Fluoride uptake by glass ionomer cements: a surface analysis approach

Despite extensive research, the mechanism by which glass ionomer cements take up fluoride ions from solution remains unclear. To date, the majority of studies have concentrated on measuring the removal of ions from solution. In this study, we demonstrate the application of X-ray photoemission spectroscopy and secondary ion mass spectrometry to the surface analysis of the cements, after the introduction of fluoride either by doping or by immersion. Fluoride ion uptake from potassium fluoride solution is correlated with the formation of a surface layer which is rich in calcium as well as fluoride.     

Immunization with genetic toxoids of the Arcanobacterium pyogenes cholesterol-dependent cytolysin,pyolysin, protects mice against infection

Pyolysin (PLO), a cholesterol-dependent cytolysin expressed by Arcanobacterium pyogenes, is an important host-protective antigen. However, this molecule is toxic and requires inactivation prior to its use as a vaccine. Three genetically toxoided, nonhemolytic PLO molecules, HIS-PLO.F(497), HIS-PLO.Delta P(499), and HIS-PLO.A(522), were found to be nontoxic, and vaccinated mice were protected from infection, indicating the potential of these toxoids as vaccines. Furthermore, in a mouse model of infection, A. pyogenes carrying the F(497) mutation was as attenuated as a PLO-deficient strain, indicating that the cytolytic activity of PLO is important in virulence.     

Follicular vascularity--the predictive value of transvaginal power Doppler ultrasonography in an in-vitro fertilization programme: a preliminary study

The aim of this prospective study was to investigate the ability of transvaginal power Doppler ultrasonography to assess the relationship between follicular vascularity and outcome in women undergoing in-vitro fertilization. Each of 38 subjects underwent a single transvaginal power Doppler ultrasound scan on the day of oocyte collection, where the vascularity of individual ovarian follicles was assessed, using a subjective system, and graded 1 to 4. In addition, conventional pulsatility indices (PI) of the uterine and intra-ovarian (stromal) arteries were calculated, which showed no significant differences between the pregnant and non-pregnant groups. Using power Doppler ultrasonography, a total of 188 follicles was studied. The follicular vascularity grade was found to be independent of follicular size and there was no significant difference in fertilization rates with different degrees of vascularity, although there was a trend towards higher fertilization rates with higher grade vascularity. There were 10 pregnancies, giving a pregnancy rate of 26.3% per embryo transfer. Pregnancies were confined to those women whose embryos were derived from follicles with grade 3 and 4 vascularity (pregnancy rates per embryo transfer of 12.5 and 61.5% respectively), with only those from grade 4 follicles resulting in livebirths. This preliminary study suggested that high grade follicular vascularity is associated with increased pregnancy rate and that there is a possible link between follicular vascularity and implantation potential.      

Towards an understanding of health status: the perceived importance of health status dimensions

Summary Interest in health status indicators and indices has grown considerably in the past few decades. This reflects the growing awareness that health can be influenced by a multiplicity of social, environmental and personal factors. An additional influence has been the realization that traditional measures of health such as mortality and morbidity data do not always provide appropriate forms of information for advanced societies. The operational constructs utilized in health status instruments to measure physical, social and mental health vary. This indicates a lack of a sound conceptual basis. If health status indices are to become useful in assessing community and individual health their conceptual basis must be adequately developed. The present paper reports the rank order and factor structure of judgements obtained from medical and lay persons on the importance of a range of concepts, many of which have the potential to contribute to valid health status indices. Some implications of these judgements for proposed health status indexes are discussed. It is concluded that to obtain a valid health status questionnaire for application in the United Kingdom consideration must initially be given to examining a broad range of concepts. It is noted that many of the conceptual relationships recorded in this study are to be examined using a trial instrument designed to assess major and secondary dimensions of health.     

Philadelphia chromosome positive childhood acute lymphoblastic leukemia

In a 3-yr period, the Philadelphia chromosome (Ph1) was found in 4 of 43 children with acute lymphoblastic leukemia (ALL) in whom chromosomes were studied at diagnosis. The clinical, morphological, cytochemical, and immunologic findings in the Ph1-positive (PH1+) CASES WERE CONsistent with typical childhood ALL, indicating that identification of cases requires chromosome studies. A review of all reported cases of Ph1 + childhood ALL shows that Ph1 + patients are older and have higher initial platelet and white blood cell counts (WBC) than most children with ALL. However, a life table comparison between the reported cases of Ph1 + ALL in children and randomly selected age-, sex-, and WBC- matched controls with ALL shows the duration of first marrow remission to be significantly shorter (p less than 0.02) for the Ph1 + cases Ph1 + ALL is a distinct subtype of childhood ALL that is not rare and can be identified only by cytogenetic studies. The prognosis is poor. Cytogenetic studies should be done prospectively in a large group of children with ALL to define further the subgroup of patients and to confirm the findings of this retrospective analysis.     

Characterization of the processed form of a ubiquitous protein displaying a variable membrane organization in erythroid cells

We recently identified a group of proteins that are present in all hematopoietic cells but are organized in the cell membrane of erythrocytes in a lineage-specific fashion (Blood 61:803, 1983). One of these polypeptides has a mol wt of approximately 37,000 (p37T) when translated in vitro from messenger RNA (mRNA) extracted from the erythroleukemic K562 cell line. The membrane-associated form of the p37 translation product has been analyzed in detail here. When detergent lysates prepared from biosynthetically labeled K562 cells were reacted with an antiserum containing anti-p37T antibodies, one of the proteins immunoprecipitated had a nominal mol wt of 36,000 to 37,000 (p37M). Several results suggest that this protein is homologous to the p37 translation product: (1) the protein, like the mRNA coding for the p37 translation product, was expressed in cell lines with diverse differentiated phenotypes; (2) the antigenic determinant(s) on p37M and p37T are oriented to the inner surface of the erythrocyte membrane while being oriented to the outer surface of erythroleukemic cells; and (3) one-dimensional peptide maps show homology between p37M and p37T. P37M does not appear to possess an N-terminal leader sequence that is proteolytically cleaved as the molecule is inserted into the membrane. In addition, p37M is not glycosylated.     

Preliminary report increased transport of intermediate density lipoprotein (LDL) with cholesterol loading

Although cholesterol loading in man generally leads to an increase in plasma cholesterol and low density lipoprotein cholesterol in particular, the mechanism for this is unknown. Because IDL formation rises in cholesterol-fed rats we have measured the transport of IDL apoprotein B in 8 men during two dietary periods containing either 200 mg or 1700 mg cholesterol per day. Radioiodinated IDL (Sf 12-20 or Sf 12-60) were reinjected and transport calculated from 48 hr specific radioactivity-time curves of apoprotein B in reisolated IDL. With cholesterol loading the IDL cholesterol and apoprotein B concentrations rose in 7 of 8 subjects (substantially in only 2). However IDL transport was stimulated more consistently and significantly (p less than 0.01), rising by at least 50% in 5 subjects. Furthermore the change in plasma total cholesterol concentration was significantly correlated with the change in IDL transport (r = +0.70, p less than 0.05). Since LDL are derived from IDL, the cholesterol-induced rise in IDL formation may explain the increase in LDL concentration with dietary cholesterol.