Topical application of fluorides on teeth

Abstract Prevention of caries in exposed root surfaces constitutes an important clinical problem. It is thus important that clinicians involved with periodontology have an insight into fluoride prophylaxis. The understanding of the cariostatic mechanism of fluoride has improved during recent years. The aim of the present review is to give a short account of the present concept. Calcium fluoride appears to be the only product which is formed on enamel, dentin or cementum during brief topical treatments with fluoride or use of toothpaste containing fluoride. This calcium fluoride is stable in the oral environment: this is contrary to what was believed until recently. The calcium fluoride constitutes a pH-dependant reservoir of fluoride which releases fluoride when pH drops. The practical consequences of this concept is discussed.     

Atypical antiglomerular basement membrane disease associated with thin membrane nephropathy

Antiglomerular basement membrane (anti-GBM) disease is characteristically described with linear deposition of IgG along the GBM. We report two unusual cases of IgA and IgM anti-GBM disease associated with diffuse thinning of the GMB, and review the literature on atypical immunoglobulin species in this disorder. Both patients were male, aged 55 and 49 years, and presented with isolated microscopic haematuria, neither having shown evidence of impaired renal or pulmonary function on follow-up for 4 and 6 years respectively. Renal histology revealed minor focal mesangial changes only, but immunoperoxidase preparations demonstrated intense linear staining of the GBM with IgA in one case, and IgM with C3 in the other. On electron-microscopy there was diffuse thinning of the GBM in both cases, mean thickness 220 and 295 nm respectively (normal range 350-450 nm). Antinuclear antibodies were not detected and their glucose tolerance tests were normal. Assays for circulating IgG anti-GBM antibodies using indirect immunofluorescence (IF) and radioimmunoassay (RIA) were negative in both patients, although IgA anti-GBM antibodies with specificity confirmed by inhibition studies were identified in the first case. Thin GBMs in these patients may expose the Goodpasture antigen to toxic or infectious insults, thus altering its antigenic profile and promoting this unusual immune response.     

The lived experience of clinical educators

This phenomenological study was undertaken to discover the everyday meanings which clinical educators of pre-registration Bachelor of Nursing students attached to their experiences as clinical educators The researcher employed a qualitative design using audiotaped in-depth interviews with four registered nurses employed as clinical educators in four different schools of nursing in Victoria, Australia Using hermeneutics, thematic analysis revealed five themes of meaning central to the lived experiences of clinical educators They are (a) being human, (b) having standards, (c) developing own teaching style, (d) learn as you go, and (e) not belonging The first three themes are described in the literature on clinical education, however, the latter two are unique to this research The results of this study indicate there is need for extensive preparation and on-going support of clinical educators The researcher, who is respectful of the enormity of the task which educators face in preparing students for practice, speculates whether clinical educators are the vanguards of student learning in the clinical field It is evident that the participants of this study did not possess many of the role requirements of clinical educators identified in the literature Further studies are needed which explore the link between student learning and clinical educator support     

Compared vectorial transmissibility of pure and mixed clonal genotypes of Trypanosoma cruzi in Triatoma infestans

A total of 15 mixtures involving 9 different stocks attributed to the 19/20, 32 and 39 major clonal genotypes of Trypanosoma cruzi were used to infect third-instar nymphs of Triatoma infestans via an artificial feeding device. Three biological parameters were considered: (1) the percentage of infected insects (%II), (2) the number of flagellates per insect (NFI), and (3) the percentage of trypomastigotes per insect (%DIF). Genetic characterization by both multilocus enzyme electrophoresis (MLEE) and random amplification of polymorphic DNA (RAPD) indicated that in almost all cases (87%), mixtures remained present after completion of the whole cycle in the insect vector. Two lines of comparison were performed: (1) pure clonal genotypes versus corresponding mixed clonal genotypes and (2) the␣actual behavior of mixed clonal genotypes versus the expected behavior of the theoretical mixture (i.e. the␣arithmetic mean of the results observed for each of the two clonal genotypes taken separately). Statistical analyses of the variables were made difficult because of the presence of large standard deviations. Nevertheless, in several cases, mixtures differed significantly from pure clonal genotypes, and in one case the actual mixture differed significantly from the theoretical mixture. In some cases, interaction (either potentialization or reciprocal inhibition) could be suspected. Received: 10 March 1997 / Accepted: 21 September 1997     

