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Biomedical subjects

R S Williams

Publications and source records attributed to R S Williams.

At least 91 records · Page 5Linked to original sources
PubMed1996

Cardioprotective effects of 70-kDa heat shock protein in transgenic mice.

Heat shock proteins are proposed to limit injury resulting from diverse environmental stresses, but direct metabolic evidence for such a cytoprotective function in vertebrates has been largely limited to studies of cultured cells. We generated lines of transgenic mice to express human 70-kDa heat shock protein constitutively in the myocardium. Hearts isolated from these animals demonstrated enhanced recovery of high energy phosphate stores and correction of metabolic acidosis following brief periods of global ischemia sufficient to induce sustained abnormalities of these variables in hearts from nontransgenic littermates. These data demonstrate a direct cardioprotective effect of 70-kDa heat shock protein to enhance postischemic recovery of the intact heart.

Adenine Nucleotides↗
PubMed1996

Postnatal development and plasticity of specialized muscle fiber characteristics in the hindlimb.

Recent progress in defining molecular components of pathways controlling early stages of myogenesis has been substantial, but regulatory factors that govern the striking functional specialization of adult skeletal muscle fibers in vertebrate organisms have not yet been identified. A more detailed understanding of the temporal and spatial patterns by which specialized fiber characteristics arise may provide clues to the identity of the relevant regulatory factors. In this study, we used immunohistochemical, in situ hybridization, and Northern blot analyses to examine the time course and spatial characteristics of expression of myoglobin protein and mRNA during development of the distal hindlimb in the mouse. In adult animals, myoglobin is expressed selectively in oxidative, mitochondria-rich, fatigue-resistant myofibers, and it provides a convenient marker for this particular subset of specialized fibers. We observed only minimal expression of myoglobin in the hindlimb prior to the second day after birth, but a rapid and large (50-fold) induction of this gene in the ensuing neonatal period. Myoglobin expression was limited, however, to fibers located centrally within the limb which coexpress myosin isoforms characteristic of type I, IIA, and IIX fibers. This induction of myoglobin expression within the early postnatal period was accompanied by increased expression of nuclear genes encoding mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial protein expression that can be induced in adult muscle fibers by continuous motor nerve stimulation. This comparison suggests that progressive locomotor activity of neonatal animals may provide signals which trigger the development of the specialized features of oxidative, fatigue-resistant skeletal muscle fibers.

Animals↗
PubMed1996

Twelve-well culture plate for the efficient collection and culture of human oocytes and embryos.

OBJECTIVE: Our goal was to assess a 12-well oocyte collection and embryo culture plate for use in the IVF laboratory. DESIGN: This was a prospective nonrandomized study. SETTING: The setting was a university in vitro fertilization program. PATIENTS: Eighty-four consecutive infertility couples presenting for IVF were studied. MAIN OUTCOME MEASURES: The main outcome measure was pregnancy (delivered). RESULTS: A 34% delivered pregnancy rate per retrieval was attained using the 12-well collection and culture plate without the use of expensive culture media and special serum supplementation. CONCLUSIONS: The use of a 12-well plate for oocyte collection and embryo culture provides a simple, economical, efficient, and effective means of producing human embryos during in vitro fertilization. This system is capable of supporting high rates of ongoing and delivered pregnancies.

Adult↗
PubMed1996

Contraception potential of neem oil: effect on pregnancy success in the mouse.

