Effect of laser-etch on bond strengths of glass ionomers.

This study evaluated the bond strength between glass ionomer cements and laser-etched dentin. Extracted human molars were sectioned sagittally, creating a flat surface. Samples were shear tested on an Instron testing machine, and mean bond strengths were recorded; statistical analyses indicated no significant differences between the Ketac cements. The bond strengths of both Ketac cements were significantly decreased when applied to laser-etched dentin, but bond strengths of Fuji-II were substantially elevated compared with the control values.     

Effect of recombinant gamma interferon on chronic myelogenous leukemia bone marrow progenitors

In order to understand its mechanism of action and explore its potential as a therapeutic agent, we studied the effect of recombinant gamma interferon (IFN) on in vitro proliferation and on karyotype of bone marrow-derived hematopoietic stem cell progenitors (BFUe, CFUmix) obtained from patients with Ph1-positive chronic myelogenous leukemia (CML). Addition of IFN to culture resulted in a dose-dependent inhibition of both normal and CML BFUe and CFUmix. The maximum dose-dependent suppression of CML BFUe (92% +/- 4%) and CML CFUmix (100%) exceeded the maximum suppression of normal BFUe (40% +/- 4%) and normal CFU mix (68% +/- 6%) (p less than 0.001 and p = 0.008). In parallel studies, CML BFUe and CFUmix were cultured with and without IFN, and cells recovered from culture were examined cytogenetically. Treatment of CML bone marrow cells (BMC) with IFN resulted in an increase in the proportion (p less than 0.001) of Ph1-negative metaphases when compared to control cells grown in the absence of IFN. Recombinant gamma interferon has a significant antiproliferative effect against CML bone marrow-derived stem cell progenitors in vitro, and the addition of this agent to culture increases our ability to identify a cell population derived from a Ph1-negative progenitor pool. Recombinant gamma interferon may selectively spare Ph1-negative hematopoietic progenitors, and may be an active agent in the treatment of CML.     

Intranasal administration of desmopressin acetate (DDAVP) to hemophiliacs

The intravenous infusion of desmopressin acetate (DDAVP), a synthetic vasopressin analogue, has been shown to cause a sustained increase in all Factor VIII related properties (VIII-C, VIIIR-Ag, VIIIR-WF) in patients with mild to moderate hemophilia and von Willebrand's disease. This study examines the effect of high doses of intranasal DDAVP (0.4 μg/kg BiD) in four patients with hemophilia A and one patient with von Willebrand's disease. In spite of a physiologic response with a decrease in urine volume and increase in urine osmolality, there was no effect on the Factor VIII complex.     

Chromosome abnormalities in malignant hematologic disorders

Certain chromosome abnormalities have been detected in routine cytogenetic studies of patients with hematologic disorders. This article is a cytogenetic and clinical review of 28 structural and 15 numeric chromosome abnormalities. As a group, the structural abnormalities involved 40 different chromosome breakpoints and included 13 types of translocations, 8 deletions, 3 isochromosomes, 3 inversions, and 1 duplication. The numeric abnormalities included 4 types of monosomy, 10 trisomies, and a near-haploid category. We determined the relative frequency for each of these anomalies in our practice by reviewing the results of 1,228 consecutive specimens studied between 1979 and 1984 in which a chromosomally abnormal clone was found; 61% of these specimens had one or more of the selected anomalies. The three most common translocations were 9;22 translocations (378 specimens), 8;21 translocations (15 specimens), and unbalanced abnormalities derived from 1;7 translocations (13 specimens). The two most common deletions were those involving the long arm of chromosomes 5 (101 specimens) and 20 (65 specimens). The most common isochromosome was i(17q) (33 specimens). The two most common types of monosomy were loss of a Y chromosome (118 specimens) and monosomy 7 (97 specimens). The three most common trisomies were + 8 (161 specimens), +21 (53 specimens), and +19 (31 specimens). Each of the 43 anomalies was observed in patients with different types of hematologic disorders, but in most cases one kind of neoplasm usually predominated.