A number of 3-substituted 1D-myo-inositols were synthesized and evaluated as substrates for phosphatidylinositol synthase and uptake by intact cells. 1D-3-Amino-, -3-chloro-, and -3-(acetylthio)-3-deoxy-myo-inositols were all synthesized by nucleophilic displacement of the 6-O-(trifluoromethyl)sulfonyl group of 1L-1,2:3,4-di-O-cyclohexylidene-5-O-methyl-6-O-[(trifluoromethyl)-sulfon yl] - chiro-inositol (which was prepared from L-quebrachitol), respectively, by reaction with LiN3, followed by reduction of the azido function, and with LiCl and KSAc to give the O-protected compounds. O-Demethylation using BBr3 and concomitant acetal hydrolysis furnished the free-hydroxy 3-amino- and 3-chloro-3-deoxy-1D-myo-inositols. The 3-mercapto analogue was obtained by removal of the acetal groups of the acetylthio analogue, followed by acetylation and purification of the peracetate, and subsequent O-demethylation and deacetylation. The 3-deoxy derivative was synthesized from the 6-O-(imidazol-1-ylthiocarbonyl) compound via Barton-McCombie deoxygenation. The 3-azido derivative was directly synthesized from 1L-1-O-tosyl-chiro-inositol via displacement with azide. The 3-keto analogue was prepared by Pt-catalyzed air oxidation of 1L-chiro-inositol. The compounds were all evaluated as substrates for phosphatidylinositol (PtdIns) synthase from mouse brain. The 3-NH2, 3-F, 3-deoxy, and 3-keto analogues all showed activity as substrates, as measured by liberation of cytidine monophosphate. These compounds also showed inhibition of the reaction of myo-[3H]inositol with PtdIns synthase. These results taken together indicate that these compounds are likely to be incorporated into phospholipids. As a further indication that these compounds might be useful as probes for the PtdIns pathway, it was demonstrated that the 3-NH2, 3-F, and 3-deoxy compounds are taken up by intact fibroblast cells as evidenced by their competing with myo-[3H]inositol uptake.

Acetates↗

PubMed1993

Effects of 5-fluorouracil substitution on the RNA conformation and in vitro translation of thymidylate synthase messenger RNA.

In vitro transcribed thymidylate synthase (TS) mRNA which is 100% substituted with 5-fluorouracil (FUra) was analyzed for changes in mRNA secondary structure, for alterations in translational efficiency, and for evidence of translational miscoding in vitro. FUra substitution in TS mRNA results in an altered migration pattern in non-denaturing RNA gels and in decreased hyperchromicity in RNA melting temperature studies, consistent with a change in mRNA secondary structure. However, no change in the translational efficiency of FUra-substituted TS mRNA is seen compared to control TS mRNA in either rabbit reticulocyte lysate or wheat germ extract in vitro translation systems. Analysis of the in vitro translation product of FUra-substituted TS mRNA by Western immunoblotting, isoelectric focusing, 5-fluoro-2'-deoxyuridine 5'-monophosphate binding, and TS catalytic activity experiments shows no difference compared to control TS mRNA. We conclude that the in vitro translation products of FUra-substituted and control TS mRNA are identical. Our findings do not support the hypothesis that changes in the mRNA template are responsible for the RNA-directed cytotoxicity of FUra.

Blotting, Western↗

PubMed1993

Globulomaxillary cyst revisited.

Classically, the globulomaxillary cyst was considered to be an inclusion or developmental cyst that arises from entrapped nonodontogenic epithelium in the globulomaxillary suture. Subsequently Christ disputed the existence and histogenesis of this lesion stating that the evidence indicated that facial processes per se did not exist. The development of the anterior maxilla was attributed to the merging of growth centers rather than fusion of facial processes, and hence ectodermal entrapment was ruled out. Recent embryologic studies, however, have demonstrated that Christ's view of facial development was incorrect. Fusion of facial processes does occur, and epithelium is entrapped in areas that later will lie between the maxillary lateral incisors and canines. This review argues that embryologically and histopathologically the globulomaxillary cyst should again be considered as an identifiable clinicopathologic entity.