PURPOSE: The aim of this study was to find out the role and mechanism of action of neem oil as a postcoital fertility blocker in mouse. METHODS: Female mice were injected with neem oil (20 or 40 microliters) surgically into each uterine horn on day 2 postcoitum (pc). Both the uterine horns of each mouse were injected. Arachis oil served as vehicle control. Pregnancy success was determined by the number of implanted embryos on day 8 pc and the number of live fetuses in the uteri on day 18 pc. Transforming growth factor-alpha (TGF alpha), epidermal growth factor (EGF), and epidermal growth factor receptor (EGFR) were immunolocalized in the paraffin-embedded sections of the uteri at 0600 hr on day 5 pc. The unimplanted embryos were assessed in the uteri at 2000 hr on day 5 pc. Uterine secretions were assessed for the leukocytes infiltration on day 4 through day 8 pc. RESULTS: The number of implantation sites on day 8 pc and the number of live fetuses on day 18 pc were lower in the neem oil-treated animals compared to their respective control animals at both the concentrations of neem oil (20 and 40 microliters/uterine horn). Neem oil also caused resorption of some embryos between day 8 pc and day 18 pc. In neem oil-treated mice, EGFR immunostaining decreased in the luminal and glandular epithelium and increased in the stroma as determined at 0600 hr on day 5 pc. Uterine secretions on day 4 through day 6 pc from the neem oil-treated mice showed massive leukocyte infiltration. Unimplanted preimplantation embryos, underdeveloped, degenerated, or at blastocyst stage, were recovered from the uteri after flushing at 2000 hr on day 5 pc from the neem oil-treated animals. A number of retrieved unimplanted embryos showed the direct attachment of the leukocytes to their zona pellucida. It is believed that the secretions of these leukocytes might be responsible for the underdevelopment of the early embryos and hence inhibition of implantation. The exact interaction of these leukocytes and their secretions with the early embryos is under investigation. CONCLUSIONS: Postcoital intrauterine treatment of neem oil during preimplantation period causes fertility block in mouse by lowering the EGFR localization in the luminal and glandular epithelium, by causing massive leukocytes infiltration into the uteri, by degenerating the early embryos, and by causing the postimplantation embryonic resorptions in the uteri. The possible mechanism of action of neem oil is discussed.

Animals↗
PubMed1996

Effect of anordrin on the development of mouse preimplantation embryos in vitro.

PURPOSE: The in vitro effect of anordrin and anordiol on the development of mouse two-cell embryos was studied. METHOD: Female mice were primed with gonadotropins for superovulation and caged with male mice. Preimplantation embryos, at the two-cell stage, were recovered from the oviducts at 40 hr post-hCG. In the first experiment, two-cell embryos were exposed to culture medium containing different concentrations of anordrin for 3, 12, 24, and 80 hr and then grown in the anordrin-free culture medium and assessed for the formation of total and hatching blastocysts at 80 hr. In the second experiment, two-cell embryos were grown in culture medium containing different concentrations of anordiol and assessed for the formation of total and hatching blastocysts at 80 hr in vitro. RESULTS: Exposure of two-cell embryos to anordrin concentrations of 2.5-7.5 micrograms/ml for 12 hr, 2.5-5.0 micrograms/ml for 24 hr, and 2.5 micrograms/ml for 80 hr caused significant inhibition of the formation of total blastocysts and to 2.5-7.5 micrograms/ml for 12 hr, 1.0-2.5 micrograms/ml for 24 hr, and 1.0 micrograms/ml for 80 hr caused significant inhibition of the formation of hatching blastocysts, in a exposure time-dependent and dose-dependent manner. Exposure of two-cell embryos to anordiol concentrations of 15-25 micrograms/ml for 80 hr caused significant inhibition of the formation of total blastocysts and to 15-20 micrograms/ml for 80 hr caused significant inhibition of the formation of hatching blastocysts in a dose-dependent manner. CONCLUSION: Anordrin and its metabolite anordiol inhibit the development of two-cell embryos in vitro.

Animals↗
PubMed1996

Ovarian intrabursal administration of transforming growth factor beta 1 inhibits follicle rupture in gonadotropin-primed mice.