Effect of Food on the Pharmacokinetics of a New Hydroxypropyl-β-Cyclodextrin Formulation of Itraconazole

Study Objective . To compare the pharmacokinetics of a single 100-mg oral dose of itraconazole administered as 10 ml of a 10-mg/ml itraconazole solution in hydroxypropyl-β-cyclodextrin under fasting versus postprandial conditions. Design . Open-label, two-way, randomized, crossover study. Setting . Janssen Research Foundation, Belgium. Patients . Twelve healthy volunteers. Interventions . Blood samples were obtained for pharmacokinetic analyses immediately before dosing and at regular intervals up to 96 hours after each dose. Blood and urine samples were obtained for hematologic, biochemical, and urinary safety analyses at baseline and at the end of the study. Measurements and Main Results . The mean peak plasma concentrations of both itraconazole and its active metabolite hydroxy-itraconazole were significantly higher under fasting conditions than under postprandial conditions. The mean times to peak concentration for both the parent compound and its metabolite were significantly shorter under fasting than under nonfasting conditions. The mean areas under the curve (AUC_0–∞ and AUC_{0–24 hrs}) were also significantly higher under fasting than under postprandial conditions. Conclusions . Our findings suggest that the higher bioavailability of this new formulation of itraconazole may be of benefit in seriously ill patients who are not able to ingest adequate quantities of food. The fact that the solution was also well tolerated and was not associated with clinically significant changes in any laboratory value further underscores the potential utility of this dosing form.     

From laparoscopic training on an animal model to retroperitoneoscopic or coelioscopic adrenal and renal surgery in human

So far, laparoscopic approaches to kidney and adrenal have been limited because of their retroperitoneal location. We here report eight renal and adrenal endoscopic procedures performed in seven patients: two adrenalectomies for hyperaldosteronism, one adrenalectomy for isolated metastasis from an adenocarcinoma of the lung; two nephrectomies for end-stage infected hydronephrosis, two partial nephrectomies for small circumscribed lesions of the kidney, and one endoscopic resection for pain relief of a voluminous cyst at the kidney. The approach was transperitoneal in two cases and retroperitoneal in five cases using the retropneumoperitoneum insufflation technique. One patient was operated by a combined approach using the retro- and transperitoneal routes. All procedures were successfully completed endoscopically. The retroperitoneoscopic approach of the kidney is safe and does not interfere with the peritoneal organs. Its working space is tenuous, but allows a direct access on the kidney with good exposure of its pedicle. For adrenal surgery, the retroperitoneoscopic dissection is more difficult, because movements of instruments are often impaired by the closeness of the costal margin and the iliac crest. However, in case of difficulties we found it very convenient to switch from a retroperitoneal endoscopic approach to a combined coelioscopic and retroperitoneoscopic operation. Far from excluding each other, both approaches are complementary, particularly for difficult situations (i.e., previous peritoneal or retroperitoneal surgery).     

A new CD43 monoclonal antibody induces homotypic aggregation of human leucocytes through a CD11a/CD18-dependent and -independent mechanism.

We describe a monoclonal antibody (mAb), designated 1.C1, that causes rapid and vigorous aggregation among normal leucocytes and among T and myeloid/monocytic cell lines. As shown by competitive binding and sequential immunoprecipitation experiments, the antigen recognized by mAb 1.C1 is a 115,000 MW sialoglycoprotein, that corresponds to the human CD43 antigen, also known as leukosialin or sialophorin. The aggregation process starts within minutes and reaches maximum level 6-18 hr after addition of the antibody. It is dependent on active cell metabolism (inhibited at low temperatures and by a mixture of the metabolic poisons azide and 2-deoxy-D-glucose), a fluid plasma membrane (inhibited by pretreatment of the cells with paraformaldehyde) and an intact cytoskeleton (inhibited by cytochalasin B). Two reference CD43 antibodies (MEM-59 and DF-T1), both binding the same or closely related sialic acid-dependent epitope as mAb 1.C1, are also capable of inducing cell clump formation. CD11a/CD18 mAb block the 1.C1-induced adhesion of resting peripheral blood leucocytes, but not of haematopoietic cell line cells. In addition, mAb 1.C1 induces homotypic aggregation of K-562 cells, which do not express members of the beta 2 integrin subfamily on their surface. These data suggest that triggering of the CD43 antigen promotes homotypic cell adhesion that is mediated by both CD11a/CD18-dependent and -independent pathways.