Epithelium↗

PubMed1993

Tensile fatigue of two composite cements bonding three base metal alloys to bovine enamel.

Tensile fatigue endurance limits were determined for three base metals (Ni-Cr, Ni-Cr-Be, and Co-Cr) bonded to bovine enamel using two composite cements: a Bis-GMA/phosphate ester composite cement which relies on a sand-blasted metal surface, and a Bis-GMA composite luting cement which relies on electrolytically etched metal surfaces. Samples were tested to failure or to 10(6) cycles at 5 hz in Ringer's solution at 37 degrees C, and endurance limits were determined using a two-point test strategy. SEM evaluation was performed on fractured samples to determine failure mode. Statistical analysis of the results showed no difference between cements when using Ni-Cr-Be; however when using Co-Cr, the Bis-GMA/phosphate ester cement produced greater values than the Bis-GMA cement that relied on electrolytical etching. The opposite result occurred when a Ni-Cr alloy was tested with both cements. Evaluation of the results for each cement with the three different alloys showed statistical significant differences. SEM fracture analysis revealed a mixed failure pattern with apparent adhesive fracture from both the composite-enamel and composite-metal interfaces and cohesive failure throughout the cement.

Animals↗

PubMed1993

Cloning and functional characterisation of the human TRH receptor.

Thyrotrophin-releasing hormone (TRH) is a hypothalamic tripeptide known to act via its receptor in the anterior pituitary gland to stimulate the release of thyrotrophin (TSH) from thyrotrophs and prolactin (PRL) from lactotrophs. It is also thought to act as a neurotransmitter/neuromodulator in the central and peripheral nervous systems. We have isolated a cDNA encoding the human pituitary TRH receptor (TRH-R) protein with a predicted amino acid sequence of 398 amino acids. Comparison of the amino acid sequences of the human TRH-R with the previously published rodent TRH-Rs showed that it is similar to both the rat and mouse TRH-Rs, except that each species has variant amino acids at the carboxy (COOH) terminus. The human TRH-R belongs to the family of seven transmembrane domain, G-protein-coupled receptors, and it is believed that the COOH terminal region of this family of receptors may play an important role in receptor downregulation/internalisation, and possibly G-protein coupling. COS-1 cells expressing the human TRH-R showed high affinity receptor binding. Stimulation of these cells with TRH produced a typical phosphoinositide response and mobilisation of intracellular calcium [Ca2+]i.

Amino Acid Sequence↗

PubMed1993

Efficacy of doramectin against warble fly larvae (Hypoderma bovis).

The efficacy of doramectin in the treatment of cattle harbouring naturally acquired infestations of first, second and third instar larvae of Hypoderma bovis was determined in two studies carried out in the Burgundy region of France. In the first study, cattle on six farms with a history of H. bovis infestations were treated during October 1989 with either doramectin at a dose of 200 micrograms kg-1 liveweight (186 animals) or with an equivalent volume of saline (157 animals). During the following March and April, all animals were examined for the presence of warbles. In the second study, cattle on four farms with warbles present in their backs were treated during March 1990, with either doramectin or saline (as before). The viability of larvae within each warble on all the animals was then assessed every 2 days for 14 days. In Study 1, no warbles were present in any of the doramectin-treated cattle at any time, whereas warbles were found in 135 saline-treated animals. In Study 2, all larvae in warbles on the backs of the doramectin-treated cattle were dead by Day 14 after treatment, whereas viable larvae were still present in warbles in the backs of all saline-treated cattle. No adverse reaction to doramectin treatment was observed in any animal at any time. It was concluded that doramectin is both safe and 100% efficacious in the treatment of first, second and third instar H. bovis infections of cattle.

Analysis of Variance↗

PubMed1993

Breast-feeding of very low birth weight infants.