We hypothesized that over-expression and/or activation of latent transforming growth factor betas (TGF betas) by various ovarian cell types may lead to disturbances in ovulation and fertilization. To test this hypothesis, active TGF beta ranging from 1 to 500 ng was administered intrabursally into the ovaries of gonadotropin-primed mice, and the rates of ovum recovery and fertilization were determined. Furthermore, the presence and cellular distribution of endogenous TGF betas and TGF beta type I and type II receptors were determined immunohistochemically in the ovarian tissues of TGF beta 1-treated and untreated groups. The total number of ova recovered per ovary from ovaries treated as pairs or treated singly with TGF beta 1 at 1 to 10 ng/ovary was similar to that from controls, whereas the number recovered from ovaries treated as pairs or singly with 50 or 100 ng of TGF beta 1 per ovary was significantly lower than the number from respective controls (p < 0.05, 0.001). The number of ova recovered per ovary from ovaries treated as pairs or singly with TGF beta 1 at 200 or 500 ng/ovary was similar to the number of ova obtained from ovaries treated with TGF beta 1 at 100 ng/ovary. The rate of in vitro fertilization was low in ova recovered from ovaries treated with 50, 100, 200, and 500 ng/ovary of TGF beta 1, compared to that in ova from untreated ovaries. Histologically, the TGF beta 1-treated ovaries contained large numbers of unruptured follicles, whereas untreated ovaries contained large numbers of corpora lutea. Immunohistochemically, the endogenous TGF beta 1 and TGF beta 2 was localized in theca, granulosa, and luteal cells, without a substantial difference in intensity or distribution, in both TGF beta 1-treated ovaries and in controls. Theca cells were the primary site of immunoreactive TGF beta protein. TGF beta type I and type II receptors were also present in these cells, and their relative immunoreactive intensity was considerably reduced, particularly in granulosa cells in TGF beta 1-treated ovaries compared to controls. The results support our hypothesis and suggest that TGF betas play an important regulatory role in follicular development, oocyte maturation, and the ovulatory process.

Animals↗
PubMed1996

Continuous contractile activity induces fiber type specific expression of HSP70 in skeletal muscle.

Continuous contractile activity of skeletal muscle elicits an early and dramatic increase in ribosomal RNA, suggesting that translational efficiency and/or capacity is enhanced during the adaptive response to increased metabolic demand. In view of the important role heat shock or stress proteins (HSPs) play as molecular chaperones during protein synthesis, we examined whether expression of the inducible 70-kDa HSP (HSP70) and/or mitochondrial 60-kDa HSP (HSP60) is altered in rabbit tibialis anterior muscle during continuous low-frequency motor nerve stimulation. Induction of the HSP70 gene was evident within 24 h after the onset of stimulation as reflected by increases in HSP70 transcription (> 20-fold) and mRNA (> 50-fold). HSP70 protein levels were significantly elevated (10- to 12-fold) after 14 and 21 days of stimulation. Mitochondrial HSP60 mRNA and protein also increased during stimulation (> 18- and > 5-fold after 21 days, respectively). In situ hybridization and immunohistochemistry coupled with myosin ATPase staining revealed that expression of HSP70 was restricted to oxidative type I and IIa fibers during the first 3 days of stimulation but shifted to primarily type II fibers after 21 days of stimulation. These findings demonstrate that induction of HSP70 during the adaptive response to chronic motor nerve stimulation proceeds from type I/IIa to type IId(x)/b fibers, suggesting that the expression of HSPs may be required to support the folding and compartmentalization of nascent proteins during the transformation process.

Animals↗
PubMed1996

Developmental regulation of cytochrome oxidase subunit VIa isoforms in cardiac and skeletal muscle.

Physiological requirements for mitochondrial respiration change during fetal and postnatal development of cardiac and skeletal muscle, particularly after the abrupt transition from the hypoxic fetal environment to the oxygen-rich milieu of the neonate. This study defines the pattern of expression of nuclear genes encoding the muscle-specific (H) and non-muscle-specific (L) isoforms of cytochrome oxidase (COX) subunit VIa during pre- and postnatal development of striated muscles in the mouse. In the early embryo, COX VIa-L was the predominant isoform expressed in all tissues. COX VIa-H mRNA was detectable as early as day 8 postcoitum (pc) in the heart, but not until gestational day 14 in skeletal myofibers of the tongue, diaphragm, and other skeletal muscles. At late fetal stages up until birth (days 16-18 pc), COX VIa-L and COX VIa-H were both expressed in striated myocytes, although the L form remained the dominant isoform. In postnatal animals, however, expression of COX VIa-H increased whereas COX VIa-L decreased in a reciprocal manner. Activation of the COX VIa-H gene also was observed during differentiation of nurine myogenic cells in culture and was followed by diminished expression of the COX VIa-L isoform in maturing myotubes, as in the intact animal. We conclude that regulation of nuclear genes encoding subunits of COX is a component of the developmental programs that govern cardiac and skeletal muscle differentiation and maturation in the mammalian fetus and neonate. COX VIa-L, the predominant isoform in all fetal tissues, is gradually replaced by the muscle-specific H isoform in both cardiac and skeletal muscles, although this transition is not complete until after birth.

