.

Animals↗
PubMed1986

A survey of the effects of proteases and glycosidases on culture of rabbit morulae to blastocysts.

The effects of a range of commercially available proteases and glycosidases on blastocyst development and hatching were examined on rabbit embryos cultured from the morula stage in a defined medium supplemented with charcoal-treated bovine serum albumin. The proteases tested were trypsin, alpha-chymotrypsin, thrombin, elastase, plasmin, papain, clostripain, collagenase, Streptomyces griseus protease and cathepsin C. The glycosidases tested were neuraminidase, alpha-mannosidase, beta-galactosidase and hyaluronidase. None of these enzymes appeared to stimulate blastocyst growth. The only enzymes which digested the embryonic investments, the zona and mucin coat, sufficiently to cause complete blastocyst hatching were trypsin and Streptomyces griseus protease at relatively low concentrations (250 ng/ml) and chymotrypsin and elastase at higher concentrations.

Animals↗