Twenty very low birth weight infants (birth weight < 1500 gm) were assessed to compare the clinical effects of breast and bottle feedings. The infants started breast-feeding during the same week that they started bottle feedings. Five breast-feedings and five bottle feedings for each infant were observed. Axillary temperature and weight before and after feedings were measured, and oxygen saturation, respiratory rate, and heart rate were monitored and recorded every 2 minutes during the feeding periods. The results showed no difference in oxygen saturation during breast-feeding (p = 0.056) but a lower incidence of oxygen desaturation (< 90%) (21% vs 38% in breast-feeding vs bottle feeding, respectively; p < 0.025). Infants with bronchopulmonary dysplasia had higher oxygen saturation during breast-feeding than during bottle feeding (p < 0.025), but weight gain during breast-feeding sessions was less (median, no gain vs 31 gm, p < 0.001). We conclude that (1) very low birth weight infants can tolerate both breast and bottle feedings at the same postnatal age; (2) very low birth weight infants are less likely to have oxygen desaturation to less than 90% during breast-feeding; and (3) weight gain is less during breast-feeding, probably because of lower intake, and may require more lactation counseling or supplementation of the feedings.

Body Weight↗

PubMed1993

Primary gastrointestinal non-Hodgkin's lymphoma: a review of 175 British National Lymphoma Investigation cases.

A retrospective analysis was performed upon 175 patients with Non-Hodgkin's Lymphoma involving the gastrointestinal tract and entered into BNLI trials and studies between 1974-1988. Malignant histiocytosis of the intestine (MHI), which was present in 16 patients, was associated with a survival of less than 25% at 18 months, and probably accounted for the poor survival of patients with jejunal involvement. Histopathological evidence of tumour origin from mucosa-associated lymphoid tissue (MALT) was found in 50% of patients with gastric involvement and in 27% of those with intestinal involvement. The overall survival of the series as a whole was 44% at 10 years. Multivariate analysis identified evidence of tumour origin from MALT as the only factor to attain prognostic significance in patients with gastric involvement, and clinical stage and the presence of MHI as the only factors to attain prognostic significance in patients with intestinal involvement. It is suggested that there is a need for a large multicentre prospective study of GIT lymphoma.

Adolescent↗

PubMed1993

Dinucleotide repeat polymorphism at the D14S294 locus.

Explore the source record for details and available documents.

Base Sequence↗

PubMed1993

Natural distribution of 5 bacteria associated with periodontal disease.

The purpose of this study was to determine the prevalence and distribution of 5 bacterial pathogens in subgingival plaque, their relationship with each other and probing depth. Plaque was collected from 6905 sites in 938 subjects. A bacterial concentration fluorescence immunoassay and bacterial specific monoclonal antibodies were used to determine the presence and level of P. gingivalis (Pg), A. actinomycetemcomitans (Aa), P. intermedia (Pi), E. corrodens (Ec) and F. nucleatum (Fn) in each plaque sample. The prevalence in subjects was lowest for Pg (32%) and highest for Ec (49%). The site-based frequency distribution of these bacterial species ranged from 10.3% for Pg to 18.7% for Ec. Pi and Ec were the bacterial combination most often found together in a subject (27.2%). While 64.0% of the sites were without any of the 5 bacterial species evaluated, 20.2% had only 1 of the 5 bacterial species evaluated. The remaining 15.8% of sites had at least 2 bacteria species present. There was a general linear association of the detection level of bacterial species and probing depth. The odds ratios were 3.9 (Pg), 3.0 (Aa), 4.0 (Pi), 2.7 (Ec) and 2.8 (Fn) of finding high levels of these bacterial pathogens at > 5 mm probing depth (p < or = 0.01). Mean probing depth at molar sites without a specific bacteria was greater (p < or = 0.01) in subjects with a specific bacterium compared to molar sites in subjects without the bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Foley catheter haemostasis for penetrating cardiac wounds: the need for caution.

Explore the source record for details and available documents.