Aging↗
PubMed1996

Gonadotropin-releasing hormone (GnRH) and GnRH receptor gene expression in human myometrium and leiomyomata and the direct action of GnRH analogs on myometrial smooth muscle cells and interaction with ovarian steroids in vitro.

The objective of the present study was to determine whether GnRH and GnRH receptor are expressed in myometrium and leiomyomata, and if GnRH analogs alone or in the presence of ovarian steroids can modulate the rate of DNA synthesis, proliferation, and transforming growth factor-beta 1 (TGF beta 1) production in myometrial smooth muscle cells in vitro. Reverse transcription-PCR revealed that leiomyomata, unaffected myometrium, and isolated myometrial smooth muscle cells express GnRH and GnRH receptor messenger ribonucleic acid. Furthermore, in a dose-dependent manner, GnRH agonist (leuprolide acetate) inhibited, but GnRH antagonist [D-pGlu1,D-Phe2,D-Trp3.6] (GnRH-Ant1) stimulated, the rate of [3H]thymidine incorporation into myometrial smooth muscle cells (P < 0.05), whereas GnRH-Ant2 (Ac-D-P-Cl-Phe1.2,D-Trp3,D-Arg6,D-Ala10) had no effect. 17 beta-Estradiol (E2) medroxyprogesterone acetate (MPA), and E2 plus MPA (1 micromol/L) stimulated the rate of DNA synthesis by smooth muscle cells (P < 0.05), which was inhibited by GnRH analogs used at 5 micromol/L (P < 0.05). GnRH analogs had no significant effect on myometrial smooth muscle cell proliferation, with the exception of GnRH-Ant1; however, they inhibited the stimulatory action of E2, MPA, and E2 plus MPA in a time-dependent manner (P < 0.05). These cells also synthesized and released approximately 1.32 +/- 0.02 ng/mL total (active plus latent) TGF beta 1, of which 0.73 +/- 0.02 ng/mL was in an active form. E2, MPA, E2 plus MPA, and GnRH analog treatments resulted in an increase in total TGF beta 1 production, whereas GnRH agonist and GnRH-Ant2, but not GnRH-An1, inhibited active TGF beta 1 (P < 0.05). GnRH analogs also inhibited the action of E2 plus MPA on total and active TGF beta 1 production, whereas GnRH-Ant1 further stimulated E2, MPA, or E2 plus MPA action on active TGF beta 1 production (P < 0.05). The data demonstrate for the first time that GnRH and GnRH receptor messenger ribonucleic acid are expressed in myometrium, leiomyomata, and myometrial smooth muscle cells. The local expression of GnRH and receptor along with the direct action of GnRH analogs on the smooth muscle cell DNA synthesis and TGF beta 1 production suggest an autocrine/paracrine role for GnRH in these tissues, a mechanism that may be involved in leiomyomata regression in women receiving GnRH agonist therapy.

Adult↗
PubMed1996

Suppression of transforming growth factor-beta (TGF beta) and TGF beta receptor messenger ribonucleic acid and protein expression in leiomyomata in women receiving gonadotropin-releasing hormone agonist therapy.

