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Biomedical subjects

J Carroll

Publications and source records attributed to J Carroll.

At least 181 records · Page 10Linked to original sources
PubMed1990

Freeze-thaw-induced changes of the zona pellucida explains decreased rates of fertilization in frozen-thawed mouse oocytes.

Frozen-thawed oocytes have a reduced rate of fertilization (48.8%) when compared with unfrozen controls (97%). In this study we have used zona-drilling to bypass the zona pellucida and investigate whether the decreased rate of fertilization is due to freezing-induced changes in the zona pellucida which prevent sperm penetration. After zona drilling the fertilization rate of frozen-thawed oocytes (87.8%) was the same as for zona-intact unfrozen controls (88%), indicating that freeze-thaw-induced changes at the level of the zona pellucida were responsible for the decreased rate of fertilization. To determine whether the changes were occurring during the manipulations before and after freezing or the complete freeze-thaw cycle, oocytes were exposed to the complete set of manipulations normally experienced during cryopreservation and appropriate control groups. A small but significant decrease in the rate of fertilization (82.8%) was apparent in oocytes exposed to the manipulations before and after freezing compared with controls (92.2%). The freeze-thaw-induced changes in the zona pellucida therefore occur primarily during the complete freeze-thaw cycle itself and not the manipulations before and after freezing and are responsible for the decreased rate of fertilization observed in frozen-thawed oocytes.

Animals↗
PubMed1990

Preliminary report of the Cardiovascular Diseases and Alimentary Comparison Study: the Israeli experience.

The relationship between blood pressure and dietary constituents including potassium, sodium, calcium, and protein was studied in 183 randomly selected men and women, 50-54 years of age. Twenty-five of the subjects were drug-controlled hypertensive patients. Subjects were investigated by automated BP measurements, 24-h urine collection, and blood sampling. Mean systolic BP (SBP) was 119 +/- 17 mm Hg, placing the sample between Shanghai and Sweden on the distribution chart of the Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study. Salt intake estimated by 24-h sodium excretion was 8.5 +/- 3.4 g/day, between Australia and Okinawa on the distribution chart. Potassium was 48.55 +/- 20 20 mEq/day, between Urumqi (China), and Beppu and Ohda (Japan). Calcium was 162.3 +/- 89.9 mg/day. Urea nitrogen, which might reflect protein intake, was 9.5 +/- 3.1 g/day. Cholesterol was 195.1 +/- 38.1 mg/dl, between Brazil and Hirosaki. The Israeli results, as well as the data on other countries participating in the CARDIAC Study, show wide variability in the profiles generated by the investigated parameters. Each parameter placed Israel with a different CARDIAC Study group.

Arteriosclerosis↗
PubMed1989

Proteolytic processing of a coleopteran-specific delta-endotoxin produced by Bacillus thuringiensis var. tenebrionis.

Insecticidal protein delta-endotoxin crystals harvested from sporulated cultures of Bacillus thuringiensis var. tenebrionis contain a major polypeptide of 67 kDa and minor polypeptides of 73, 72, 55 and 46 kDa. During sporulation, only the 73 kDa polypeptide could be detected at stage I. The 67 kDa polypeptide was first detected at stage II and increased in concentration throughout the later stages of sporulation and after crystal release, with a concomitant decrease in the 73 kDa polypeptide. This change could be blocked by the addition of proteinase inhibitors. Trypsin or insect-gut-extract treatment of the delta-endotoxin crystals after solubilization resulted in a cleavage product of 55 kDa with asparagine-159 of the deduced amino acid sequence of the toxin [Höfte, Seurinck, van Houtven & Vaeck (1987) Nucleic Acids Res. 15, 71-83; Sekar, Thompson, Maroney, Bookland & Adang (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 7036-7040; McPherson, Perlak, Fuchs, Marrone, Lavrik & Fischhoff (1988) Biotechnology 6, 61-66] at the N-terminus. This polypeptide was found to be as toxic in vivo as native delta-endotoxin.

Amino Acid Sequence↗
PubMed1989

A cytolytic delta-endotoxin from Bacillus thuringiensis var. israelensis forms cation-selective channels in planar lipid bilayers.

In order to determine the mechanism of action of the 27 kDa mosquitocidal delta-endotoxin of Bacillus thuringiensis var. israelensis we have studied its effects on the conductance of planar lipid bilayers. The toxin formed cation-selective channels in the bilayers, permeable to K+ and Na+ but not to N-methylglucamine or Cl-, showing very fast, cooperative opening and closing. Channel opening was greatly reduced in the presence of divalent cations (Ca2+, Mg2+) and the effect was reversed when these ions were removed. These results are consistent with our proposal that B. thuringiensis toxins act by a mechanism of colloid-osmotic lysis.

Bacillus thuringiensis↗
PubMed1989

The effects of tritium on embryo development: the embryotoxic effects of [3H]tryptophan.