Adult↗

PubMed1993

Assignment of the human UDP glucuronosyltransferase gene (UGT1A1) to chromosome region 2q37.

UDP glucuronosyltransferases (UGTs) comprise a multigene family of drug-metabolizing enzymes. The sub-family of UGTs that conjugate bilirubin and phenolic compounds with glucuronic acid has been termed UGT1A1. In man, UGT1A1 isoforms are encoded by a single gene, UGT1A1. Protein isoforms encoded by UGT1A1 originate by alternative splicing. In the present study, we used the cDNA of UGT1A1*4, a bilirubin-conjugating isoform, to localize the UGT1A1 locus in the human genome. The UGT1A1 gene was assigned by in situ hybridization to chromosome region 2q37.

Chromosome Mapping↗

PubMed1993

Functional expression and molecular characterization of the thyrotrophin-releasing hormone receptor from the rat anterior pituitary gland.

We have isolated the TRH receptor (TRH-R) from a rat anterior pituitary cDNA library, determined its sequence and examined its functional characteristics. Expression studies were carried out in Xenopus oocytes and in COS-7 cells. Microinjection of sense RNA transcripts into Xenopus oocytes showed electrophysiological responses of between 800 and 1000 nA under voltage-clamp conditions. COS-7 cells were transiently transfected with the cDNA clone under the control of a cytomegalovirus promoter and inositol phosphate (IP) measurements carried out. In TRH-R transfected cells, TRH (100 nM) produced an approximately twofold increase in total IP production. In-situ hybridization in the rat anterior pituitary revealed a heterogeneous distribution of label, a characteristic pattern of TRH-R expression. The rat 3.3 kb insert coded for a protein of 411 amino acids compared with 393 for the mouse protein. Over its length, the rat TRH-R protein showed considerable homology with that of the mouse, except for a deletion of 232 bp in the 3'-coding region. This deletion did not appear to affect the functional characteristics of the receptor, as shown by electrophysiological studies with Xenopus oocytes and by transfection of the cDNA into COS-7 cells. The sequence given for the 3'-untranslated region is 1.5 kb longer than that reported for the mouse receptor, and extends to the poly(A) tail.

Amino Acid Sequence↗

PubMed1993

Characterization of the gonadotrophin-releasing hormone receptor in alpha T3-1 pituitary gonadotroph cells.

The present study has characterized the gonadotrophin-releasing hormone (GnRH) receptor in immortalized alpha T3-1 pituitary gonadotroph cells. GnRH and GnRH analogues produced both a dose- and time-dependent increase in total inositol phosphate (IP) accumulation. The rank order of potency of these analogues was the same as that obtained in parallel receptor-binding studies in alpha T3-1 cells. These responses were abolished following pretreatment with a GnRH antagonist. The use of a specific inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) assay demonstrated a rapid but short-lived rise in Ins(1,4,5)P3 production. Intracellular calcium ([Ca2+]i) was subsequently measured in alpha T3-1 cells using dual wavelength fluorescence microscopy combined with dynamic video imaging. GnRH produced a biphasic rise in [Ca2+]i. The initial calcium transient was complete within seconds while the smaller secondary plateau phase lasted several minutes. G-protein involvement in the IP response to GnRH in alpha T3-1 cells was investigated using sodium fluoride (NaF) and pertussis toxin (PTx) which activate and inactivate G-proteins respectively. Like GnRH, NaF produced a dose- and time-dependent increase in IP accumulation. Activation of phospholipase C in these cells by either GnRH or NaF was PTx-insensitive, suggesting that the G-protein involved was neither Gi nor Go but more probably Gq. Immunoblot analysis of alpha T3-1 cell membranes using antisera raised against the predicted C-terminal decapeptide of the alpha subunit of Gq demonstrated the presence of Gq in alpha T3-1 cells. Collectively these results show that the GnRH receptors expressed in alpha T3-1 cells are coupled to the phosphatidylinositol second messenger pathway via a specific G-protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Buserelin↗