Potentiation of fibroblast DNA synthesis by a phenytoin-induced mononuclear cell derived factor in vitro

Abstract – Human mononuclear cells purified by Lymphoprep flotation were incubated with phenytoin (PHT) (20 μg/ml) or its metabolite p-HPPH (2 μg/ml) in the presence of Concanaval-in A (10 μg/ml) in vitro. The results indicate that phenytoin and its metabolite p-HPPH induce the release of a mononuclear cell factor(s) that activates quiescent human gingival fibroblast to synthesize DNA.     

Identification of an in vivo chrysene diol epoxide adduct in human hemoglobin

Human blood samples were analyzed by fluorescence and mass spectrometry for the presence of polycyclic aromatic hydrocarbon metabolites covalently bound to hemoglobin. Globin was prepared by HCl-acetone precipitation and enzymatically digested. The polycyclic aromatic alcohols generated from ester adducts during digestion were concentrated by monoclonal antibody immunoaffinity chromatography and separated by C-18 HPLC. Analysis of collected fractions by room temperature fluorescence spectroscopy revealed the presence of the anti-tetrahydrotetrols of benzo[a]pyrene and another component possessing a phenanthrene chromophore. Gas chromatographic-mass spectral analysis of the HPLC fractions revealed that the latter compound was r-1,t-2,t-3,c-4-tetrahydroxy-1,2,3,4-tetrahydrochrysene, arising from a hemoglobin-chrysene diol epoxide adduct.     

In vivo dosimetry of 4-aminobiphenyl in rats via a cysteine adduct in hemoglobin

The feasibility of monitoring doses of 4-aminobiphenyl (ABP) via adduction to hemoglobin was investigated. Rats dosed with ABP (from 0.5 micrograms/kg to 5 mg/kg) formed a stable covalent hemoglobin:ABP adduct. Approximately 5% of a single dose was bound as hemoglobin:ABP; chronic dosing led to an accumulation of the adduct to a level 30 times greater than that found after a single dose. Facile in vitro hydrolysis of the adduct regenerated ABP, allowing detection at the sub-ng level. Human hemoglobin was also readily adducted, using N-hydroxy-ABP in vitro. The predominant site of adduction appeared to be the cysteine residue in hemoglobin. The use of such adducts as dosimeters for arylamine exposures in humans is discussed.     

Killing of Torulopsis glabrata by Saccharomyces cerevisiae Killer Factor

The Saccharomyces cerevisiae killer factor glycoproteins killed the pathogen Torulopsis glabrata by a mechanism involving membrane damage. Some other yeast species were unaffected by these glycoprotein toxins.     

Intra-arterial digital subtraction angiography of the spinal cord

Digital subtraction angiography (DSA) of the spinal cord was performed in 6 patients using selective intra-arterial injections of contrast material. Two arteriovenous malformations of the spinal cord, 1 dural fistula, and 1 case of multiple hemangioblastomas were studied. Contrast and spatial resolution were satisfactory for defining normal and abnormal vascularity while reducing examination time, contrast dosage, patient discomfort, and film cost. The only significant limitation was misregistration artifacts seen on lateral views encompassing the diaphragm.     

Effects of malnutrition on the erythrocyte fatty acid composition and plasma vitamin E levels of Pakistani children

Abstract Erythrocyte fatty acids and plasma vitamin E concentrations were determined in 47 grade 2 and 21 grade 3 malnourished Pakistani children (ages 4–56 months). Data were compared with those of 26 age- and sex-matched apparently healthy controls. Evaluation with three statistical approaches revealed that both grade 2 and grade 3 malnourished children had decreased erythrocyte ω6 fatty acids and to a lesser extent decreased ω3 fatty acids. These decreases were compensated for by increased ω9 fatty acids. The patients tended to have lower plasma vitamin E concentrations. We conclude that malnourished Pakistani children have low essential fatty acid status, notably those of the ω6 series. The combination of low erythrocyte 22:6ω3 and a low 22:5ω6/22:4ω6 ratio in grade 2 patients suggests low Δ4-desaturation activity, which may be due to impaired peroxisomal β-oxidation.     

Histologic chorioamnionitis in pregnancies of various gestational ages. II: Implications in preterm labor

A retrospective review of placental materials (membranes, chorionic plate, umbilical cord) derived from preterm birth is reported. All those studied had intact membranes on admission and did not have spontaneous rupture. Those with preterm labor unresponsive to tocolysis, including those with brief and more prolonged labors, were compared with those delivered preterm because of maternal or fetal indications without labor. Those with labor had inflammatory changes in all three sites of greater frequency than those without labor. Those with longer labors had significantly higher rates of inflammation than those without labor. In this population, removing the influence of spontaneous rupture and labor over 6 hours long greatly diminished the likelihood of inferring that inflammation of the choriamniotic environment is a cause of preterm labor unresponsive to tocolysis.     

The cellular distribution of calcium in freeze-dried rabbit vas deferens using EM autoradiography

The role of calcium in initiating smooth muscle contraction is widely accepted. The sources of this calcium are thought to be located both intracellularly and extracellularly. We have recently developed a method by which the cellular localization of calcium in smooth muscle can be determined. This method involves exposing the tissue to 45Ca, rapidly freezing and vacuum dehydrating the tissue, and preparing the tissue for electron microscopic autoradiography (EM ARG). In the present study the distribution of calcium in control and potassium-contracted tissue of the rabbit vas deferens was compared. No significant differences in distribution were observed in the two treatments. This finding provides morphological support for the hypothesis that the calcium used in potassium-induced contraction is primarily of extracellular origin. In addition, significant sequestration by intracellular organelles does not occur during a potassium contraction. In other experiments, the effect of rinsing tissue in cold calcium prior to freezing was investigated. From these data is appears that calcium is removed from the cytoplasmic matrix, plasma membrane, and organelles in a nonuniform manner. Further investigation into these findings should enable us to characterize more precisely the intracellular redistribution of calcium that occurs as a result of a variety of physiological manipulations.     

Preferential growth of bloodborne cancer cells in colonic anastomoses

Intracardiac injection, in hooded Lister rats, of syngeneic MC28 sarcoma cells never induced tumour growth in normal bowel. Tumour growth occurred at the site of a colonic anastomosis if surgery preceded tumour injection but not if it followed tumour injection, even by as little as 1 h. Maximum enhancement of tumour growth occurred when the healing process had progressed between 2 and 8 days, with a peak at 5 to 7 days. The enhancing effect was largely over by the time the healing had progressed 14 days. The syngeneic OES5 breast carcinoma also grew at colonic anastomoses when surgery preceded tumour injection by 5 days, but not in normal colon. The MC28 sarcoma also grew at ileal anastomoses but not in the normal ileum after intracardiac injection. By injecting radiolabelled sarcoma cells, an estimate of the probability of a single bloodborne tumour cell lodging at a colonic anastomosis and leading to a tumour deposit was calculated to be of the order of 1:43 whereas the probability of the cell lodging in normal colon and causing a deposit is less than 1:4 x 10(4).