The expression and cellular distribution of transforming growth factor-1 (TGF beta 1) through TGF beta 3 and TGF beta type I-III receptor messenger ribonucleic acid (mRNA) and protein were analyzed in leiomyomata from patients receiving GnRH agonist (GnRHa; leuprolide acetate) compared to those in untreated controls. Standard reverse transcription-PCR revealed that the unaffected myometrium and leiomyomata from leuprolide-treated and untreated patients express TGF beta 1-3 and TGF beta type I-III receptor mRNA. The myometrial and leiomyomata smooth muscle cells were the primary site of TGF beta 1-3 and TGF beta type I and II receptor mRNA and protein expression, as determined by in situ hybridization and immunohistochemical localization. These observations indicate that leiomyomata express a higher of level of TGF beta and TGF beta receptor mRNA and protein than unaffected myometrium during the secretory phase of the menstrual cycle, and women who received leuprolide acetate therapy had a substantially lower level of expression than untreated controls. Furthermore, competition-based quantitative reverse transcription-PCR using synthetic internal standards revealed that leiomyomata express a significantly higher number (copies per cell) of TGF beta type II receptor mRNA, followed by TGF beta 1, TGF beta type I receptor, TGF beta 2, and TGF beta 3 (P < 0.05). However, there was a significant decrease in the levels (copies per cell) of TGF beta 1, TGF beta 3, and TGF beta type I and type II receptor mRNA expression in leiomyomata from leuprolide-treated compared to untreated patients (P < 0.05). The data provide further evidence that leiomyomata express mRNA and protein for all components of the TGF beta system, and GnRHa therapy results in down-regulation of their expression. More specifically, these data suggest that TGF beta 1 and TGF beta 3 may play a more important role in leiomyomata growth than TGF beta 2, which leads us to propose that lowering TGF beta and receptor expression may have a direct effect on leiomyomata regression.

Adult↗
PubMed1995

Cloning and characterization of three new murine genes encoding short homologues of RNase P RNA.

Three novel genes encoding small RNAs homologous to human and mouse RNase P RNA have been isolated from a mouse genomic library. As assessed by Northern blot analysis and nuclease protection assays, transcripts derived from one or more of these genes are expressed in murine cells and tissues. The RNA products of these RNase P RNA-homologous genes are smaller in size (238-248 nucleotides) than the 305-nucleotide transcript previously identified. These smaller transcripts are uniformly less abundant than the larger RNase P RNA, but their expression varies severalfold among different mouse tissues. Similar short homologues of RNase P RNA also are expressed in rat, rabbit, and human cells. We conclude that higher vertebrates express multiple isoforms of RNase P RNA.

Animals↗
PubMed1995

Changing strategies in the performance of laparoscopic Nissen fundoplication as a result of experience with 230 operations.

From September 1991 to January 1995 we performed 230 Nissen fundoplications by a laparoscopic technique. Whilst a loose 360 degree fundoplication secured by 3 or 4 sutures was performed in all instances, there was variation between surgeons regarding the performance of hiatal repair and division of short gastric vessels; 207 operations were completed laparoscopically and 23 were converted to an open operation when a satisfactory wrap could not be achieved. Operating time ranged from 30 to 260 min (median 95) and the median postoperative stay was 3 days (1-19). Twenty-three patients (10%) underwent a subsequent operation (14 within 3 months of the original surgery), 2 for recurrent reflux, 10 for para-esophageal herniation, 2 for a misplaced fundoplication resulting in gastric obstruction, 7 for persistent dysphagia (4 due to stenosis of the esophageal hiatus), 1 for bleeding, and 1 for mesenteric thrombosis. (This patient died.) Five other patients were readmitted to hospital subsequent to their discharge--four because of pulmonary emboli and one because of gastric obstruction. Some 226 patients (98%) are free of reflux symptoms with follow-up ranging up to 40 months (median 16). Absence of reflux and the integrity of the fundoplication has been confirmed by postoperative esophageal manometry and pH monitoring in 90 patients, and by barium meal in 126. Postoperative recovery has been quick and wound-related morbidity minimal. Although the rate of surgical revision was significant in this series, the likelihood of complications or further surgery, as well as incidence of conversion to open surgery, decreased in the second half of the experience.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