The effects of tritiated amino acids on the development of the early mouse embryo in vitro are described. [3H]tryptophan was extremely toxic, compared with [3H]glutamic acid, and inhibited growth of the two-cell embryo to the blastocyst stage. The LD50 values for the two amino acids were, respectively, 1 and 296 kBq/ml of medium. The two-cell embryo was more sensitive to the irradiation from incorporated [3H]tryptophan is selectively incorporated into two chromosomal proteins in the two-cell embryo, and that those proteins were stage-specific markers of development.

Age Factors↗
PubMed1989

Increase in digyny explains polyploidy after in-vitro fertilization of frozen-thawed mouse oocytes.

Fewer frozen-thawed mouse oocytes cleaved to the 2-cell stage compared to fresh control oocytes fertilized in vitro (46% vs 79%). The reduced rate of 2-cell formation was only partly explained by a decreased rate of fertilization (63% vs 85%). However, subsequent development to expanded blastocysts was not different (75% vs 78%). An increased frequency of second polar body retention by fertilized frozen-thawed oocytes compared with controls (11.8% vs 1.3%) was shown to be largely responsible for the higher incidence of polyploidy (16.3% vs 3.7%). The frequency of polyspermic fertilization was not different in the two groups (3.9% vs 2.3%).

Animals↗
PubMed1988

The effect of cryopreservation on functional correlates of embryo integrity.

To assess possible functional effects of the procedures involved in freezing/thawing of mammalian embryos, uptake of 3H-glycine and 125I-BSA (bovine serum albumin) was measured in mouse two-cell embryos and morulae before and after freezing. None of the procedures of dehydration, rehydration, or freezing affected glycine uptake significantly. Earlier results for uptake of 125I-BSA by fresh embryos which indicated an increase in endocytic activity between morula and blastocyst stages were confirmed, and hydrolysis of endocytosed 125I-BSA by morulae but not two-cell embryos was observed. Only 53 +/- 9% of two-cell embryos but 83 +/- 7% of morulae were apparently normal after freezing and thawing. Apparently normal frozen/thawed two-cell embryos were twice as active in 125I-BSA uptake as controls. This was not the case for morulae. The results suggest that freezing/thawing effects endocytotic processes in two-cell embryos but not morulae.

Animals↗
PubMed1988

Contrast echocardiography during coronary arteriography in humans: perfusion and anatomic studies.

In humans, the physiologic relation between myocardial blood flow and epicardial coronary artery anatomy remains poorly defined. With the recent development of sonicated microbubble contrast agents, it is now possible to use contrast echocardiography to assess myocardial perfusion and to correlate blood flow with angiographically identified coronary artery anatomy. The purpose of the current study was to determine myocardial perfusion patterns in patients without significant coronary artery disease. The results may be used as a reference to analyze myocardial blood flow in patients with coronary artery disease. Sonicated meglumine sodium diatrizoate solution (Renografin-76), which contains microbubbles measuring 4.5 +/- 2.8 micrograms in diameter by laser analysis, was used as the echocardiographic contrast agent during elective coronary arterriography in 14 patients without significant coronary artery disease. Patients received intracoronary injections of 1.5 to 2 ml of sonicated Renografin-76 without complications. Perfusion characteristics were studied by visual assessment of the two-dimensional echocardiographic images obtained after individual injections. In patients found to be free of significant coronary artery disease by arteriography, the left coronary system always supplied the anteroseptal, anterior, anterolateral and posterior regions of the left ventricle at the mid-papillary, cross-sectional level. The right coronary artery system perfused the inferior and inferoseptal regions in 89% of the patients identified with a right dominant system. The anterolateral papillary muscle was perfused from the left coronary system in all cases. The posteromedial papillary muscle was perfused from the left coronary system in 58% of the patients and from the right system in 42% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1987

Detection and localization of antigens on the surface of mouse spermatozoa. Antigen synthesis in the epididymis.

Spermatozoa achieve functional maturity during their transit through the epididymis and this maturation process is accompanied by changes in the composition and proteins of their surface. The addition of secretory products from the epididymis to the plasma membranes of the spermatozoa is considered to be a prerequisite for the acquisition by the spermatozoa of the capacities for forward motility and ovum recognition. An antibody was purified from an antiserum raised in the rabbit against fluid from the cauda epididymis of the mouse. This antibody, in combination with fluorescein isothiocyanate-conjugated goat anti-rabbit antibody, was used to demonstrate a progressive increase in the synthesis and secretion of antigens along the length of the epididymis. Immunoaffinity chromatography of [35S]methionine-labelled proteins, synthesized by segments of the epididymis maintained in vitro, showed that the predominant protein synthesized by the cauda, but not by the caput, epididymis, migrated on electrophoresis with an apparent Mr of 26,000. This same protein was the major antigen found on the plasma membrane of cauda spermatozoa that had been radioactively labelled with the non-penetrating probe isethionyl [1-14C]acetimidate.

Animals↗